Emerging Solutions for Water, Sanitation and Hygiene

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
ChemEngineering ChemEngineering	2.5	4.7	2017	17.2 Days	CHF 1600
Clean Technologies cleantechnol	3.8	4.5	2019	26.6 Days	CHF 1600
International Journal of Environmental Research and Public Health ijerph	-	5.4	2004	29.6 Days	CHF 2500
Pollutants pollutants	-	-	2021	21.7 Days	CHF 1000
Water water	3.4	5.5	2009	16.5 Days	CHF 2600

11 pages, 327 KiB

Open AccessArticle

Improving Toilet Usability and Cleanliness in Public Schools in the Philippines Using a Packaged Operation and Maintenance Intervention

by Denise Duijster, Bella Monse, Marvin Marquez, Ubo Pakes, Nicole Stauf and Habib Benzian

Int. J. Environ. Res. Public Health 2022, 19(16), 10059; https://doi.org/10.3390/ijerph191610059 - 15 Aug 2022

Cited by 2 | Viewed by 33860

Abstract

This study evaluated the impact of packaged interventions for operation and maintenance (O&M) on the usability and cleanliness of toilets in public schools in the Philippines. In this cluster-randomized controlled trial, the divisions of Roxas City and Passi City were randomly assigned to [...] Read more.

This study evaluated the impact of packaged interventions for operation and maintenance (O&M) on the usability and cleanliness of toilets in public schools in the Philippines. In this cluster-randomized controlled trial, the divisions of Roxas City and Passi City were randomly assigned to the intervention or control group. Schools in Roxas City (n = 14) implemented the packaged O&M interventions; schools in Passi City (n = 16) formed the control group. Outcome variables were toilet usability—defined as accessible, functional and private—and toilet cleanliness, measured using the Sanitation Assessment Tool (SAT) and the Cleaner Toilets, Brighter Future (CTBF) instruments at baseline and at four months follow-up through direct observation of school toilets. SAT results showed that intervention schools had a 32.0% (4.6%; 59.3%) higher percentage of usable toilets than control schools at follow-up after full adjustment (p = 0.024). CTBF results found a similar result, although this was not statistically significant (p = 0.119). The percentage of toilets that were fully clean was 27.1% (3.7%; 50.6%) higher in intervention schools than in control schools after adjustment (p = 0.025). SAT results also showed an improvement in cleanliness of toilets in intervention schools compared to those in controls, but this did not remain significant after adjustment. The findings indicate that the additional implementation of O&M interventions can further stimulate progress towards reaching Water, Sanitation and Hygiene service levels aligned with the Sustainable Development Goals. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

15 pages, 337 KiB

Open AccessArticle

Formative Research Using Settings and Motives to Explore Child Faeces Disposal and Management in Rural Solomon Islands

by Adam Biran, Rosie Sanderson, Diana Gonzalez, Hugo Bugoro, Mohammad Kadir, David Gegeo, Jamesford Keboy, Clement Lifoia, Sheilla Funubo, Hellenda Honimae, Lanique Naolina Pitasua, Joanna Tatalu, Patishadel Jonah and Regina Souter

Int. J. Environ. Res. Public Health 2022, 19(16), 9815; https://doi.org/10.3390/ijerph19169815 - 09 Aug 2022

Viewed by 1821

Abstract

Unsafe child faeces management can lead to adverse health and wellbeing outcomes for children. In Solomon Islands, diarrhoeal disease is a leading cause of under-5 mortality, though there is limited research into CFM practices and promotion of safe behaviours. The formative research applied [...] Read more.

Unsafe child faeces management can lead to adverse health and wellbeing outcomes for children. In Solomon Islands, diarrhoeal disease is a leading cause of under-5 mortality, though there is limited research into CFM practices and promotion of safe behaviours. The formative research applied a Behaviour-Centred Design framework to investigate the habits, motives and settings related to child faeces management in rural Solomon Islands villages. Data were collected through structured recall demonstrations by caregivers (n = 61), household infrastructure observations (n = 57), semi-structured interviews with caregivers (n = 121) and community leaders (n = 30), focus group discussions (n = 26), and three participatory activities with caregivers. The findings identified a range of CFM-related behaviours, some of which would be considered safe and some, such as outside defecation and disposal to a waterway, as unsafe. Convenience is important in shaping CFM practice and may help health benefits to be achieved without women bearing the cost of an increased work burden. Nurture and disgust may provide the basis for behaviour change communication in SI as they have elsewhere. Critically, the participation in and promotion of safe CFM by fathers in households should be promoted, and motivating such behaviours might be achieved through focus on nurture as a motive. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

25 pages, 4495 KiB

Open AccessArticle

Aqueous Adsorptive Removal of Bisphenol A Using Tripartite Magnetic Montmorillonite Composites

by Okon E. Okon, Edu J. Inam, Nnanake-Abasi O. Offiong and Ukana D. Akpabio

Pollutants 2022, 2(3), 363-387; https://doi.org/10.3390/pollutants2030025 - 01 Aug 2022

Cited by 1 | Viewed by 1709

Abstract

The adsorption of bisphenol A into untreated montmorillonite clay, doped titanium composite and cationic polymer modified tripartite magnetic montmorillonite composite was investigated under different conditions. The magnetic property of the modified adsorbent was ascertained by action of external magnetic field on the materials [...] Read more.

The adsorption of bisphenol A into untreated montmorillonite clay, doped titanium composite and cationic polymer modified tripartite magnetic montmorillonite composite was investigated under different conditions. The magnetic property of the modified adsorbent was ascertained by action of external magnetic field on the materials when dispersed in aqueous media. The XRD results for the unmodified and modified adsorbents showed that interlayer spacing of the clay material increases due to intercalation of the precursor molecules. The textural properties of the adsorbents from BET analysis showed that pore size and specific surface area of the tripartite magnetic composite was calculated to be 288.08 m²/g while that of the unmodified clay was 90.39 m²/g. The TGA results showed the tripartite magnetic composite was more stable with the lowest percentage mass loss compared to the unmodified montmorillonite. The tripartite magnetic composite showed higher adsorption capacity. Adsorption was best described by the Freundlich isotherm model, which confirmed that the adsorption process was multilayer coverage unto the uneven surface of the adsorbents. Kinetic treatment of the adsorption data confirmed the the process followed a pseudo-second-order kinetic model and predominantly chemisorption process. The standard Gibb’s free energy computed for the adsorbents showed that the adsorption processes were favourably spontaneous with highly negative energy values of −336.70, −533.76 and −1438.38 KJ/mol, respectively, for the unmodified montmorillonite, doped titanium composite and the tripartite magnetic composite. It was observed that the addition of cationic aromatic moiety to the clay material increased pollutant-adsorbent interactions and improved adsorption capacity for micro-pollutants in a simulated industrial effluent. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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15 pages, 13347 KiB

Open AccessArticle

Evaluation and Evolution of the Physico-Chemical Parameters of Ocnei and Rotund Lakes Located near the “Salina Turda” Mine, Romania

by Simona Elena Avram, Liliana Rus, Valer Micle and Sergiu Stelian Hola

Water 2022, 14(15), 2366; https://doi.org/10.3390/w14152366 - 30 Jul 2022

Cited by 1 | Viewed by 1880

Abstract

The present research brings an input of information regarding the evolution of several physico-chemical parameters of two salt lakes (Lake Ocnei and Lake Rotund), part of the ”Salina Turda” resort, Cluj County, Romania, by means of on-site determinations. Measurements were carried out at [...] Read more.

The present research brings an input of information regarding the evolution of several physico-chemical parameters of two salt lakes (Lake Ocnei and Lake Rotund), part of the ”Salina Turda” resort, Cluj County, Romania, by means of on-site determinations. Measurements were carried out at six depths for each sampling point. We attempted to describe the behaviors of the two lakes under different natural conditions, in order to identify the impact of anthropogenic activities on the quality parameters of the two lakes. Our studies showed that the qualitative parameters of the water fluctuate as an effect of anthropogenic activities. A comparative analysis of the results gathered during three monitoring campaigns in 2016, 2018, and 2020 indicated that water quality was affected by anthropogenic activities such as mixing water layers which were characterized by different salinity values. The lakes tended to lose basicity, pH values varying between 9 at the surface level and 7 at −4 m. The thermal stratification phenomenon was only evident in the first year of monitoring; later on, the waters of both lakes appeared thermally homogenous down to the depth of −2 m. It was determined that the lakes had an uppermost freshwater layer, which disappeared during the bathing season because of vertical mixing. Interestingly, the two lakes showcased different behaviors at depths beyond −3 m. In addition, the infiltration of meteoric water that was polluted with nitrites and nitrates demonstrated the fact that anthropogenic activities that take place in the vicinity of the lakes generate negative effects on water quality. The presence of the heliothermal phenomenon was confirmed by the measurements made in the upper segment of the lakes. This layer of water consists of a mixture of fresh and salt water. The purpose of the research was to evaluate the water quality of the lakes, monitor its evolution during the bathing season and update the situation regarding the water quality of the two salt lakes by testing specific parameters. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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11 pages, 1449 KiB

Open AccessArticle

Efficient Removal of Nonylphenol Isomers from Water by Use of Organo-Hydrotalcites

by Daniel Cosano, Dolores Esquivel, Francisco J. Romero-Salguero, César Jiménez-Sanchidrián and José Rafael Ruiz

Int. J. Environ. Res. Public Health 2022, 19(12), 7214; https://doi.org/10.3390/ijerph19127214 - 12 Jun 2022

Cited by 2 | Viewed by 1845

Abstract

The presence of potent organic endocrine-disrupting chemicals (EDCs) in natural aquifers can have adverse impacts on public health and the environment. 4-nonylphenol, one such EDC, can be efficiently removed from water by adsorption onto a clayey material. In this work, we created an [...] Read more.

The presence of potent organic endocrine-disrupting chemicals (EDCs) in natural aquifers can have adverse impacts on public health and the environment. 4-nonylphenol, one such EDC, can be efficiently removed from water by adsorption onto a clayey material. In this work, we created an effective sorbent for this purpose by using co-precipitation and subsequent ion-exchange to intercalate the organic anion deoxycholate into a Mg/Al hydrotalcite. Intercalating deoxycholate ions increased the organophilicity of the hydrotalcite surface. The solid was used to adsorb 4-nonylphenol at different pollutant concentrations and temperatures. The adsorption process was subjected to a kinetic study. Based on the results, the EDC was adsorbed by chemisorption. In addition, based on the equilibrium isotherms used for the process, the Freundlich model was the most accurate in reproducing the adsorption of 4-nonylphenol onto deoxycholate-intercalated hydrotalcite. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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12 pages, 1028 KiB

Open AccessArticle

Assessing Access to WASH in Urban Schools during COVID-19 in Kazakhstan: Case Study of Central Kazakhstan

by Berik Toleubekov, Zhanerke Bolatova and Martin Stafström

Int. J. Environ. Res. Public Health 2022, 19(11), 6438; https://doi.org/10.3390/ijerph19116438 - 25 May 2022

Cited by 4 | Viewed by 2021

Abstract

The WHO/UNICEF Joint Monitoring Program (JMP) for Water Supply, Sanitation and Hygiene (WASH) produces global estimates of the real situation of access to water, sanitation and hygiene services, and sanitation and hygiene in households, educational institutes and health care facilities; however it is [...] Read more.

The WHO/UNICEF Joint Monitoring Program (JMP) for Water Supply, Sanitation and Hygiene (WASH) produces global estimates of the real situation of access to water, sanitation and hygiene services, and sanitation and hygiene in households, educational institutes and health care facilities; however it is lacking data on schools in Kazakhstan. Thus, the aim of this research was to assess access to WASH in schools of urban area in Kazakhstan. The study was conducted in seven schools of Central Kazakhstan during the COVID-19 pandemic and restrictive measures. Three data collection methods were used: a questionnaire for administrative staff, a questionnaire for parents and observation. Parents of offline study pupils (only second and third grades due to the pandemic) were included in the survey. Students had access to in-building toilets in all schools connected to the centralized sewer. The number of school toilets varied from 7 (KAZ200085) to 61 (KAZ200089). The average amount of toilets was 28.08 ± 16.97. Only two out of seven schools complied with the requirements of Kazakhstan national sanitary standards for the ratio of school toilets to the number of students. From the questionnaire with the school administrations, it was defined that the primary source of drinking water was the public water supply. All schools regularly disinfect and check the water supply system. At the same time, the results also revealed discrepancies in the answers between administration and parents (2.6% of parents showed that their children have rare access to drinking water), and insufficient monitoring of implementation of WASH services. This study also confirmed that the full provision of access to water and water services in the structure of educational institutions solves several SDG targets. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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19 pages, 7222 KiB

Open AccessArticle

Vulnerability Hotspots Mapping for Enhancing Sanitation Services Provision: A Case Study of Jordan

by Nezar Hammouri, Mohammad Talafha, Qais Hamarneh, Zeina Annab, Rami Al-Ruzouq and Abdallah Shanableh

Water 2022, 14(11), 1689; https://doi.org/10.3390/w14111689 - 25 May 2022

Cited by 1 | Viewed by 3417

Abstract

Enhancing sanitation services is a major challenge for sustainable development and plans. This work aims at developing a vulnerability hotspot mapping for improving sanitation services provision in Jordan based on a multi-weighted criteria model. Multiple spatial, physical, demographic, social, economic, and sanitation data [...] Read more.

