Optimization of Energy Recovery from Cellulosic Wastewater Using Mesophilic Single-Stage Bioreactor

Abstract

The efficiency of single-stage biohythane production from synthetic cellulosic wastewater under mesophilic temperature was investigated. A lab-scale continuously stirred tank reactor was conducted at a hydraulic retention time of 10 days using mixed microflora without pretreatment. The experimental results show that a stable methane and hydrogen yields of 18.2 ± 0.16 and 5.6 ± 0.31 L/kg VS were maintained for 240 days, respectively with acetate/butyrate ratio of 0.39 as the main byproducts. Based on COD mass balance, more than 45% of the decomposed COD converted to bio-hythane, which means that the setting temperature 37 °C and pH improved the conditions of degradation efficiency. The energy recovery calculations indicated that the total net energy was 4.54 MJ/m3 of cellulosic wastewater. This work contributes to the limited knowledge on continuous cellulosic-hythane conversion into a safe and clean form of energy.