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"Catching Water Pollutants at the Source" |
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By JON SAVELLE
Journal Environment Editor
September 15, 1998
With increasing anxiety over water quality, salmon habitat and toxins in sediments -- all of which are affected by surface water runoff -- one may reasonably ask: Why not filter the runoff before it enters the pipe?
That's just what Jim Hutter wondered. So, almost eight years ago, he decided to try it.
Hutter invented a filtration system that fits in storm drains. Then he started a company, Enviro-Drain, to manufacture and market them. Now, at long last, he has received a patent on the design. The device is extremely simple. It consists of a stainless steel assembly that nests under the storm drain grate, and holds one to three filters. The filters can be configured for any application, trapping sand, silt, grease, oil and metals.
"We can clean all the way up to 97 percent of pollutants" Hutter said in a recent interview.
Each Enviro-Drain unit contains screens on top to trap sediments. Below that, smaller-mesh screens catch silt. At the bottom a variety of filters can be used, including activated carbon, geo-membranes and Absorbent W, an oil- absorbing cellulose product made by International Absorbents in Bellingham. Although conditions vary widely, the units are designed to work for about a month before the screens need to be cleaned and filters changed. The filters cost about $1 apiece. Prices for the filter units range from $450 for a single-tray model to $1,600 for a three-tray, depending on the application and the number of units ordered. "If they order more, they get a better price," Hutter said.
Enviro-Drain, based in Snohomish, has been selling filters all over North America and even in Australia. Their customers are mainly industrial companies, although Hutter initially tried to interest local governments. That didn't work out. Hutter found that trying to get multiple agencies and jurisdictions to work together to try his products was more hassle than it was worth. He said some agencies incorrectly assembled and maintained the units, and therefore got unsatisfactory results.
"I've tried to encourage construction site filters," he said. "But it's a long process to get someone to do something the government isn't requiring them to do."
Not filtering runoff, however, has dramatic consequences. In the Lake City neighborhood where Enviro-Drain has a small manufacturing facility, it wasn't hard to find examples of the problem. Hutter lifted up a storm drain grate on 33rd Avenue Northeast and found a catchment basin loaded with sediment and debris one foot deep.
Across the street, where sickly-looking Thornton Creek briefly emerges into daylight, the creek-bed sediments sparkled with what Hutter said were metal particles. Rocks showed signs of oil staining. On the stream bank, and draining into it, was a green plastic wastewater pipe that carried runoff from the AA Rentals equipment yard above. The yard's asphalt paving bore numerous oil and grease deposits from parked trucks and machinery, similar to thousands of other paved lots in the region.
"We let [the city of] Kirkland try a filter for free for quite a few months," Hutter said. "Every 30 days we would pull at least 40 pounds of oil and grease from the catch basin. It was from 25 cars that drained to the catch basin -- which was just 100 yards from Lake Washington."
The filter also trapped plastic bags, cigarette butts and human hair. "I noticed a lot of hair," Hutter said. "It was just phenomenal." Looking over the AA Rentals yard, Hutter said the best solution would be to make filtration of the runoff mandatory, and require the user to fill out a maintenance schedule. He believes that would be much more effective than relying on voluntary efforts.
"It's going to take government," Hutter said. "They don't want to be the bad guy, but they have to." What's more, local governments control a lot of storm drains. Hutter said the city of Seattle spends $47 million annually to clean and maintain its catch basins, which is enough to install and maintain as many filter units.
Hutter believes the system would pay for itself in one year by reducing maintenance costs, and would nearly eliminate pollution from runoff at the same time.
Neil Thibert, supervising civil engineer with Seattle Public Utilities, said he is familiar with Hutter's Enviro-Drain system and thinks it is an excellent product for certain applications. But after Seattle and other cities tested it and other filter devices, they found that it wasn't suitable for large municipal storm water systems.
"Jim has been approaching us with this idea and trying to convince us to use them for about 10 years," Thibert said. "His product does remove a lot of contaminants that go into a catch basin extremely well. We were interested in seeing how well these would work. Seattle, Bellevue and other cities sponsored two different research studies on these and other [filters], and found that they work really well for a week or two or up to a month. Then they have to be maintained -- to remove the filter media and the dirt they contained. "With 32,000 in the city, that would be an awesome task."
Thibert said the city now uses a large Vactor pumper truck to suck deposits out of each basin once a year. That material is dewatered and sent to a landfill. A storm-drain filter, by contrast, would have to be serviced 12 times a year and the filters themselves disposed of.
The catch basins actually do a good job of trapping sediments and other solids, according to Thibert. Most of them are large -- four to five feet in diameter -- and he said they do not have a small rectangular grate on top. But Thibert said filters will do a better job of trapping oil than a catch basin alone.
"These [filters] would be good for a small business, like a 7-11 or something, that can't afford a Vactor truck," Thibert said. "They could put one of these things in, and throw the filter in the dumpster. I think it's a big problem -- and for the right application, it's a great product."
At the Kenworth truck assembly plant on the Duwamish River, Stephan Alm-Plouff was the environmental manager who two years ago installed a dozen of Hutter's drains on the site. He said each one was configured for its specific function and the kinds of runoff it would collect. "They work very well," Alm-Plouff said. "I would recommend them to anyone on the river who has critical exposure issues."
Particularly for older properties with no storm water detention facilities, Alm-Plouff said the Enviro-Drain provides a measure of protection against pollutant releases that is cheap and effective. And that may become more important, he said, as regulations tighten under the National Pollutant Discharge Elimination System (NPDES) permitting program. "Everyone should have a system like his, especially on a waterway," Alm-Plouff said.
Dick Peltzer, facilities manager for the Food Services of America distribution center in Kent, believes the dozen Enviro-Drain filters he uses in his loading area are worth the roughly $20,000 he invested in them. "We're putting them in high-traffic areas," he said. "It's the only product on the market that allows three levels of filtration mediums. You don't have to constantly change that first level." The filters catch runoff from a truck staging area. Peltzer said the frequency of maintenance depends on rainfall; the more it rains, the more often the filters need to be changed. That's once a month on average, but during rainy periods maintenance could be as frequent as once a week. For his application, Peltzer uses absorbent filters to catch oil and grease before it drains into a spillwell. And why did he volunteer to filter his runoff? "I'm a fisherman," Peltzer said.
Copyright (c) 1991-1997 Seattle Daily Journal of Commerce. All rights reserved. Do not duplicate or redistribute in any form.
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