Enhancing sanitation services is a major challenge for sustainable development and plans. This work aims at developing a vulnerability hotspot mapping for improving sanitation services provision in Jordan based on a multi-weighted criteria model. Multiple spatial, physical, demographic, social, economic, and sanitation data were collected and compiled using GIS. We also considered experts’ and stakeholders’ opinions to determine the necessary indicators needed to develop Sanitation Hotspot Index (SHI). We used the Analytic Hierarchy Process (AHP) analysis to assign the relative weights of ten criteria. We also checked the consistency of AHP results. We found that the sanitation and population density got the highest relative weights, while soil hydraulic conductivity got the lowest. Based on the results of AHP, we developed two SHI mapping for two administrative levels: district and neighborhood levels. The maps classified the sanitation vulnerability into five classes ranging from most vulnerable to least vulnerable. The developed SHI maps can be used as a decision support tool for decision-makers and planners to allocate the necessary funds and orient the aids from donors and international agencies to enhance sanitation services in the country’s most vulnerable areas. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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13 pages, 2162 KiB

Open AccessArticle

Human Excreta and Food Waste of a Typical Rural Area in China: Characteristics and Co-Fermentation

by Jean Joël Roland Kinhoun, Ao Li, Minghuan Lv, Yunpeng Shi, Bin Fan and Tingting Qian

Int. J. Environ. Res. Public Health 2022, 19(8), 4731; https://doi.org/10.3390/ijerph19084731 - 14 Apr 2022

Viewed by 1666

Abstract

Human excreta (HE) and food waste (FW) are the primary contaminants in rural regions. Prior to treating these contaminants, mastering their properties is required. In this study, the characteristics of the HE leaving the body and FW leaving the kitchen to the subsequent [...] Read more.

Human excreta (HE) and food waste (FW) are the primary contaminants in rural regions. Prior to treating these contaminants, mastering their properties is required. In this study, the characteristics of the HE leaving the body and FW leaving the kitchen to the subsequent respective fermentation were studied. Moreover, two kinds of co-fermentation processes for HE and FW were also investigated on the basis of mastering the properties. The results showed that, for a healthy adult, fresh feces, urine, and FW produced were about 163 g/cap/d (57.3 gCOD/cap/d), 1.6 L/cap/d (6.7 gN/cap/d), and 250 g/cap/d (35.0 gCOD/cap/d), respectively. In HE, about 75% of nitrogen and phosphorus were contained in urine. It takes at least three days for crushed FW discharged via water flushing to settle completely, and the COD removal efficiency after precipitation was around 75%. Mixing HE with FW after discharge, i.e., the initial unit of the process was 20% more efficient in fermentation than mixing after the respective pre-fermentation. This paper presents the characteristics of HE and FW and provides the optimized co-fermentation process, which provides technical support for the realization of environmental sanitation in rural areas. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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16 pages, 707 KiB

Open AccessArticle

Shared but Clean Household Toilets: What Makes This Possible? Evidence from Ghana and Kenya

by Prince Antwi-Agyei, Isaac Monney, Kwaku Amaning Adjei, Raphael Kweyu and Sheillah Simiyu

Int. J. Environ. Res. Public Health 2022, 19(7), 4271; https://doi.org/10.3390/ijerph19074271 - 02 Apr 2022

Cited by 1 | Viewed by 2398

Abstract

Shared sanitation facilities are not considered as basic sanitation owing to cleanliness and accessibility concerns. However, there is mounting evidence that some shared household toilets have a comparable level of service as private toilets. This study examined the factors that contribute to the [...] Read more.

Shared sanitation facilities are not considered as basic sanitation owing to cleanliness and accessibility concerns. However, there is mounting evidence that some shared household toilets have a comparable level of service as private toilets. This study examined the factors that contribute to the quality of shared household toilets in low-income urban communities in Ghana and Kenya. The study design comprised household surveys and field inspections. Overall, 843 respondents were interviewed, and 838 household shared sanitation facilities were inspected. Cleanliness scores were computed from the facility inspections, while a total quality score was calculated based on 13 indicators comprising hygiene, privacy, and accessibility. Regression analyses were conducted to determine predictors of cleanliness and the overall quality of the shared sanitation facilities. More than four out of five (84%) shared toilets in Ghana (N = 404) were clean, while in Kenya (N = 434), nearly a third (32%) were clean. Flush/pour-flush toilets were six times (p < 0.01 aOR = 5.64) more likely to be clean. A functional outside door lock on a toilet facility and the presence of live-in landlords led to a threefold increase (p < 0.01 aOR = 2.71) and a twofold increase (p < 0.01 aOR = 1.92), respectively in the odds of shared sanitation cleanliness. Sanitation facilities shared by at most five households (95% CI: 6–7) were generally clean. High-quality shared toilets had live-in landlords, functional door locks, and were water-dependent. Further studies on innovative approaches to maintaining the quality of these high-quality shared toilets are needed to make them eligible for classification as basic sanitation considering the increasing reliance on the facilities. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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17 pages, 2444 KiB

Open AccessArticle

Biological Layer in Household Slow Sand Filters: Characterization and Evaluation of the Impact on Systems Efficiency

by Helen Lubarsky, Natália de Melo Nasser Fava, Bárbara Luíza Souza Freitas, Ulisses Costa Terin, Milina Oliveira, Atônio Wagner Lamon, Natalia Pichel, John Anthony Byrne, Lyda Patricia Sabogal-Paz and Pilar Fernandez-Ibañez

Water 2022, 14(7), 1078; https://doi.org/10.3390/w14071078 - 29 Mar 2022

Cited by 7 | Viewed by 3819

Abstract

Schmutzdecke, the biofilm formed on the top of the sand bed in household slow sand filters (HSSF) is a key factor for the filters’ high efficiency in removing particles and microorganisms from water. This paper aims to investigate the extracellular polymeric substances [...] Read more.

Schmutzdecke, the biofilm formed on the top of the sand bed in household slow sand filters (HSSF) is a key factor for the filters’ high efficiency in removing particles and microorganisms from water. This paper aims to investigate the extracellular polymeric substances composition (carbohydrates and proteins), biomass, dissolved oxygen, and microbial community in two types of HSSFs and identify a correlation between them and their efficiency. A continuous- and an intermittent-HSSF (C-HSSF and I-HSSF) were studied to treat river water for 48 days. Their efficiencies for bacteria (E. coli and total coliforms), turbidity, and apparent color removals were analyzed. Results clearly showed an increase of carbohydrates (from 21.4/22.5 to 101.2/93.9 mg·g⁻¹ for C-/I-HSSF) and proteins (from 34.9 to 217/307.8 mg g⁻¹ for C-/I-HSSF), total solids (from 0.03/<0.03 to 0.11/0.19 g L⁻¹ for C-/I-HSSF), dissolved oxygen depletion inside the filter (6.00 and 5.15 mg L⁻¹ for C- and I-HSSF) and diversity of microorganisms over time, pointing out the schmutzdecke development. A clear improvement on the HSSFs’ efficiency was observed during operation, i.e., E. coli removal of 3.23 log and 2.98 log for total coliforms, turbidity from 60 to 95%, and apparent color from 50 to 90%. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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9 pages, 1418 KiB

Open AccessArticle

UV-C Light-Based Surface Disinfection: Analysis of Its Virucidal Efficacy Using a Bacteriophage Model

by Stefan A. Rudhart, Frank Günther, Laura Dapper, Boris A. Stuck and Stephan Hoch

Int. J. Environ. Res. Public Health 2022, 19(6), 3246; https://doi.org/10.3390/ijerph19063246 - 10 Mar 2022

Cited by 7 | Viewed by 2767

Abstract

Background: The reprocessing of medical devices has become more complex due to increasing hygiene requirements. Previous studies showed satisfactory bactericidal disinfection effects of UV-C light in rigid and flexible endoscopes. Especially in the context of the current COVID-19 pandemic, virucidal properties are of [...] Read more.

Background: The reprocessing of medical devices has become more complex due to increasing hygiene requirements. Previous studies showed satisfactory bactericidal disinfection effects of UV-C light in rigid and flexible endoscopes. Especially in the context of the current COVID-19 pandemic, virucidal properties are of high importance. In the present study, the virucidal efficacy of UV-C light surface disinfection was analyzed. Methods: MS-2 bacteriophages were applied to the test samples and irradiated by UV-C light using the UV Smart D25 device; unirradiated test samples were used as controls. A dilution series of the samples was mixed with

1 \times 10^{8}

Escherichia coli and assayed. Results: 8.6 × 10¹² pfu could be harvested from the unprocessed test samples. In the control group without UV-C exposure, a remaining contamination of 1.2 × 10¹² pfu was detected, resulting in a procedural baseline reduction rate with a LOG₁₀ reduction factor of 0.72. The LOG₁₀ reduction factor was found to be 3.0 after 25 s of UV-C light exposure. After 50 and 75 s of UV-C radiation LOG₁₀ reduction factors 4.2 and 5.9, respectively, were found, with all reductions being statistically significantly different to baseline. Conclusions: The tested UV system seems to provide a significant virucidal effect after a relatively short irradiation time. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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14 pages, 49563 KiB

Open AccessArticle

Monitoring the Impact of National Sanitation and Hygiene Programme for Rural Communities in Chamwino (Tanzania)

by Beatriz González-Rodrigo, Ana Esteban-Zazo, Cristina Vela-Plaza, Esnati James Chaggu and José Antonio Mancebo

Water 2022, 14(5), 735; https://doi.org/10.3390/w14050735 - 25 Feb 2022

Cited by 2 | Viewed by 3243

Abstract

The Sustainable Development Goals promulgate access to sanitation and hygiene for all and the end to open defecation in the framework of the human right to sanitation. Tanzania has one of the lowest levels of access to sanitation, with increasing open defecation. Ending [...] Read more.

The Sustainable Development Goals promulgate access to sanitation and hygiene for all and the end to open defecation in the framework of the human right to sanitation. Tanzania has one of the lowest levels of access to sanitation, with increasing open defecation. Ending open defecation has been identified as a top priority for reducing global inequalities in WASH (water, sanitation and hygiene). In this context, the coordinated work of NGOs, universities and governments developed a hygiene and sanitation programme (UMATA), whose methodologies and lessons learnt are ready to be scaled up. This research analyses the information collected from more than 21,000 households and discusses the challenges of monitoring and tracking the degree of achievement of the Sustainable Development Goals and the human right to sanitation. A characterisation of the hygiene and sanitation situation and the degree of adoption of different latrine types was assessed before (baseline) and after (follow-up) the implementation of the UMATA programme using the WHO/UNICEF JMP (Joint Monitoring Programme for Water Supply, Sanitation and Hygiene) metrics and approach. This allowed evaluating the efficacy of the strategy implemented in Tanzania to reduce open defecation that led to a decrease from 40.7% to 9.70% in the monitored period. Finally, we discuss the critical economic factors affecting the adoption and sustainability of improved sanitation systems. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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14 pages, 1729 KiB

Open AccessArticle

Environmental and Socioeconomic Factors for Gastric Cancer in 14 Counties of the Huai River Basin from 2014 to 2018

by Yongqing Lin, Bixiong Ye, Qin Wang and Shaoxia Dong

Int. J. Environ. Res. Public Health 2022, 19(4), 2213; https://doi.org/10.3390/ijerph19042213 - 15 Feb 2022

Cited by 1 | Viewed by 2919

Abstract

To explore the potential relationship between environmental and socioeconomic factors and the risk of gastric cancer (GC) in the Huai River Basin, the GC incidence rate (GIR) and GC mortality rate (GMR) data from 2014 to 2018 in 14 counties of the Huai [...] Read more.

To explore the potential relationship between environmental and socioeconomic factors and the risk of gastric cancer (GC) in the Huai River Basin, the GC incidence rate (GIR) and GC mortality rate (GMR) data from 2014 to 2018 in 14 counties of the Huai River Basin were collected from the Chinese Cancer Registration Annual Report. Environmental and socioeconomic parameters were collected through the Statistical Yearbook. The 14 counties were classified into three groups with low, moderate, and high risk of GC according to the point density of environmental factors (PDF) and index of socioeconomic factors (ISF). Significant differences in GIR and GMR were found among the counties with PDF (χ² = 21.36, p < 0.01) and ISF (χ² = 11.37, p < 0.05) levels. Meanwhile, significant differences in mortality rate were observed among counties with different PDF (χ² = 11.25, p < 0.01) and ISF (χ² = 18.74, p < 0.01), and the results showed that the ISF and PDF were increased while the GIR and GMR were decreased. Meanwhile, there was a lag effect between them, and we used two models to explore the lag effects between ISF, PDF and GIR and GMR; the coefficient influence between the ISF lag phase and GIR was −2.9768, and the coefficient influence between PDF and the lag phase on the GIR was −0.9332, and there were both significant impact when there was a probability of more than 95%. The results showed that the higher the ISF and PDF that lags in one stage, the more GIR was reduced, while the impact of the ISF and PDF on lag stage on mortality was not obvious. We used differential GMM to test the results, and also research results were relatively robust. Overall, GIR and GMR decreased with increasing point density of environmental factors and index of socioeconomic factors. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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16 pages, 3279 KiB

Open AccessArticle

Trends and Causes of Raw Water Quality Indicators in the Five Most Famous Lakes of Jiangsu Province, China

by Yajun Chang, Zheyuan Feng, Jixiang Liu, Junfang Sun, Linhe Sun, Qiang Tang and Dongrui Yao

Int. J. Environ. Res. Public Health 2022, 19(3), 1580; https://doi.org/10.3390/ijerph19031580 - 29 Jan 2022

Cited by 2 | Viewed by 3295

Abstract

Due to pollutants from industrial and agricultural activities, the lakes in China are faced with ecological and environmental problems. The five most famous lakes of Jiangsu Province, Taihu Lake, Gehu Lake, Gaobaoshaobo Lake, Hongze Lake, and Luoma Lake, have long-term fixed monitoring points [...] Read more.

