Research

19 pages, 2856 KiB

Open AccessFeature PaperArticle

Woven-Fiber Microfiltration (WFMF) and Ultraviolet Light Emitting Diodes (UV LEDs) for Treating Wastewater and Septic Tank Effluent

by Sara E. Beck, Poonyanooch Suwan, Thusitha Rathnayeke, Thi Minh Hong Nguyen, Victor A. Huanambal-Sovero, Boonmee Boonyapalanant, Natalie M. Hull and Thammarat Koottatep

Water 2021, 13(11), 1564; https://doi.org/10.3390/w13111564 - 31 May 2021

Cited by 8 | Viewed by 4206

Abstract

Decentralized wastewater treatment systems enable wastewater to be treated at the source for cleaner discharge into the environment, protecting public health while allowing for reuse for agricultural and other purposes. This study, conducted in Thailand, investigated a decentralized wastewater treatment system incorporating a [...] Read more.

Decentralized wastewater treatment systems enable wastewater to be treated at the source for cleaner discharge into the environment, protecting public health while allowing for reuse for agricultural and other purposes. This study, conducted in Thailand, investigated a decentralized wastewater treatment system incorporating a physical and photochemical process. Domestic wastewater from a university campus and conventional septic tank effluent from a small community were filtered through a woven-fiber microfiltration (WFMF) membrane as pretreatment for ultraviolet (UV) disinfection. In domestic wastewater, WFMF reduced TSS (by 79.8%), turbidity (76.5%), COD (38.5%), and NO₃ (41.4%), meeting Thailand irrigation standards for every parameter except BOD. In septic tank effluent, it did not meet Thailand irrigation standards, but reduced TSS (by 77.9%), COD (37.6%), and TKN (13.5%). Bacteria (total coliform and Escherichia coli) and viruses (MS2 bacteriophage) passing through the membrane were disinfected by flow-through UV reactors containing either a low-pressure mercury lamp or light-emitting diodes (LEDs) emitting an average peak wavelength of 276 nm. Despite challenging and variable water quality conditions (2% < UVT < 88%), disinfection was predictable across water types and flow rates for both UV sources using combined variable modeling, which enabled us to estimate log inactivation of other microorganisms. Following UV disinfection, wastewater quality met the WHO standards for unrestricted irrigation. Full article

(This article belongs to the Special Issue Advanced Technologies and Perspectives in Wastewater Agricultural Reuse)

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12 pages, 644 KiB

Open AccessArticle

Innovative Multistage Constructed Wetland for Municipal Wastewater Treatment and Reuse for Agriculture in Senegal

by Antonina Torrens, David de la Varga, Abdou Khafor Ndiaye, Montserrat Folch and Adrien Coly

Water 2020, 12(11), 3139; https://doi.org/10.3390/w12113139 - 09 Nov 2020

Cited by 12 | Viewed by 3476

Abstract

This paper reports on the performance of using a multistage constructed wetland (CW) to treat municipal raw wastewater and an analysis of its suitability for agricultural irrigation. The pilot plant consists of two stages of vertical flow CWs plus one stage of a [...] Read more.

This paper reports on the performance of using a multistage constructed wetland (CW) to treat municipal raw wastewater and an analysis of its suitability for agricultural irrigation. The pilot plant consists of two stages of vertical flow CWs plus one stage of a horizontal CW built in 2018 with different local materials at the Gaston Berger University Campus, Saint Louis (Senegal). Each CW stage is composed of several filters with different type of media (silex, granite, or river gravel), filtering media depths, and macrophytes (Phragmites and Typha). The physicochemical and microbiological indicators were monitored over six months at each bed inlet and outlet to evaluate the efficiency and achievements of the Senegalese, European, and WHO regulations/recommendations for disposal or reuse in irrigation. This study demonstrates the viability of this new multistage CW design to treat raw municipal wastewater and produce an effluent of good quality suitable for reuse in agriculture. The removal of organic matter, suspended solids, and nutrients was very high (>95% for SS, BOD₅ and N-NH₄⁺, >90% for COD and P-PO₄³⁻), as was the reduction of microbiological indicators (fecal coliform reduction >5 log units and helminth egg removal of 100%). First, trends related to the influence of design (the type of gravel, filter depth, and type of macrophyte), operational modes, and the CW treatment efficiency were determined. The use of non-crushed gravel and Typha spp. seemed to provide better removal rates. On the contrary, no differences were found between the use of silex or granite gravel. For the studied Senegalese conditions under dry and hot climates, the preliminary results indicate that no resting periods are necessary for vertical flow CWs (VFCWs), thus resulting in a reduction in construction and operation costs. The main outcome of our study is evidence that multistage CWs can provide robust, cost-effective treatments, as well as allow for safe water reuse, which is imperative in areas with severe water scarcity and endemic microbiological waterborne diseases. Full article

