In Orrville, Ohio, it’s never business as usual at the wastewater treatment plant. Visitors to the plant’s administration building are treated to a clever first-hand demonstration of the plant’s high-quality effluent.
At the main entryway of the building, one might expect to see shrubs, flowers and a manicured lawn. Instead, visitors find an effluent-fed pond, home to some 30 flourishing goldfish and colorful Koi. “It’s a great way for us to demonstrate the high quality of our effluent,” says wastewater superintendent Bob Auten.
Something different
The Orrville plant (design flow 3.2 mgd, average 2.1 mgd) uses a three-stage biological treatment system consisting of rock media roughing filters and two separate stages of activated sludge, followed by tertiary sand filtration.
Plant staff hatched the idea for the fish pond about five years ago when they decided to improve the landscaping outside the administrative building. “Rather than spend money on the same old thing, we thought, ‘Why not build a pond to showcase our effluent, and a wetland to treat the pollutants produced by the fish?’” says Auten.
The plant did catch some flack along the way from a few residents and fellow employees. “When you write a purchase order for goldfish and start digging a large hole outside your office building, someone is sure to question your sanity,” says Auten. “After I explained what we were doing and its benefits, I got the support of the mayor and the utilities director. We also made sure the Ohio EPA was aware of our project. We were technically creating another discharge point because the pond overflows into our receiving stream.”
The pond has a surface area of about 300 square feet and a 3,500-gallon capacity. It is up to 4 feet deep and is continually fed by about 20 gpm of effluent. A small 1/4 hp recirculation pump cycles water through a decorative fountain and a 100-square-foot wetland, containing decorative plants including dwarf cattails, zebra rush, water lilies and water lettuce.
The fish thrive and reproduce in the pond. To control overpopulation, at least once a year fish are given away to fellow Orrville “ponders.”
Wastewater reuse
The Orrville plant has been proving consistently high-quality effluent since 1996, when it began using 600,000 gpd for cooling water makeup at a municipally owned 60 MW power plant. To date more than a billion gallons of clean effluent has been pumped the half-mile to the power plant through a 12-inch force main.
In another demonstration of effluent quality, plant workers recently discovered live freshwater sponges in the plant’s 50,000-gallon post-air tank. “We had the tank down for routine maintenance and cleaning when a co-worker called me and said, ‘You won’t believe what we just found growing on the walls of the tank!’” Auten says.
One sponge about the size of a fist can filter up to 100 gpd. “They need clean water, so we’re really glad to see them,” says Auten. “It tells us our effluent is clean, and their presence helps us make it even cleaner.”
Auten knows other treatment plants have sponges, but the unique thing about Orrville’s crop is how they found a home in the post-air tank. “Because of the way our plant is constructed, there is no pathway for the sponges to migrate into the post-air tank from the discharge stream,” he says. “I kind of think they came in through spores in the air, or possibly via ducks that sometimes swim in our final clarifiers.
“We know chlorine kills them because they only grow in the portion of the tank downstream from dechlorination. Since we chlorinate year-round because of our reuse system, we think airborne spores is probably how they were introduced.”
Proving it daily
In addition to its 8,500 residents, Orrville is home to major corporations like the J.M. Smucker Company (known for jellies and jams) and Ohio region’s Smith Dairy. In 2008, Orrville celebrated the 100-year anniversary of its wastewater treatment plant with an open house attended by hundreds of people.
The open house included plant tours and hands-on children’s activities provided by the Orrville City Schools’ Earth Science Club. Each participant received a souvenir coffee mug and saw the fish pond.
