A floating coverage system for digestate liquid fraction storage

Area of Science:

• Environmental Engineering
• Renewable Energy Technologies
• Agricultural Waste Management

Background:

• Anaerobic digestion is expanding in Europe, with significant potential in residual biogas from manure.
• Current digestate storage in uncovered tanks leads to unrealized biogas potential and emissions.
• Massive digestate production necessitates efficient and cost-effective storage solutions.

Purpose of the Study:

• To design, construct, and test a low-cost cover system for digestate storage tanks.
• To mitigate carbon dioxide equivalent (CO2eq) atmospheric emissions from digestate.
• To enable the recovery of residual biogas from digestate storage.

Main Methods:

• Development and implementation of a novel, affordable digestate storage tank cover.
• Experimental testing at a 1 MW electric anaerobic digestion plant.
• Quantification of atmospheric emission abatement and biogas recovery.

Main Results:

• The system effectively abated atmospheric emissions, preventing up to 1260t CO2eq annually.
• Biogas recovery from the digested liquid fraction storage tank increased overall methane yield by 3%.
• The low-cost design proved practical for existing anaerobic digestion facilities.

Conclusions:

• The developed digestate storage tank cover system is a viable solution for emission control and biogas enhancement.
• Implementing such systems can significantly improve the environmental and economic performance of anaerobic digestion plants.
• This technology offers a scalable approach to maximizing resource recovery in biogas production.