Planting Trees A Cheap Solution To Wastewater Discharge Regs

Trees are a solution for small water utilities who are concerned about the cost of cooling treated wastewater before it is discharged into the environment.

“Five years ago Medford, Oregon, had a problem common for most cities — treating sewage without hurting fish. The city’s wastewater treatment plant was discharging warm water into the Rogue River. Fish weren’t dying, but salmon in the Rogue rely on cold water. And the Environmental Protection Agency has rules to make sure they get it,” Environmental Health News reported.

The Oregon Department of Environmental Quality explained why temperature rules exist.

“The temperature water quality standard is intended to protect salmon, steelhead, trout and other cold-water fishes, the most sensitive beneficial uses in the water body. The temperature standard is also protective of the different life stages of cold water fishes including spawning, rearing, and migration,” the regulator says.

Medford figured out a relatively cheap fix: planting trees.

“Instead of spending millions on expensive machinery to cool the water to federal standards, the city of Medford tried something much simpler,” the Environmental Health News report said. “It bought credits that paid others to handle the tree planting, countering the utility's continued warm-water discharges. Shady trees cool rivers, and the end goal is 10 to 15 miles of new native vegetation along the Rogue.”

Water-quality credit trading is on the rise in Oregon. Using credits to offset warm discharges is a new practice. “Supporters say it’s a win-win: wastewater plants save money, streams stay cool and the trees do other good things like provide habitat and suck up carbon,” the report said.

Joe Whitworth, president of the Freshwater Trust, which helped organize the effort, described the thinking that led to this plan: “We thought, what else is out there, what can we do different to enhance the entire watershed?”

Critics say this approach is harmful to fish. Nina Bell, executive director of the nonprofit, Northwest Environmental Advocates, explained this viewpoint.

“It is a get-out-of-jail card,” she said, per the report. “It takes care of [wastewater] plant’s responsibility but doesn’t have the kind of real water quality benefits we need.”

Water temperature affects the entire ecosystem, not just fish, according to the EPA: “Temperature affects the oxygen content of the water (oxygen levels become lower as temperature increases); the rate of photosynthesis by aquatic plants; the metabolic rates of aquatic organisms; and the sensitivity of organisms to toxic wastes, parasites, and diseases.”

For similar stories, visit Water Online’s Wastewater Regulations And Legislation Solutions Center.