Sewage Sludge Treatment and Reuse

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Wastewater Treatment and Reuse".

Deadline for manuscript submissions: closed (30 September 2020) | Viewed by 38315

Special Issue Editors


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Guest Editor
Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, 10129 Torino, Italy
Interests: water and wastewater treatment; biological processes; water reuse; industrial waste management; life cycle impact assessment
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Guest Editor
Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Torino, Italy
Interests: wastewater treatment, processes and technologies; anaerobic digestion processes; energy optimization in wastewater treatment plants; mathematical modelling of biological processes

Special Issue Information

Dear colleagues,

Traditional processes for the treatment of wastewater generate large volumes of primary and secondary sludge that are collectively termed sewage sludge. To give an idea of the amounts of sludge generated in a wastewater treatment plant treating municipal wastewaters, it can be pointed out that the specific production of only secondary sludge is presently in the order of 22–30 g VS/inhabitant/day.

Since both kinds of sludge contain decomposable organic matter, pathogens, harmful insect eggs, and possibly diverse pollutants (polycyclic aromatic hydrocarbons, dioxins, furans, heavy metals, etc.), innovative and cost-effective treatment is a prerequisite for the safe and environmentally friendly management of sewage sludge. Furthermore, several studies have demonstrated that sludge management costs account for approximately 50%–60% of the total operating costs of a wastewater treatment plant.

This Special Issue focuses on treatments of sewage sludge chiefly intended for reuse, resource recovery, or energy valorization, and encourages contributions that refer to:

  • biorefinery and resource recovery approaches aimed at extracting value-added products (such as, but not limited to, enzymes, bioplastics, biopesticides, proteins) and nutrients (nitrogen, phosphorous) from sewage sludge, even in the framework of a circular economy concept, and control options for metal elements and micropollutants;
  • energy recovery routes, such as anaerobic digestion (including pre- and intermediate treatments), incineration, pyrolysis, gasification, hydrothermal carbonization (HTC) and enhanced digestion using microbial fuel cells, along with their comparative evaluation, to measure their suitability for different sludge compositions and their resource availability.

Original research papers and critical reviews will be considered. All scales of application will be well received.

Prof. Dr. Barbara Ruffino
Dr. Giuseppe Campo
Guest Editors

Manuscript Submission Information

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Keywords

  • primary and waste-activated sludge
  • sludge-to-energy processes
  • anaerobic digestion
  • pre-, intermediate, and post-treatments
  • incineration
  • pyrolysis, gasification, and hydrothermal carbonization
  • agricultural reuse
  • microbial fuel cells
  • nutrient recovery
  • biorefinery

Published Papers (7 papers)

