2.1. Digester feed
A batch sample of rice husk was used throughout the main series of experiments to provide a standard material for digestion. Rice husks were collected from four different rice mills, namely: Ikwo, Onueke, Ezillo and Abakaliki Rice Mills in Ebonyi State, Nigeria. These samples were sun-dried and stored in a stoppered polyethylene container and used as a digester feed when required. The inoculum used for the stabilization of wastes was collected from the cow rumen of slaughtered cows in an abattoir in Abakaliki, Ebonyi State. It was strained in cheesecloth and stored in an air-tight container, in order to keep the microorganisms in an anaerobic environment. Anaerobic condition was maintained during the anaerobic digestion by sealing the mouth of the digesters.