The Santa Clara Valley Water District board will be asked today
to authorize spending up to $1,050,000 to buy, install and operate
a treatment system to remove the chemical from water taken from one
municipal well.
The Santa Clara Valley Water District board will be asked today to authorize spending up to $1,050,000 to buy, install and operate a treatment system to remove the chemical from water taken from one municipal well.
The system should be up and running by July 1, Mayor Dennis Kennedy.
“That is excellent news,” Kennedy said Monday. “The proposal came from our city staff and we’re very pleased that the water district is moving forward in this direction.”
City Manager Ed Tewes requested that the water district provide treatment to remove the chemical at one of its existing wells by July.
The plant will likely be installed at the Tennant Avenue well across the street from the Olin site at Railroad Avenue, Kennedy said. That well was closed in spring of 2002 when its water tested far above the four parts per billion level where the state mandates “action” by reporting that fact to water users.
The city responded by taking the well off line.
Since that time, three other city wells tested positive – though at low levels – and were taken off line. Three wells off line leaves the city in a bind as the high water-use summer period nears. A new well replacing the Tennant Avenue well was dug at the soccer fields on San Pedro in 2002 and the bill sent to Olin Corp. A check for partial payment was returned by the city.
Tewes announced last week that the Nordstrom and East Dunne wells have retested nondetect, which is below the action level. The Condit well tested at 5.0 ppb. However, all wells remain off line until the levels have stabilized, Tewes said.
The city has acted more conservatively than the state requires until the state sets a mandatory contaminant level by Jan. 1, 2004, according to Anthony Eulo, assistant to the city manager. Wells will be tested for perchlorate next on May 28.
The $1 million is for the capital outlay and the $50,000 will cover operating funds for Calgon’s changeout of the units – a separate contract.
“The only cost city will incur will be the cost of power (electricity) for pumping, which we normally would take care of anyway,” Kennedy said.
Still out in the cold are residents of more than 1,000 private wells between south Morgan Hill and north Gilroy except in a general way and the two San Martin municipal water systems.
“The theory is that while it (the proposed treatment system) doesn’t solve San Martin’s problems, it does help,” said Mike DiMarco, spokesman for the water district. “It’s not the be all – end all but if water is being pumped out by a huge well like that, if perchlorate is one-third of that water, it will help. And it’s something that we can do right now.”
DiMarco said he doesn’t know yet if there is a similar plan in the works for San Martin municipal systems. Nothing has been proposed for private wells in San Martin or Morgan Hill.
“Pumping at the Tennant Avenue site will decrease the spread of the plume south and draw the contamination back towards the site,” DiMarco said. “This may, in fact, help the San Martin residents as well.”
Adding to a potential problem, though opinions differ on this, are the percolation ponds the water district maintains in Morgan Hill on San Pedro and on East Main avenues. One theory maintains that, as the water filters down into the aquifer, it dilutes the contaminated water.
DiMarco was backed up by Jim Ashcraft, public works director for the City of Morgan Hill. He said the percolation pond water is “as far as we know” is perchlorate free. That water, DiMarco said, comes from the Sacramento/San Joaquin delta via the San Luis Reservoir.
However, another point of view is that the more water that enters the aquifer, the faster the perchlorate plume is pushed south toward San Martin. DiMarco does not agree.
“The percolation ponds are not the villain here,” he said. “If you are not putting water back in the underground basin, you lose your water source and land will start sinking. There is a fairly involved system of underground pipelines and it would be affected too.”
The perchlorate came from a highway safety flare manufacturing plant the Olin Corp. ran at Tennant and Railroad avenues from 1955 to 1996. The chemical was rinsed into a percolation pond on the site, leached down into the underground aquifer and has been found in municipal and private wells as far south as Leavesley Road in Gilroy.
While Olin has claimed ‘responsibility’ and is, with the water district, providing bottled drinking water for residents who have contaminated wells, the company is required by the state Regional Water Quality Control Board to begin to operate its plan for clean up of the soil and water by the end of the year.
The water district staff report said the city’s urgency about the treatment plant is challenging to finding a “permitted, installed and operating system”. The state Department of Health Services has approved only two perchlorate removal systems, Calgon’s Ion-Exchange System and Envirogen’s Fluidized Bed Reactor System.
The water district staff’s analysis concluded that only the Calgon system would satisfy the July deadline.
According to the report, the Calgon system is a “self-contained, skid-mounted ion-exchange unit that can be installed at one of the city’s existing well sites.” It is smaller, cheaper and quicker to install than the Environen method.
The Calgon system, the water district report claims, is also a “non-regenerative system that has no waste discharge.”
Calgon will replace the spent units – they last from several days to several months – and will remove them offsite, the report said, keeping the process consistent with California Environmental Quality Act.
The ion exchange method draws water into cells containing adsorbent material. Ion exchange resins are common but silica gels, activated carbon and molecular sieves are also used, according to the Calgon Carbon Corp. The perchlorate ions attach themselves to resin units and add chloride molecules; the altered chemical configuration renders the perchlorate harmless.
However, in the past, along with treated water, the process produced a brine solution which must be disposed of. This was dumped, in the ocean or elsewhere or burned. Dumping will become illegal in California by 2006. Ion exchange is frequently used to treat water in Southern California which has a serious perchlorate problem because of the numerous defense facilities.
Calgon Carbon will provide start-up services and will work with the water district and city staff. The report said that the water district has staff who are state-licensed, and can operate the plant, as does city staff, but that additional personnel may be required. The report said that the district would prefer to operate the plant itself.
Olin has already started with the remediation efforts plan for the soil, he said, and this will be the first step toward remediation on the ground water itself.
Perchlorate interferes with the uptake of iodide to the thyroid and, in sensitive systems, can cause problems. Infants and pregnant women are especially susceptible because of the developing brains of fetuses and newborns.
Results of the Morgan Hill municipal wells will be posted on the city’s website at www.morgan-hill.ca.gov and on the cable Channel 17 bulletin board.
PERCHLORATE MEETING
The follow-up community meeting to discuss perchlorate contamination and its effects in South Valley will be held Saturday, May 3, 10 a.m. to 1 p.m. at three sites on the Gavilan College campus, 5055 Santa Teresa Blvd.
Rotating panels of experts will discuss the perchlorate situation, the chemical’s effect on health and agriculture and clean up procedures.
The meeting will be held in the student union building, the fine arts building and the lawn area between the two buildings at Gavilan. Details: www.valleywater.org or 888-HEY-NOAH.
