Anaerobic Co-digestion of Cow Dung and Rice Straw to Produce Biogas using Semi-Continuous Flow Digester: Effect of Urea Addition

Authors:
Open Access
Publisher website
Google Scholar
Abstract
The objective this research was to investigate the effect of urea addition on the biogas yield from co-digestion of rice straw and cow dung using semi-continuous anaerobic digester. The experiment was conducted by using self-made semi-continuous anaerobic digester having a working volume of 30 L. Cow dung was provided from Department of Animal Husbandry, University of Lampung; while rice straw was collected from farmer at Way Galih, Tanjung Bintang, South Lampung. Rice straw was sun-dried to about 12% of moisture content and then ground into fine particles. Cow dung and ground straw were mixed at a dung-to-straw ratio of 3:1 based on total solid (TS) and four different urea additions (0, 0.25, 0.65, and 1.30 g/L) were applied to have a C/N ratio between 20 and 30. The mixture was diluted with water to create TS content of 10%. As much as 30 L of the substrate mixture was introduced into the digester as a starting load. The same substrate was added daily at a loading rate of 0.5 L/d. The experiment was made in triplicate and observation was performed for two months. Total and volatile solids of influent and effluent and daily biogas production were observed. The biogas quality was measured by its methane content using gas chromatography. Results showed that urea addition influenced the biogas yield and its quality. Substrate mixture with urea addition of 0.25 g/L (C/N ratio of 27.3) was the best in terms of biogas yield (434.2 L/kgVSr), methane content (50.12%), and methane yield (217.6 L/kgVSr).

This publication has 16 references indexed in Scilit: