The Oro Loma Sanitary District (OLSD), like most wastewater agencies in the Bay Area, is challenged by how to cost-effectively remove nutrients to meet future effluent limits. OLSD chose to take a proactive approach by negotiating nutrient limits with the Regional Water Quality Control Board in advance of when the new effluent limits are anticipated to take effect.
The proactive approach allowed the District to obtain customized nutrient effluent limits that could be met cost-effectively. The District selected KJ via a competitive process to plan and design the Nutrient Optimization Project to comply with the limits. In addition, because of the higher quality effluent, the Project will allow the District to reduce their cost contribution to the East Bay Dischargers Authority (EBDA). The cost savings will be used as a significant source of funds to pay for the Project, which will cost about $20 million.
The Project will upgrade the existing secondary process originally designed by KJ over 50 years ago to provide nitrification and denitrification to treat an average annual flow of 16 mgd. KJ worked collaboratively with the District to continually improve the capacity, reliability, and operability of Project compared to original project concept developed at the planning level. This included many process analyses using the BioWin process modeling software. In addition, the KJ design optimized the energy efficiency of the project to avoid the need for over $1 million of electrical system capacity improvements. The energy efficiency of the aeration system will allow the District to obtain an estimated energy rebate of $150,000 from PG&E. A Local Outfall Pump Station will automatically divert effluent to a near shore outfall in the Bay to limit effluent flow to EBDA to 30 mgd to reduce the District’s EBDA cost contribution.
The major project elements consist of the following:
- New Aeration Basin
- New fine bubble diffusers for all aeration basins
- New blower building with Neuros high speedturbo blowers
- Fully automated system to control air header valves to supply air to meet dissolved oxygen setpoints
- Mixed liquor recycle pumps to control denitrification
- 40 mgdLocal Outfall Pump Station
- Sodium bisulfite addition facilities for dechlorination
- New instrumentation to monitor and control the process
KJ participated in the groundbreaking ceremony of the Oro Loma Sanitary District’s Nutrient Optimization Project on October 16th, 2018 kicking off construction of the new facility.