ABSTRACT
Energy crisis and increasing rigorous management standards pose significant challenges for solid waste management worldwide. Several emerging diseases such as COVID-19 aggravated the already complex solid waste management crisis, especially sewage sludge and food waste streams, because of the increasingly large production year by year. As mature waste disposal technologies, landfills, incineration, composting, and some other methods are widespread for solid wastes management. This paper reviews recent advances in key sewage sludge disposal technologies. These include incineration, anaerobic digestion, and valuable products oriented-conversion. Food waste disposal technologies comprised of thermal treatment, fermentation, value-added product conversion, and composting have also been described. The hot topic and dominant research foci of each area are summarized, simultaneously compared with conventional technologies in terms of organic matter degradation or conversion performance, energy generation, and renewable resources production. Future perspectives of each technology that include issues not well understood and predicted challenges are discussed with a positive effect on the full-scale implementation of the discussed disposal methods. © 2022 Elsevier Ltd
ABSTRACT
Due to the characteristics of rapid transmission of COVID-19 and extended survival time on the plastic surface, resulting in a sharp increase in the number of microplastics (MPs) in sludge. In this paper, different amounts of terephthalate (PET) were added to four earthworm-assisted sludge treatment wetland (ESTW) reactors to investigate the effect of MPs on the operation process of ESTW. The results show that the addition of a small number of MPs had little effect on the ESTW reactor, and the negative impact was evident when a large number of MPs. The ESTW4 reactor with 200000 particles/kg the worst organic matter removal and sludge stability. The plant height, root length and chlorophyll growth of the ESTW4 reactor were significantly inhibited, and the yield of catalase (CAT) increased significantly, which proved that a large number of MPs had noticeable side effects on plants. The number of MPs (35.21particles/kg) and small size MPs (62.6%) in earthworm casts reached maximum, CAT (38.1U/mg prot) and acetylcholine esterase (AChE) (14.3U/mg prot) have the same trend in ESTW4. A large number of MPs during the ESTW reactor lead to an obvious oxidative stress reactions and lasting neurotoxicity of earthworm. Additionally, the type and quantity of bacteria in the ESTW reactor could reduce when the MPs adding too much. © 2021 Elsevier Ltd
ABSTRACT
The rapid global spread of coronavirus disease 2019 (COVID-19) has promoted concern over human pathogens and their significant threats to public health security. The monitoring and control of human pathogens in public sanitation and health facilities are of great importance. Excessive sludge is an inevitable byproduct of sewage that contains human and animal feces in wastewater treatment plants (WWTPs). It is an important sink of different pollutants and pathogens, and the proper treatment and disposal of sludge are important to minimize potential risks to the environment and public health. However, there is a lack of comprehensive analysis of the diversity, exposure risks, assessment methods and inactivation techniques of pathogenic microorganisms in sludge. Based on this consideration, this review summarizes the control performance of pathogenic microorganisms such as enterovirus, Salmonella spp., and Escherichia coli by different sludge treatment technologies, including composting, anaerobic digestion, aerobic digestion, and microwave irradiation, and the mechanisms of pathogenic microorganism inactivation in sludge treatment processes are discussed. Additionally, this study reviews the diversity, detection methods, and exposure risks of pathogenic microorganisms in sludge. This review advances the quantitative assessment of pathogenic microorganism risks involved in sludge reuse and is practically valuable to optimize the treatment and disposal of sludge for pathogenic microorganism control.