(This article belongs to the Special Issue Advanced Technologies and Perspectives in Wastewater Agricultural Reuse)

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26 pages, 3045 KiB

Open AccessArticle

Constructed Wetlands as Sustainable Technology for the Treatment and Reuse of the First-Flush Stormwater in Agriculture—A Case Study in Sicily (Italy)

by Teresa Tuttolomondo, Giuseppe Virga, Mario Licata, Claudio Leto and Salvatore La Bella

Water 2020, 12(9), 2542; https://doi.org/10.3390/w12092542 - 11 Sep 2020

Cited by 12 | Viewed by 3383

Abstract

This paper describes a case study that was carried out on a Sicilian company (Italy) dealing with separate waste collection and recycling of glass. The aims of this study were to evaluate the overall efficiency of a vertical subsurface flow system (VSSFs) constructed [...] Read more.

This paper describes a case study that was carried out on a Sicilian company (Italy) dealing with separate waste collection and recycling of glass. The aims of this study were to evaluate the overall efficiency of a vertical subsurface flow system (VSSFs) constructed wetland (CW) operating for the treatment of first-flush stormwater and the effects of treated wastewater on the morphological and aesthetic characteristics of ornamental pepper and rosemary plants. The system had a total surface area of 46.80 m² and was planted with common reed and giant reed. Wastewater samples were taken from October 2018 to July 2019 at the CW inlet and outlet for chemical-physical and microbiological characterization of the wastewater. Two separate experimental fields of rosemary and ornamental pepper were set up in another Sicilian location. Three sources of irrigation water, two accessions of rosemary and two varieties of ornamental pepper were tested in a split-plot design for a two-factor experiment. The results showed very high organic pollutant removal (BOD₅ 75–83%, COD 65–69%) and a good efficiency of nutrients (TN 60–66%) and trace metals (especially for Cu and Zn) removal. Escherichia coli concentration levels were always lower than 100 CFU 100 mL⁻¹ during the test period. Irrigation water and plant habitus had significant effects on all the morphological and aesthetic characteristics of the plants. For both the crops, plants irrigated with freshwater and treated wastewater had greater growth and showed a better general appearance in comparison with plants irrigated with wastewater. The higher trace metal levels in the wastewater produced adverse effects on plant growth and reduced the visual quality of the plants. Our results suggest the suitability of a VSSFs constructed wetland for the treatment of first-flush stormwater and the reuse of treated wastewater for irrigation purposes, in accordance with legislation requirements concerning wastewater quality. Full article

(This article belongs to the Special Issue Advanced Technologies and Perspectives in Wastewater Agricultural Reuse)

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14 pages, 3494 KiB

Open AccessArticle

Treatment of Winery Wastewater with a Multistage Constructed Wetland System for Irrigation Reuse

by Mirco Milani, Simona Consoli, Alessia Marzo, Alessandra Pino, Cinzia Randazzo, Salvatore Barbagallo and Giuseppe Luigi Cirelli

Water 2020, 12(5), 1260; https://doi.org/10.3390/w12051260 - 29 Apr 2020

Cited by 28 | Viewed by 5475

Abstract

This paper reports a study on the performance of a multistage constructed wetland (CW) system adopted for winery wastewater and on the analysis of its suitability for irrigation reuse. The CW system treats about 3 m³·day⁻¹ of wastewater produced by [...] Read more.

