Biogas production from the blends of wastewater and macro algae

Abstract

Energy is the fundamental requirements for the economic development of the world. It can be obtained from renewable and non-renewable sources. Energy from non-renewable sources has been exploited to assure and sustain the need for sustainable development. However, non-renewable energy sources have been depleted and forced researchers to search for alternative cost effective and environmental friendly energy sources. Thus, energy production from biomass has obtained considerable attention. The aim of this study was to investigate the enhancement of biogas production through AD from blends of WW and MA. The MA are functioned as a co-substrate. A single factor experimental design with three level of mix in triplicate of each level was used with the response variable; quantity of biogas varies with the variation of mix ratio. Series of laboratory scale batch anaerobic co-digestion of the WW and algae biomass were carried out under mesophilic condition for 21days. Biogas production rates from WW alone, and different blends of WW and MA were analysed. In addition, the nutrient values and reduction in volume of the WW after digestion were determined. The results show that CH4 productions of 39.7%, 51.7% and 57.9% were obtained for WW alone and for WW: MA mix ratios of 3:1 and 3:2, the values of TS, VS and COD also reduced by 43.11%, 40.09% and 71.99% at optimum mix ratio respectively. At optimum mix ratio 1732.77, 77.14 and 174.26 kg/year of Urea, diammonium phosphate and potash fertilizer respectively were obtained. The results indicate that biogas production can be improved through co-digestion of WW and MA as a co-substrate; thus warranting further investigation for practical application in the energy production.