It’s a challenge servicing sanitary and storm sewersystems in a county comprising 616 square miles with a population of half a million.

That’s especially true in a Pacific Northwest state with strict environmental regulations, and when wastewater effluent discharges to the county’s only river, which is also the major local supply of drinking water.

Clean Water Services tackles that challenge in Washington County, Ore. CWS is a water resource management utility established in 1970 to consolidate the water and wastewater services of a dozen communities. It has diverse responsibilities that in addition to wastewater and stormwater include flood management, water quality and stream enhancement projects, street sweeping, and fish habitat protection.

Strict attention to environmental regulations is paramount, but CWS finds that superior results are best achieved by giving team members the latitude to adopt innovative policies and to select the technology that best suits the job.

Dane Smith, purchasing and fleet coordinator, and Ted Claussen, maintenance supervisor, have logged 32 years apiece with CWS. “Dane started in April, and I started in June,” jokes Claussen. “He’ll go before I do.”

They describe the CWS service area as a puzzle. The utility must carefully allocate resources to each community — the largest is Hillsboro — and ensure that no activity in one community adversely affects the outcome in another. At the end of the day, success is measured by the health of the Tualatin River, a tributary of the Willamette River, where wastewater treatment plant effluent is released.

Strict regulations

Keeping the county’s sewer and stormwater system clean and televised is a CWS priority. At the county’s disposal is a fleet of combination trucks, waterjetters and TV inspection vans.

The backbone of the maintenance fleet is a team of six Aquatech B-10 combination trucks and an Aquatech SJ1500 jetter, all from Hi-Vac Corp. Crews can also deploy two Model 800-H truck jetters from Sewer Equipment Co. of America.

Smith likes the versatility of the Aquatech units to service both sanitary and stormwater lines. “For our purposes and our budget, they give us the broadest service,” he says. “Our crews like the B-10 in particular because it has the hose reels on the rear bumper, which lets the operator maintain an upright position. They say it’s better for their backs and more ergonomically friendly.”

The department operates five TV vans, four from Aries Industries and one from Rausch Electronics USA.

The county has more than 800 miles of sanitary sewer lines and 39 lift stations feeding four treatment plants. The pipes are concrete except for about 5 percent PVC. It’s a relatively new system: roughly two-thirds has been installed since 1975.

“Most of the sanitary lines are in good shape, with tight joints,” says Claussen. “We try and clean the sanitary system once every three years. I prefer to keep it closer to 24 months, and we’ve been meeting that goal significantly during the past four years.”

Basin by basin

The system is divided into basins and sub-basins. The sanitary sewer system comprises three basins and 115 sub-basins. The lines are also regularly hydroflushed with the Aquatech units, and the entire system is inspected every seven to eight years. In-house crews carry out much of the repair work.

“They’re capable of virtually every kind of repair,” says Claussen. “A lot of it is old school dig-and-replace, because we don’t get a lot of freezing weather here — maybe two weeks out of the year.” The county also owns pipe bursting units from Vermeer Corp. and TRIC Tools and a chemical grouting truck from Aries Industries. Outside contractors handle cured-in-place pipe lining for larger pipes 36 inches and up.

Stormwater management is critical because mountains surround the communities. “The water goes where it goes,” says Claussen. Heavy rains can cause flash flooding, but combined sewers are a distant memory. A series of smaller surge basins help collect excess rainfall, although occasional floods clog storm drains, necessitating midnight flush-and-vacuum operations.

“Heavy rains always seem to hit between midnight and two in the morning, when it’s hard to find the drains in the dark,” notes Claussen. The stormwater system comprises about 470 miles of lines, including trunks and interceptors. The agency also maintains 13,500 catch basins, and 600 water quality manholes.

Like the sanitary system, the stormwater system is divided into basins and sub-basins. The stormwater system consists of four main basins and 65 sub-basins.

No flushing

Only the Aquatech units are used for stormwater system maintenance, and only to clean and vacuum the system; jetting would raise sediment and flush it through the system instead of removing it.

“Our goal is to clean out 25 percent of the storm lines annually as a minimum goal, but we generally exceed that,” says Claussen. “We clean all of the catch basins annually and all of the water quality manholes twice a year.”

Checking the water quality manholes is crucial, because they contain a baffle system that traps floatables, oil, grease and silt. The lines are generally televised after cleaning. “We like to get a nice clean shot of the lines as we leave them,” says Claussen.

CWS has taken on the duty of street sweeping because it directly affects the quality of stormwater. “In 1990, the surface water management program identified the amount of phosphates, oil and sediment coming in off the streets, so we adopted an aggressive street sweeping program,” says Claussen.

The sweepers use a regenerative air system, not mechanical brooms, to lift dirt from the streets. They’re limited to traveling at five miles per hour, and their progress is constantly monitored to ensure that the roads are clean.

“The sweepers may soon be outfitted with GPS to monitor their exact coverage, speed and hours of service,” says Claussen. “Our thinking is that the cheapest way to eliminate impurities is to sweep them up before they get into the system. We figure it costs four times as much to pull the dirt out of the catch basins than to sweep it up.”

Claussen notes that once impurities descend below road level, the cost of dumping increases from next to nothing to almost $80 a ton, because the debris is then classified as hazardous waste.

Industries on board

Customers are educated about containing contaminants before they enter the system. Industrial clients are monitored and are required to report any contamination accidentally introduced into the system.

“We have on-site labs that go to the client to do sampling of the contaminants,” says Smith. “We can’t just wait at the treatment plant to identify what’s coming down the pipe.” Restaurants participate in a fats, oils and grease (FOG) program. Bacterial treatment of food grease at the retail level is discouraged because it can interfere with microbes in the wastewater treatment process.

Roots are a problem in both the sanitary and stormwater systems. The guilty parties here are primarily corkscrew willows and silver leaf maples. For pipes up to 12 inches, crews use hydraulic cutters to pulverize roots. “Anything above that, there’s too much pressure loss,” says Claussen. “We use chain cutters in the bigger lines.”

The department uses root foaming treatments in the sanitary sewer system, but such chemicals are not allowed in the stormwater system.

Innovative equipment

Innovation is part of the CWS culture. Crews are allowed to select specialized equipment to suit their needs. They use special easement machines (KWMI Manufacturing) to move hose reels long distances across properties and through the county’s many canyons.

“They’re powered by a gasoline engine and take the hose reels about 500 feet,” says Smith. “Then we have another 300 feet we can take off the reel from there. It

allows us to send out one or two people to those jobs, instead of the three or four required to carry the heavy water-filled hoses.”

The first set of easement machines bogged down in the mud, so the department ordered a new unit that crawls on a set of tank-like tracks.

One of the department’s own innovations on the combination trucks is a lazy Susan device affixed to the side for storing aluminum vacuum tubes upright instead of carrying them on the bumper, where they’re subject to damage. “General Equipment built the units for us to our specs,” says Smith. “Now the crews just spin

the platter and turn the next pipe toward them as they take them off the truck.”

Complying with strict environmental regulations doesn’t require CWS to regulate and stifle innovation within the department, notes Smith. “Our crews are pretty creative and we listen to their suggestions,” he says. “We’re also given enough freedom within the rules to choose the best equipment for the job.”