EFFECT OF BIODIGESTER COLOUR AND MANURE TYPE ON BIOGAS PRODUCTION

Abstract

Four plastic biodigesters with blue, yellow, black and white colours were used to carry out anaerobic digestion of three wastes, namely, cow dung, poultry manure and swine manure, in a 3 × 4 factorial experiment laid out in a randomized complete block design with the aim of studying the effect on biogas production. Substrate temperature, pH and biogas yields were monitored during the 63-day study. The results showed that both biodigester colour and manure type had significant (p ≤ 0.05) effect on biogas yield. Biogas yield (dm3 kg-1 VS fed day-1) was highest in oultry manure (57.9) followed by swine manure (27.3) and cow dung (6.85). The bio-digesters had biogas yields in the order: black (34.2)>blue (32.5)>yellow (29.5)>white (26.5). However, the blue biodigester was equally (p > 0.05) as effective as the black biodigester in biogas production. Poultry manure in the black digester had the highest biogas production. In terms of stability of biogas production, the blue digester performed best compared to the other biodigesters based on the least number of non-production days. Considering the biogas yield and stability of production, it was concluded that poultry manure had the highest biogas yield while blue biodigester is suitable for enhancing sustainable biogas production.