Due to pollutants from industrial and agricultural activities, the lakes in China are faced with ecological and environmental problems. The five most famous lakes of Jiangsu Province, Taihu Lake, Gehu Lake, Gaobaoshaobo Lake, Hongze Lake, and Luoma Lake, have long-term fixed monitoring points for water body-related indicators. Over a five-year period, the monitoring showed that Gehu Lake had the highest average total nitrogen (TN) and total phosphorus (TP) concentrations among all lakes which were close to the Grade V critical value of the China’s Environmental Quality Standards for Surface Water (CEQSW). The NH₃-N concentrations in all lakes were Grade IV according to the China’s Water Quality Standard for Drinking Water Sources (CWQSDWS) and Grade II according to the CEQSW. In addition, although TP concentrations in Taihu Lake did not exceed Grade V in the CEQSW, TP removal was the main factor controlling eutrophication. It was also found that the petroleum concentrations in all lakes were lower than the Grade I according to the CEQSW. Despite this relatively low petroleum pollution, the concentration of petroleum was negatively correlated with the phytoplankton densities in all lakes. This indicated that phytoplankton density was very sensitive to petroleum concentration. For heavy metals, the concentrations of Pb, Cu, As, and Cd in all lakes were significantly lower than Grade I (CEQSW) from 2013 to 2017. However, the accumulated heavy metals in sediments will remain an important pollution source affecting water quality and aquatic products in the future. The comprehensive pollution index analysis showed that the five lakes were often moderately polluted, indicating that the protection of lake resources in China should not be relaxed for a long time in the future. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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15 pages, 1526 KiB

Open AccessArticle

Urban Water Access and Use in the Kivus: Evaluating Behavioural Outcomes Following an Integrated WASH Intervention in Goma and Bukavu, Democratic Republic of Congo

by Hugo Legge, Shahana Fedele, Florian Preusser, Patrycja Stys, Papy Muzuri, Moritz Schuberth and Robert Dreibelbis

Int. J. Environ. Res. Public Health 2022, 19(3), 1065; https://doi.org/10.3390/ijerph19031065 - 18 Jan 2022

Cited by 1 | Viewed by 1913

Abstract

Increasing the availability and reliability of community water sources is a primary pathway through which many water supply interventions aim to achieve health gains in communities with limited access to water. While previous studies in rural settings have shown that greater access to [...] Read more.

Increasing the availability and reliability of community water sources is a primary pathway through which many water supply interventions aim to achieve health gains in communities with limited access to water. While previous studies in rural settings have shown that greater access to water is associated both with increased overall consumption of water and use of water for hygiene related activities, there is limited evidence from urban environments. Using data collected from 1253 households during the evaluation of a community water supply governance and hygiene promotion intervention in the cities of Goma and Bukavu, Democratic Republic of Congo, we conducted a secondary analysis to determine the impact of these interventions on household water collection and use habits. Using multiple and logistic regression models we compared differences in outcomes of interest between households in quartiers with and without the intervention. Outcomes of interest included litres per capita day (lpcd) of water brought to the household, lpcd used at the household, and lpcd used for hygiene-related activities. Results demonstrated that intervention households were more likely to use community tapstands than households located in comparison quartiers and collected on average 16.3 lpcd of water, compared with 13.5 lpcd among comparison households (adj. coef: 3.2, 95 CI: 0.84 to 5.53, p = 0.008). However, reported usage of water in the household for domestic purposes was lower among intervention households (8.2 lpcd) when compared with comparison households (9.4 lpcd) (adj. coef: −1.11, 95 CI: −2.29 to 0.07), p = 0.066) and there was no difference between study groups in the amount of water allocated to hygiene activities. These results show that in this setting, implementation of a water supply governance and hygiene promotion intervention was associated with a modest increase in the amount of water being bought to the household, but that this did not translate into an increase in either overall per capita consumption of water or the per capita amount of water being allocated to hygiene related activities. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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15 pages, 1449 KiB

Open AccessCommunication

The Suitability of Hybrid Fe⁰/Aggregate Filtration Systems for Water Treatment

by Ran Tao, Huichen Yang, Xuesong Cui, Minhui Xiao, Nadège Gatcha-Bandjun, Joseline Flore Kenmogne-Tchidjo, Mesia Lufingo, Bernard Konadu Amoah, Raoul Tepong-Tsindé, Arnaud Igor Ndé-Tchoupé, Marquise Touomo-Wouafo, Brice Donald Btatkeu-K, Willis Gwenzi, Rui Hu, Jean Bosco Tchatchueng, Hans Ruppert and Chicgoua Noubactep

Water 2022, 14(2), 260; https://doi.org/10.3390/w14020260 - 17 Jan 2022

Cited by 9 | Viewed by 2080

Abstract

Metallic iron (Fe⁰) corrosion under immersed conditions (Fe⁰/H₂O system) has been used for water treatment for the past 170 years. Fe⁰ generates solid iron corrosion products (FeCPs) which are known to in situ coat the surface [...] Read more.

Metallic iron (Fe⁰) corrosion under immersed conditions (Fe⁰/H₂O system) has been used for water treatment for the past 170 years. Fe⁰ generates solid iron corrosion products (FeCPs) which are known to in situ coat the surface of aggregates, including granular activated carbon (GAC), gravel, lapillus, manganese oxide (MnO₂), pyrite (FeS₂), and sand. While admixing Fe⁰ and reactive aggregates to build hybrid systems (e.g., Fe⁰/FeS₂, Fe⁰/MnO₂, Fe⁰/sand) for water treatment, it has been largely overlooked that these materials would experience reactivity loss upon coating. This communication clarifies the relationships between aggregate addition and the sustainability of Fe⁰/H₂O filtration systems. It is shown that any enhanced contaminant removal efficiency in Fe⁰/aggregate/H₂O systems relative to the Fe⁰/H₂O system is related to the avoidance/delay of particle cementation by virtue of the non-expansive nature of the aggregates. The argument that aggregate addition sustains any reductive transformation of contaminants mediated by electrons from Fe⁰ is disproved by the evidence that Fe⁰/sand systems are equally more efficient than pure Fe⁰ systems. This demonstration corroborates the concept that aqueous contaminant removal in iron/water systems is not a process mediated by electrons from Fe⁰. This communication reiterates that only hybrid Fe⁰/H₂O filtration systems are sustainable. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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20 pages, 1331 KiB

Open AccessArticle

Whether the Agricultural Insurance Policy Achieves Green Income Growth—Evidence from the Implementation of China’s Total Cost Insurance Pilot Program

by Zhifeng Zhang, Haodong Xu, Shuangshuang Shan, Qingzhi Liu and Yuqi Lu

Int. J. Environ. Res. Public Health 2022, 19(2), 852; https://doi.org/10.3390/ijerph19020852 - 13 Jan 2022

Cited by 10 | Viewed by 2174

Abstract

With the rise and popularization of the concept of green sustainable development, green income growth of agricultural insurance policies has attracted wide attention. Whether green income growth can be achieved has become an important criterion for measuring an agricultural insurance policy. In this [...] Read more.

With the rise and popularization of the concept of green sustainable development, green income growth of agricultural insurance policies has attracted wide attention. Whether green income growth can be achieved has become an important criterion for measuring an agricultural insurance policy. In this context, this paper attempts to test whether the agricultural insurance policy achieves green income growth. Based on the panel data of 31 provinces (the research sample of this paper selects 31 provincial-level units (province for short) in China, including 22 provinces, 5 autonomous regions and 4 municipalities directly under the central government. Hong Kong Special Administrative Region, Macau Special Administrative Region and Taiwan Province are not included in the research sample) from 2009 to 2020 in China, this paper empirically evaluates the triple-effect of total cost insurance pilot program (TCI) on farmers’ income, environment and public health by employing a difference-in-difference model (DID). The results show that TCI increases farmers’ income, but deteriorates the environment and residents’ health without achieving green income growth. In the analysis of heterogeneity, compared with central and western regions, farmers’ income is more likely to increase in the eastern regions. However, environmental pollution is more severe, and residents’ health deteriorates more, in eastern regions. In addition, the positive effect of TCI on farmers’ income and the deterioration of residents’ health is more obvious in areas with a higher degree of damage, while the negative effect of TCI on the environment is more obvious in areas with a lower degree of damage. Furthermore, the mechanism analysis shows that TCI not only promotes the increase in farmers’ income through insurance density, but also affects the environment and residents’ health through straw burning. Therefore, the government should raise the subsidy standard for farmers to use straw-processing equipment and also to implement differentiated subsidies in regions with different levels of economic development and areas with different degrees of damage. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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26 pages, 25146 KiB

Open AccessArticle

The Effect of Sanitizing Treatments on Respirator Filtration Performance

by Jürg A. Schütz, Anthony P. Pierlot and David L. J. Alexander

Int. J. Environ. Res. Public Health 2022, 19(2), 641; https://doi.org/10.3390/ijerph19020641 - 06 Jan 2022

Cited by 3 | Viewed by 3367

Abstract

The potential for alcoholic vapors emitted by common sanitizing treatments to deteriorate the (electrostatic) filtration performance of disposable respirator masks has been investigated. Reports in the literature and some standard test methods provide a confusing and ambiguous picture concerning the relevance of this [...] Read more.

The potential for alcoholic vapors emitted by common sanitizing treatments to deteriorate the (electrostatic) filtration performance of disposable respirator masks has been investigated. Reports in the literature and some standard test methods provide a confusing and ambiguous picture concerning the relevance of this effect. Four different types of exposure were investigated in this study to clarify the effect of alcoholic vapor emissions on respirator masks. These included exposure to saturated vapors, use of hand sanitizers, cleaning of table surfaces and sanitization of masks by spraying them with alcohol-containing solutions. Methods employed were designed to be as real-world oriented as possible while remaining reproducible. Filtration performance and deterioration effects on exposure to the different treatments were determined on three different types of certified commercial respirator masks—a P2 and two KN95 masks. This study provides substantial evidence that disposable respirator masks with an accepted performance rating are seriously compromised from an exposure to saturated alcoholic vapors, can tolerate a one-off spray treatment with an alcoholic solution and retain their attested protection under the influence of alcoholic vapors from the use of hand sanitizer or spray sanitizer. Considering the range of vastly different outcomes obtained from the four treatments investigated, it seems prudent to assess in each case the specific effects of alcoholic solution treatments and vapors on respirator masks before use. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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13 pages, 11157 KiB

Open AccessFeature PaperArticle

UASB Performance and Perspectives in Urban Wastewater Treatment at Sub-Mesophilic Operating Temperature

by Daniele Cecconet, Arianna Callegari and Andrea G. Capodaglio

Water 2022, 14(1), 115; https://doi.org/10.3390/w14010115 - 05 Jan 2022

Cited by 12 | Viewed by 4147

Abstract

UASBs present several advantages compared to conventional wastewater treatment processes, including relatively low construction cost facilities, low excess sludge production, plain operation and maintenance, energy generation in the form of biogas, robustness in terms of COD removal efficiency, pH stability, and recovery time. [...] Read more.

UASBs present several advantages compared to conventional wastewater treatment processes, including relatively low construction cost facilities, low excess sludge production, plain operation and maintenance, energy generation in the form of biogas, robustness in terms of COD removal efficiency, pH stability, and recovery time. Although anaerobic treatment is possible at every temperature, colder climates lead to lower process performance and biogas production. These factors can be critical in determining the applicability and sustainability of this technology for the treatment of urban wastewater at low operating temperature. The purpose of this study is the performance evaluation of a pilot-scale (2.75 m³) UASB reactor for treatment of urban wastewater at sub-mesophilic temperature (25 °C), below the optimal range for the process, as related to biogas production and organic matter removal. The results show that, despite lower methane production and COD removal efficiency compared to operation under ideal conditions, a UASB can still achieve satisfactory performance, and although not sufficient to grant effluent discharge requirements, it may be used as a pretreatment step for carbon removal with some degree of energy recovery. Options for UASB pretreatment applications in municipal WWTPs are discussed. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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17 pages, 3466 KiB

Open AccessArticle

Connection between Anthropogenic Water Diversion and Hydrodynamic Condition in Plain River Network

by Hua Wang, Zilin Shen, Yichuan Zeng, Huaiyu Yan, Yiping Li and Weihao Yuan

Water 2021, 13(24), 3596; https://doi.org/10.3390/w13243596 - 14 Dec 2021

Cited by 8 | Viewed by 2396

Abstract

The increase in the rate of water renewal driven by hydrodynamics contributes to improving the water quality of the plain river network. Taking the lakeside river network in Wuxi as an example, through numerical simulation, polynomial fitting, correlation analysis, and principal component analysis, [...] Read more.

The increase in the rate of water renewal driven by hydrodynamics contributes to improving the water quality of the plain river network. Taking the lakeside river network in Wuxi as an example, through numerical simulation, polynomial fitting, correlation analysis, and principal component analysis, the hydrodynamic responses of urban lake-connected river networks to water diversion and hydrodynamic grouping were researched. Based on numerical model and influence weight analysis, we explored the improvement of hydrodynamic conditions of plain river network with strong human intervention and high algal water diversion. The results showed that: (1) The relationship between water diversion impact on river network flow velocity and water diversion flux was not as simple a linear relationship. It could be reflected by polynomial. The water transfer interval in dry season with high hydrodynamic efficiency (HE) was lower than 10 m³/s and higher than 30 m³/s, and the HE increased significantly when the water transfer flow was higher than 20 m³/s in the wet season. (2) According to the main hydrodynamic driving factors, the channels in the river network could be divided into three types: water conservancy projects, river and lake water level difference, and river channel characteristic. The correlations of rivers’ flow velocity in each group were very high. (3) The influence weights of water conservancy projects, river and lake water level difference, and river channel characteristic on the whole river network dynamics were 65, 21, and 12.4%, respectively, and the other factors contributed 1.6% of the weight. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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16 pages, 4131 KiB

Open AccessArticle

Characteristics of and Influencing Factors of Hydrochemistry and Carbon/Nitrogen Variation in the Huangzhouhe River Basin, a World Natural Heritage Site

by Chenpeng Hu, Ziqi Liu, Kangning Xiong, Xiaoxi Lyu, Yuan Li and Renkai Zhang

Int. J. Environ. Res. Public Health 2021, 18(24), 13169; https://doi.org/10.3390/ijerph182413169 - 14 Dec 2021

Cited by 5 | Viewed by 2394

Abstract

In karst areas, the characteristics of water chemistry and carbon and nitrogen are of great significance to basic research. The contents of Ca²⁺, Mg²⁺, K⁺, Na⁺, HCO₃⁻, SO₄²⁻, NO [...] Read more.

