The Washington State Conservation Commission has awarded researchers at Washington State University Tri-Cities a USD 200,000 grant to test an innovative manure management process. This new method holds promise for reducing greenhouse gas emissions, cutting costs for dairy farmers, and improving cow health.
“This research aims to enhance both local and global agriculture by advancing manure management techniques,” said Birgitte Ahring, a WSU Tri-Cities professor specializing in biomass conversion and anaerobic digestion. “We hope this research will demonstrate significant benefits and address key challenges faced by dairy farmers.”
Cow manure is a significant source of greenhouse gases, including carbon dioxide and methane. Traditionally, dairies manage manure by storing it in ponds or lagoons before spreading it as fertilizer. This approach not only emits greenhouse gases but can also lead to contamination of water sources.
Some large dairies have adopted a method of separating manure solids using screw presses, which are then used as bedding material. However, this can sometimes cause infections in cows, negatively affecting milk quality and quantity.
Anaerobic digestion, which generates biogas from manure, is another approach some farmers have tried. While this method reduces environmental impact and produces bioenergy, the presence of recalcitrant lignocellulosic material in manure limits biogas production efficiency and can be economically unfeasible for many farmers.
Ahring’s team will test a pre-treatment technology designed to improve the carbon conversion efficiency of anaerobic digestion. This process could potentially increase biogas production by up to 100% and enhance carbon conversion efficiency to 80%, compared to the 50% achievable with conventional methods. The pre-treatment is also expected to sanitize manure solids, making them safe for use as bedding material.
To assess the impact of this pre-treatment on infectious microbes, Ahring is collaborating with Craig McConnell, an associate professor at WSU Pullman and director of the veterinary medicine extension.
The goal of this project is to reduce methane and greenhouse gas emissions by producing renewable natural gas for the grid, while also improving milk production economics through better cow health and reduced infections.
As part of the grant, Ahring and McConnell will share their findings with Washington dairies and relevant industries in June 2025.
“We hope that demonstrating the positive economic and environmental impacts of this technology will encourage wider adoption and implementation,” Ahring said. The Washington State Conservation Commission is dedicated to conserving natural resources across the state through collaborative, incentive-based programs with conservation districts and other partners.
Source: Washington State University
