Anaerobic treatment of source-separated domestic bio-wastes with an improved upflow solid reactor at a short HRT.

Anaerobic treatment is the core technology for resource and energy recovery from source-separated domestic bio-wastes. The higher efficiency of an improved upflow solid reactor (IUSR) designed in this study was demonstrated in the treatment of concentrated black water and kitchen waste. The highest methane production of 48L/person/day was achieved at the hydraulic retention time (HRT) of 7days, while the other measures of performance at the HRT of 8.3days were better than at the HRT of 7 or 10days, achieving a methane production of 43L/person/day, removal of total chemical oxygen demand (TCOD) of 89%, removal of soluble chemical oxygen demand (SCOD) of 92%, and conversion of chemical oxygen demand (COD) to methane of 71%. It is not recommended to decrease HRT lower than 7days due to the instability of the initial period. The concentrations of volatile fatty acids (VFAs) in the IUSR were less than 10mg/L, indicating that the anaerobic process was stable. Sludge bed development showed that sludge bed with high microbial activity was formed in the bottom and that the precipitation zone of effluents formed should preferably occupy 30% of the height of the IUSR. The effluents of the IUSR could be used for irrigation in agriculture in combination with a settling tank accompanied by disinfection to remove solids and pathogens.