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Research

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10 pages, 10534 KiB  
Article
Application of the Anammox Process for Treatment of Liquid Phase Digestate
by Joanna Majtacz, Dominika Grubba and Krzysztof Czerwionka
Water 2020, 12(11), 2965; https://doi.org/10.3390/w12112965 - 22 Oct 2020
Cited by 3 | Viewed by 1973
Abstract
The liquid phase of the digestate (LPD) contains a relatively high concentration of nitrogen, with total ammonium nitrogen being the dominant form of nitrogen, as well as other essential nutrients such as phosphorus and potassium. Consequently, it must be treated before it is [...] Read more.
The liquid phase of the digestate (LPD) contains a relatively high concentration of nitrogen, with total ammonium nitrogen being the dominant form of nitrogen, as well as other essential nutrients such as phosphorus and potassium. Consequently, it must be treated before it is released into the environment. However, there are no reports of co-purification of LPD in the anammox process in sequencing batch reactor with granular sludge, which is a novelty for the presented research. The main objective of this paper is to assess the possibility of nitrogen removal in the anammox process with LPD from biogas plants conducting the co-fermentation process along with the participation of agricultural products (cattle slurry). This publication presents the research results of the efficiency of the anammox process, accounting for the effect of dissolved organic matter. The conducted experiments revealed the potential of LPD purification, which co-ferments waste activated sludge and bovine slurry for the anammox process. In the reactor ammonium utilization rate (AUR) process with LPD addition increased from 2.3 mg N/(g VSS∙h) with 0.5% LPD addition to 8.5 mg N/(g VSS∙h) with 7.5% LPD addition. SAA in the reactor with LPD addition increased from 5.3 mg N/(g VSS∙h) with 0.5% LPD addition to 18.5 mg N/(g VSS∙h) with 4 and 5% LPD addition. With the addition of 7.5% LPD, SAA dropped to a value of 18.1 mg N/(g VSS∙h) in the LPD reactor. Full article
(This article belongs to the Special Issue Sewage Sludge Treatment and Reuse)
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28 pages, 6112 KiB  
Article
Integrating Life-Cycle Perspectives and Spatial Dimensions of Sewage Sludge Mono-Incineration
by David Wagner, Georg Neugebauer, Florian Kretschmer and Gernot Stoeglehner
Water 2020, 12(5), 1267; https://doi.org/10.3390/w12051267 - 29 Apr 2020
Cited by 1 | Viewed by 3258
Abstract
The mono-incineration of sewage sludge offers new opportunities to develop wastewater infrastructure as regional energy cells and resource recovery sites. At the moment, the most important products of this technology are electric energy and heat from combined heat and power plants, as well [...] Read more.
The mono-incineration of sewage sludge offers new opportunities to develop wastewater infrastructure as regional energy cells and resource recovery sites. At the moment, the most important products of this technology are electric energy and heat from combined heat and power plants, as well as ash for the recovery of phosphorus. With spatial analysis, scenarios of the decentralized and centralized spatial organization of mono-incineration are assessed with regard to the energy balances of the incineration process, transport demands, and the possibility to accommodate excess heat in the surrounding spatial fabric, and these are evaluated by applying a multi-criteria analysis. The study is based on the Austrian case and shows that the utilization, not only of phosphorus and excess energy but also of other potential resources should be aimed for. The transport of sludge and the potential to use excess heat in the surrounding spatial fabric decide if centralized or decentralized scenarios are environmentally more feasible, whereas an “economy of scale” clearly gives leeway to the centralized options. Therefore, this study clearly demonstrates that introducing mono-incineration should not only focus on the process engineering itself but should also consider spatial planning provisions to reduce transport demands and to deliver excess energy to the surrounding spatial fabric. Full article
(This article belongs to the Special Issue Sewage Sludge Treatment and Reuse)
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13 pages, 1118 KiB  
Article
Electrodialytic Hydrogen Production and Critical Raw Materials Recovery from Secondary Resources
by Joana Almeida, Cátia Magro, Eduardo P. Mateus and Alexandra B. Ribeiro
Water 2020, 12(5), 1262; https://doi.org/10.3390/w12051262 - 29 Apr 2020
Cited by 11 | Viewed by 3518
Abstract
Electrodialytic technologies are defined as treatment processes that promote the removal/recovery of substances in a matrix, based on the application of low-level current intensities. Additionally, along these processes hydrogen is self-generated, allowing them to operationally produce clean energy. This energy carrier is produced [...] Read more.
Electrodialytic technologies are defined as treatment processes that promote the removal/recovery of substances in a matrix, based on the application of low-level current intensities. Additionally, along these processes hydrogen is self-generated, allowing them to operationally produce clean energy. This energy carrier is produced due to electrolysis reactions occurring at the cathode end of the electrodialytic reactor, when using inert electrodes. Herein, hydrogen production during the electrodialytic treatment of sewage sludge and mining residues suspensions (coupled with effluent or sewage sludge), at 50 and 100 mA, was assessed. During the electrodialytic treatment of sewage sludge, hydrogen purity production achieved 33%. When effluent or sewage sludge were used as enhancements in mining residues suspensions, hydrogen purity reached 71% and 34%, respectively. Furthermore, a proton-exchange membrane fuel cell was connected to the cathode compartment of the electrodialytic reactor. The electrical energy generated from self-hydrogen produced at 100 mA achieved ≈1 V in all performed experiments. Simultaneously, critical raw materials extraction, namely phosphorus and tungsten, was evaluated. When the process was applied to mining residue suspensions combined with sewage sludge, the highest extraction ratio of phosphorus (71%) and tungsten (62%) was observed. Full article
