Published: Jan 05, 2016 | 13:13 PM

IRWD Biosolids and Energy Recovery Project Achieves Major Milestone

In November, stainless steel domes were lifted with a crane onto three egg-shaped methane digesters at the Irvine Ranch Water District’s Biosolids and Energy Recovery construction site, marking a significant milestone for the project. Construction on the facility began in 2013, with completion expected in early 2017.

The $167 million Biosolids and Energy Recovery Project is hailed as a state-of-the art organics-handling system, located at the Michelson Water Recycling Plant in Irvine. Biosolids are the organics removed during the recycled water treatment process. They will be converted into pellets for use as fertilizer and the biogas produced during the process will be used to generate electricity.

The egg-shaped digesters are considered the heart of the facility for their function. Sewage sludge, the by-product of the water recycling plant, will fill the egg-shaped digesters up to the bottom of their stainless steel domes. The bacteria in the digesters will reduce the volume of sludge and generate biogas. It is here that the biogas will be collected under the dome, cleaned and used on-site to generate the electricity to help power the recycling process at MWRP. The remaining sludge will be dried and made into fertilizer.

The egg-shaped digesters are constructed of carbon steel metal plates, bolted together and seismically bolted to the foundation. They will be covered with green metal cladding when complete. The unique shape is seen as more efficient for heating and mixing than digesters shaped like water tanks and used at other treatment facilities.

Processing biosolids on-site at the Michelson Water Recycling Plant is expected to save IRWD customers an average of $100 each year over the next 20 years. Currently, biosolids produced at MWRP are sent through buried pipelines to the Orange County Sanitation District for processing.

More information about the Biosolids and Energy Recovery Project is available on our website.