Methane emission during on-site pre-storage of animal manure prior to anaerobic digestion at biogas plant: Effect of storage temperature and addition of food waste

Abstract

This study investigated the temperature dependency of CH₄ emission from pre-storage of animal manure prior to anaerobic digestion at 15, 20, 25 and 30 °C using lab-scale anaerobic digesters. The manure was added and removed daily to simulate the pre-storage process at biogas plants. CH₄ emission accounted for 1-46% of total CH₄ potential from pig manure (PM) and 1-2% of that from cattle manure (CM) at the investigated temperatures, with significant increases above 25 °C. Addition of food waste (FW) reduced the CH₄ emission when storage temperature was 20 °C or lower for PM and 25 °C or lower for CM due to volatile fatty acid accumulation and lower pH (<5.5) but emissions increased with higher storage temperatures.

Keywords: Anaerobic digestion; Cattle manure; Greenhouse gases; Pig manure; Pre-storage.