Major housing developments, such as proposed housing project at Park Road Ngara in Nairobi, are bound to produce vast amounts of solid organic waste primarily food waste. This waste needs to be managed in an environmentally sustainable and economical manner. This study focuses on biodigestion as a means of managing the organic solid waste.
The study estimated the amount of food waste produced by a housing development containing 1500 units using a sample estate with organized garbage disposal. It then evaluated the biodigestibility of food waste under mesophilic conditions using a laboratory bench scale biodigestion system with mixed food waste as the feedstock.
The food waste generated by the housing development was estimated to be 411,075 kg per year. Two tests were carried out with laboratory bench scale biodigestion system. Test 1 and Test 2 had different food content as the samples for each were collected on different days. Test 1 produced 171 cm3 of biogas and exhibited a loss in mass of 1.47 g. Test 2 produced 549 cm3 and exhibited a loss in mass of 7.31 g.
In conclusion, the biodigestion plant for the housing development should have a minimum capacity of 412 TPA. The mixed food waste was highly biodigestible. Based on the results of the study, further studies were recommended on the following: longer retention times, scalability of laboratory scale digestion test to a larger scale biodigestion system and continuous feed biodigestion systems.