In karst areas, the characteristics of water chemistry and carbon and nitrogen are of great significance to basic research. The contents of Ca²⁺, Mg²⁺, K⁺, Na⁺, HCO₃⁻, SO₄²⁻, NO₃⁻, Cl⁻, dissolved organic carbon (DOC), and total nitrogen (TN) in water samples from 18 rivers and 14 springs in the Huangzhouhe River Basin were determined. The results showed that the water chemistry type in the Huangzhouhe River Basin is HCO₃-Ca-Mg. The chemical composition is mainly affected by dolomite weathering and also by ion exchange and other human activities. The river and spring DIC remain at the same level in the upper and middle reaches and decrease in the lower reaches. The NO₃-N and TN of river water and TN of spring water increase in the middle reaches, while NO₃-N of spring water decreases in the lower reaches. The DOC in the basin increases with the increase of SO₄²⁻ and Cl⁻, mainly due to the human influence of agricultural and domestic sewage. In the basin, the NO₃-N and TN in spring water are larger, and the DOC in river water is larger, mainly because there are more phytoplankton and human activities in the river water. The carbon and nitrogen in the Huangzhouhe River Basin are mainly HCO₃⁻ and NO₃⁻ ions. The evaluation of pH, Cl⁻, NO₃-N, SO₄²⁻, and TDS shows that the water quality is good and the ecological environment is good. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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19 pages, 5259 KiB

Open AccessArticle

Quantitative Analysis of a Spatial Distribution and Driving Factors of the Urban Heat Island Effect: A Case Study of Fuzhou Central Area, China

by Meizi You, Riwen Lai, Jiayuan Lin and Zhesheng Zhu

Int. J. Environ. Res. Public Health 2021, 18(24), 13088; https://doi.org/10.3390/ijerph182413088 - 11 Dec 2021

Cited by 16 | Viewed by 3354

Abstract

Land surface temperature (LST) is a joint product of physical geography and socio-economics. It is important to clarify the spatial heterogeneity and binding factors of the LST for mitigating the surface heat island effect (SUHI). In this study, the spatial pattern of UHI [...] Read more.

Land surface temperature (LST) is a joint product of physical geography and socio-economics. It is important to clarify the spatial heterogeneity and binding factors of the LST for mitigating the surface heat island effect (SUHI). In this study, the spatial pattern of UHI in Fuzhou central area, China, was elucidated by Moran’s I and hot-spot analysis. In addition, the study divided the drivers into two categories, including physical geographic factors (soil wetness, soil brightness, normalized difference vegetation index (NDVI) and modified normalized difference water index (MNDWI), water density, and vegetation density) and socio-economic factors (normalized difference built-up index (NDBI), population density, road density, nighttime light, park density). The influence analysis of single factor on LST and the factor interaction analysis were conducted via Geodetector software. The results indicated that the LST presented a gradient layer structure with high temperature in the southeast and low temperature in the northwest, which had a significant spatial association with industry zones. Especially, LST was spatially repulsive to urban green space and water body. Furthermore, the four factors with the greatest influence (q-Value) on LST were soil moisture (influence = 0.792) > NDBI (influence = 0.732) > MNDWI (influence = 0.618) > NDVI (influence = 0.604). The superposition explanation degree (influence (Xi ∩ Xj)) is stronger than the independent explanation degree (influence (Xi)). The highest and the lowest interaction existed in ”soil wetness ∩ MNDWI” (influence = 0.864) and “nighttime light ∩ population density” (influence = 0.273), respectively. The spatial distribution of SUHI and its driving mechanism were also demonstrated, providing theoretical guidance for urban planners to build thermal environment friendly cities. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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14 pages, 2010 KiB

Open AccessArticle

Role of River–Lake System Sediments and Microbial Activity in the Hyporheic Zone

by Angela Kuriata-Potasznik, Sławomir Szymczyk, Agnieszka Bęś, Marcin Sidoruk, Andrzej Skwierawski and Szymon Kobus

Water 2021, 13(24), 3499; https://doi.org/10.3390/w13243499 - 08 Dec 2021

Cited by 2 | Viewed by 2422

Abstract

The effect of river–lake systems on the surface water self-purification process is a significant and not fully recognised scientific issue. The conditions prevailing in the hyporheic zone of these ecosystems are of great importance in the process of component exchange between water and [...] Read more.

The effect of river–lake systems on the surface water self-purification process is a significant and not fully recognised scientific issue. The conditions prevailing in the hyporheic zone of these ecosystems are of great importance in the process of component exchange between water and sediments. The aim of this study was to investigate the influence of the type of sediments located at the bottom of the riverbed being part of a river–lake system on microbial activity in the hyporheic zone. An ex situ experiment was used to study the microbiological activity and the transformation of components in the collected river sediments. It was found that the specific properties of sediments varied depending on their location in the riverbed between the lakes comprising the system and that the prevailing meteorological conditions can also have an effect on microbial activity in the hyporheic zone, e.g., aerobic conditions. These conditions determined the intensity of component conversion in the sediments due to microbial metabolism. A closer understanding of the processes occurring in the hyporheic zone may allow the processes of water self-purification within river–lake systems to be supported in the future, which will contribute to the improvement of surface water quality. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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19 pages, 6622 KiB

Open AccessArticle

An Experimental Study of Fluoride Removal from Wastewater by Mn-Ti Modified Zeolite

by Bo Yang, Guirong Sun, Bingxu Quan, Jiawei Tang, Chunhui Zhang, Chaomin Jia, Yuanhui Tang, Xinling Wang, Mengmeng Zhao, Wenqian Wang and Binhu Xiao

Water 2021, 13(23), 3343; https://doi.org/10.3390/w13233343 - 25 Nov 2021

Cited by 8 | Viewed by 2855

Abstract

The emerging interest in fluoride-removal from wastewater has attracted attention to zeolite since it has been considered as a natural adsorbent. However, the fluoride-removal efficiency of natural zeolite is generally low. As part of the effort to improve the zeolite adsorption efficiency, we [...] Read more.

The emerging interest in fluoride-removal from wastewater has attracted attention to zeolite since it has been considered as a natural adsorbent. However, the fluoride-removal efficiency of natural zeolite is generally low. As part of the effort to improve the zeolite adsorption efficiency, we have produced and tested the Mn-Ti modified zeolite. In the current work, the material preparation is discussed, and prepared materials were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy, and Fourier transform infrared (FTIR) spectra. Both static and dynamic experiments were conducted to examine the effects of independent variables. In the static adsorption section, sensitivity analysis experiments were conducted for independent variables, such as adsorbent dosage, pH, temperature, and competitive ions. The maximum adsorption capacity is 2.175 mg/g, which was obtained at PH = 7, temperature = 25 °C, and initial fluoride concentration = 10 mg/L. For adsorption kinetics, both Lagergren and Pseudo-second order models predict the experiments very well, which probably demonstrates that the current process is a combination of physical sorption and chemisorption. For adsorption isotherms, the Freundlich model performs better than the Langmuir model since it is usually applied to illustrate adsorption on inhomogeneous surfaces. In the dynamic adsorption section, sensitivity analysis experiments were also conducted for independent variables, such as adsorbent thickness, flow velocity, initial fluoride concentration, and PH. Additionally, the adsorption mechanism is also discussed. The main reason is the hydrated metal fluoride precipitate formation. As we know, the current work provides the first quantified comparison of the natural zeolite and the Mn-Ti modified zeolite regarding fluoride-removal efficiency. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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17 pages, 4268 KiB

Open AccessArticle

Anthropogenic Disturbances Have Contributed to Degradation of River Water Quality in Arid Areas

by Li Ji, Yuan Li, Guixiang Zhang and Yonghong Bi

Water 2021, 13(22), 3305; https://doi.org/10.3390/w13223305 - 22 Nov 2021

Cited by 6 | Viewed by 2991

Abstract

The earth has been reshaped for millennia. The accelerating pace of anthropogenic activities has generated enormous impacts on the water environment. As one of the main drivers of landscape change, anthropogenic disturbance has brought many negative effects on rivers. Studying the relationship between [...] Read more.

The earth has been reshaped for millennia. The accelerating pace of anthropogenic activities has generated enormous impacts on the water environment. As one of the main drivers of landscape change, anthropogenic disturbance has brought many negative effects on rivers. Studying the relationship between anthropogenic disturbances and river water quality is of significance for regional conservation and ecosystem management, while the relationship remains poorly understood in the current. In this study, we quantified anthropogenic disturbances by introducing the concept of the hemeroby index and evaluated rivers’ water quality in eight sub-watersheds on the Loess Plateau. The results indicated that 37.5% of the sub-watersheds were in Eutrophic status, and 62.5% were in Marginal water quality index. The river water quality was most poor in the southwestern region near the Yellow River with high-level anthropogenic disturbance. A correlation analysis between water quality indicators and hemeroby suggested that anthropogenic disturbance contributed to a significant water quality deterioration trend (p < 0.01). The river water quality was relatively sensitive to the changes of completely disturbed land-use covers, including urban and industrial land. Our findings provide theoretical guidance for regional water resources conservation and ecosystem management in arid areas. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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11 pages, 2618 KiB

Open AccessArticle

The Effect of Multi-Years Reclaimed Water Irrigation on Dryland Carbon Sequestration in the North China Plain

by Yanbing Chi, Qiang Zheng, Peiling Yang, Shumei Ren and Ning Ma

Water 2021, 13(22), 3260; https://doi.org/10.3390/w13223260 - 17 Nov 2021

Cited by 2 | Viewed by 1904

Abstract

Reclaimed water is an alternative water source which could alleviate the shortage of water resources in agricultural systems. Many researchers have studied the effect of reclaimed water on soil environment, crop yield, etc. However, carbon sequestration in reclaimed water irrigated agricultural systems is [...] Read more.

Reclaimed water is an alternative water source which could alleviate the shortage of water resources in agricultural systems. Many researchers have studied the effect of reclaimed water on soil environment, crop yield, etc. However, carbon sequestration in reclaimed water irrigated agricultural systems is less studied. This study investigates methane uptake and photosynthesis in reclaimed water irrigation systems contributing to carbon sequestration estimation and analyzes the important factors impacting them. The results show that CH₄ uptake is related to soil water-filled pore space (WFPS) with a quadratic and it has the highest uptake when WFPS is between 40 and 50%. Long-term reclaimed water irrigation could significantly decrease (p < 0.05) CH₄ uptake and macroaggregate stability in the topsoil. However, reclaimed water had no significant impact on photosynthesis in comparison. The type of fertilizer is an important factor which impacts CH₄ emission from soil; urea had a lower CH₄ uptake and a higher CO₂ emission than slow-released fertilizer. Overall, reclaimed water irrigation could effectively decrease soil carbon sequestration. A soil wetted proportion level of 40–50% was recommended in this study for favorable methane oxidation. Slow-released fertilizer in reclaimed water irrigated agriculture could better control soil carbon emission and soil carbon absorption. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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31 pages, 781 KiB

Open AccessReview

A Review on Emerging Pollutants in the Water Environment: Existences, Health Effects and Treatment Processes

by Nor Zaiha Arman, Salmiati Salmiati, Azmi Aris, Mohd Razman Salim, Tasnia Hassan Nazifa, Mimi Suliza Muhamad and Marpongahtun Marpongahtun

Water 2021, 13(22), 3258; https://doi.org/10.3390/w13223258 - 17 Nov 2021

Cited by 71 | Viewed by 12950

Abstract

Emerging pollutants (EPs), also known as micropollutants, have been a major issue for the global population in recent years as a result of the potential threats they bring to the environment and human health. Pharmaceuticals and personal care products (PPCPs), antibiotics, and hormones [...] Read more.

Emerging pollutants (EPs), also known as micropollutants, have been a major issue for the global population in recent years as a result of the potential threats they bring to the environment and human health. Pharmaceuticals and personal care products (PPCPs), antibiotics, and hormones that are used in great demand for health and cosmetic purposes have rapidly culminated in the emergence of environmental pollutants. EPs impact the environment in a variety of ways. EPs originate from animal or human sources, either directly discharged into waterbodies or slowly leached via soils. As a result, water quality will deteriorate, drinking water sources will be contaminated, and health issues will arise. Since drinking water treatment plants rely on water resources, the prevalence of this contamination in aquatic environments, particularly surface water, is a severe problem. The review looks into several related issues on EPs in water environment, including methods in removing EPs. Despite its benefits and downsides, the EPs treatment processes comprise several approaches such as physico-chemical, biological, and advanced oxidation processes. Nonetheless, one of the membrane-based filtration methods, ultrafiltration, is considered as one of the technologies that promises the best micropollutant removal in water. With interesting properties including a moderate operating manner and great selectivity, this treatment approach is more popular than conventional ones. This study presents a comprehensive summary of EP’s existence in the environment, its toxicological consequences on health, and potential removal and treatment strategies. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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25 pages, 1303 KiB

Open AccessReview

Reductive and Oxidative UV Degradation of PFAS—Status, Needs and Future Perspectives

by Muhammad Umar

Water 2021, 13(22), 3185; https://doi.org/10.3390/w13223185 - 11 Nov 2021

Cited by 12 | Viewed by 4911

Abstract

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) consist of a group of environmentally persistent, toxic and bio-accumulative organic compounds of industrial origin that are widely present in water and wastewater. Despite restricted use due to current regulations on their use, perfluorooctanoic acid (PFOA) and perfluorooctane [...] Read more.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) consist of a group of environmentally persistent, toxic and bio-accumulative organic compounds of industrial origin that are widely present in water and wastewater. Despite restricted use due to current regulations on their use, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) remain the most commonly detected long-chain PFAS. This article reviews UV-based oxidative and reductive studies for the degradation of PFAS. Most of the UV-based processes studied at lab-scale include low pressure mercury lamps (emitting at 254 and 185 nm) with some studies using medium pressure mercury lamps (200–400 nm). A critical evaluation of the findings is made considering the degradation of PFAS, the impact of water quality conditions (pH, background ions, organics), types of oxidizing/reducing species, and source of irradiation with emphasis given to mechanisms of degradation and reaction by-products. Research gaps related to understanding of the factors influencing oxidative and reductive defluorination, impact of co-existing ions from the perspective of complexation with PFAS, and post-treatment toxicity are highlighted. The review also provides an overview of future perspectives regarding the challenges in relation to the current knowledge gaps, and future needs. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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25 pages, 2396 KiB

Open AccessReview

Improvement of Log Reduction Values Design Equations for Helminth Egg Management in Recycled Water

by Daryl P. Stevens, Vivek Daniel, Esmaeil Shahsavari, Arturo Aburto-Medina, Sarvesh K. Soni, Leadin S. Khudur, Basma Khallaf, Aravind Surapaneni, Jonathan Schmidt, Alexandra Keegan, Nicholas D. Crosbie, Judy Blackbeard, James Hampton, Dan Deere, Nick O’Connor and Andrew S. Ball

Water 2021, 13(22), 3149; https://doi.org/10.3390/w13223149 - 09 Nov 2021

Viewed by 3658

Abstract

Understanding and managing the risk posed by helminth eggs (HE) is a key concern for wastewater engineers and public health regulators. The treatment processes that produce recycled water from sewage at wastewater treatment plants (WWTPs) rely on achieving a defined log₁₀ reduction [...] Read more.

