Anaerobic digestion dung dilution experiment

This experiment was conducted to investigate whether the current practice of 1:1 dilution of dung to water is necessary for anaerobic digestion (AD) systems in rural areas of sub-Saharan Africa. We used 4 different concentrations of cow dung with 3 replicates and ran a semi-continuous system over 75 days with a reactor retention time of 25 days. We found the greatest COD and removal efficiency was achieved with undiluted, indicating that AD could potentially be implemented more widely than is currently practiced, as shortage of water is a key barrier to the creation of biogas energy systems in much of sub-Saharan Africa. We measured the regularly measured the chemical oxygen demand (COD), total solids (TS) and volatile solids (VS) content of the digestate and present the mean values with standard deviation here.