Rising disposal fees, diminishing disposal sites and hauling grease 100 miles to the treatment plant motivated John Ball of Roto-Rooter in Lewiston, Idaho, to turn his dream into action.
Ball had envisioned his own treatment plant since he and John Freand bought Roto Rooter in 1997. When ex-farmer Scott Meyer joined the partners, they agreed that the time was approaching to do something. The men started talking about dewatering the waste and land applying the biosolids. In 2002, they formed Clearwater Tech LLC and jumped into the unknown.
Despite two false starts, turning Ball’s dream into reality wasn’t difficult. Today, the plant, located in Port of Wilma, Wash., directly across the Snake River from Lewiston, processes all the waste produced by the Roto-Rooter business. The venture proved so successful that it became a model facility for Washington State’s Department of Ecology.
AUCTION BARGAIN
An auction containing some dewatering equipment was the first lure. “The Auto-Vac filter from Alar Engineering Corp. was really cheap, which was why we bought it,” says Freand. However, they decided to part with the filter and keep most of the other equipment that accompanied the dewatering system.
After investigating dewatering boxes, the partners bought a 15-cubic-yard unit from Consolidated Fabricators Corp. “The company had a silent auction at the 2003 Pumper & Cleaner Environmental Expo, and we got a great deal,” says Freand. “The box is simple to operate. Septage gravity feeds through filters that catch all the solids, and effluent runs out the bottom.”
Before building their facility, the men visited private dewatering sites. Levar Parker of Parker’s Septic Tank Cleaning Service in Idaho Falls, Idaho, helped them the most. They learned more about screens and tank agitation from a facility in Grants Pass, Ore., which used an Auto-Vac filter. A plant in California provided more design ideas.
“The best wisdom we can pass on is to visit as many sites as possible before attempting to build your treatment plant,” says Meyer. “That eliminated most of the trial-and-error factor for us.”
Another recommendation is being on good terms with the agency responsible for environmental quality. “We were ready to build, but spent 18 months working out permitting and land application issues,” Meyer continues. “This process took the longest, but the department of ecology staff was very helpful. They love our facility and give us great reviews.”
The partners built Clearwater Tech on 2.5 acres of leased land in Port of Wilma, an uninhabited area. “We didn’t want any odor issues,” says Freand.
Their Cover-All Building Systems steel frame and fabric structure is divided into a 40- by 62-foot room for the holding tanks and dewatering equipment, and a 60- by 62-foot storage area for the dry cakes. Heaters in the building keep the temperature just above freezing in winter. The partners recently built a 30- by 30-foot Cover-All over the 8,000-gallon concrete dump pit to protect it from wind and keep out rain.
RECIPE CALLS FOR …
The plant went operational in May 2004. For their first 3,500-gallon batch, the partners tried injecting the polymer into the septage before it reached the dewatering box. “It was a disaster,” says Meyer. “The solids stayed suspended in the liquid and wouldn’t dewater.”
They pumped out the box with a vacuum truck and started over, but not before Levar Parker arrived to help. He recommended using a batch tank, so they purchased a 500-gallon Poly-Mate tank from Flo Trend Systems Inc. It came with a variable-speed progressive cavity pump that injects the correct amount of polymer into the septage as it streams from the holding tank to the batch tank. “The batch tank gives the polymer time to age, enabling the septage to dewater better,” says Freand.
The idea for a bar screen to filter garbage and hair came from the Grants Pass operator. The partners built a 3 1/2-foot-square enclosed steel box with vertical 1/4-inch carbon steel bars spaced 3/4 inch apart. The height of the bars increases 30 degrees from front to rear.
The bar screen, on a catwalk spanning the middle of the dump pit, rolls on rails. When Roto-Rooter vacuum trucks arrive, the box is rolled to the vehicle and a 6-inch hose attached to its discharge valve. Liquid runs through the screen and into the pit.
After discharging, a worker on the catwalk rolls the bar screen to a gutter, opens the door in the back of the box, rinses debris from the container, and rakes out whatever small solids remain. The bar screen produces a cubic yard of garbage a week, which is sprinkled with lime, bagged, and taken to the landfill.
A 7.5-hp Vaughan grinder pump pulls septage from the dump pit through a Muffin Monster grinder, which sends it to a 14,000- or 16,000-gallon steel holding tank. “If anything gets past our bar screen, these two grinders reduce it to 1/4-inch or smaller pieces,” says Freand.
The receptacles, both recycled oil and diesel tanks, sit on blocks so they drain to the front. They are top loaded to eliminate accidental spills. A valve stack enables the partners to fill tanks individually. When one is full, the waste is processed.
TREATMENT TRAIN
The polymer is mixed with water, aged in the batch tank, and injected into the septage as a Grundfos 7.5-hp processing pump draws the slurry into the dewatering box at 165 gallons per minute. Simultaneously, a 10-hp Roots blower injects air through a perforated 2-inch pipe at the bottom of the tank. Aeration agitates the solids and grit, preventing them from accumulating.
A batch contains 80 percent septage and 20 percent grease. “We use a lot less polymer with that ratio and it dewaters better and cleaner,” says Meyer. “If we start getting too much grease in our septage holding tanks, we store it in a 5,000-gallon grease tank for future use.”
Filtrate water from the dewatering box flows through a floor sump, then submersible pumps send it to the facility’s two 10,000-gallon steel storage tanks. A 1989 Kenworth 4,700-gallon tanker, and sometimes a 5,000-gallon Beall trailer tanker, haul the liquid to the Roto-Rooter shop. “We discharge it into a cleanout through a 1 1/2-inch hose so the stream enters the city flow slowly,” says Freand. The Lewiston treatment plant charges a small fee to treat the wastewater.
GIVE ME LAND, LOTS OF LAND
After dewatering, the box is rolled into the storage room and the dry cakes of humus dumped out. When enough accumulate to fill the company dump truck, they are transported 22 miles to a field and stacked in windrows.
“The cakes form a crust after a few days, which seals in odors and keeps out moisture,” says Freand. “Moisture really isn’t a concern here, as this area’s annual rainfall is only 12 to 14 inches.”
The cakes are land applied only after fall harvest or before spring planting. As a front-end loader breaks up the windrows, they release a slight odor, but no one complains. The nearest house is two miles away, and the farmer owns thousands of acres for dispersing biosolids.
Traditional manure spreaders would not distribute loads evenly enough, so the partners researched and purchased a Model 8132 Pro Twin Slinger side delivery spreader from Kuhn Knight, and a used J.I. Case farm tractor to pull it. Two augers lying lengthwise in the spreader bed move the material into the hammer drum, which chops the cakes into dime-size pieces and disperses them in a 70-foot-wide path.
“Our permit states that we must incorporate the biosolids within six hours of applying them,” says Meyer. “The farmer does that with a cultivator and tine harrow, then seeds wheat or barley.”
One thing the partners learned is that offering free fertilizer is not enough. “You have to sweeten the pie,” says Freand. “We pay the farmer for his time to incorporate the biosolids and rent the acre where we windrow the cakes. It’s a good deal for both of us.”
Clearwater Tech operates cheaply and efficiently, saves driver time, lowers fuel and maintenance costs, enhances customer service, and has solved Roto-Rooter’s problem of how to dispose of its septage and grease trap waste.
