Demonstration of Advanced Primary and Secondary Wastewater Treatment Technology

Advanced Primary and Secondary Wastewater Treatment Technology

Gate 5 Energy Partners, Inc


Irvine, CA

Recipient Location


Senate District


Assembly District



Amount Spent



Project Status

Project Update

Gate 5 completed the system benchmarking report. Gate 5 is now working with its subcontractor on the foundation and utility design for the advance primary system.

The Issue

The long-used Conventional Activated Sludge (CAS) treatment paradigm is fundamentally at odds with the goals of energy efficiency and recovery because it misdirects influent solids. Up to 88 percent of influent organic material in wastewater treatment plants is in a particulate form that is not rapidly biodegradable. Much of this material passes through typical primary clarifiers into CAS treatment where it requires a long residence time to decompose, requiring large reactor footprints. Wastewater must be aerated during this decomposition, consuming substantial power to oxidize and destroy most of the chemical energy in the wastewater. Only one third of the energy is transferred to biomass with a potential recovery value. This biomass has a high initial moisture content and is just 30-50 percent digestible, limiting its potential for resource recovery. These limitations result in a 20-50 percent maximum recovery of the chemical energy in wastewater treated with CAS. Although CAS can reliably achieve today’s U.S. Secondary Effluent standards, it does so at a high cost in terms of energy, footprint, and complexity. Its chief byproduct, biosolids, are of limited resource value, contain controversial “contaminants of concern,” and require additional management costs for volume reduction, pathogen destruction, and transport.

Project Innovation

This project will use an advanced primary treatment system that relies on two filtration mechanisms, a micro screen and a continuously backwashed upflow media filter (CBUMF), to extract energy-rich solids from wastewater. A follow-up advanced secondary treatment system consisting of a moving-bed biofilm reactor (MBBR) and tertiary CBUMF removes remaining soluble contaminants. By diverting solids early in the wastewater treatment process, this complete system enables treatment in much smaller footprints, with dramatically less aeration required. Energy consumption is also reduced dramatically, while the diverted solids enable more efficient energy recovery and export of power.

Project Goals

To demonstrate an advanced primary treatment system that relies on filtration mechanisms, a microscreen and CBMLF filter.

Project Benefits

This project will lead to technological advancement and breakthroughs to overcome barriers to the achievement of the State of California's statutory energy goals by demonstrating the new MG5 wastewater treatment at Chiquita that reduce electricity consumption aligning with the objectives of SB 350 and SB 100. By reducing energy needs for electricity purchase and biosolids transport, this project also directly address AB 32 and SB 32 to reduce greenhouse gas emissions.

Lower Costs


This project could lower energy costs and yield approximately $32 million in rate payer savings annually from reduced energy consumption (assuming 20% market penetration in 25 years). Because the energy is saved locally, it directly reduces the cost to local rate payers and provides energy security.



Stanford University - Civil and Environmental Engineering


Match Partners


Gate 5 Energy Partners, Inc


Contact the Team