(This article belongs to the Special Issue Sewage Sludge Treatment and Reuse)
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16 pages, 2133 KiB  
Article
Sewage Sludge Thermal Treatment Technology Selection by Utilizing the Analytical Hierarchy Process
by Dinko Đurđević, Maja Trstenjak and Ivona Hulenić
Water 2020, 12(5), 1255; https://doi.org/10.3390/w12051255 - 28 Apr 2020
Cited by 26 | Viewed by 4935
Abstract
Sewage sludge management has gained significance in the last several years, due to its nutrient and energy content. However, technology selection is one of the greater challenges because it is not possible to implement a technology that covers all the requirements of the [...] Read more.
Sewage sludge management has gained significance in the last several years, due to its nutrient and energy content. However, technology selection is one of the greater challenges because it is not possible to implement a technology that covers all the requirements of the considered environments. Consequently, this paper shows an example of the utilization of an analytical hierarchy process, as a decision-making tool in terms of technology selection, for sewage sludge management in Rijeka, Croatia. The criteria structuring and evaluation process with the description of several possible alternatives for thermal treatment technologies are defined within this research. For the case of Rijeka, the best and most suitable technology for sewage sludge treatment is gasification, which coincides with the results obtained from the analysis of the literature review. According to the results in this paper, the possibilities of the use of this scientific method on the national level for the selection of sewage sludge treatment technology should be considered, due to the simplicity of its use and capability of its adaptation to various situations and areas. Full article
(This article belongs to the Special Issue Sewage Sludge Treatment and Reuse)
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12 pages, 897 KiB  
Article
Polyhydroxyalkanoates (PHAs) Production: A Feasible Economic Option for the Treatment of Sewage Sludge in Municipal Wastewater Treatment Plants?
by Dafne Crutchik, Oscar Franchi, Luis Caminos, David Jeison, Marisol Belmonte, Alba Pedrouso, Angeles Val del Rio, Anuska Mosquera-Corral and José Luis Campos
Water 2020, 12(4), 1118; https://doi.org/10.3390/w12041118 - 14 Apr 2020
Cited by 79 | Viewed by 14689
Abstract
Sludge is a by-product of municipal wastewater treatment plants (WWTPs) and its management contributes significantly to the operating costs. Large WWTPs usually have anaerobic sludge digesters to valorize sludge as methane and to reduce its mass. However, the low methane market price opens [...] Read more.
Sludge is a by-product of municipal wastewater treatment plants (WWTPs) and its management contributes significantly to the operating costs. Large WWTPs usually have anaerobic sludge digesters to valorize sludge as methane and to reduce its mass. However, the low methane market price opens the possibility for generating other high value-added products from the organic matter in sludge, such as polyhydroxyalkanoates (PHAs). In this work, the economic feasibility of retrofitting two types of WWTPs to convert them into biofactories of crude PHAs was studied. Two cases were analyzed: (a) a large WWTP with anaerobic sludge digestion; and (b) a small WWTP where sludge is only dewatered. In a two-stage PHA-production system (biomass enrichment plus PHAs accumulation), the minimum PHAs cost would be 1.26 and 2.26 US$/kg PHA-crude for the large and small WWTPs, respectively. In a single-stage process, where a fraction of the secondary sludge (25%) is directly used to accumulate PHAs, the production costs would decrease by around 15.9% (small WWTPs) and 19.0% (large WWTPs), since capital costs associated with bioreactors decrease. Sensitivity analysis showed that the PHA/COD (Chemical Oxygen Demand) yield is the most crucial parameter affecting the production costs. The energy, methane, and sludge management prices also have an essential effect on the production costs, and their effect depends on the WWTP’s size. Full article
(This article belongs to the Special Issue Sewage Sludge Treatment and Reuse)
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19 pages, 2145 KiB  
Article
Comparative Analysis of Bacterial and Archaeal Community Structure in Microwave Pretreated Thermophilic and Mesophilic Anaerobic Digesters Utilizing Mixed Sludge under Organic Overloading
by Gokce Kor-Bicakci, Emine Ubay-Cokgor and Cigdem Eskicioglu
Water 2020, 12(3), 887; https://doi.org/10.3390/w12030887 - 21 Mar 2020
Cited by 18 | Viewed by 2889
Abstract
The effects of microwave (MW) pretreatment were investigated by six anaerobic digesters operated under thermophilic and mesophilic conditions at high organic loading rates (4.9–5.7 g volatile solids/L/d). The experiments and analyses were mainly designed to reveal the impact of MW pretreatment and digester [...] Read more.
The effects of microwave (MW) pretreatment were investigated by six anaerobic digesters operated under thermophilic and mesophilic conditions at high organic loading rates (4.9–5.7 g volatile solids/L/d). The experiments and analyses were mainly designed to reveal the impact of MW pretreatment and digester temperatures on the process stability and microbial community structure by correlating the composition of microbial populations with volatile fatty acid (VFA) concentrations. A slight shift from biogas production (with a reasonable methane content) to VFA accumulation was observed in the thermophilic digesters, especially in the MW-irradiated reactors. Microbial population structure was assessed using a high-throughput sequencing of 16S rRNA gene on the MiSeq platform. Microbial community structure was slightly affected by different MW pretreatment conditions, while substantially affected by the digester temperature. The phylum Bacteroidetes proliferated in the MW-irradiated mesophilic digesters by resisting high-temperature MW (at 160 °C). Hydrogenotrophic methanogenesis (mostly the genus of Methanothermobacter) was found to be a key route of methane production in the thermophilic digesters, whereas aceticlastic methanogenesis (mostly the genus of Methanosaeta) was the main pathway in the mesophilic digesters. Full article
(This article belongs to the Special Issue Sewage Sludge Treatment and Reuse)
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Review