This paper reports a study on the performance of a multistage constructed wetland (CW) system adopted for winery wastewater and on the analysis of its suitability for irrigation reuse. The CW system treats about 3 m³·day⁻¹ of wastewater produced by a small winery located in Sicily (insular Italy). Wastewater samples were collected at the CW inlet and outlet for physical–chemical and microbiological quality characterization. CW efficiency was evaluated on the basis of water quality improvement and of the achievement of Italian and EU irrigation reuse regulation limits. The CW system showed Chemical Oxygen Demand (COD) and Total Suspended Solids (TSS) mean removal rates of about 81% and 69%, and a maximum removal of about 99% (for both COD and TSS) occurred during grape harvest phase. The CW removal efficiencies for nutrients were 56% for TN and 38% for PO₄-P, considering their low average concentrations at CW inlet. The CW system evidenced an effluent average quality compatible with the limits imposed by the Italian regulation and EU proposal regulation on the minimum requirement for water reuse. The CW vegetated area showed regular growth and vegetative development; phytotoxicity phenomena were not detected. The results of the study suggest the important role of CW systems in the treatment of winery wastewater and for their subsequent reuse in agriculture. Full article

(This article belongs to the Special Issue Advanced Technologies and Perspectives in Wastewater Agricultural Reuse)

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13 pages, 3488 KiB

Open AccessArticle

Effect of Primary Variables on A Confined Plunging Liquid Jet Reactor

by Bader S. Al-Anzi

Water 2020, 12(3), 764; https://doi.org/10.3390/w12030764 - 10 Mar 2020

Cited by 9 | Viewed by 3091

Abstract

The effects of operating conditions including a novel downcomer geometry on the gas/air entrainment rate, Q_a, were investigated for a local vertical confined plunging liquid jet reactor (CPLJR) as an alternative aeration process that is of interest to Kuwait and can [...] Read more.

The effects of operating conditions including a novel downcomer geometry on the gas/air entrainment rate, Q_a, were investigated for a local vertical confined plunging liquid jet reactor (CPLJR) as an alternative aeration process that is of interest to Kuwait and can be used in various applications, such as in wastewater treatment as an aerobic activated sludge process, fermentation, brine dispenser, and gas–liquid reactions. Operating conditions, such as various downcomer diameters (D_c = 45−145 mm), jet lengths (L_j = 200–500 mm), nozzle diameters (d_n = 3.5–15 mm), and contraction angles (Ɵ =20–80°), were investigated. A newly designed downcomer with various mesh openings/pores (D_m = 0.25ʺ (6.35 mm)–1ʺ (25.4 mm)) was also investigated in the current study. The air entrainment results showed that these were the primary parameters for the measured air entrainment rate in confined systems. The highest gas entrainment rates were achieved when the ratio of the downcomer diameter (D_c) to the nozzle diameter (d_n) was greater than approximately 5, as long as the liquid superficial velocity was sufficient to carry bubbles downward. Furthermore, a downcomer with mesh openings (D_m) less or equal to 0.5ʺ (12.7 mm) provided a higher entrainment rate than that of conventional downcomer (without a mesh). Full article

(This article belongs to the Special Issue Advanced Technologies and Perspectives in Wastewater Agricultural Reuse)

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21 pages, 4876 KiB

Open AccessArticle

Evapotranspiration from Horizontal Subsurface Flow Constructed Wetlands Planted with Different Perennial Plant Species

by Mirco Milani, Alessia Marzo, Attilio Toscano, Simona Consoli, Giuseppe Luigi Cirelli, Delia Ventura and Salvatore Barbagallo

Water 2019, 11(10), 2159; https://doi.org/10.3390/w11102159 - 17 Oct 2019

Cited by 29 | Viewed by 3671

Abstract

This paper presents the results of an experiment carried out in Southern Italy (Sicily) on the estimation evapotranspiration (ET) in pilot constructed wetlands planted with different species (Chrysopogon zizanioides, Myscanthus x giganteus, Arundo donax, Phragmites australis, and Cyperus papyrus [...] Read more.

This paper presents the results of an experiment carried out in Southern Italy (Sicily) on the estimation evapotranspiration (ET) in pilot constructed wetlands planted with different species (Chrysopogon zizanioides, Myscanthus x giganteus, Arundo donax, Phragmites australis, and Cyperus papyrus). In the two monitored growing seasons, reference ET₀ was calculated with the Penman-Monteith formula, while actual ET and crop coefficients were measured through a water balance and the FAO 56 approach, respectively. The highest average seasonal ET value was observed in Phragmites australis (17.31 mm d⁻¹) followed by Arundo donax (11.23 mm day⁻¹) Chrysopogon zizanioides (8.56 mm day⁻¹), Cyperus papyrus (7.86 mm day⁻¹), and Myscanthus x giganteus (7.35 mm day⁻¹). For all plants, crop coefficient values showed different patterns in relation to growth stages and were strongly correlated with phenological parameters. Myscanthus x giganteus and Arundo donax showed a water use efficiency values significantly higher than those observed for the other tested species. Results of this study may contribute to select appropriate plant species for constructed wetlands located in semi-arid regions, especially when the use of reclaimed water and/or the use of aboveground biomass are planned. Full article

