The Effect of Adding Maize Silage as a Co-Substrate for Anaerobic Animal Manure Digestion

Abstract

The objective of this study is to evaluate anaerobic co-digestion of different animal waste with maize silage. Cattle, broiler, sheep, and goat manure were digested with/without maize silage and chopped grass on mesophilic conditions (37°C) in batch anaerobic reactor for a period of 69 days. Anaerobic digestion may reduce the Volatile Solid (VS) ratio of the solids and VS degradation efficiencies of the reactors were approximately 40–45%. Maximum VS reduction occurred in cattle, goat manure, and maize silage combination about 46.86% but maximum specific methane yield was obtained in cattle manure and maize silage mixture (CM) as 215.2 mL CH4/g VSdegraded. The methane yield increased by adding maize silage compared to not adding an addition maize silage supplement. C/N ratio, carbohydrate and chemical oxygen demand (COD) amounts were decreased in all reactors with a related to total biogas and methane production. Maximum carbohydrate and COD degradation rates were obtained in CM about 63.03%, 53.5% respectively. The result of this study showed, using maize silage in anaerobic co-digestion of animal manure increased total biogas and methane formation and improved digestion behavior for waste utilization.