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13 pages, 804 KiB

Open AccessArticle

Reagent Deodorization and Detoxification of Sewage Sludge with the Production of Reclamation Material

by Anna Tsybina, Christoph Wünsch and Irina Glushankova

Energies 2024, 17(5), 987; https://doi.org/10.3390/en17050987 - 20 Feb 2024

Viewed by 546

This article is devoted to the search for effective ways of neutralizing sewage sludge to obtain sludge-based reclamation material. It was necessary to solve the problems of deodorizing the sludge and fixing the mobile forms of heavy metals in its composition. The composition, [...] Read more.

This article is devoted to the search for effective ways of neutralizing sewage sludge to obtain sludge-based reclamation material. It was necessary to solve the problems of deodorizing the sludge and fixing the mobile forms of heavy metals in its composition. The composition, effective for solving the assigned problems, was experimentally determined; it included quicklime, sodium hypochlorite and peat. In the presence of sodium hypochlorite in the sludge-based composition, oxidation processes occur with the chemical transformation of ammonia and hydrogen sulfide into non-toxic and odorless compounds. Lime combined with peat promotes the humification of sewage sludge and the binding of heavy metals. Based on the composition that showed the best results, a technology has been developed for the chemical treatment of sewage sludge in situ to produce reclamation material. Full article

(This article belongs to the Special Issue Sewage Sludge Management within Circular Economy and Bioeconomy: Policies, Economy and State-of-the-Art Technologies)

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11 pages, 2725 KiB

Open AccessArticle

Production of Alternative Fuels Based on Sewage Sludge

by Krzysztof Rećko

Energies 2024, 17(1), 48; https://doi.org/10.3390/en17010048 - 21 Dec 2023

Cited by 1 | Viewed by 890

Abstract

Due to the growing demand for energy, conventional fossil fuels are being depleted. Reducing dependence on energy sources based on fossil fuels is possible by using the energy potential of biomass. Sewage sludge deserves special attention. The increase in the amount of sewage [...] Read more.

Due to the growing demand for energy, conventional fossil fuels are being depleted. Reducing dependence on energy sources based on fossil fuels is possible by using the energy potential of biomass. Sewage sludge deserves special attention. The increase in the amount of sewage sludge produced around the world poses a serious problem with its management. The use of sewage sludge to produce fuel with the possibility of energy recovery seems to be an excellent solution. The article presents the results of laboratory tests on the production of fuel in the form of granulates from mixed sewage sludge, rubber waste, and wood waste in the form of sawdust. Fuel mixtures were tested, and fuel parameters were determined. The calorific value of the tested fuel ranged from 13.92 MJ/kg to 22.15 MJ/kg, and the moisture content from 41.57% to 18.36%, depending on the percentage composition of the mixtures used to produce the granules. The ash content ranged from 14.82% to 17.40%. The composition of granulated fuel mixtures has been designed to avoid additional drying or pre-drying of sewage sludge. In this way, fuel was obtained without additional energy consumption associated with drying sewage sludge. Moreover, it should be stated that the share of sewage sludge in granulated fuel should not exceed 25%. Nowadays, such fuel can be an alternative to fossil fuels used in the cement or energy industry. Full article

(This article belongs to the Special Issue Sewage Sludge Management within Circular Economy and Bioeconomy: Policies, Economy and State-of-the-Art Technologies)

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16 pages, 13083 KiB

Open AccessArticle

Development and Substantiation of Approaches to the Management of Sewage Sludge of Different Storage Periods

by Anna Tsybina, Christoph Wünsch, Irina Glushankova and Anna Arduanova

Energies 2023, 16(15), 5698; https://doi.org/10.3390/en16155698 - 30 Jul 2023

Cited by 1 | Viewed by 810

Abstract

A widespread method of sewage sludge disposal is still simple storage in sludge lagoons. Subsequent thermal utilization is hardly possible because sludge properties change over time and energy content is reduced. Use as a soil conditioner in agriculture or landscaping is usually not [...] Read more.

A widespread method of sewage sludge disposal is still simple storage in sludge lagoons. Subsequent thermal utilization is hardly possible because sludge properties change over time and energy content is reduced. Use as a soil conditioner in agriculture or landscaping is usually not possible due to high heavy metal contents. This paper describes a method in which a 10-year-old accumulated sewage sludge can be utilized as technical soil by mixing it with pyrolized fresh sewage sludge. For this purpose, physicochemical and toxicological characteristics of sewage sludge of different storage periods were identified, processes of thermal destruction of sewage sludge analyzed, toxicological characteristics of solid products of thermal sludge treatment determined, and the possibility of using the sewage sludge–pyrolysate mixture as technical soil was assessed. Results show that the gross calorific value of fresh and one-year stored sewage sludge is with approx. 15,000 kJ/kg dry basis sufficient to produce pyrolysate autothermally. It is also shown that when the pyrolysis residue is mixed with fresh or 1-year old sewage sludge, heavy metals can be immobilized and thus the leaching of heavy metals significantly reduced by up to 75%. The method described can thus be a possible option for recycling accumulated sewage sludge. Full article

