The Inland Empire Utilities Agency (IEUA) is using an innovative anaerobic digester to eliminate the greenhouse gases and other pollutants resulting from dairy farm manure.

The IEUA had a problem: it is responsible for water management and other services for 700,000 people in California's Central Valley, and the area has a number of dairy farms whose waste causes air and water pollution in the region. As part of its management strategy, the agency designed and installed two state-of-the-art anaerobic digesters that break down the manure and capture the gas for use as a fuel.

Treating the waste avoids the release of methane and other greenhouse gases. At a typical dairy farm, the waste is stored in open air "lagoons" which continuously release methane gas into the atmosphere. At the IEUA facility the gas is collected in closed digester vessels and combusted in generators to produce renewable energy.

This innovative project has other benefits as well. The electricity generated from the biogas is used to power a reverse-osmosis plant that purifies the groundwater. And treating the waste also helps prevent nutrients, salts and pathogens from leaching into the groundwater in the first place. These environmental benefits have been quantified with the help of the California Energy Commission.

By employing an innovative technology to help manage its waste problem, the IEUA has charted a path for reducing greenhouse gas emissions, cleaning up the air and water, and reducing grid electricity consumption. The protocols developed by ERT are now being funded for replication by the US Department of Agriculture as a model for sensible waste management.