Assessment of the Effect of Mixing Pig and Cow Dung on Biogas Yield

Abstract

Household energy is increasingly becoming a scarce resource in developing countries. In these countries, cooking accounts for about 90% of all household energy consumption. Motivated by the need to meet the ever-increasing energy demand and sustainability consciousness, many Governments have promoted renewable energy technologies such as biogas. However, biogas technology in Uganda is constrained by insufficient gas production due to lack of enough feedstock. This paper presents the findings of a research that was carried out to determine the effect of mixing pig and cow dung on biogas yield. Fifteen plastic bottles of capacity one and half litres were used as digesters and each fed with 1kg of pig and cow dung mixture in proportions of 0%, 25%, 50%, 75% and 100% with three replications.

Results from this study show that co-digestion of cow dung with pig manure increased biogas yield as compared to pure samples of either pig or cow dung. Comparing to samples of pure cow dung and pig manure, the maximum increase of almost seven and three fold was respectively achieved when mixed in proportions of 1:1. Ultimately, co-digestion of pig and cow dung is one way of addressing the problem of insufficient gas production in this country.

Key words:  Biogas, cow dung, pig manure, co-digestion, compact system, Uganda