Treatment and Reuse of Sewage Sludge

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 2021) | Viewed by 14943

Special Issue Editor


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Guest Editor
Department of Industrial Engineering (DIN), University of Bologna, Viale Fontanelle, 40-47121 Forli, Italy
Interests: renewable energy; multiphase flow plant; waste treatment; waste recovery and waste-to-energy plants; health and safety at work
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Special Issue Information

Dear Colleagues,

The management of sewage sludge is an issue of great concern. Since the improvement of collecting and treatment systems for wastewater is increasing the annual sludge production, a further increase of the total sludge production is expected in the upcoming years. It is therefore urgent to find a solution to the problem of sewage sludge disposal. Sewage sludge disposal routes should be designed coherently with the waste management hierarchy (i.e., prevention, minimisation, reuse, recycling, energy recovery and, as a final and undesired option, landfilling) and according to the circular economy concept. Nevertheless, normative and legislative framework should be adapted and redesigned to promote sustainable recovery pathways and to overcome the barriers that are now limiting material and energy recovery from sewage sludge.

This Special Issue aims to collect and share innovative solutions developed in the field of sewage sludge treatment and reuse. In particular, the submission of research articles, case studies, and review articles related but not limited to the following topics is encouraged:

  • Life-cycle analysis of sewage sludge treatment and reuse pathways;
  • Future developments and the state of the art in advanced treatment for land-spreading of sewage sludge;
  • Techno-economic and social assessment of sewage sludge-to-energy technologies/processes;
  • Novel and state-of-the-art processing of sewage sludge to separate high-value feedstocks (i.e., rare earth elements, precious elements).
  • Novel and state-of-the-art processing of sewage sludge to produce high-value products (i.e., fertilizer, bio-based feedstocks).
  • Circular economy and sewage sludge;
  • Development and impact of regional, national, international legislation relating to sewage sludge treatment and reuse.
  • Development and impact of national and international technical norms relating to sewage sludge treatment and reuse.

Dr. Marco Pellegrini
Guest Editor

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Keywords

  • Sewage sludge treatment
  • sewage sludge reuse
  • sewage sludge recovery
  • sewage sludge gasification
  • sewage sludge pyrolysis
  • sewage sludge legislation
  • sewage sludge norms

Published Papers (5 papers)

