Biogas Conditioning System Turns Byproduct into Revenue

Since 1977, the Papillion Creek Water Resource Recovery Facility has treated wastewater by separating solids from liquids. The liquids are treated, disinfected and discharged into the Missouri River. The solids are sent to anaerobic digesters, which use bacteria to break down and stabilize the solids. Once stabilized and dewatered, solids are applied as fertilizer on nearby agricultural land.

Biogas, largely made up of methane and carbon dioxide, is generated as a byproduct of this anaerobic process. For the last 40 years, biogas has been collected and used as fuel for boilers and power engine-driven raw sewage pumps, as well as used in power-generating engines for making heat and electricity at the facility.

At Papillion Creek WRRF, the largest installation at a Nebraska wastewater facility, the technology changes how engineers view biogas. Previously, biogas was a byproduct used for heat and electricity within the facility. Now, it is seen as a valuable byproduct of the treatment process, and engineers are exploring ways for WRRFs to accept more waste to generate even more biogas. 

As part of this project, the existing equipment to remove gas moisture was upgraded for preliminary biogas treatment before the gas is sent to the main biogas treatment process. The end product is renewable natural gas ready for injection into the local natural gas grid allowing the City of Omaha to turn a byproduct into revenue. It is estimated to generate up to $7 million per year from gas sales and renewable energy credits, providing project payback in as little as three years and setting the path toward becoming energy neutral. Most importantly, the project establishes a cleaner, greener way of life for future generations by reducing the need to flare any excess biogas.

The project includes space for future equipment to handle increased biogas production and potential higher delivery pressures. It also plans for post-treatment compressors in the Conditioning Building to deliver RNG at 350 pounds per square inch or more.