Anaerobic digestion and composting are attracting increasing attention due to the increased production of animal manure. It is essential to know about the fate and bioavailability of heavy metals (HMs) for further utilisation of animal manure. This review has systematically summarised the migration of HMs and the transformation of several typical HMs (Cu, Zn, Cd, As, and Pb) during anaerobic digestion and composting. The results showed that organic matter degradation increased the HMs content in biogas residue and compost (with the exception of As in compost). HMs migrated into biogas residue during anaerobic digestion through various mechanisms. Most of HMs in biogas residue and compost exceeded relevant standards. Then, anaerobic digestion increased the bioavailable fractions proportion in Zn and Cd, decreased the F4 proportion, and raised them more than moderate environmental risks. As (III) was the main species in the digester, which extremely increased As toxicity. The increase of F3 proportion in Cu and Pb was due to sulphide formation in biogas residue. Whereas, the high humus content in compost greatly increased the F3 proportion in Cu. The F1 proportion in Zn decreased, but the plant availability of Zn in compost did not reduce significantly. Cd and As mainly converted the bioavailable fractions into stable fractions during composting, but As (V) toxicity needs to be concerned. Moreover, additives are only suitable for animal manure treated with slightly HM contaminated. Therefore, it is necessary to combine more comprehensive methods to improve the manure treatment and make product utilisation safer.
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http://dx.doi.org/10.1016/j.wasman.2022.06.033 | DOI Listing |
Bioresour Technol
December 2024
School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China. Electronic address:
Biodegradable plastics (BPs) and lignite, both rich in organic matter, present significant challenges for efficient conversion into clean energy. This study examined the anaerobic co-digestion of BPs and lignite under controlled laboratory conditions. The results demonstrated that the co-digestion of polylactic acid (PLA) and lignite (at a 1:2 mass ratio, with 5 g PLA and 10 g lignite as the model system) rapidly acclimated to the anaerobic environment, enhancing cumulative biogas production by 57 % compared to the mono-digestion of lignite alone.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
College of Environmental Science and Engineering, Institute of Carbon Neutrality, State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
Anaerobic digestion (AD) reject water serves as a significant reservoir for antibiotic resistance genes (ARGs), underscoring the importance of understanding ARGs dynamics during treatment processes. Partial nitritation /anammox (PN/A) has become an increasingly adopted process, while comprehensive investigation on ARG behavior within this system, especially in full-scale, remains limited. This study explores the distribution of ARGs in a full-scale two-stage PN/A system, with an anaerobic/anoxic/oxic (AAO) system for comparison.
View Article and Find Full Text PDFChemosphere
December 2024
School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea. Electronic address:
Genes in microorganisms influence the biological processes in anaerobic digestion (AD). However, key genes involved in the four metabolic steps (hydrolysis, acidogenesis, acetogenesis, and methanogenesis) remain largely unexplored. This study investigated the abundance and distribution of key functional genes in full-scale anaerobic digesters processing food waste (FWDs) and municipal wastewater (MWDs) through 16S rRNA gene and shotgun metagenomic analysis.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2024
Biochemical Conversion Division, Sardar Swaran Singh National Institute of Bio-Energy, Kapurthala, Punjab, 144 603, India.
The disposal of municipal solid waste (MSW) in urban areas is a big issue nowadays in most of the countries. Developing countries like India are struggling with the continuous indiscriminate disposal of MSW due to rapid increase in the urbanization, industrialization, and human population growth. The mismanagement of MSW causes adverse environmental impacts, public health risks, and other socio-economic problems.
View Article and Find Full Text PDFBioresour Technol
December 2024
Civil Engineering, College of Science and Engineering, University of Galway, Galway H91 TK33, Ireland; Ryan Institute, University of Galway, Ireland; SFI MaREI Research Centre, University of Galway, Ireland. Electronic address:
Butyrate accumulation significantly affects the efficiency and stability of anaerobic digestion, while its specific impact on methane yield and butyrate degradation remains unclear. This study investigated how butyrate concentrations (2.0, 5.
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