The Los Angeles County Board of Supervisors will decide Tuesday whether to invest $150,000 in a pilot project in Acton which, if successful, could lead to increased groundwater pumping – and potentially not just in Acton.
According to a report from Public Works Director Gail Farber, the public water agency in Acton – County Waterworks District No. 37 – could save its customers a bunch of money, on the order of $400,000 a year, if only it could pump more groundwater.
But it can’t, because if it did, the nitrate levels would exceed the regulatory standard. So instead it purchases “treated surface water to meet approximately 30 percent of its customers’ demand at a much higher cost than it would cost to pump groundwater from district wells.”
So Public Works wants to partner with the Denver-based Water Research Foundation to hire a Chatsworth engineering firm – WQTS, or Water Quality & Treatment Solutions Inc. – to “evaluate the effectiveness of the biological nitrate removal process.”
According to a document from WQTS, many groundwater wells have nitrate levels near or above maximum contaminant levels, so water providers either blend the water with purer water or treat it with ion exchange or reverse osmosis technologies. The trouble with ion exchange and reverse osmosis, it says, is that they create a brine stream that’s difficult to dispose of. (The county Public Works director says the same thing.)
WQTS says biological denitrification solves the waste problem because the backwash can be disposed of into any municipal sewer system. But it isn’t widely used in the United States, so it says more testing is needed before it will be “well accepted by utilities and regulatory agencies.”
Peers who reviewed WQTS’ proposal for the Water Research Foundation said the company wasn’t cutting any new scientific ground, but WQTS said that’s not the point.
“The project is not intended to be a scientific research project, but a practical engineering and operations project,” WQTS said in response to the peer review. “The greatest limitation for the county is the waste backwash water. To our knowledge, there has been no demonstration work done on the reuse of waste backwash water from a groundwater denitification system that is used to generate drinking water.”
It said other biological nitrate removal systems are in the works, but none has been approved.
“No water system that we know is ready to implement this technology without a lot more information and validation of stability and robustness,” it said. “This is the position of L.A. County, also, and that is the driver behind their interest in the project.”
As for prior experience, WQTS said it previously evaluated systems for removing perchlorate and nitrate from the city of Pasadena’s groundwater, and nitrate from Glendale’s groundwater.
At Acton, the company said it will also be assessing the potential of the process for removing co-contaminants such as TCE and Chromium-6.
“The goal of evaluating co-contaminant removal with the (biological denitification) process if of great interest to water agencies having groundwaters with multiple contaminants,” the company said. “Many Southern California groundwater basins fall into this category, including the San Gabriel Basin, the Chino Basin and the Reymond Basin. Agencies drawing water from these and similar basins could greatly benefit from the outcome of this project.”
The county’s goal is focused: “The study will evaluate the effectiveness of the biological nitrate removal process in the District’s groundwater and identify regulatory, operational, and maintenance requirements for a full-scale implementation of the treatment,” Farber’s report states.
As proposed, the county and the Water Research Foundation would each put up $150,000 for the project, which has a 15-month timeline to a final report.