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Classification and Sources of Pollutants
Published in Mary K. Theodore, Louis Theodore, Introduction to Environmental Management, 2021
Mary K. Theodore, Louis Theodore
Sewage sludge is the solid, semisolid, or liquid residue produced from treating municipal wastewater. Some sewage sludges contain high levels of disease-carrying microorganisms, toxic metals, or toxic organic chemicals. Because of the large quantities generated, sewage sludge is a major waste management problem in a number of municipalities [2].
Animal and Municipal Organic Wastes and Water Quality
Published in R. Lal, B. A. Stewart, Soil Processes and Water Quality, 2020
Sewage sludge is the residual solid material from waste water treatment plants consisting of a mixture of sedimented, microbiologically produced and phosphorus-precipitated sludge. Different forms of sewage sludge can be distinguished. Raw or primary sludge, that has not undergone any further treatment, are biologically very active due to the high content of easily decomposable carbon. Activated or anaerobically digested sewage sludges have been stabilized by the removal of readily decomposable carbon. Composted sludges, which are usually anaerobically digested before composting, are the most stabilized materials.
Introduction
Published in Alice B. Outwater, Reuse of Sludge and Minor Wastewater Residuals, 2020
The organic and nutrient contents of sewage sludge are a valuable resource for improving marginal lands and as a supplement to fertilizers and soil conditioners. Sludge use as a fertilizer can both increase crop yields and decrease the farmer’s costs for chemical fertilizers. Studies done across the country have shown that the benefits to farmers that reuse this resource extend beyond avoiding the costs of chemical fertilizers. The increased organic content in sludge-amended soil improves water retention and drainage, lightens heavy soils, and enriches sandy soils. Depending on crop rotation, previous soil management practices, soil type, and the level of sludge application, farmers can enjoy substantial financial benefits from this resource. About two thirds of the sludge that is land applied in this country is used to improve the condition and the nutrient content of the soil for agricultural crops, including row and feed crops and pastures.
Disintegration of sewage sludge using pulsed electrical field technique: PEF optimization, simulation, and anaerobic digestion
Published in Environmental Technology, 2022
Özlem Selçuk Kuşçu, Selçuk Çömlekçi, Nihal Çört
Biological wastewater treatment processes are widely used in both domestic and industrial wastewater treatments around the world. Sewage sludge is generated during the treatment process in the primary and secondary clarifiers. This sludge must be treated and disposed safely because of environmental, economic, social, and legal factors [1]. Anaerobic digestion is the most widely used technique for the treatment of sewage sludge, as it produces biogas and it reduces problems associated with sludge disposal [2]. The anaerobic digestion processes consist of three steps: hydrolysis, acidogenesis, and methanogenesis. Among these three steps, hydrolysis is the rate-limiting stage of the anaerobic digestion [3]. For this reason, a real-world application of anaerobic digesters is limited by the long digestion time (20–30 days) and the low-degradation efficiency of organic matter (20–50%) [4].
Antibiotic resistance in agricultural soils: Source, fate, mechanism and attenuation strategy
Published in Critical Reviews in Environmental Science and Technology, 2022
Jinhua Wang, Lanjun Wang, Lusheng Zhu, Jun Wang, Baoshan Xing
The application of sewage sludge as fertilizer is a common agricultural practice aimed at supplying valuable nutrients and organic matter to soil. Nevertheless, sewage sludge and sewage sludge-amended soils have been reported as hotspots for the appearance and dissemination of antibiotic resistance (Urra, Alkorta, Mijangos, et al., 2019). As the by-product of wastewater treatment plant (WWTPs), huge amounts of sewage sludge are produced, an important reservoir of antibiotic residues, ARB and ARGs (Rizzo et al., 2013; Cesare et al., 2016; McConnell et al., 2018). Although WWTPs are designed to remove carbonaceous materials, nutrients and pathogenic bacteria, they are not specifically designed to remove antibiotics and resistance elements (Barancheshme & Munir, 2017). Antibiotics persist in activated sludge basins at sublethal concentrations, thus leading to the selection of resistant bacteria. ARB and ARGs may subsequently be transferred to the environment through the land application of sewage sludge.
Preparation of non-sintered fly ash filter (NSFF) for ammonia nitrogen adsorption
Published in Environmental Technology, 2019
Qing Shao, Mingming Lu, Jingchun Zhou, Zufu Zhu, Yinqiang Song
In China, proper disposal and utilization of fly ash and sewage sludge is a challenging issue due to their very large quantities [12,13]. Currently, sewage sludge, a by-product of wastewater treatment, is generated at approximately 30 million tonnes every year and will be over 60 million tonnes in 2020 [13]. Sewage sludge contains both useful components, such as organic matter, nitrogen, phosphorus, etc., and also harmful substances such as heavy metals, organic pollutants and pathogens organisms. Fly ash, a by-product from coal-fired power plants, contains more than 70% of Al2O3, SiO2 and Fe2O3. Its high porosity and specific surface area (SSA) can be potentially used as adsorbent. Thus, reuse of these waste materials environmentally friendly and cost effectively has become an urgent need. Recently, making adsorbents or ceramsite particles from fly ash, sewage sludge as filter media for wastewater treatment has become a research hotspot [14–25]. The fly ash adsorbent products suitable for treatment of heavy metals, printing and dyeing, coking, oil content, fluorine, ammonia nitrogen and phosphorous wastewater have been developed [14].