Tetra Tech Awarded California Wastewater Contract for Digital Systems Integration and Emission Reduction

Tetra Tech has won a contract from California's Encina Wastewater Authority (EWA) to digitally integrate new clean energy systems at the agency's North San Diego County plant. The work is part of EWA's Cogeneration Low-Emission Augmentation and Retrofit — known as the CLEAR project — which aims to connect a 1.5 megawatt-hour battery, new biogas conditioning equipment, and emissions controls into a single unified network, according to Hannah Herald.
Tetra Tech CEO Dan Batrack said the company's Digital Systems specialists will provide "the integration of siloed information systems to support EWA in optimizing its operations and achieving its sustainability goals." The plant currently serves over 350,000 residents in North San Diego County.
The CLEAR project is an overhaul of EWA's energy recovery systems. Wastewater treatment naturally produces biogas — a gas made from decomposing sewage. EWA already burns that gas to generate electricity. But the old systems ran in isolation, meaning data from one part of the plant couldn't talk to another. The CLEAR project fixes that by tying everything together digitally, according to Daily Herald Tribune.
The new setup includes oxidation catalyst emissions controls, biological trickling filters, a biogas conditioning facility, and the 1.5 MWh battery storage system. Tetra Tech's job is to connect all of these into EWA's existing operational technology (OT) network — essentially the plant's central nervous system. The design-build construction team handles the physical installation, while Tetra Tech handles the digital layer.
The CLEAR project is largely a response to tightening state rules. California's Air Resources Board (CARB) requires wastewater plants to sharply cut nitrogen oxide (NOx) and carbon monoxide emissions from their engines. The state's SB 1383 law also mandates a 75% cut in organic waste going to landfills by 2025, pushing more biogas through plant systems — but without adding air pollution, according to Paris Star Online.
EWA currently generates roughly 60–80% of its own power from biogas. The CLEAR upgrades are designed to push that closer to 100% during peak periods. By storing excess energy in the 1.5 MWh battery, the plant can avoid drawing from the main San Diego grid during expensive peak hours — a strategy called "peak shaving" that is expected to save millions in costs over the next decade.
Adding physical equipment is straightforward. Getting that equipment to share data with a plant built over decades is not. Industry experts describe "information silos" as one of the biggest risks in modern utility management. When a battery system, a biogas condenser, and an emissions scrubber each run on separate software, operators can't see the full picture — and can't respond quickly to problems, according to County Market.
Tetra Tech's Digital Systems division has roughly 1,200 specialists focused on exactly this kind of work. Analysts at Baird have noted that by winning contracts like EWA's, Tetra Tech is moving away from lower-margin construction work toward higher-margin software and integration services. The company employs 28,000 people globally.
If EWA pulls this off cleanly, the ripple effects could be significant. California's Association of Sanitation Agencies is watching closely. State legislators may use a successful CLEAR project as a template for requiring similar upgrades at medium and large wastewater plants across the state, including facilities in Los Angeles and San Francisco.
Energy analysts add another angle. Once EWA's microgrid is live, the plant stops being just a power customer. It becomes what analysts call a "prosumer" — an entity that can both use and supply power. During heat waves, EWA could draw on its 1.5 MWh battery instead of the main grid, helping to stabilize electricity supply across the San Diego region. For 350,000 North County residents, the most immediate benefit is cleaner air from lower NOx and particulate emissions in the Carlsbad area.
Publishers
4
Articles
4
Reach
4