Understanding and managing the risk posed by helminth eggs (HE) is a key concern for wastewater engineers and public health regulators. The treatment processes that produce recycled water from sewage at wastewater treatment plants (WWTPs) rely on achieving a defined log₁₀ reduction value (LRV) in HE concentration during the production of recycled water from sewage to achieve the guideline concentration of ≤1.0 HE/L. The total concentration of HE in sewage reaches thousands of HE/L in developing countries and therefore, an LRV of 4.0 is generally accepted to achieve a safe concentration in recycled water, as this will meet the guideline value. However, in many developed countries with good sanitation and public health standards, the HE concentration in sewage is generally <10 HE/L. Therefore, validation of the sewage treatment process relied on to achieve an LRV of 4.0 can be difficult. Because of these limitations, design equations to predict LRVs from hydraulic retention times (HRT), which are geographically non-specific, are commonly relied on to ensure the production of safe quality recycled water with respect to HE. However, these design equations could be further refined by defining the design and management of the treatment process in greater detail and thus be used more effectively for determining the LRV required. This paper discusses the limitations and possible improvements that could be applied to LRV design equations for predicting HE removal at WWTPs and identifies the data requirements to support these improvements. Several options for LRV design equations are proposed that could be validated experimentally or via the ongoing operation of WWTPs. These improvements have the potential to assist the rationalization of the HE removal requirements for specific treatment options, exposure scenarios and use of recycled water in agriculture. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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13 pages, 25174 KiB

Open AccessArticle

Metal Pollution Assessment of Surface Water in the Emission Field of the Slovinky Tailing Impoundment (Slovakia)

by Danica Fazekašová, Juraj Fazekaš and Lenka Štofejová

Water 2021, 13(21), 3143; https://doi.org/10.3390/w13213143 - 08 Nov 2021

Cited by 4 | Viewed by 1786

Abstract

The focus of this work is on the evaluation of selected water quality indicators as per the applicable regulations, taking into account European and national legislation and the evaluation of the risk of contamination of surface waters with toxic elements using the contamination [...] Read more.

The focus of this work is on the evaluation of selected water quality indicators as per the applicable regulations, taking into account European and national legislation and the evaluation of the risk of contamination of surface waters with toxic elements using the contamination factor (

C_{f}^{i}

) and the degree of pollution (

C_{d}

). The studied area of Slovinky is an important ore region, with rich deposits of copper and silver ores that have been mined for centuries. One of the most important remnants of mining activities in this area is the Slovinky tailing impoundment. The sludge pond area has an area of 15 ha, and the height of the dam is 113 m above sea level, which makes the sludge pond one of the tallest water structures in Slovakia. The Slovinský creek was monitored in the years 2010, 2011, and 2019 at five sampling points, which were selected to map the entire length of the water flow from the source to the estuary to the river Hornád. Risk elements (As, Cu, Cd, and Fe) and physicochemical parameters (such as temperature, dissolved oxygen concentration, conductivity, resistivity, salinity, total dissolved solids, NaCl, redox potential, and pH) were included in this study and evaluated according to applicable regulations, taking into account European legislation (Act No. 269/2010 Coll., guideline value WHO 2011). The results of the experimental studies showed that the highest values of As and Cu were measured at the site where drainage waters from the Slovinky tailing impoundment and mining water of the Alžbeta shaft flow into the creek. The concentration of As exceeded the limit value by up to 31 times and the concentration of Cu 16.8–134.5 times. At the same time, the highest values of conductivity, salinity, total dissolved solids, and NaCl were found, and there was no acidification of water at the site that had the highest pollution. Water contamination was assessed based on

C_{f}^{i}

and

C_{d}

; our findings showed that the surface water from the site of contamination, along the entire length of the stream, was very highly contaminated with risk elements in the order of As > Fe > Cu, and the level of contamination decreased with distance from the site of contamination. Our research shows that seepage of toxic substances from sludge ponds and abandoned mines has caused the requirements for the quality of surface water of the Slovinský creek not to be met. In connection with mining activities, surface streams act as a transport medium through which other components of the environment can be polluted. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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19 pages, 3086 KiB

Open AccessArticle

Multi-Objective Optimal Allocation of River Basin Water Resources under Full Probability Scenarios Considering Wet–Dry Encounters: A Case Study of Yellow River Basin

by Xike Guan, Zengchuan Dong, Yun Luo and Dunyu Zhong

Int. J. Environ. Res. Public Health 2021, 18(21), 11652; https://doi.org/10.3390/ijerph182111652 - 06 Nov 2021

Cited by 7 | Viewed by 1935

Abstract

Wet–dry encounters between basins and regions have an important impact on the allocation of water resources. This study proposes a multi-objective allocation model for basin water resources under full probability scenarios considering wet–dry encounters (FPS-MOWAM) to solve the problem of basin water resource [...] Read more.

Wet–dry encounters between basins and regions have an important impact on the allocation of water resources. This study proposes a multi-objective allocation model for basin water resources under full probability scenarios considering wet–dry encounters (FPS-MOWAM) to solve the problem of basin water resource allocation. In the FPS-MOWAM model, the sub-regions were merged by precipitation correlation analysis. Next, the joint probability distribution of basin runoff and region precipitation was constructed using copula functions. The possible wet–dry encounter scenarios and their probabilities were then acquired. Finally, the multi-objective allocation model of water resources was constructed using the full probability scenario for wet–dry encounters in each region. The FPS-MOWAM is calculated by the NSGA-II algorithm and the optimal water resource allocation scheme was selected using the fuzzy comprehensive evaluation method. Using the Yellow River Basin as an example, the following conclusions were obtained: (1) the Yellow River Basin can be divided into four sub-regions based on precipitation correlations: Qh-Sc (Qinghai, Sichuan), Sg-Nx-Nmg (Gansu, Ningxia, Inner Mongolia), Sxq-Sxj (Shaanxi, Shanxi), and Hn-Sd (Henan, Shandong), (2) the inconsistencies in synchronous–asynchronous encounter probabilities in the Yellow River Basin were significant (the asynchronous probabilities were 0.763), whereas the asynchronous probabilities among the four regions were 0.632, 0.932, and 0.763 under the high, medium, and low flow conditions in the Yellow River Basin respectively, and (3) the allocation of water resources tends to increase with time, allocating the most during dry years. In 2035, the expected economic benefits are between 11,982.7 billion CNY and 12,499.6 billion CNY, while the expected water shortage rate is between 2.02% and 3.43%. In 2050, the expected economic benefits are between 21,291.4 billion CNY and 21,781.3 billion CNY, while the expected water shortage rate is between 1.28% and 6.05%. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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15 pages, 2055 KiB

Open AccessArticle

Optimal Sensor Placement in Hydraulic Conduit Networks: A State-Space Approach

by Caspar V. C. Geelen, Doekle R. Yntema, Jaap Molenaar and Karel J. Keesman

Water 2021, 13(21), 3105; https://doi.org/10.3390/w13213105 - 04 Nov 2021

Cited by 1 | Viewed by 1926

Abstract

Conduit bursts or leakages present an ongoing problem for hydraulic fluid transport grids, such as oil or water conduit networks. Better monitoring allows for easier identification of burst sites and faster response strategies but heavily relies on sufficient insight in the network’s dynamics, [...] Read more.

Conduit bursts or leakages present an ongoing problem for hydraulic fluid transport grids, such as oil or water conduit networks. Better monitoring allows for easier identification of burst sites and faster response strategies but heavily relies on sufficient insight in the network’s dynamics, obtained from real-time flow and pressure sensor data. This paper presents a linearized state-space model of hydraulic networks suited for optimal sensor placement. Observability Gramians are used to identify the optimal sensor configuration by maximizing the output energy of network states. This approach does not rely on model simulation of hydraulic burst scenarios or on burst sensitivity matrices, but, instead, it determines optimal sensor placement solely from the model structure, taking into account the pressure dynamics and hydraulics of the network. For a good understanding of the method, it is illustrated by two small water distribution networks. The results show that the best sensor locations for these networks can be accurately determined and explained. A third example is added to demonstrate our method to a more realistic case. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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16 pages, 3912 KiB

Open AccessFeature PaperArticle

Silver-Modified β-Cyclodextrin Polymer for Water Treatment: A Balanced Adsorption and Antibacterial Performance

by Xin Wang, Huafeng Chen, Jianyu Wang, Yi Zhou, Changzheng Cui and Yanbo Zhou

Water 2021, 13(21), 3004; https://doi.org/10.3390/w13213004 - 26 Oct 2021

Cited by 8 | Viewed by 2538

Abstract

Water pollution caused by organic pollutants and pathogenic microorganism is a critical issue. In this study, we reported a silver-modified β-cyclodextrin polymer (CD-CA/PDA-Ag) used for the removal of dyes and the suppression of microorganisms from water. In order to avoid silver nanoparticles agglomeration, [...] Read more.

Water pollution caused by organic pollutants and pathogenic microorganism is a critical issue. In this study, we reported a silver-modified β-cyclodextrin polymer (CD-CA/PDA-Ag) used for the removal of dyes and the suppression of microorganisms from water. In order to avoid silver nanoparticles agglomeration, the material was first coated with polydopamine (PDA) on β-cyclodextrin matrix, whose reducing catechol groups subsequently immobilized silver ions in situ to form uniformly dispersed silver nanoparticles. CD-CA/PDA-0.5Ag displayed a high adsorption capacity of methylene blue (535.93 mg/g), which is mainly attributed to electrostatic interactions, host-guest inclusions and π-π bond stacking effects. Furthermore, both diffusion inhibition zone tests and colony formation unit tests were investigated, which showed excellent antimicrobial capability on Escherichia coli (E. coli) and Staphylococcus aureus (S. auerus). Overall, CD-CA/PDA-Ag proved to have an excellent adsorption capacity and antibacterial performance, which provides a great potential in water purification. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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16 pages, 12005 KiB

Open AccessArticle

Changes in Selected Water Quality Parameters in the Utrata River as a Function of Catchment Area Land Use

by Katarzyna Dębska, Beata Rutkowska, Wiesław Szulc and Dariusz Gozdowski

Water 2021, 13(21), 2989; https://doi.org/10.3390/w13212989 - 22 Oct 2021

Cited by 16 | Viewed by 3154

Abstract

Surface waters are very important for society, as they are a source of potable water, as well a water supply for agricultural, industrial and recreational purposes. This paper presents changes in the quality of the water in the Utrata River, along its entire [...] Read more.

Surface waters are very important for society, as they are a source of potable water, as well a water supply for agricultural, industrial and recreational purposes. This paper presents changes in the quality of the water in the Utrata River, along its entire length, as a function of the catchment area’s land use. Water-quality measurements were carried out once a month for a total period of one year (April 2019–March 2020) at 24 measurement points. The concentrations of the following compounds were measured: total phosphorus, ammonia nitrogen and nitrate nitrogen, dissolved oxygen, and chemical oxygen demand. The results were compared with the limit values specified in the Regulation of the Minister of Maritime Economy and Inland Navigation. In order to determine the impact of land use on water quality in the Utrata River, principal component analyses (PCA) were conducted. The research demonstrated a considerably negative impact of agricultural land use and the presence of urban areas on the water quality of the Utrata River, with elevated concentrations of total phosphorus, ammonia nitrogen, nitrate nitrogen and COD, and decreasing concentrations of dissolved oxygen. The presented results point to the need for effective strategies to mitigate the adverse impact of agriculture and urbanisation on the environment and surface waters. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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18 pages, 940 KiB

Open AccessArticle

Understanding Rural Women’s Domestic Work Experiences (DWE) in Ibadan, Nigeria: Development of a Measurement Tool Using Confirmatory Factor Analysis

by Abisola Osinuga, Brandi Janssen, Nathan B Fethke, William T Story, John A Imaledo and Kelly K Baker

Int. J. Environ. Res. Public Health 2021, 18(21), 11043; https://doi.org/10.3390/ijerph182111043 - 21 Oct 2021

Cited by 1 | Viewed by 2037

Abstract

Gender norms prescribe domestic labor as primarily a female’s responsibility in developing countries. Many domestic tasks depend on access to water, so the physical, emotional, and time demands of domestic labor may be exacerbated for women living in water-insecure environments. We developed a [...] Read more.

