Bioenergy production by anaerobic co-digestion of sewage sludge and food waste using temperature-phased anaerobic sequencing batch reactor system

Abstract

The applications of anaerobic biological systems could be a viable option due to low operational costs and energy recovery from organic waste. Systems based on anaerobic biological processes have traditionally been adopted to stabilize both primary and secondary waste sludge. Due to low efficiency of conventional anaerobic digestion resulted from feed characteristics, co-digestion could be one of the most useful strategies. It has been demonstrated that co-digestion of different organic wastes led to distinct enhancement in process performance, however, there are not enough information explaining what the definite factors of enhancements are. The efficiencies of anaerobic co-digestion processes for solid waste treatment were not high due to limitations on reactor performance because biological degradation pathways involved in anaerobic digestion are complex and influenced by various factors. Thus, efforts to improve the performance of anaerobic digester have resulted in several new or modified reactor designs for the high-rate anaerobic biodegradation of solid wastes. The scattered technologies have their own unique target waste or wastewater. If two or more unique technologies are integrated properly, there can be a better access for the solid waste management. Accordingly, this research was performed to improve the low efficiency of anaerobic digestion of sewage sludge by suggesting integrated high-rate anaerobic digestion (IHAD) systems, mesophilic two-stage anaerobic sequencing batch reactor (MTSASBR) system and temperature-phased anaerobic sequencing batch reactor (TPASBR) system, adopting sequencing batch operation, co-digestion and temperature-phased anaerobic digestion (TPAD). First, using biochemical methane potential (BMP) assays on the degradation characteristics of the wastes, an optimized substrate condition was suggested using statistical analyses. To overcome the incorrect estimation of linear regression, the complex remodified Gompertz equa...