Effects on the biogas and methane production of cattle manure treated with urease inhibitor

•The effects of urease inhibitor K on methane and biogas production were performed.•The inhibitor K was tested with two different substrates (manure and cellulose).•Average biogas + methane production in cellulose was 740 and 403 LN/kgODM.•Average biogas + methane production in treated manure was 471 and 295 LN/kgODM.•The inhibitor K had no significant effect on the biogas and methane production.

Urease inhibitors are in general known as potential measure for reducing ammonia emissions in dairy and cattle housing systems. Due to the application of the urease inhibitor on the exercise areas within a housing system the inhibitor is “mixed” with cattle manure and this “mixture” remains unchanged during manure storage. In Germany, a large part of the total stored cattle manure is utilized as a substrate in biogas plants. Therefore, the aim of the current study was to test if different concentrations of urease inhibitor mixed with typical cattle slurry will have any (negative) effects on the biogas and methane yield. The Hohenheim Biogas Yield Test (HBT) was used to determine if the biogas and methane production of cattle manure is influenced by the admixture with urease inhibitor. Altogether, four urease inhibitor concentrations (0%, 0.1%, 1% und 10% of total Kjeldahl nitrogen) were tested in the HBT experiments with two different substrates, cattle manure and cellulose, as a reference, in repetitions each. The average biogas and methane production of cellulose was 740 LN/kgODM and 403 LN/kg ODM and of cattle manure 471 LN/kgODM and 295 LN/kgODM. Both substrates treated with urease inhibitor showed no significant change in the biogas and methane production compared to the untreated ones. The use of urease inhibitors to reduce ammonia is harmless from the view of biogas plants.