Gender norms prescribe domestic labor as primarily a female’s responsibility in developing countries. Many domestic tasks depend on access to water, so the physical, emotional, and time demands of domestic labor may be exacerbated for women living in water-insecure environments. We developed a set of domestic work experience (DWE) measures tailored to work in rural areas in developing countries, assessed rural Nigerian women’s DWE, and examined relationships among the measures. Interviewer-administered survey data were collected between August and September from 256 women in four rural Nigerian communities. Latent factors of DWE were identified by analyzing survey items using confirmatory factor analysis. Pearson’s correlation was used to examine relationships among latent factor scores, and multivariate linear regression models were used to determine if factor scores significantly differed across socio-demographic characteristics. The DWE measures consisted of latent factors of the physical domain (frequency of common domestic tasks, water sourcing and carriage, experience of water scarcity), the psychosocial domain (stress appraisal and demand–control), and the social domain (social support). Significant correlations were observed among the latent factors within and across domains. Results revealed the importance of measuring rural Nigerian women’s DWE using multiple and contextual approaches rather than relying solely on one exposure measure. Multiple inter-related factors contributed to women’s DWE. Water insecurity exacerbated the physical and emotional demands of domestic labor DWE varied across age categories and pregnancy status among rural Nigerian women. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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13 pages, 2107 KiB

Open AccessArticle

Reduction in Arsenic Exposure by Domestic Water Purification Devices in Shanghai Area and Related Health Risk Assessment

by Qin Qin, Hongtao Lu, Zhiliang Zhu, Minghao Sui, Yanling Qiu and Daqiang Yin

Water 2021, 13(20), 2916; https://doi.org/10.3390/w13202916 - 16 Oct 2021

Cited by 2 | Viewed by 2243

Abstract

Domestic water purification devices (point-of-use) are important choices for people to deal with sudden drinking water contamination. Especially for sudden heavy metal and arsenic contamination, home water purification units can play a key role as a secondary line of defense. Most of the [...] Read more.

Domestic water purification devices (point-of-use) are important choices for people to deal with sudden drinking water contamination. Especially for sudden heavy metal and arsenic contamination, home water purification units can play a key role as a secondary line of defense. Most of the arsenic removal studies are limited to meeting the requirements of local water quality standards and few studies have been conducted on arsenic removal from household water purifiers. In this paper, the distribution characteristics of arsenic in water at the end of the pipeline network in the Shanghai water supply area have been investigated. Three types of household water purifiers, mainly with membrane separation technology, were selected to treat the simulated arsenic contamination in tap water sources. The effects of pH and inorganic salts on arsenic removal were studied in comparison to the results of coexisting ion concentrations in tap water. The results showed that the total arsenic concentrations in different tap water samples range from 0.479–1.195 µg L⁻¹, which is lower than the limit value for arsenic concentration set by China’s drinking water standard GB 5749–2006 (10 µg L⁻¹) and by the World Health Organization (10 µg L⁻¹). It is found that reverse osmosis and nanofiltration water purifiers were more effective in removing As(V), with removal rate above 97.7%, and less effective in removing As(III), the rate ranging from 40.1 to 56.3%. Preliminary validation was provided for the safety of household water purifiers in securing universal and sudden drinking water contamination. Domestic water purifiers are effective in reducing the risk of arsenic exposure in drinking water. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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14 pages, 1125 KiB

Open AccessArticle

Study of Long-Term Effectiveness of Water Safety Plan Applied to Microfiltered Water Dispensers to Improve Water Quality

by Marta Mazzotta, Silvano Salaris, Maria Rosaria Pascale, Luna Girolamini, Graziella Ciani and Sandra Cristino

Water 2021, 13(20), 2905; https://doi.org/10.3390/w13202905 - 16 Oct 2021

Cited by 1 | Viewed by 2982

Abstract

The use of Microfiltered Water Dispensers (MWDs) is increasing in offices, companies, or commercial facilities, as a response to plastic pollution. Despite their widespread use, poor data are available about the water quality and pathogens developed. Starting from a high contamination found in [...] Read more.

The use of Microfiltered Water Dispensers (MWDs) is increasing in offices, companies, or commercial facilities, as a response to plastic pollution. Despite their widespread use, poor data are available about the water quality and pathogens developed. Starting from a high contamination found in MWDs, a Water Safety Plan (WSP) was implemented on 57 MWDs to improve the water quality. To assess the effectiveness of WSP during the period 2017–2021, the environmental monitoring of heterotrophic plate counts (HPCs) at 36 °C and 22 °C, Enterococcus spp., Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Clostridium perfringens, as prescribed by Italian regulation for drinking water, was conducted. A high level of HPCs at both temperatures was observed, over the regulation limit; contrarily, the pathogenic bacteria were absent. The contamination found was studied with respect to the temperature threshold of 25 °C, suggested by directives. No significant differences were found between samples above and below the threshold, while a significant decrease over the years was observed for HPCs at 36 °C (p = 0.0000000001) and 22 °C (p = 0.000006). The WSP implementation resulted in a 43.09% decrease for HPCs at 36 °C and a 24.26% decrease for HPCs at 22 °C. Moreover, during the SARS-CoV-2 pandemic, the WSP contributed to limit the microbial contamination, preserving the MWDs’ functionality and hygienic conditions and the drinking water quality. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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17 pages, 1898 KiB

Open AccessReview

Effective Communication for Water Resilient Communities: A Conceptual Framework

by Mohammad Fahmi Abu Bakar, Wenyan Wu, David Proverbs and Eirini Mavritsaki

Water 2021, 13(20), 2880; https://doi.org/10.3390/w13202880 - 14 Oct 2021

Cited by 3 | Viewed by 6315

Abstract

Communication campaigns to promote the importance of water as a vital but limited resource have evolved in many ways. Nowadays, the resources, techniques and skills to deliver effective communication campaigns are far greater than ever before. Over the past decades, there has been [...] Read more.

Communication campaigns to promote the importance of water as a vital but limited resource have evolved in many ways. Nowadays, the resources, techniques and skills to deliver effective communication campaigns are far greater than ever before. Over the past decades, there has been a significant body of research towards improving water conservation campaign communication but with limited success in promoting more resilient behaviours on behalf of water consumers. While the media and technology have rapidly evolved and awareness among consumers may have increased, this has not been sufficient to make the communication effective in changing behaviour. Communications to promote resilience among consumers need to reach a wide audience, capture audiences’ attention, build awareness and motivate water consumers to consume water sustainably. This represents a subject in need of further theoretical and conceptual investigation. This research reviews various approaches to effective communication and through a synthesis of the concepts aims to present a new, socio-psychological water conservation conceptual framework. The present conceptual framework integrates emotional appeal, for use on social media platforms and in order to foster more water resilient communities. This framework represents a potentially major contribution in providing guidelines for water sectors to deliver effective video communications on social media platforms. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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12 pages, 15824 KiB

Open AccessArticle

The Effect of Urban Land-Use Change on Runoff Water Quality: A Case Study in Hangzhou City

by Li Li, Qidi Yu, Ling Gao, Bin Yu and Zhipeng Lu

Int. J. Environ. Res. Public Health 2021, 18(20), 10748; https://doi.org/10.3390/ijerph182010748 - 13 Oct 2021

Cited by 5 | Viewed by 2402

Abstract

The main functions of this research are to guide the proportion of urban land that is used and the layout of the facilities on it, help understand the changes to surface runoff that are caused by land being used in urban development, and [...] Read more.

The main functions of this research are to guide the proportion of urban land that is used and the layout of the facilities on it, help understand the changes to surface runoff that are caused by land being used in urban development, and thus solve surface runoff pollution. Hangzhou City, China has been selected for the experiment, and the way in which its land is utilized as well as the grading of urban construction projects in the demonstration area are specifically analyzed. This study systematically distinguishes the definitions of impervious area based on the Sutherland equation and analyzes the impact of different impervious area subtypes on surface runoff water quality. Then, we compare the impact of impervious area subtypes with the impact of other land-use patterns on surface runoff water quality. This study shows the relationship between different land-use types and runoff water bodies: Land-use index can affect runoff water quality; Greening activities, impervious surface, and the water quality index are negatively correlated; the effective impervious area rate is positively correlated with the water quality index. The paper suggests that increasing the proportion of green spaces and permeable roads in build-up land reduces the effective impervious area (EIA) and thus controls land runoff pollution and improves runoff water quality. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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21 pages, 6082 KiB

Open AccessArticle

Upper Limit and Power Generation Loss of Water Supplement from Cascade Hydropower Stations to Downstream under Lancang-Mekong Cooperation

by Jiahui Deng, Yu Li, Wei Ding, Bingyao Zhang, Bo Xu and Huicheng Zhou

Water 2021, 13(20), 2826; https://doi.org/10.3390/w13202826 - 11 Oct 2021

Cited by 3 | Viewed by 2417

Abstract

In cross-border water supplement cooperation, the supplement water discharged from upstream hydropower stations is the key to improving downstream benefits, but will lead to upstream power generation loss, so the upstream hydropower stations have to be aware of how much water they can [...] Read more.

In cross-border water supplement cooperation, the supplement water discharged from upstream hydropower stations is the key to improving downstream benefits, but will lead to upstream power generation loss, so the upstream hydropower stations have to be aware of how much water they can offer and how much power they will lose to make the water supplement cooperation more reasonable. Therefore, this study puts forward a model to calculate the upper limit flow of water supplement of cascade hydropower stations under firm power constraints and water level constraints and proposes a new optimization method called the “collaborative-independent” joint optimization method to calculate the power generation loss under water supplement constraints. The results show that the upper limit flow will increase with the increase of annual inflow, and the uncertainty of the distribution of inflow in the year will also affect the upper limit flow: the larger the proportion of non-flood season inflow, the higher the upper limit flow. In normal and wet years, delaying water supplement time can significantly increase the upper limit flow by about 5% per month. Additionally, the “collaborative-independent” joint optimization method newly proposed in this paper can significantly improve the local optimization problem compared to the traditional optimization method. The power generation loss increases with the increase of water supplement flow, and delaying water supplement time can significantly reduce the power generation loss. The results of this paper can provide essential data support for future water resources cooperation negotiations in the Lancang-Mekong river basin to promote efficient and orderly water resources cooperation in the basin. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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16 pages, 6436 KiB

Open AccessArticle

Study on Sludge and Dissolved Oxygen Distribution in a Full-Scale A2/O Oxidation Ditch

by Chengyi Li, Zhao Han, Yuquan Zhang, Yuan Zheng, Hepeng Zhang and Emmanuel Fernandez-Rodriguez

Water 2021, 13(19), 2776; https://doi.org/10.3390/w13192776 - 06 Oct 2021

Cited by 3 | Viewed by 2570

Abstract

The distribution of velocity, sludge, and dissolved oxygen in a full-scale anaerobic-anoxic-oxic (A2/O) oxidation ditch was numerically simulated under three rotation speed scenarios. The viscosity and settling rate of activated sludge were defined through a user-defined function (UDF), and the sludge phase was [...] Read more.

The distribution of velocity, sludge, and dissolved oxygen in a full-scale anaerobic-anoxic-oxic (A2/O) oxidation ditch was numerically simulated under three rotation speed scenarios. The viscosity and settling rate of activated sludge were defined through a user-defined function (UDF), and the sludge phase was calculated using the mixture multiphase flow model. Dissolved oxygen (DO) was set as a user-defined source (UDS) and its generation and consumption rates were defined with UDFs. The relationship between velocity and sludge concentration was found to be contradictory, with dead zones leading to large sludge concentrations at the bottom of the oxidation ditch (OD), but not at the middle-curved wall of the anoxic pool. The flow rate of the reflux slot and aerator oxygenation rate were checked and correlated with DO concentrations in the anaerobic pool. The majority of the large sludge concentrations were concentrated in the biological selection pool and these remained constant with bed height. With reduced propeller and agitator rotation speed, the sludge concentrations reduced in the biological selection pool, but increased in the anaerobic and anoxic pools. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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19 pages, 2869 KiB

Open AccessFeature PaperArticle

Improving Formaldehyde Removal from Water and Wastewater by Fenton, Photo-Fenton and Ozonation/Fenton Processes through Optimization and Modeling

by Ahmad Hosseinzadeh, Ali Asghar Najafpoor, Ali Asghar Navaei, John L. Zhou, Ali Altaee, Navid Ramezanian, Aliakbar Dehghan, Teng Bao and Mohsen Yazdani

Water 2021, 13(19), 2754; https://doi.org/10.3390/w13192754 - 04 Oct 2021

Cited by 7 | Viewed by 3661

Abstract

This study aimed to assess, optimize and model the efficiencies of Fenton, photo-Fenton and ozonation/Fenton processes in formaldehyde elimination from water and wastewater using the response surface methodology (RSM) and artificial neural network (ANN). A sensitivity analysis was used to determine the importance [...] Read more.

This study aimed to assess, optimize and model the efficiencies of Fenton, photo-Fenton and ozonation/Fenton processes in formaldehyde elimination from water and wastewater using the response surface methodology (RSM) and artificial neural network (ANN). A sensitivity analysis was used to determine the importance of the independent variables. The influences of different variables, including H₂O₂ concentration, initial formaldehyde concentration, Fe dosage, pH, contact time, UV and ozonation, on formaldehyde removal efficiency were studied. The optimized Fenton process demonstrated 75% formaldehyde removal from water. The best performance with 80% formaldehyde removal from wastewater was achieved using the combined ozonation/Fenton process. The developed ANN model demonstrated better adequacy and goodness of fit with a R² of 0.9454 than the RSM model with a R² of 0. 9186. The sensitivity analysis showed pH as the most important factor (31%) affecting the Fenton process, followed by the H₂O₂ concentration (23%), Fe dosage (21%), contact time (14%) and formaldehyde concentration (12%). The findings demonstrated that these treatment processes and models are important tools for formaldehyde elimination from wastewater. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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14 pages, 2264 KiB

Open AccessArticle

Does Long-Term Training in a Water Immersion Environment Change Interoception?

by Yasuhiro Baba, Daisuke Sato, Naofumi Otsuru, Koyuki Ikarashi, Tomomi Fujimoto and Koya Yamashiro

Int. J. Environ. Res. Public Health 2021, 18(19), 10259; https://doi.org/10.3390/ijerph181910259 - 29 Sep 2021

Cited by 1 | Viewed by 2418

Abstract

The aim of this study was to investigate individual interoception by comparing the responses of swimmers and baseball players when exposed to specific water environments, depending on training content and environment. Forty-eight healthy male university students were evaluated for their interoceptive response (accuracy, [...] Read more.