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Research

19 pages, 1774 KiB  
Article
Agricultural Use of Urban Sewage Sludge from the Wastewater Station in the Municipality of Alexandria in Romania
by Eugen Marin and Carmen Otilia Rusănescu
Water 2023, 15(3), 458; https://doi.org/10.3390/w15030458 - 23 Jan 2023
Cited by 6 | Viewed by 5969
Abstract
Considering the increase in the amount of sewage sludge as a result of the development of urbanization, and the pollution of the environment through the storage of this sludge, the objective of this paper is to analyze the effects of the action of [...] Read more.
Considering the increase in the amount of sewage sludge as a result of the development of urbanization, and the pollution of the environment through the storage of this sludge, the objective of this paper is to analyze the effects of the action of different doses of urban sewage sludge as a fertilizer for agricultural soil. Starting from the legislative recommendations regarding the use of urban sewage sludge in agriculture, we analyzed the sludge resulting from the sewage treatment plant in the Municipality of Alexandria, Romania. This sewage treatment plant, with two technological lines of water and sludge treatment, produces urban sewage sludge without pathogenic bacteria. We highlighted that by applying sewage sludge doses of 15 t/ha and 25 t/ha to agricultural soils, on which we planted soybean and wheat crops. We obtained high yields, and the concentration of heavy metals in the roots, stems and grains of soybean and wheat crops did not exceed the maximum standard limits allowed. Having a high content of organic matter and nutrients important for plants such as nitrogen, ammonium, potassium and zinc, sewage sludge has improved the fertility, physical, chemical and biological properties of the soil, and is able to be used as a fertilizer for degraded soils. Full article
(This article belongs to the Special Issue Treatment and Reuse of Sewage Sludge)
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15 pages, 3910 KiB  
Article
Influence of Organic Content on the Mechanical Properties of Organic-Rich Soils Stabilized with CaO-GGBS Binder and PC
by Yuqing Zhong, Guanghua Cai, Shiquan Wang, Huajin Qin, Caihong Zhang and Jiangshan Li
Water 2022, 14(19), 3053; https://doi.org/10.3390/w14193053 - 28 Sep 2022
Cited by 2 | Viewed by 1427
Abstract
Organic-rich soil is a typical special soil often encountered in foundation treatment. Previous research has revealed that Portland cement (PC) not only pollutes the environment but is significantly affected by organic matter during its hydration and cementation. Although quicklime (CaO)-GGBS binder (CG) is [...] Read more.
Organic-rich soil is a typical special soil often encountered in foundation treatment. Previous research has revealed that Portland cement (PC) not only pollutes the environment but is significantly affected by organic matter during its hydration and cementation. Although quicklime (CaO)-GGBS binder (CG) is an effective alternative to PC, its efficiency in treating organic-rich soils has not been studied. In this study, organic-rich soil was treated with two binders of CG and PC. The physical, mechanical, and chemical characteristics of the stabilized soils were tested at various organic contents, binder contents, and curing ages. The results show that the cracks in two treated soils increase with the increase in organic content and the reduction in binder content. CG-treated soils are more likely to shed big lumps after damage than PC-treated soils. The unconfined compressive strength (qu) and deformation modulus (E50) of stabilized soils increase with the increasing curing age and binder content but the decreasing organic content. The E50 of PC-treated soil is about 22~73 times qu, and the E50 of CG-treated soil shows an excellent linear relationship with qu. The moisture content of two treated soils increases as the organic content grows, but it falls as the curing age and binder content increase. The soil pH rises with the increasing organic content and binder content, but it declines with increased curing age. The strength development of organic-rich soils treated by the CG binder has an evident attenuation with the organic content. Given its possible environmental benefit, alkali (especially low calcium)-activated binder is appropriate for practical engineering with modest strength needs. Full article
(This article belongs to the Special Issue Treatment and Reuse of Sewage Sludge)
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11 pages, 7281 KiB  
Article
Influence Mechanism of Fulvic Acid on the Strength of Cement-Solidified Dredged Sludge
by Shiquan Wang, Xingxing He, Shunmei Gong, Guanghua Cai, Lei Lang, Hongrui Ma, Zhiyong Niu and Fangming Zhou
Water 2022, 14(17), 2616; https://doi.org/10.3390/w14172616 - 25 Aug 2022
Cited by 9 | Viewed by 1435
Abstract
Cement solidification was a widely used method to broaden the resource utilization of dredged sludge. However, the organic matter in sludge limit the application of cement solidification. The fulic acid (FA) was used to simulate the natural organic matter in sludge. With the [...] Read more.
