A full-scale survey of sludge landfill: sludge properties, leachate characteristics and microbial community structure.

In this study, a full-scale survey was conducted of a sludge landfill that had been sealed for 10 years to investigate sludge properties, leachate characteristics and microbial community structure. Vertical distribution of sludge and leachate pollutants in the landfill site showed that the sludge and soluble pollutants in the leachate were both distributed almost evenly even after long-term anaerobic digestion, and higher concentrations of soluble pollutants and richness of microbial community were observed at the middle layer. Compared to dewatered excess sludge generated from the activated sludge process before landfill, landfill sludge had a much lower organic content (28.

Enhancing methane production of anaerobic sludge digestion by microaeration: Enzyme activity stimulation, semi-continuous reactor validation and microbial community analysis.

Effects of microaeration pretreatment on sludge hydrolysis, biogas production and microbial community structure in anaerobic digestion (AD) were investigated by bench-scale tests and semi-continuous experiments. Bench tests showed that microaeration led to the release of dissolved organic matters, generation of volatile fatty acids and stimulation of enzyme activity. Correlation analysis showed that methane production was significantly correlated with the activity of α-glucosidase at 0.

Sludge reduction and microbial community structure in an anaerobic/anoxic/oxic process coupled with potassium ferrate disintegration.

An anaerobic/anoxic/oxic (AAO) wastewater treatment system combining with a potassium ferrate (KFeO) oxidation side-stream reactor (SSR) was proposed for sludge reduction. Batch experiments showed that optimal KFeO dosage and reaction time for sludge disintegration was 100mg/g suspended solids (SS) and 24h, respectively. Subsequently, an AAO-SSR and a conventional AAO were operated in parallel to investigate effects of KFeO oxidation on process performance, sludge characteristics and microbial community structures.

Optimization for zeolite regeneration and nitrogen removal performance of a hypochlorite-chloride regenerant.

Simultaneous zeolites regeneration and nitrogen removal were investigated by using a mixed solution of NaClO and NaCl (NaClO-NaCl solution), and effects of the regenerant on ammonium removal performance and textural properties of zeolites were analyzed by long-term adsorption and regeneration operations. Mixed NaClO-NaCl solution removed more NH exchanged on zeolites and converted more of them to nitrogen than using NaClO or NaCl solution alone. Response surface methodological analysis indicated that molar ratio of hypochlorite and nitrogen (ClO/N), NaCl concentration and pH value all had significant effects on zeolites regeneration and NH conversion to nitrogen, and the optimum condition was obtained at ClO/N of 1.