Microvi commissions first commercial sidestream treatment system in US Pacific Coast Region

The filtrate treatment system will reduce the nutrient load from Oro Loma Sanitary District by 8,000,000lbs over the next 20 years

Microvi and Oro Loma/Castro Valley Sanitary Districts (OLSD/CVSan) have announced the commissioning of the first dewatered filtrate treatment system in the Pacific Coast Region of the US. This 12 million-gallons-per-day (MGD) plant utilises the former’s MNE technology to reduce the latter’s nitrogen discharge to the San Francisco Bay by up to 400,000 pounds per year.

Funded by the US Environmental Protection Agency and OLSD/CVSan, the project represents a collaboration between Microvi, OLSD, CVSan, consulting engineer HDR, and project design engineer EKI Environment and Water. The system will reduce the nutrient load from OLSD by 8,000,000lbs over 20 years. The project also established a local internship programme to provide training and career pathways into the wastewater industry.

Rita Duncan, board president of OLSD, commented: “Sidestream treatment is a natural first step to addressing nutrient concerns in the San Francisco Bay and beyond. The stream is concentrated and warm – allowing for significant nutrient reductions with modest investment.

“Microvi’s technology could be a game changer for our industry as it allows targeted treatment to specific water quality concerns, and we are pleased to partner them to make it happen.”

Dr Fatemeh Shirazi, CEO of Microvi, added: “We are pleased to showcase our MNE technology for the removal of nitrogen at OLSD/CVSan’s 12 MDG plant. This installation will aid in efforts to protect the San Francisco Bay from significant nitrogen discharge.”

This sidestream is the liquid resulting from the dewatering of anaerobically digested biosolids, which is routed back into the facility’s treatment process. According to Microvi, this stream can represent approximately 1% of the flow entering a wastewater facility but can comprise 20% or more of the nitrogen loading.

Nitrogen treatment in the sidestream has been growing in prominence for its potential for reductions in capital and operation costs as well as reduced process risk. The treatment of high-strength ammonia allows alternative, more efficient microbiology to be utilised. Microvi’s MNE technology for treatment of nitrogen simplifies the overall treatment process, and can be retrofitted into existing infrastructure.

By treating this sidestream, the Microvi MNE technology will improve the reliability of nitrogen removal across the entire treatment process by converting ammonia only to nitrite, reducing energy consumption by 25% and reducing carbon dosing by 40%.

The heart of Microvi MNE technology is its biocatalytic composites that intensify and extend the life of biological processes, while maintaining a controlled population of microorganisms at a much higher density than existing technologies. Despite the complexity of the MNE biocatalysts themselves, the design and operation of the systems are simple with “no complex process controls,” the company claimed. In addition, Microvi MNE does not produce additional solids and reduces energy and carbon requirements.

The project builds upon the successful demonstration of Microvi MNE at OLSD showing full nitrogen removal in less than two hours. Microvi MNE has also been implemented for drinking water projects, including Sunny Slope Water Company and Cucamonga Valley Water District.