Experimental and Kinetics Studies for Biogas Production Using Water Hyacinth (Eichhornia crassipes [Mart.] Solms) and Sugar Mill Effluent

Abstract

The present study investigated the kinetics of biogas production by co-digestion of Eichhornia crassipes supplemented with sugar mill effluent. The influence of digester temperature (30 and 40 °C) on biogas production during the anaerobic digestion of mixed substrates was evaluated. Experimental values obtained in 15 days batch study revealed that the digester incubated at 40 °C produced higher biogas production (6771 mL) than the digester incubated at 30 °C (6325 mL). For digester incubated at 40 °C, value of kinetic constants i.e. µm (biogas production potential), λ (lag phase) and P (cumulative biogas production) were 0.21 day−1, 8.89 days and 6862.60 mL, respectively, while values of µm,λ and P for other digester (incubated at 30 °C) were 0.20 day−1, 9.47 days and 6426.47 mL, respectively. Modified Gompertz plot showed significant coefficient of determination (0.99) for co-digestion process at both temperatures. Digester incubated at 40 °C was found with maximum drop in pH (6.4), chemical oxygen demand (488.89 mg L−1), total solids (21.49%), total kjeldahl nitrogen (0.82%), total organic carbon (14.19%) and volatile solids (16.53%) on 15th day of hydraulic retention time. Analysis of co-substrate by Fourier transform infrared spectroscopy further confirmed the presence of organic compounds responsible for biogas production. These results proved that biogas production can be enhanced in co-digestion process at 40 °C with simultaneous treatment of industrial effluent. The present study will be useful for the integrated management of biomass and industrial waste for energy recovery.