Measurement of methane production from pig and cattle manure in Lithuania

The current experiment was conducted to quantify methane (CH 4 ) productivity from pig and cattle manure.The manure was collected from twenty commercial farms in different parts of Lithuania.The biogas production and ultimate methane production were measured in a batch experiment according to the international standard.Manure was stored for a period of up to 70 days at constant 35 ± 1°C temperature.Infrared or electrochemical detection was adopted to analyze the methane and carbon dioxide content in biogas.Theoretical methane production was calculated according to the chemical composition of manure.In our study, the theoretical methane production from the total volatile solids (VS) for both pig and cattle manure was in the range of 0.41-0.46m 3 kg -1 CH 4 VS.Theoretical methane production from easily degradable volatile solids was by 26.72% lower than that from total volatile solids.During the storage period, up to 64% of total manure volatile solids and up to 89% of easily degradable volatile solids had decomposed.The ultimate methane production for pig liquid manure was the highest and reached 0.29 m 3 kg -1 CH 4 VS.The methane production for pig solid fraction of manure was 0.12 m 3 kg -1 CH 4 VS, for the liquid fraction of pig manure -0.18 m 3 kg -1 CH 4 VS.The methane production for dairy cattle liquid and solid manure, also non dairy cattle solid manure reached 0.20-0.21m 3 kg -1 CH 4 VS.For dairy cattle slurry the methane production was the lowest -0.05 m 3 kg -1 CH 4 VS, in comparison with other samples.Our study showed that methane production for pig and cattle manure in Lithuania was from 13% to 36% lower than the default values recommended for Europe (IPCC Guidelines…, 2006) and are used for calculations of national methane emission from manure.