The aim of this study was to investigate individual interoception by comparing the responses of swimmers and baseball players when exposed to specific water environments, depending on training content and environment. Forty-eight healthy male university students were evaluated for their interoceptive response (accuracy, sensibility, and awareness) and heart rate following 25 min of water immersion (WI) at 35 °C. We assessed three conditions: pre-WI, during WI, and post-WI. The results indicated that interoceptive accuracy (IAcc) did not differ between groups because both swimming and baseball do not require emotional expression, as opposed to an activity such as dance. The heart rate was significantly decreased at post-WI compared to that at pre-WI. The IAcc of post-WI presented as higher than that of pre-WI. In addition, there was a significant negative correlation between the ratio of IAcc and that of HR among subjects. Moreover, the attention regulation subscale of the MAIA changed in the WI environment and the ratio of IAcc was negatively correlated with that of the not-distracting subscale of the MAIA. These results suggested that interoception did not differ among the athletes who had long-term training, which enabled them to acquire multi-modal sensorimotor integration, compared to that of non-athlete control participants. We conclude that interoception did not differ among athletes who had long-term training compared to that of non-athlete control participants. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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22 pages, 5540 KiB

Open AccessEditor’s ChoiceReview

Heavy Metals Removal from Water by Efficient Adsorbents

by Muhammad Zaim Anaqi Zaimee, Mohd Sani Sarjadi and Md Lutfor Rahman

Water 2021, 13(19), 2659; https://doi.org/10.3390/w13192659 - 27 Sep 2021

Cited by 64 | Viewed by 14097

Abstract

Natural occurrence and anthropogenic practices contribute to the release of pollutants, specifically heavy metals, in water over the years. Therefore, this leads to a demand of proper water treatment to minimize the harmful effects of the toxic heavy metals in water, so that [...] Read more.

Natural occurrence and anthropogenic practices contribute to the release of pollutants, specifically heavy metals, in water over the years. Therefore, this leads to a demand of proper water treatment to minimize the harmful effects of the toxic heavy metals in water, so that a supply of clean water can be distributed into the environment or household. This review highlights several water treatment methods that can be used in removing heavy metal from water. Among various treatment methods, the adsorption process is considered as one of the highly effective treatments of heavy metals and the functionalization of adsorbents can fully enhance the adsorption process. Therefore, four classes of adsorbent sources are highlighted: polymeric, natural mineral, industrial by-product, and carbon nanomaterial adsorbent. The major purpose of this review is to gather up-to-date information on research and development on various adsorbents in the treatment of heavy metal from water by emphasizing the adsorption capability, effect of pH, isotherm and kinetic model, removal efficiency and the contact of time of every adsorbent. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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12 pages, 1121 KiB

Open AccessArticle

Effect of Chemical Oxygen Demand Concentration on Nutrient Removal in Simultaneous Nitrification, Denitrification and Phosphorus Removal System in High-Altitude Areas

by Yani Zhao, Liling Zhang, Meng Zhang, Jingya Wu, Shuping Li, Douzhi Ran, Liwei Sun and Guangcan Zhu

Water 2021, 13(19), 2656; https://doi.org/10.3390/w13192656 - 26 Sep 2021

Viewed by 3425

Abstract

The application of biological nitrogen and phosphorus removal processes in high-altitude areas faces severe challenges due to low temperature, low atmosphere pressure and low oxygen concentration. In this study, a simultaneous nitrification, denitrification and phosphorus removal (SNDPR) system was operated under low atmosphere [...] Read more.

The application of biological nitrogen and phosphorus removal processes in high-altitude areas faces severe challenges due to low temperature, low atmosphere pressure and low oxygen concentration. In this study, a simultaneous nitrification, denitrification and phosphorus removal (SNDPR) system was operated under low atmosphere pressure. The chemical oxygen demand (COD) concentrations in influent were decreased from 300 mg/L (stage I) to 200 mg/L (stage II), corresponding to the low COD concentration of sewage in high-altitude areas. The removal of COD and total phosphate was efficient at the H1 reactor (72 kPa). The removal rates of COD and total phosphate were 94.08% (stage I), 90.66% (stage II) and 98.43% (stage I), 99.34% (stage II), respectively, which were similar to L1 (100 kPa). The removal rates of total inorganic nitrogen and simulation nitrification and denitrification were from 81.21% (stage I) and 59.48% (stage I) to 72.86% (stage II) and 31.95% (stage II), respectively, which were also improved compared to L1. Cycle experiment results indicated that the activity of phosphorus accumulating organisms was enhanced, while the ammonia oxidation process was inhibited under low atmosphere pressure. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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13 pages, 2360 KiB

Open AccessArticle

Sheet-like Skeleton Carbon Derived from Shaddock Peels with Hierarchically Porous Structures for Ultra-Fast Removal of Methylene Blue

by Panlong Dong, Hailin Liu, Shengrui Xu, Changpo Chen, Suling Feng and Anying Long

Water 2021, 13(18), 2554; https://doi.org/10.3390/w13182554 - 17 Sep 2021

Cited by 1 | Viewed by 2039

Abstract

To remove the pollutant methylene blue (MB) from water, a sheet-like skeleton carbon derived from shaddock peels (SPACs) was prepared by NaOH activation followed by a calcination procedure under nitrogen protection in this study. Characterization results demonstrated that the as-prepared SPACs displayed a [...] Read more.

To remove the pollutant methylene blue (MB) from water, a sheet-like skeleton carbon derived from shaddock peels (SPACs) was prepared by NaOH activation followed by a calcination procedure under nitrogen protection in this study. Characterization results demonstrated that the as-prepared SPACs displayed a hierarchically porous structure assembled with a thin sheet-like carbon layer, and the surface area of SPAC-8 (activated by 8 g NaOH) was up to 782.2 m²/g. The as-prepared carbon material presented an ultra-fast and efficient adsorption capacity towards MB due to its macro-mesoporous structure, high surface area, and abundant functional groups. SPAC-8 showed ultrafast and efficient removal capacity for MB dye. Adsorption equilibrium was reached within 1 min with a removal efficiency of 99.6% at an initial concentration of 100 mg/g under batch adsorption model conditions. The maximum adsorption capacity for MB was up to 432.5 mg/g. A pseudo-second-order kinetic model and a Langmuir isotherm model described the adsorption process well, which suggested that adsorption rate depended on chemisorption and the adsorption process was controlled by a monolayer adsorption, respectively. Furthermore, column adsorption experiments showed that 96.58% of MB was removed after passing through a SPAC-8 packed column with a flow rate of 20 mL/min, initial concentration of 50 mg/L, and adsorbent dosage of 5 mg. The as-prepared adsorbent displays potential value in practical applications for dye removal due to its ultrafast and efficient adsorption capacity. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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8 pages, 786 KiB

Open AccessArticle

A Study of Environmentally Friendly Menstrual Absorbents in the Context of Social Change for Adolescent Girls in Low- and Middle-Income Countries

by Jasmin Foster and Paul Montgomery

Int. J. Environ. Res. Public Health 2021, 18(18), 9766; https://doi.org/10.3390/ijerph18189766 - 16 Sep 2021

Cited by 7 | Viewed by 6638

Abstract

Girls in low- and middle-income countries struggle to maintain good menstrual hygiene in part due to a lack of affordable sanitary products. The unaffordability of reliable sanitary products can lead to school absenteeism and is a barrier to education attainment and gender equality [...] Read more.

Girls in low- and middle-income countries struggle to maintain good menstrual hygiene in part due to a lack of affordable sanitary products. The unaffordability of reliable sanitary products can lead to school absenteeism and is a barrier to education attainment and gender equality for girls in low-income contexts. Further, the lack of adequate disposal facilities can lead to social embarrassment and environmental pollution. Low-cost biodegradable absorbents (cotton terry cloth, linen, hemp cloth and bamboo wadding) were investigated in gelatine solution in terms of their absorption for use in menstrual hygiene. Bamboo wadding exhibits the highest absorption index (7.86), greater than cotton terry cloth (0.84), hemp cloth (1.4), linen (1.57) and a commercial sanitary pad (4.38). Though the absorption index of bamboo wadding is promising, especially in light of the vast availability of bamboo in tropical low- and middle-income countries, challenges lie in overcoming complex extraction processes from bamboo plants, which is discussed. This simple research of a physical material from a technical aspect, if further investigated with a social science and policy lens, could increase school attendance, improve the education levels attained by girls and be a key step towards gender equality in low- and middle-income countries. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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14 pages, 1533 KiB

Open AccessArticle

Reed Biochar Addition to Composite Filler Enhances Nitrogen Removal from BDBR Systems in Eutrophic Rivers Channel

by Yajun Chang, Jie Liu, Qiang Tang, Linhe Sun, Jian Cui, Xiaojing Liu, Dongrui Yao and Shiqun Han

Water 2021, 13(18), 2501; https://doi.org/10.3390/w13182501 - 12 Sep 2021

Cited by 2 | Viewed by 2069

Abstract

With the rapid development of urbanization in China, the eutrophication or black stink of urban rivers has become a critical environmental problem. As a research hotspot in wastewater purification, biofilm technology has shortcomings, such as insufficient carbon sources for denitrification. This study used [...] Read more.

With the rapid development of urbanization in China, the eutrophication or black stink of urban rivers has become a critical environmental problem. As a research hotspot in wastewater purification, biofilm technology has shortcomings, such as insufficient carbon sources for denitrification. This study used a Biofilm Denitrification Batch Reactor (BDBR) system constructed using reed biochar as the carbon source required in denitrification, significantly accelerating the biofilm formation. To determine the suitable amount of biochar for water purification from the urban eutrophic rivers by the BDBR system, 0%, 5%, 10%, and 15% reed biochar was added to the viscose fiber combined packing. The combined packing reactor involved in this study had a high removal efficiency of the eutrophication channel COD throughout the experiment. However, adding 5% and 10% biochar in the combined filler effectively increased the number of nitrifying and denitrifying bacteria on the biofilm, improved the dominant bacteria diversity and microbial activity, and enhanced denitrification efficiency in the BDBR system. It provides new ideas and methods for developing and applying in situ denitrification technology for urban polluted rivers. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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17 pages, 4809 KiB

Open AccessArticle

Enhanced Denitrification of Integrated Sewage Treatment System by Supplementing Denitrifying Carbon Source

by Dongkai Chen, Peizhen Chen, Xiangqun Zheng, Weimin Cheng, Qiang Wang and Xiaocheng Wei

Int. J. Environ. Res. Public Health 2021, 18(18), 9569; https://doi.org/10.3390/ijerph18189569 - 10 Sep 2021

Cited by 7 | Viewed by 2421

Abstract

Integrated sewage treatment system (ISTY) is a new technology for rural domestic sewage treatment. In the ISTY, the carbon source in the denitrification stage is often insufficient, affecting the denitrification efficiency. In order to improve the denitrification efficiency, several commonly available agricultural wastes, [...] Read more.

Integrated sewage treatment system (ISTY) is a new technology for rural domestic sewage treatment. In the ISTY, the carbon source in the denitrification stage is often insufficient, affecting the denitrification efficiency. In order to improve the denitrification efficiency, several commonly available agricultural wastes, peanut shell (PS), sawdust (SD), peat (PT), and their mixtures (MT), were selected as supplementary carbon sources in the denitrification stage of ISTY to study the denitrification efficiency. Results show that PS exhibited a high carbon release capacity. PS released an enormous amount of carbon in 144 h, and the cumulative total organic carbon was 41.99 ± 0.7 mg/(g·L). The optimum carbon source dosage was 3 g/L, the nitrate removal rates of PS exceeded 95% after 48 h, and the denitrification rates were 9.35 mg/(g·L), which were 63.92% higher than that of the control group. After running the ISTY for 120 h, and with PS as supplementary carbon sources, the removal rate of TN increased from 29.76% to 83.86%. At the genus level, the dominant denitrifying bacteria in ISTY, after adding PS, were Pseudomonas and Cupriavidus, accounting for 78.68%, an increase of 72.90% compared with the control group. This evidence suggested that PS can obviously enhance the denitrification efficiency of the ISTY as a supplementary carbon source. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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17 pages, 1663 KiB

Open AccessFeature PaperArticle

Machine Learning Models for Predicting Water Quality of Treated Fruit and Vegetable Wastewater

by Gurvinder Mundi, Richard G. Zytner, Keith Warriner, Hossein Bonakdari and Bahram Gharabaghi

Water 2021, 13(18), 2485; https://doi.org/10.3390/w13182485 - 10 Sep 2021

Cited by 13 | Viewed by 3411

Abstract

Wash-waters and wastewaters from the fruit and vegetable processing industry are characterized in terms of solids and organic content that requires treatment to meet regulatory standards for purpose-of-use. In the following, the efficacy of 13 different water remediation methods (coagulation, filtration, bioreactors, and [...] Read more.