Cement solidification was a widely used method to broaden the resource utilization of dredged sludge. However, the organic matter in sludge limit the application of cement solidification. The fulic acid (FA) was used to simulate the natural organic matter in sludge. With the increase in FA content, the sludge gradually changed from low-liquid-limit clay to high-liquid-limit clay. The unconfined compression test showed that the strength of cement-solidified dredged sludge (CDS) decreased with FA content. The influence mechanism of the FA on cement solidification was revealed by a water content test, a hydration heat test, scanning electron microscopy, and thermogravimetric analysis. FA hindered the conversion of pore water to combined water and reduced the hydration heat inside CDS. The FA in sludge weakened the internal bond within CDS by hindering the development of C-S-H gel from spheroidal to flake. At the same time, the final amount of hydrates such as C-S-H, C-A-H and AFt also decreased in the CDS containing FA. The weakening mechanism of FA on the strength of CDS can be attributed to three aspects: (1) FA adsorbed on the surface of cement minerals and hindered the contact between cement minerals and pore water; (2) acidic FA reduced the pH of the pore liquid in CDS; (3) the carboxyl and hydroxyl functional groups of FA adsorbed calcium ions in pore liquid through ion coordination. Full article
(This article belongs to the Special Issue Treatment and Reuse of Sewage Sludge)
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17 pages, 3406 KiB  
Article
E. coli CB390 as an Indicator of Total Coliphages for Microbiological Assessment of Lime and Drying Bed Treated Sludge
by Camilo Venegas, Andrea C. Sánchez-Alfonso, Crispín Celis Zambrano, Mauricio González Mendez and Fidson-Juarismy Vesga
Water 2021, 13(13), 1833; https://doi.org/10.3390/w13131833 - 30 Jun 2021
Cited by 2 | Viewed by 3002
Abstract
The use of a single host strain that allows for an evaluation of the levels of total coliphages in any type of environmental sample would facilitate the detection of and reduction in complexity and costs, favoring countries or areas with technical and economic [...] Read more.
The use of a single host strain that allows for an evaluation of the levels of total coliphages in any type of environmental sample would facilitate the detection of and reduction in complexity and costs, favoring countries or areas with technical and economic limitations. The CB390 strain is a candidate for this type of simultaneous determinations, mainly in water samples. The objective of the study was to establish the recovery capacity of the CB390 strain in solid and semi-solid samples and to evaluate the microbiological quality of the sludge generated and stabilized by lime and drying beds in two WWTPs in Colombia. The results of both matrices indicated that CB390 recovered similar numbers of total coliphages (p > 0.05) against the two host strains when evaluated separately. Only the drying bed treatment was able to reduce between 2.0 and 2.9 Log10 units for some microorganisms, while the addition of lime achieved a maximum reduction of 1.3 Log10 units for E. coli. In conclusion, the CB390 strain can be used in solid and semi-solid samples, and the treatment in a drying bed provided a product of microbiological quality. However, the results are influenced by the infrastructure of the WWTP, the treatment conditions, and the monitoring of the stabilization processes. Full article
(This article belongs to the Special Issue Treatment and Reuse of Sewage Sludge)
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14 pages, 1156 KiB  
Article
Thickening and Storage of Sewage Sludge Contribute to the Degradation of LAS and EOX and the Humification of Organic Matter
by Ali Khakbaz, Daniele Goi, Carlo Bravo and Marco Contin
Water 2021, 13(7), 933; https://doi.org/10.3390/w13070933 - 29 Mar 2021
Cited by 3 | Viewed by 1811
Abstract
Land application of sewage sludge on agricultural soils can be sustainable only if pollutant contents and organic matter quality meet the requirements imposed by minimization of environmental risks. This study investigated the degradation of linear alkylbenzene sulfonates (LAS) and extractable organic halogens (EOX) [...] Read more.
Land application of sewage sludge on agricultural soils can be sustainable only if pollutant contents and organic matter quality meet the requirements imposed by minimization of environmental risks. This study investigated the degradation of linear alkylbenzene sulfonates (LAS) and extractable organic halogens (EOX) and the formation of humic substances (HS) during the thickening and storage phases of sewage sludge treatment. Changes in spectroscopic properties (UV-Vis, FT-IR, and excitation-emission matrix (EEM) fluorescence) of HS were also evaluated to assess the occurrence of biological activities during these curing phases of sewage sludge (SS). Humic acids (HA), fulvic acids (FA), EOX, and LAS were extracted from sewage sludge sampled from four municipal wastewater treatment plants of different size and treatment sequence, before and after 90 days of aerobic or anaerobic storage. During storage, the loss of organic C in the SS ranged from almost null to 31%. No significant changes of FA were registered, whereas HA increased in almost all samples, up to 30%. The amount of humic substances synthesized during storage correlated with the percentage of C lost. Spectroscopic changes of FA and HA showed an increase in their aromaticity, with a corresponding decrease in the aliphatic contribution. These changes show the improved agronomical quality of SS. LAS decreased during storage up to 30%, surprisingly more under anaerobic than aerobic conditions, whereas EOX decreased significantly in all samples, even up to 81%. In conclusion, although storage may be normally considered not influencing the quality of SS, their organic matter quality improved and contamination decreased during 90 days of storage, whatever the conditions of oxygen availability applied. Full article
(This article belongs to the Special Issue Treatment and Reuse of Sewage Sludge)
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