(This article belongs to the Special Issue Sewage Sludge Management within Circular Economy and Bioeconomy: Policies, Economy and State-of-the-Art Technologies)

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24 pages, 6176 KiB

Open AccessArticle

Utilizing Sewage Sludge Slag, a By-Product of the Circulating Fluidized Bed Combustion Process, to Efficiently Remove Copper from Aquatic Environment

by Tomasz Kalak and Yu Tachibana

Energies 2023, 16(15), 5688; https://doi.org/10.3390/en16155688 - 29 Jul 2023

Viewed by 1277

Abstract

Currently, one of the greatest threats to the aquatic environment is industrial wastewater containing heavy metals and other toxic substances. Hence, it seems necessary to search for ecological and cheap technologies for removing metals from wastewater. In this research, slag was used as [...] Read more.

Currently, one of the greatest threats to the aquatic environment is industrial wastewater containing heavy metals and other toxic substances. Hence, it seems necessary to search for ecological and cheap technologies for removing metals from wastewater. In this research, slag was used as waste obtained in the circulating fluidized bed combustion technology (CFBC), which is considered to be a modern, clean, and very effective method of incineration of municipal sewage sludge. The physicochemical properties of the waste material were characterized using selected analytical techniques. Next, the processes of adsorption of Cu(II) ions on slag in aqueous solutions were investigated. The results showed a high metal removal efficiency of 98.8% at pH 1.8 and slag dosage 5 g/L. Numerous studies have demonstrated that high process efficiency at a level of at least 90% is attainable. Based on the Langmuir equation, the maximum adsorption capacity was calculated to be 70.3 mg/g. Kinetic analysis revealed that the process fits better into the pseudo-second-order reaction model and the Freundlich isotherm. The intraparticle diffusion model was considered as a rate-controlling step for Cu(II) adsorption. In summary, the slag waste produced in the CFBC technology seems to be a highly effective adsorbent for potential use in adsorption processes to remove heavy metals from the aquatic environment. This solution is in line with the current European ‘zero waste’ strategy and the assumptions of a sustainable development economy. Full article

(This article belongs to the Special Issue Sewage Sludge Management within Circular Economy and Bioeconomy: Policies, Economy and State-of-the-Art Technologies)

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16 pages, 780 KiB

Open AccessArticle

Market Opportunities in Portugal for the Water-and-Waste Sector Using Sludge Gasification

by Octávio Alves, Bruno Garcia, Bruna Rijo, Gonçalo Lourinho and Catarina Nobre

Energies 2022, 15(18), 6600; https://doi.org/10.3390/en15186600 - 9 Sep 2022

Cited by 6 | Viewed by 1594

Abstract

The water-and-waste sector has shown a marked interest in innovative management practices for dewatered sludge. The need to manage increased sludge volumes at rising disposal costs, coupled with the recognition of the potential for on-site energy production, have been the key drivers for [...] Read more.

The water-and-waste sector has shown a marked interest in innovative management practices for dewatered sludge. The need to manage increased sludge volumes at rising disposal costs, coupled with the recognition of the potential for on-site energy production, have been the key drivers for this recent appeal. With the current political view supporting the development of a renewable-gas industry in Portugal, renewable gases are considered an attractive solution for dewatered-sludge valorization. Moreover, investment in renewable-gas supply chains would help the industry to mature to a level at which the technology and market are rapidly established. Recognizing this interest, dewatered-sludge gasification was selected as a possible valorization pathway, with the potential for hydrogen and bio-SNG production, as well as decentralized heat and power. This document identifies the market opportunities for the establishment of sewage-sludge gasification in Portugal. The analysis starts with a brief overview of the Portuguese water-and-waste sector, and a description of the current status of the renewable-gas markets. Finally, the dewatered-sludge amounts are quantified, and the potential for energy and renewable-gas production is estimated to support the interest in wastewater management in advanced processes, and to pave the way for future feasibility studies. Full article

(This article belongs to the Special Issue Sewage Sludge Management within Circular Economy and Bioeconomy: Policies, Economy and State-of-the-Art Technologies)

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15 pages, 1209 KiB

Open AccessArticle

Socio-Economic, Technical and Environmental Indicators for Sustainable Sewage Sludge Management and LEAP Analysis of Emissions Reduction

by Dinko Đurđević, Saša Žiković and Tomislav Čop

Energies 2022, 15(16), 6050; https://doi.org/10.3390/en15166050 - 20 Aug 2022

Cited by 2 | Viewed by 1598

Abstract

The waste management sector is transitioning from a dirty and undesirable industry towards a green and sustainable future where energy and materials are recycled. Recycling has potential in sewage sludge treatment, where energy and highly valuable nutrients can be recovered through innovative and [...] Read more.

