Biofiltration as an Advanced Primary Treatment Method to Achieve Substantial Energy Savings

Energy Savings and Other Benefits of Biofiltration for Wastewater Treatment

Kennedy/Jenks Consultants


Irvine, CA

Recipient Location


Senate District


Assembly District



Amount Spent



Project Status

Project Update

Biofiltration generates energy savings by removing more organic load, which in turn reduces aeration electricity consumption in the downstream biological treatment and increases digester gas energy production from the diverted organic material. This project quantified a electrical energy reduction between 15 to 20 percent achieved by biofiltration based on demonstration results at the Linda County Water District plant. The biofiltration demonstration proved the technology to be a feasible alternative to conventional primary wastewater treatment processes.

The Issue

The secondary biological wastewater treatment process method is accomplished by aerating wastewater and is very energy intensive, typically accounting for 40 to 60 percent of the total wastewater treatment plant (WWTP) electricity consumption. Achieving a higher amount of removal of organic material before the aerated activated sludge process provides a breakthrough opportunity to reduce electrical power demand. Biofiltration as an advanced primary treatment method is an emerging technology for removal of total organic load, both soluble and particulate material, however it has never been implemented at full scale at WWTPs.

Project Innovation

Conventional wastewater primary treatment uses clarification for solids removal and activated sludge treatment for secondary treatment to remove organics. Biofiltration is an emerging advanced primary-treatment technology that more efficiently and economically removes particulate and soluble material than the conventional primary method of clarification that removes only particulate material. In a biofiltration system, particulate material is removed mainly through filtering, and soluble organic material is removed by using microorganisms to capture and biologically degrade the pollutants. This project demonstrated that biofiltration is a technically viable and commercially attractive approach to achieve significant electrical energy savings at wastewater treatment plants with a full scale demonstration at Linda County Water District plant.

Project Benefits

Biofiltration as an advanced primary treatment method could reduce the aeration electrical energy needed for secondary treatment, increase energy production in the anaerobic digester from the removed organic material and increase existing secondary treatment capacity and forestall the need for future treatment plants. Based on pilot studies outside of California, Biofiltration has the potential to decrease aeration power by 45 to 60 percent, increase gas production from 25 to 40 percent and increase treatment capacity by 50 percent.

Lower Costs


Aeration power requirements are estimated to decrease by approximately 45 to 60 percent compared to conventional treatment methods. Assuming 25% implementation of the technology, it is estimated that the annual electrical energy and cost savings for the wastewater treatment plant operators in California will be 110,000,000 kWh and $12,900,000 per year, respectively.

Key Project Members

Project Member

Onder Caliskaner

Project Manager



Professor George Tchobanoglous, Ph.D., P.E.

Match Partners


Professor George Tchobanoglous, Ph.D., P.E.

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