Dairy digesters slash methane emissions by 80% on California farm

A recent University of California, Riverside study demonstrates that sealed dairy digesters can reduce methane emissions from manure by approximately 80% on a California dairy farm. Methane, a greenhouse gas over 80 times more potent than carbon dioxide over 20 years, is a significant contributor to global warming, with California dairy farms being major sources due to manure management. The study involved detailed atmospheric methane measurements before and after installing a digester at a Tulare County family-run dairy, revealing substantial emission reductions after addressing initial system leaks through collaboration between scientists, the system operator, and the farmer. Dairy digesters work by covering manure pits with gas-tight membranes that trap methane produced during anaerobic decomposition. The captured methane is then cleaned and repurposed as fuel, often powering trucks that would otherwise use diesel. While highly effective, digesters have limitations: they can leak if not properly maintained, do not reduce other pollutants like ammonia or fine particles, and require significant investment and regulatory permits, making them less feasible