Improving Biogas Yield Using Organic Fraction of Plant and Animal Wastes by Co-Digestion

Abstract

This study presented the effects of co-digestion and catalysts on the performance of biogas production. Poultry dropping and walnut waste were used as feedstock materials while clay, KOH and NaOH were used as catalysts. The experiment was divided into five setups. The retention time was 45days. The digester temperature floated around 20-44°C while the PH varies from 5.7-8.7. Gas composition, physicochemical properties, calorific value as well as elemental composition of the organic waste were analyzed. The result revealed that the gas produced has high methane content ranging from 66.52 – 73.44% with low CO2 concentration ranging from 9.97 -16.92%. The total volume of gas was noted to be 135.2l, 115.2l, 82.2l, 162.4l and 115.7l for each sample. The physicochemical properties revealed that the TS varies from 3.04% – 4.15%, while VS varies from 3.27% – 4.49%. The TOC ranges from 3.13% – 3.84% while the nitrogen content ranges within 0.112% – 0.392%, while Crude fibre ranges from 0.70 – 1.79%. Ash content ranges within 1.16 – 2.67% and moisture content varies between 87.77 – 92.34%. The COD and BOD were also obtained. The calorific values of the samples obtained ranges from 15,882 – 22,036KJ/kg. The phosphorus content was between 0.33% and 0.43% while potassium was between 0.29and 0.42% on average.