Narrow Results

Owing to the growing concern for alternative sources of energy, the use of brewery spent grains as potential sources of energy (biogas) has been investigated. Brewery derived biowastes (spent grains) were collected from different breweries in southeast Nigeria. These wastes were digested anaerobically in IL laboratory scale digesters over a hydraulic retention time of 14 days (HRT 14) using cow rumen liquor as source of inoculums. An optimization study was carried out by varying some parameters as water dilution and nutrient supplements (wood ash, urea and poultry dropping). The spent grains gave biogas yield of 58-65% methane. Out of the four sets of spent grains used, feed to water ratio of 1:4w/v gave the best biogas yield for three while feed to water ratio of 1:6w/v gave the best yield for one. During nutrient supplementation, highest biogas yield was recorded for wood ash while urea supplements gave the least biogas yield. Increased carbon to nitrogen ratio was found to encourage biogas production. Wood ash increased carbon to nitrogen ratio while urea decreased it. These tests indicated that brewers spent grains can be utilized for biogas production when digested anaerobically and the sludge generated thereafter can provide high quality manure since nitrogen content of the stabilized bio-wastes increased at the end of the digestion as revealed by the proximate analysis.