The waste management sector is transitioning from a dirty and undesirable industry towards a green and sustainable future where energy and materials are recycled. Recycling has potential in sewage sludge treatment, where energy and highly valuable nutrients can be recovered through innovative and sustainable sludge management. Although there are many technologies and techniques already used for sewage sludge, the indicators for their sustainability are not developed. In terms of sustainable and innovative sewage sludge treatment, usually, only techno-economic aspects of existing and current technologies are considered. We explore the existing indicators and propose new indicators for sustainable and innovative sewage sludge treatment technologies. The indicators are differentiated into four main categories: technical, social, environmental and economic, where specific indicators are explained, followed by a description of their impact on sustainability. We also consider a case study using the LEAP tool, which considered GHG emissions when utilizing sewage sludge as an energy feedstock to replace existing fossil fuels in the energy mix in several scenarios. The results showed a significant emissions reduction when sludge is used—37.6% and 90.9% in 2030 and 2050, respectively. Full article

(This article belongs to the Special Issue Sewage Sludge Management within Circular Economy and Bioeconomy: Policies, Economy and State-of-the-Art Technologies)

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18 pages, 4879 KiB

Open AccessArticle

Investigation of Pyrolysis Behavior of Sewage Sludge by Thermogravimetric Analysis Coupled with Fourier Transform Infrared Spectrometry Using Different Heating Rates

by Norbert Miskolczi and Szabina Tomasek

Energies 2022, 15(14), 5116; https://doi.org/10.3390/en15145116 - 13 Jul 2022

Cited by 6 | Viewed by 1394

Abstract

In this study, pyrolysis of municipal sewage sludge samples from different sources including cattle and chicken manure as well as brook mud, was investigated using a thermogravimetric analysis coupled with a Fourier transform infrared spectrometer (TG-FTIR) at different heating rates (25, 50 and [...] Read more.

In this study, pyrolysis of municipal sewage sludge samples from different sources including cattle and chicken manure as well as brook mud, was investigated using a thermogravimetric analysis coupled with a Fourier transform infrared spectrometer (TG-FTIR) at different heating rates (25, 50 and 100 °C/min). In order to determine the kinetic parameters, Arrhenius, model-free Kissinger–Akira–Sunose (KAS), as well as Friedman and Flynn–Wall–Ozawa (FWO) methods were compared. The thermogravimetric results revealed that pyrolysis involved different stages, and that the main decomposition reactions took place in the range of 200–600 °C. In this range, decomposition of biodegradable components (e.g., lipids and polysaccharides), proteins and carbohydrates occurred; meanwhile, there were samples (e.g., cattle manure, brook mud) in which the decomposition step could be observed even at temperatures above 700 °C. According to the Arrhenius method, the activation energies of the first decomposition stage were between 25.6 and 85.4 kJ/mol, while the activation energies of the second and third stages were in the ranges of 11.4–36.3 kJ/mol and 20.2–135 kJ/mol, respectively. The activation energies were also calculated by the KAS, Friedman and FWO methods, which were in the range of 100–300 kJ/mol for municipal sewage sludge or distillery sludge, and ranged between 9.6 and 240 kJ/mol for cattle manure, chicken manure and brook mud samples. Full article

(This article belongs to the Special Issue Sewage Sludge Management within Circular Economy and Bioeconomy: Policies, Economy and State-of-the-Art Technologies)

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23 pages, 2469 KiB

Open AccessArticle

Sustainable Sewage Sludge Management Technologies Selection Based on Techno-Economic-Environmental Criteria: Case Study of Croatia

by Dinko Đurđević, Saša Žiković and Paolo Blecich

Energies 2022, 15(11), 3941; https://doi.org/10.3390/en15113941 - 26 May 2022

Cited by 11 | Viewed by 3745

Abstract

The management and disposal of sewage sludge is becoming a growing concern at the global level. In the past, the main goal was to completely eliminate sewage sludge since it was deemed a threat to humans and the environment, but recently different possibilities [...] Read more.

The management and disposal of sewage sludge is becoming a growing concern at the global level. In the past, the main goal was to completely eliminate sewage sludge since it was deemed a threat to humans and the environment, but recently different possibilities for energy generation and material recovery are emerging. Existing technologies such as incineration or direct application in agriculture contribute to quantity reduction and nutrient recovery but are unable to fully exploit the potential of sewage sludge within the frameworks of circular economy and bioeconomy. This paper developed a model within the PROMETHEE method, which analyses technologies for the sustainable management of sewage sludge, which could make the most from it. For the empirical part of the study, the Republic of Croatia was used as a country in which sewage sludge is increasing in quantity as a result of recent upgrades and expansions in the wastewater system. Incineration, gasification, anaerobic digestion, and nutrient recovery were analyzed as treatment concepts for the increased amounts of sewage sludge. The model reveals that the best solution is the material recovery of sewage sludge, using the struvite production pathway through analysis of selected criteria. Full article

(This article belongs to the Special Issue Sewage Sludge Management within Circular Economy and Bioeconomy: Policies, Economy and State-of-the-Art Technologies)

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