(This article belongs to the Special Issue Advanced Technologies and Perspectives in Wastewater Agricultural Reuse)

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13 pages, 1298 KiB

Open AccessArticle

Assessing Reclaimed Urban Wastewater for Reuse in Agriculture: Technical and Economic Concerns for Mediterranean Regions

by Giacomo Giannoccaro, Stefania Arborea, Bernardo C. de Gennaro, Vito Iacobellis and A. Ferruccio Piccinni

Water 2019, 11(7), 1511; https://doi.org/10.3390/w11071511 - 21 Jul 2019

Cited by 24 | Viewed by 3699

Abstract

Direct reuse of treated wastewater can offer a realistic supply alternative for irrigation in Mediterranean areas. In this study, we conducted a spatial cost-benefit analysis to quantify and locate the volume of technically and economically feasible and readily available reclaimed urban wastewater. We [...] Read more.

Direct reuse of treated wastewater can offer a realistic supply alternative for irrigation in Mediterranean areas. In this study, we conducted a spatial cost-benefit analysis to quantify and locate the volume of technically and economically feasible and readily available reclaimed urban wastewater. We considered the case of Puglia (Italy) and the results are discussed in terms of the implications for policy-making and pointing out future research needs. The results showed that the main technical barrier is the shortness of the irrigation season. On the other hand, the main economic concern is related to filtration followed by lack of conveyance systems. While our results are based on estimates, future research should try to include practical experiments based on actual data. Further research should also address the issue of transaction costs by establishing the obligations of wastewater treatment plants to deliver reclaimed water to farmers. Full article

(This article belongs to the Special Issue Advanced Technologies and Perspectives in Wastewater Agricultural Reuse)

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14 pages, 876 KiB

Open AccessArticle

Monitoring Opportunistic Pathogens in Domestic Wastewater from a Pilot-Scale Anaerobic Biofilm Reactor to Reuse in Agricultural Irrigation

by Bingjian Cui and Shengxian Liang

Water 2019, 11(6), 1283; https://doi.org/10.3390/w11061283 - 20 Jun 2019

Cited by 20 | Viewed by 4016

Abstract

Wastewater reuse for agricultural irrigation in many developing countries is an increasingly common practice. Regular monitoring of indicators can help to identify potential health risks; therefore, there is an urgent need to understand the presence and abundance of opportunistic pathogens in wastewater, as [...] Read more.

Wastewater reuse for agricultural irrigation in many developing countries is an increasingly common practice. Regular monitoring of indicators can help to identify potential health risks; therefore, there is an urgent need to understand the presence and abundance of opportunistic pathogens in wastewater, as well as plant phyllosphere and rhizosphere. In this study, an anaerobic biofilm reactor (ABR) was developed to treat rural domestic wastewater; the performance of pollutants removal and pathogenic bacteria elimination were investigated. Additionally, we also assessed the physicochemical and microbiological profiles of soil and lettuces after wastewater irrigation. Aeromonas hydrophila, Arcobacter sp., Bacillus cereus, Bacteroides sp., Escherichia coli, Legionella sp., and Mycobacterium sp. were monitored in the irrigation water, as well as in the phyllosphere and rhizosphere of lettuces. Pathogens like B. cereus, Legionella sp. and Mycobacterium sp. were present in treated effluent with relatively high concentrations, and the levels of A. hydrophila, Arcobacter sp., and E. coli were higher in the phyllosphere. The physicochemical properties of soil and lettuce did not vary significantly. These data indicated that treated wastewater irrigation across a short time period may not alter the soil and crop properties, while the pathogens present in the wastewater may transfer to soil and plant, posing risks to human health. Full article

(This article belongs to the Special Issue Advanced Technologies and Perspectives in Wastewater Agricultural Reuse)

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