The recalcitrant nature of extracellular polymeric substances (EPS) in sewage sludge severely limits dewatering efficiency. While advanced oxidation processes (AOPs) disrupt EPS matrices, their optimization remains challenging. This study integrates machine learning (ML) with AOPs to establish predictive frameworks for parameter optimization.
View Article and Find Full Text PDFLittle scientific evidence on metal passivation, antibiotic degradation and resistance genes removal, is available under autogenetic electrochemical reactions during composting process. This study established microbial fuel cell (MFC)-assisted composting procedure to ascertain the removal performance and detoxification mechanisms involving metals, antibiotics and their resistance genes. Compared to control treatment, the bioavailability of zinc (Zn) and copper (Cu) in MFC-assisted treatment decreased by 7.
View Article and Find Full Text PDFLimited scientific evidence exists on phosphorus immobilization under autogenetic electrochemical reactions in composting systems. This study exploited a composting procedure using microbial fuel cell (MFC) to ascertain phosphorus redistribution during composting process. Compared to the control without MFC equipment, MFC-assisted treatment yielded a 13 % decrease in phosphorus availability due to the transformation of exchangeable fraction (Ex-P) to aluminum-bound (Al-P) and calcium-bound (Ca-P) fractions.
View Article and Find Full Text PDFBiomass-derived carbonaceous materials with graphene/graphene-like structures (BGS) have attracted tremendous attention in the field of environmental remediation. The introduction of graphene/graphene-like structures into raw biochars can effectively improve their properties, such as electrical conductivity, surface functional groups, and catalytic activity. In 2021, the International Organization for Standardization defined graphene as a "single layer of carbon atoms with each atom bound to three neighbours in a honeycomb structure".
View Article and Find Full Text PDFHuan Jing Ke Xue
July 2020
The anaerobic conversion efficiency of excess sludge in China is significantly lower than that in developed countries. Sludge characteristics are important influencing factors in the anaerobic degradability of sludge. The typical differences between excess sludge in China and in developed countries are mainly reflected in three aspects:long sludge age, high content of micro-sized grits, and high content of metal ions.
View Article and Find Full Text PDFHuan Jing Ke Xue
January 2018
To improve anaerobic digestion biogas yield, the removal of organic-bonding metals by EDTA pretreatment was investigated to strengthen the anaerobic biogas effect. The results showed that after EDTA pretreatment (experimental group), the organic-bonding metals were reduced from (5.09±0.
View Article and Find Full Text PDFDigested sludge, as the main by-product of the sewage sludge anaerobic digestion process, still contains considerable organic compounds. In this protocol, we report a facile method for preparing digested sludge-derived self-doped porous carbon material for high-performance supercapacitor electrodes via a sustainable pyrolysis/activation process. The obtained digested sludge-derived carbon material (HPDSC) exhibits versatile O-, N-doped hierarchical porous framework, high specific surface area (2103.
View Article and Find Full Text PDFHuan Jing Ke Xue
March 2017
Biochemical methane potential experiments were conducted to investigate the effects of organic loading rate on the performance of anaerobic digesters with vinegar residues. According to the comparisons of methane production and liquid phase compositions, as well as thermogravimetry, X-ray Diffraction and infrared spectroscopy analyses, the conclusions could be drawn that:①Lower organic loading rate was better to mitigate the accumulation of VFAs and pH decrease during the hydrolysis and acidification of organic matters, which consequently improved methane production. When the inoculum to substrate ratio was 1:1[organic loading rate of 1.
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February 2017
High free ammonia nitrogen (FAN) is regarded as a main factor that inhibits biogas production in high solid anaerobic digestion systems with dewatered sludge. Two mesophilic semi-continuous anaerobic digesters fed with dewatered sludge (input total solids=15%) were operated and their performance under different FAN concentrations by two regulation methods including pH reduction and total ammonia nitrogen (TAN) promotion were investigated. Results showed that when FAN was elevated from (400±174) mg·L to (526±25) mg·L with the increase of TAN, the daily biogas yield declined from (11.
View Article and Find Full Text PDFFluoroquinolone antibiotics (FQs), as the common pharmaceuticals and personal care products (PPCPs), are widespread in the environment. FQs contained in wastewater would be ultimately enriched in sludge, posing a potential threat to the consequent sludge utilization. To optimize the analytical method applicable to the determination of FQs in sludge, the authors selected ofloxacin (OFL), norfioxacin (NOR), ciprofloxacin (CIP) and lomefloxacin (LOM) as the target FQs, and established a method which was based on cell lysis, FQs extraction with triethylamine/methanol/water solution, Solid Phase Extraction (SPE) and HPLC-Fluorescence Detection (FLD) determination.
View Article and Find Full Text PDFDeveloping efficient, low-cost, and stable carbon-based catalysts for oxygen reduction reaction (ORR) to replace the expensive platinum-based electrocatalysts remains a major challenge that hamper the practical application of fuel cells. Here, we report that N, Fe, and S co-doped nanoporous carbon material, derived via a facile one-step pyrolysis of sewage sludge, the major byproduct of wastewater treatment, can serve as an effective electrocatalyst for ORR. Except for the comparable catalytic activity with commercial 20% Pt/C via a nearly four-electron transfer pathway in both alkaline and acid medium, the as-synthesized co-doped electrocatalyst also exhibits excellent methanol crossover resistance and outstanding long-term operation stability.
View Article and Find Full Text PDFHuan Jing Ke Xue
November 2014
In this research, a new method for sewage sludge (SS) disposal was introduced, by which heavy metals were implanted into sewage sludge before pyrolysis. Cu was adopted as the representative of heavy metals to test this process and was implanted in the form of CuCl2. Effects of Cu implanting concentration and reaction temperature on the residual ratio and immobilization of heavy metals in pyrolysis char were studied.
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February 2013
The effects of mild pretreatment at temperature of 100 degrees C on the solubilization anP anaerobic digestibility of high solid sludge with low organic content were studied with the variation of heating times. Experimental results show soluble organic concentrations in supernatant increase with the prolonging of thermal pretreatment time rapidly, and slowly after 30 min. The dissolution rates of COD, protein and carbohydrate with 30 min of thermal pretreatment at 100 degrees C were 10.
View Article and Find Full Text PDFHuan Jing Ke Xue
January 2013
At solid retention time (SRT) of 20 days, biogas production, volatile solid (VS) degradation and system stability in co-digestion systems of dewatered sludge (DS) and kitchen garbage (KG) were investigated in semi-continuous completely mixed reactors numbered R1-R5 (the DS/KG of their feeding substrate based on wet mass was 1:0, 4:1, 3:2, 2:3 and 0:1, respectively). The results showed that, with larger proportion of KG in feeding substrate, higher methane yield and biogas yield were obtained with lower methane content. For certain reactor at given SRT, KG addition could significantly improve the organic loading rate (OLR) and volume biogas production.
View Article and Find Full Text PDFAbout 20 million tonnes of sludge (with 80% moisture content) is discharged by the sewage treatment plants per year in China, which, if not treated properly, can be a significant source of greenhouse gases (GHGs) emissions. Anaerobic digestion is a conventional sewage sludge treatment method and will continue to be one of the main technologies in the following years. This research has taken into consideration GHGs emissions from typical processes of sludge thickening+anaerobic digestion+dewatering+residue land application in China.
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