HIGH-TECH FILTER—Employees from Boeing Co. stand above the newly installed chemical treatment system at Silvernale Pond, the largest reservoir at the Santa Susana Field Lab. Water from the pond is first pumped into this tank, where chemicals are added to clump solids and sediments together so that they can more easily be strained. The cleaned water is then discharged off-site. JANN HENDRY/Acorn Newspapers At the Santa Susana Field Laboratory, rain is Public Enemy No. 1.

The property formerly utilized by the Department of Defense now must do all it can to defend itself from the elements.

When the forecast calls for precipitation, workers at the former rocket engine and nuclear test site grab tarps and sandbags to make sure tainted soil doesn’t wash off the mountain.

Though sudden downpours can be wearisome for the workers who must protect the hillside, the rains are worrisome for local residents who keep a keen eye on the mostly vacant facility in the hills two miles south of Simi.

COVER UP—A plastic tarp and sandbags cover ground polluted with cesium-137 at a NASA-owned drainage area at the field lab. The dirt will be removed once a proper disposal place can be located. JANN HENDRY/Acorn Newspapers It’s no secret that communities surrounding the lab have long been concerned about contaminants coming off the site. The primary pathway is via stormwater.

Droplets that hit the ground, especially during heavy winter rains, can pick up contaminants in the soil. That water flows into numerous creeks traversing the site.

The field lab has the potential to discharge hundreds of millions of gallons of stormwater runoff and wastewater per day.

About 60 percent exits the southern portion of the property and flows into Bell Creek, a tributary to the Los Angeles River. The rest is discharged to the northwest into the Arroyo Simi, a tributary of Calleguas Creek.

WILDLIFE—A black cormoranstands on a water aerator in a treated pond at the field lab. JANN HENDRY/Acorn Newspapers With the extensive reach of rain runoff, keeping it clean is vital and an around-the-clock job.

A problematic past

The Boeing Co.—the largest landowner at the 2,850-acre site and one of the property’s three responsible parties—has a history of failing to meet water quality discharge limits at the field lab.

These limits are set by a National Pollutant Discharge Elimination System (NPDES) permit, which was adopted in 2004 and is monitored by the Los Angeles Regional Water Quality Control Board.

Stormwater tested from 2005 through 2008 showed higher levels of certain contaminants than allowed, but the excess levels were very small, some measured in parts per billion

Even in the fourth quarter of 2009, excess levels of nitrate, pH, dioxins and metals were reported at four of the field lab’s 16 active outfalls, or watershed drainage areas.

Part of the issue is that the numeric limits Boeing must meet are, in some cases, stricter than drinking water standards.

Paul Costa, manager of the environmental protection program for Boeing, said violations need to put in perspective.

“It may be (exceeding limits) but it may be (up to) drinking standards anyway,” he said, adding, “This water is not hazardous waste.”

Even materials used to filter the water can cause an excess-levels reading, Costa said.

The limits are so stringent because they were developed to protect aquatic life, said Cassandra Owens, chief of the industrial permitting unit for the regional water board.

Compounding the problem is that the size of the field lab and the number of discharge points increase the chance for violations.

Just as Boeing has been tackling cleaning up the soil, it has been working on cleaning up the water. At the beginning of the year, the aerospace giant implemented new on-site technologies to do just that.

“Within the last couple of years they’ve done some major upgrades. . . . Some of the technologies they are using there are far and above what normal dischargers of stormwater are using,” Owens said. “Most of them are not putting that level of effort in, in terms of technology or manpower for treating storm water.”

Rainy season measures

The field lab must have systems in place to handle Southern California’s unpredictable rainy season. This year, when it rained, it poured.

Boeing uses a variety of measures to capture, control and clean the runoff. Sandbags, silt fencing, miles of straw wattles (or fiber rolls) and retention basins are among those measures.

Hydromulch is used to cover exposed soil and facilitate revegetation—particularly in burn areas— and protect against erosion. Plants are also used in erosion control, and tarps cover areas currently being investigated or remediated.

“We keep a very close eye on the weather forecast, and when rain is imminent, we get tarps and sandbags out to stop the soil from migrating,” said Dixie Hambrick, a principal hydrogeologist with one of Boeing’s consultants, MWH.

One of Boeing’s newest methods of dealing with the rain is its new chemical treatment system at the largest reservoir on site, Silvernale Pond. It has a capacity of 6 million gallons.

Lori Blair, surface water program manager for Boeing, said that after two years of using high-tech filters and still not getting 100 percent compliance, the company decided to add the chemical treatment system.

First, water from the pond is pumped to a tank that uses chemicals to clump solids together to make them easier to remove. The water then goes through a sand filter, a superfine bag filter and a carbon filter before being discharged.

Though complicated, the process is fast.

“We’re basically treating three swimming pool-size amounts of water every hour,” Costa said.

Dirty water from a smaller reservoir nearby is also pumped to Silvernale to be treated. However, the chemical system is designed to handle only 2½ inches of rain, Blair said, so when there’s a large storm, the overflow is filtered by the property’s original flow-through system at outfall 18, which uses rocks and sediment to strain the water and carbon to absorb some constituents.

Because the chemical system is so new, Boeing can’t yet back up its effectiveness with numbers, but Blair said she’s encouraged by the clarity of the discharged water, which, to the naked eye, looks good enough to drink.

All the outfalls on site are selfmonitoring, meaning they take automatic composite samples during rain events. In addition, the regional water board checks in on the field lab periodically. Owens said someone is at the site two or three times a month and even more frequently during soil removal activities and rainy weather.

Just like Boeing, the water board staff collects confirmation samples at excavation sites to make sure the targeted constituents are being removed.

Boeing submits monitoring reports to the board on a quarterly basis.

Limitations of the systems

While the field lab may be on the cutting edge of treating stormwater, Owens said neither Boeing nor the water board will know just how effective the new technologies are until the end of the rainy season.

She said data from January through March would not be submitted to the water board until May 15.

Costa said the site is much better off this year than last year because of the improved treatment systems but meeting requirements will still be a struggle.

Owens said Boeing should be given credit for all it’s done to get its stormwater under control but added she’d never say the issue has been resolved once and for all.