Wastewater Possible Source for Drinking Water
Marina, CA – Whether you pour it down the drain, grind it up in the garbage disposal or flush: everything that goes into area sewer pipes ends up at the Monterey Regional Wastewater Treatment Plant.
On a tour, General Manager Keith Israel opens the lid to a large cylinder where gravity separates the solids from the wastewater. "Basically this is the first level of treatment. This is probably what used to occur in most treatment plants up until maybe the 50s or 1960s," said Israel. Things have changed since then. Most of the year, this wastewater goes through three levels of treatment before it's used to irrigate agriculture fields. But in the winter, the water goes through two levels of treatment before it is piped out two miles into the Monterey Bay. "Wastewater is a valuable resource and our goal is to get to the point of 100% reuse of that wastewater," said Israel.
So the Monterey Regional Water Pollution Control Agency has developed a groundwater replenishment project. Modeled after a plant operating in Orange County, the wastewater would go through a different third level of treatment which begins with micro-filtration to filter out bacteria. Then reverse osmosis to eliminate viruses and pharmaceuticals. And finally ultraviolet light and hydrogen peroxide are used to break down organic compounds. At that point, the recycled water would be diluted and injected into the Seaside Basin. "Once you put it into the ground it's going to get some additional treatment. It's going to go through all the different aquifers. And so basically, after it's in the ground for say a year or so, eventually it will blend in with other water resources, the rain fall and other sources and eventually it will be part of your water drinking supply," said Israel.
This could happen in four years, or never, depending on the outcome of an environmental impact report. At the end of January, the California Public Utilities Commission is expect to release a draft report comparing two different desalination plants proposed by California American Water to a multi-part solution called Water for Monterey County.
Led by UC Santa Cruz economist Steve Kasower, the Water for Monterey County Coalition is made up of the who's who in local water issues. The group has met for more than a year, and during that time everyone from CalAm to taxpayer associations to citizens have had a seat at the table.
The plan includes the groundwater replenishment project, desalinating intruded groundwater and conservation. Kasower says it approaches the water shortage like one would retirement investments. It's a diversified solution. "We have water supplies that are not dependent on the same phenomenon that each other is dependent on. So for example, there are times when the Salinas River is not going to have excess winter flows. And therefore we would have to fall back on a component of the project that has less impact from climate than a river or a watershed and that would be our desalination component, which can operate pretty much no matter what the climate issue is," said Kasower.
Once the draft environmental impact report is released, sixty days of public comment will follow. And eventually, the PUC will recommend the one of the three projects.