Joint Manure Digester Offers Opportunities For Reducing Ammonia And Greenhouse Gases

Implementing a low-emission housing system, in which slurry is removed, fermented and stripped daily, can lead to significant ammonia and greenhouse gas emission reductions for dairy farms. This is evident from model-based research into the possibility of joint mono-manure fermentation at 26 dairy farms.

Wageningen Livestock Research conducted this research on behalf of the Friese Drieslag, an energy cooperative in Wijnjewoude. The model study concludes that the 26 participating companies have the potential to achieve an ammonia reduction of between 30 and 62% across the entire manure processing chain. Greenhouse gas emissions from manure, especially methane emissions, can be reduced by up to approximately 78%.

This can be achieved by removing liquid manure from the stable daily, fermenting it after a short storage time and stripping the digestate. This processing of the manure allows the group of 26 dairy farmers, even without a derogation, to become land-based. No manure needs to be removed.

Furthermore, assuming that RENURE fertilizers may be used as fertilizer in the future, a fertilizer saving of 160 tons per year can be achieved. RENURE (Recovered Nitrogen form manURE) are nitrogen fertilizers extracted from animal manure, or digestate for which animal manure has been used. This saving is equivalent to €700,000 per year.

Finally, central fermentation of manure and upgrading it to green gas can prevent an equivalent of 1,786 tons of CO ₂ emissions.

It is important not to interpret the results of this model study as fixed data, but to see it as a guideline for what can potentially be achieved in practice.

The actual reduction can be determined with certainty when a specific housing system is chosen and the emissions are measured in practice, taking into account company-specific characteristics.