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16 pages, 1011 KiB  
Review
Land Application of Biosolids in Europe: Possibilities, Con-Straints and Future Perspectives
by Andrea Gianico, Camilla Maria Braguglia, Agata Gallipoli, Daniele Montecchio and Giuseppe Mininni
Water 2021, 13(1), 103; https://doi.org/10.3390/w13010103 - 05 Jan 2021
Cited by 61 | Viewed by 6007
Abstract
The agricultural use of good quality sludge represents a value-added route to ensure growth sustainability in Europe, where raw material availability, for example, for phosphorus, is insufficient to meet demand. However, the possible presence of pathogens, pharmaceuticals and heavy metals requires specific regulations [...] Read more.
The agricultural use of good quality sludge represents a value-added route to ensure growth sustainability in Europe, where raw material availability, for example, for phosphorus, is insufficient to meet demand. However, the possible presence of pathogens, pharmaceuticals and heavy metals requires specific regulations to minimize sludge-related health issues and environmental risks. The current regulation on sludge agricultural use applied by many EU countries is here presented and compared, highlighting scarce harmonization of the legislative framework among Member States. Actual issues, such as the fate of emerging micropollutants and microplastics in sludge-amended soils, and public health concerns regarding sludge spreading during the COVID-19 epidemic, are considered, too. Full article
(This article belongs to the Special Issue Sewage Sludge Treatment and Reuse)
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