Wash-waters and wastewaters from the fruit and vegetable processing industry are characterized in terms of solids and organic content that requires treatment to meet regulatory standards for purpose-of-use. In the following, the efficacy of 13 different water remediation methods (coagulation, filtration, bioreactors, and ultraviolet-based methods) to treat fourteen types of wastewater derived from fruit and vegetable processing (fruit, root vegetables, leafy greens) were examined. Each treatment was assessed in terms of reducing suspended solids, total phosphorus, nitrogen, biochemical and chemical oxygen demand. From the data generated, it was possible to develop predictive modeling for each of the water treatments tested. Models to predict post-treatment water quality were studied and developed using multiple linear regression (coefficient of determination (R²) of 30 to 83%), which were improved by the generalized structure of group method of data handling models (R² of 73–99%). The selection of multiple linear regression and the generalized structure of group method of data handling models was due to the ability of the models to produce robust equations for ease of use and practicality. The large variability and complex nature of wastewater quality parameters were challenging to represent in linear models; however, they were better suited for group method of data handling technique as shown in the study. The model provides an important tool to end users in selecting the appropriate treatment based on the original wastewater characteristics and required standards for the treated water. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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12 pages, 7468 KiB

Open AccessArticle

Removal of Hydrogen Peroxide Residuals and By-Product Bromate from Advanced Oxidation Processes by Granular Activated Carbon

by Feifei Wang, Lu Zhang, Liangfu Wei and Jan Peter van der Hoek

Water 2021, 13(18), 2460; https://doi.org/10.3390/w13182460 - 07 Sep 2021

Cited by 5 | Viewed by 3926

Abstract

During drinking water treatment, advanced oxidation process (AOP) with O₃ and H₂O₂ may result in by-products, residual H₂O₂ and BrO₃⁻. The water containing H₂O₂ and BrO₃⁻ often flows [...] Read more.

During drinking water treatment, advanced oxidation process (AOP) with O₃ and H₂O₂ may result in by-products, residual H₂O₂ and BrO₃⁻. The water containing H₂O₂ and BrO₃⁻ often flows into subsequent granular activated carbon (GAC) filters. A concentrated H₂O₂ solution can be used as GAC modification reagent at 60 °C to improve its adsorption ability. However, whether low concentrations of H₂O₂ residuals from AOP can modify GAC, and the impact of H₂O₂ residuals on BrO₃⁻ removal by the subsequent GAC filter at ambient temperature, is unknown. This study evaluated the modification of GAC surface functional groups by residual H₂O₂ and its effect on BrO₃⁻ removal by GAC. Results showed that both H₂O₂ and BrO₃⁻ were effectively removed by virgin GAC, while pre-loaded and regenerated GACs removed H₂O₂ but not BrO₃⁻ anymore. At the ambient temperature 150 µmol/L H₂O₂ residuals consumed large amounts of functional groups, which resulted in the decrease of BrO₃⁻ removal by virgin GAC in the presence of H₂O₂ residuals. Redox reactions between BrO₃⁻ and surface functional groups played a dominant role in BrO₃⁻ removal by GAC, and only a small amount of BrO₃⁻ was removed by GAC adsorption. The higher the pH, the less BrO₃⁻ removal and the more H₂O₂ removal was observed. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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20 pages, 2201 KiB

Open AccessArticle

Suitability of the Decentralised Wastewater Treatment Effluent for Agricultural Use: Decision Support System Approach

by William Musazura and Alfred O. Odindo

Water 2021, 13(18), 2454; https://doi.org/10.3390/w13182454 - 07 Sep 2021

Cited by 2 | Viewed by 2461

Abstract

The decentralised wastewater treatment system (DEWATS) is an onsite sanitation technology that can be used in areas away from municipal sewerage networks. The discharge of effluent emanating from DEWATS into water bodies may cause pollution. Agricultural use of the effluent may improve crop [...] Read more.

The decentralised wastewater treatment system (DEWATS) is an onsite sanitation technology that can be used in areas away from municipal sewerage networks. The discharge of effluent emanating from DEWATS into water bodies may cause pollution. Agricultural use of the effluent may improve crop yields and quality thereby contributing to food security in low-income communities. There are drawbacks to the agricultural use of treated wastewater. Therefore, the study assessed the crop, environmental and health risks when irrigating with anaerobic filter (AF) effluent using the Decision Support System (DSS) of the South African Water Quality Guideline model, in four South African agroecological regions, three soil types, two irrigation systems and three different crops. The model was parameterised using AF effluent characterisation data and simulated for 45 years. The model predicted that there are no negative impacts for using AF effluent on soil quality parameters (root zone salinity, soil permeability and oxidisable carbon loading), leaf scorching and irrigation equipment. The problems were reported for nutrient loading (N and P) in maize and microbial contamination in cabbage and lettuce. It was recommended that the effluent should be diluted when used for maize production and advanced treatment should be explored to allow unrestricted agricultural use. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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14 pages, 2142 KiB

Open AccessArticle

The Role of Modification of the Structure of Water and Water-Containing Systems in Changing Their Biological, Therapeutic, and Other Properties Overview

by Galina Sidorenko, Mitja Brilly, Boris Laptev, Nikolay Gorlenko, Leonid Antoshkin, Andrej Vidmar and Andrej Kryžanowski

Water 2021, 13(17), 2441; https://doi.org/10.3390/w13172441 - 05 Sep 2021

Cited by 7 | Viewed by 5477

Abstract

Based on published research on modifying the structure of water and water-containing systems, we assess external influence methods: temperature, magnetic field, light radiation, and their combination. We evaluate changes in the electrophysical, photo- and pH-metric biological, therapeutic, and other properties of water systems [...] Read more.

Based on published research on modifying the structure of water and water-containing systems, we assess external influence methods: temperature, magnetic field, light radiation, and their combination. We evaluate changes in the electrophysical, photo- and pH-metric biological, therapeutic, and other properties of water systems using non-destructive electrophysical research methods, i.e., thermometry, pH, laser interference, dynamic light scattering, microelectrophoresis, conductivity, surface tension, dielectric constant, polarimetric measurements, atomic force microscopy, and UV and EPR spectroscopy. The effects of temperature or magnetic field lead to a change in the content and size of water clusters, and physicochemical, biological, therapeutic, and other changes in the properties of water and water-containing systems. The combined effect of a magnetic field and curative mud and the impact of magnetised mineral water have a more pronounced therapeutic effect than only mineral water or curative mud. The data presented indirectly indicate structural changes in water and water-containing systems. We conclude that the primary mechanism of action of a magnetic field, light, or a combination of these factors on water and water-containing systems, including mineral water and therapeutic mud, is a change in the structure of water. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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21 pages, 2838 KiB

Open AccessArticle

Eco-Friendly Coagulant versus Industrially Used Coagulants: Identification of Their Coagulation Performance, Mechanism and Optimization in Water Treatment Process

by Nadiah Khairul Zaman, Rosiah Rohani, Izzati Izni Yusoff, Muhammad Azraei Kamsol, Siti Aishah Basiron and Aina Izzati Abd. Rashid

Int. J. Environ. Res. Public Health 2021, 18(17), 9164; https://doi.org/10.3390/ijerph18179164 - 31 Aug 2021

Cited by 17 | Viewed by 3742

Abstract

The evaluation of complex organic and inorganic coagulant’s performances and their relationships could compromise the surface water treatment process time and its efficiency. In this work, process optimization was investigated by comparing an eco-friendly chitosan with the industrially used coagulants namely aluminum sulfate [...] Read more.

The evaluation of complex organic and inorganic coagulant’s performances and their relationships could compromise the surface water treatment process time and its efficiency. In this work, process optimization was investigated by comparing an eco-friendly chitosan with the industrially used coagulants namely aluminum sulfate (alum), polyaluminum chloride (PAC), and aluminum chlorohydrate (ACH) in compliance with national drinking water standards. To treat various water samples from different treatment plants with turbidity and pH ranges from 20–826.3 NTU and 5.21–6.80, respectively, 5–20 mg/L coagulant dosages were varied in the presence of aluminum, ferum, and manganese. Among all, 10 mg/L of the respective ACH and chitosan demonstrated 97% and 99% turbidity removal in addition to the removal of the metals that complies with the referred standard. However, chitosan owes fewer sensitive responses (turbidity and residual metal) with the change in its input factors (dosage and pH), especially in acidic conditions. This finding suggested its beneficial role to be used under the non-critical dosage monitoring. Meanwhile, ACH was found to perform better than chitosan only at pH > 7.4 with half dosage required. In summary, chitosan and ACH could perform equally at a different set of optimum conditions. This optimization study offers precise selections of coagulants for a practical water treatment operation. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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21 pages, 3056 KiB

Open AccessArticle

Application of Two Indigenous Strains of Microalgal Chlorella sorokiniana in Cassava Biogas Effluent Focusing on Growth Rate, Removal Kinetics, and Harvestability

by Mohamad Padri, Nittaya Boontian, Neung Teaumroong, Pongdet Piromyou and Chatlada Piasai

Water 2021, 13(17), 2314; https://doi.org/10.3390/w13172314 - 24 Aug 2021

Cited by 4 | Viewed by 2898

Abstract

Microalgae cultivation in wastewater is an emerging approach to remove its contaminants and generate microalgal biomass. This study aimed to screen and isolate potential strains in a cassava biogas effluent wastewater (CBEW) treatment system and produce algal biomass. Chlorella sorokiniana strains P21 and [...] Read more.

Microalgae cultivation in wastewater is an emerging approach to remove its contaminants and generate microalgal biomass. This study aimed to screen and isolate potential strains in a cassava biogas effluent wastewater (CBEW) treatment system and produce algal biomass. Chlorella sorokiniana strains P21 and WB1DG were isolated from CBEW and found to grow by utilizing various carbon sources. Experiments conducted in a batch reactor using an unsterilized substrate were done to evaluate the nutrient removal and growth of isolated strains from CBEW. The results showed that C. sorokiniana P21 and WB1DG could achieve biomass accumulation of more than 2564 and 1301 mg L⁻¹, respectively. The removal efficiencies of chemical oxygen demand (COD), total phosphorous (TP), and total inorganic nitrogen (TIN) were found up to be 63.42, 91.68, and 70.66%, respectively, in a WB1DG culture and 73.78, 92.11, and 67.33%, respectively, in a P21 culture. Harvestability of the P21 strain was examined using several coagulant–flocculants. FeCl₃ was found to remove more than 90% of the cells. Nutrient removal and growth rates resulting from these indigenous strains with application of untreated CBEW support the possibility of this strain being a promising candidate to couple a CBEW treatment and algal biomass generation with minimal process adjustment. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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15 pages, 14717 KiB

Open AccessArticle

Access to Water and Sanitation Infrastructures for Primary Schoolchildren in the South-Central Part of Côte d’Ivoire

by Parfait K. Kouamé, Anaïs Galli, Maryna Peter, Georg Loss, Diarassouba Wassa, Bassirou Bonfoh, Jürg Utzinger and Mirko S. Winkler

Int. J. Environ. Res. Public Health 2021, 18(16), 8863; https://doi.org/10.3390/ijerph18168863 - 23 Aug 2021

Cited by 4 | Viewed by 2458

Abstract

In rural settings of Côte d’Ivoire, access to water, sanitation, and hygiene (WASH) at schools is often lacking. The purpose of this study was to assess the availability, quality, and use of WASH infrastructure in schools in the south-central part of Côte d’Ivoire, [...] Read more.

In rural settings of Côte d’Ivoire, access to water, sanitation, and hygiene (WASH) at schools is often lacking. The purpose of this study was to assess the availability, quality, and use of WASH infrastructure in schools in the south-central part of Côte d’Ivoire, and to determine the hygiene practices of schoolchildren. A cross-sectional study was conducted in 20 primary schools with (n = 10) or without (n = 10) direct access to drinking water. The survey was comprised of a questionnaire directed at schoolchildren aged 8–17 years, an assessment of the WASH infrastructure, and the testing of drinking water samples for Escherichia coli and total coliforms. Overall, 771 schoolchildren were enrolled in the study. One out of four children (24.9%) reported that they used available toilets. Among those children not using toilets, more than half (57.5%) reported that they practised open defecation. Drinking water infrastructure was limited in most schools because of poor storage tanks, the low flow of water, or broken wells. All drinking water samples (n = 18) tested positive for total coliforms and 15 (83.3%) tested positive for E. coli. The lack of WASH infrastructures in primary schools in the south-central part of Côte d’Ivoire, in combination with poor hygiene practices, might govern disease transmission and absenteeism at school, especially among females. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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13 pages, 1659 KiB

Open AccessArticle

A New Green Model for the Bioremediation and Resource Utilization of Livestock Wastewater

by Linhe Sun, Huijun Zhao, Jixiang Liu, Bei Li, Yajun Chang and Dongrui Yao

Int. J. Environ. Res. Public Health 2021, 18(16), 8634; https://doi.org/10.3390/ijerph18168634 - 16 Aug 2021

Cited by 15 | Viewed by 2501

Abstract

The rapid growth of the livestock and poultry industries has resulted in the production of a large amount of wastewater, and the treatment of this wastewater requires sustainable and environmentally friendly approaches such as phytoremediation. A substrate-free floating wetland planted with water dropwort [...] Read more.

The rapid growth of the livestock and poultry industries has resulted in the production of a large amount of wastewater, and the treatment of this wastewater requires sustainable and environmentally friendly approaches such as phytoremediation. A substrate-free floating wetland planted with water dropwort (Oenanthe javanica), a common vegetable in Southeast China, was constructed to purify a lagoon with anaerobically and aerobically treated swine wastewater in Suqian, China. The average removal rates of total nitrogen, ammonium nitrogen, nitrite nitrogen, and chemical oxygen demand were 79.96%, 95.04%, 86.14%, and 59.91%, respectively, after 40 days of treatment. A total of 98.18 g∙m⁻² nitrogen and 19.84 g∙m⁻² phosphorus were absorbed into plants per harvest through the rapid growth of water dropwort biomass, and the nitrogen accumulation ability was similar to that observed of other plants, such as water hyacinth. In addition, the edible part of water dropwort was shown to comply with the Chinese National Food Sanitation Standards and be safe for human consumption. Its low soluble sugar content also makes it a suitable addition to the daily diet. Overall, substrate-free floating constructed wetlands planted with water dropwort could be more widely used for livestock wastewater purification and could be integrated with plant–livestock production in China because of its high removal efficiency and recycling utilization of water dropwort biomass. Full article

(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)

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