A special session of the San Juan City Council was held on July 13 at the site of the city’s Well #6 to give the council members an opportunity to see for themselves what could be an important element in resolving the city’s long-standing water problems.
Microvi Biotech Inc. has installed an experimental water processing plant at the well located at 830 Mission Vineyard Road. The plant removes nitrates from the groundwater, a persistent problem with San Juan’s wells and a cause for multiple fines from the California Water Board and the Environmental Protection Agency.
“The system was fully installed and running since last Thursday,” said Microvi Vice President of Development Ali Dorri. “Everything is dialed in and now it’s just a matter of running water through the system and working out minor kinks. Once the results pan out, we submit them to the water board and get feedback from them. Hopefully, everything works out.”
Well #6 has been offline since March 2020, when the water being drawn began to spike up into unacceptable levels of nitrates.
The system uses biological agents to break down the nitrates in the groundwater, converting them into nitrogen gas which can be harmlessly discharged into the atmosphere. The technology is clean, with no biological waste or sludge.
At the moment, since the EPA has not cleared the well for use, the processed water is being dumped into the city sewer system. In the short term, this helps with another of San Juan’s problems by diluting pollutants at the wastewater treatment plant.
When the system is fully online, the processed water would be mixed back in with unprocessed water. Using treated water to dilute the nitrate-rich groundwater will drop the average nitrates in the water supply to below the maximum allowed. As a result, there is no need to process all the water from the well—just enough to make the water safe to drink.
The processed water will be tested regularly as adjustments are made to the system. The monitoring and any changes in routine will be done remotely from Microvi headquarters in Hayward.
The new system is capable of processing 50 gallons of water a minute, not quite a drop in a bucket but far from the peak output of the well, which can produce 600 gallons a minute.
After a two-month trial period, the city will decide whether to buy a full-scale system capable of processing more of the well’s output. If the city decides to move forward with a system, it will look for grants to cover the costs, according to city engineer Julie Behzad. The current system is being lent to the city at no cost through a series of grants received by Microvi to help small communities with what is becoming a common problem.
“Especially in the Central Valley and the Monterey area, you see a lot of nitrate contamination in the wells,” said Dorri. “People’s first thoughts are to drill more wells, but eventually the nitrates catch up with you. It becomes more difficult to blend waters because the nitrate concentrations have been going up. So we are seeing more and more people wanting to treat the problem at the wellhead—at the source.”
City Manager Don Reynolds had been finalizing solutions to the city’s water issues, including importing water from the San Benito County Water District and exporting waste to the Hollister Wastewater Treatment Plant, when he was approached by Microvi to run this trial.
He looked pleased during the presentation of the system, which seems to offer an important tool he can use in fighting the water problems inherited from previous city managers.
“Right now this will provide us with more water security,” Reynolds said. “It will keep us from being victims to high nitrates in the soil that we can’t control. I can’t tell you how complicated it has been integrating this into our system. There are a lot of moving pieces and it has taken a lot of coordination and hard work from our city engineer and staff. But we have been at this for a year so it is a great time to celebrate.”
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