Paul Kaldahl, a horticulturist with the city landscaping department, prepares to water a thirsty tree in this July file photo. The city will soon use effluent water for irrigation.

The Lawrence Parks and Recreation Department has trucked more than 1 million gallons of potable water to saplings, grass and flowers in medians, roundabouts and the like throughout the city this summer.

“We have four trucks hauling 1,000 gallons of water each,” said Mark Hecker, the department’s assistant director. “They probably fill up four or five times a day, depending on the weather.”

Soon those trucks will pull up next to the wastewater treatment facility in east Lawrence instead of a fire hydrant. There, the trucks’ tanks will be filled with effluent, or treated, wastewater instead of potable water.

The Kansas Department of Health and the Environment recently approved a plan developed jointly by city’s parks and utilities departments to integrate effluent water from the wastewater treatment facility into the city’s irrigation plan, said Jeanette Klamm, the city’s utilities program manager.

“This is something we’ve had on the shelf for years,” Klamm said. “The drought this summer has spurred us into action and allowed us to get this approved pretty quickly.”

Lawrence isn’t the only city recycling wastewater. Wichita pumps effluent water from Cowskin Creek Water Quality Reclamation Facility to recreational ponds used for fishing and boating. And many Kansas towns have been pumping their effluent water to golf courses for years. In much drier San Antonio, Texas, recycled water is used to augment the flow of the San Antonio River so tourists along the famous River Walk aren’t moseying along a dry creek bed.

In the final stages of treatment before pumping it back into the Kansas River, wastewater is infused with sodium bisulfate to soften the effects of an earlier chlorine treatment.

On a characteristically sweltering summer day in late August, Klamm stood next to a spitting, churning, compartmented pool of water being treated with sodium bisulfate. The water looked brackish, similar to the water in the Kaw flowing to her north beyond a line of trees. Klamm pointed to a small PVC pipe pouring a steady stream of crystal clear water into the mix.

“This water is constantly sampled to make sure it meets certain requirements before we pump it into the Kaw,” Klamm said. “That pipe is putting the sampled water back in the mix. See how clear it is? If I hold up a glass of tap water and a glass of this effluent, you wouldn’t be able to tell the difference — not even smell.”

Human contact with effluent water isn’t harmful, though ingestion is discouraged. For plants, however, it packs a little punch that could be useful.

“There’s a little nitrogen in there — not very much because it has to be pumped back into the Kaw, but what’s in there should actually be good for the plants and trees,” Klamm said.

The wastewater facility, which sits on a lush knoll in east Lawrence, has been using effluent water in its own sprinklers for more than a decade. Other sprinkler systems throughout the city are plugged into the potable water system.

“We’d love to use effluent in the flower box sprinklers downtown, but that wouldn’t be economical at this point,” Hecker said. “We’d have had to build the system that way originally. Changing it now would be a huge expense.”

Lawrence’s 2012 city budget allotted more than $45 million (27.1 percent of the budget) to water and wastewater treatment. That’s more money than the city allots to any other utility by more than $33 million.

But when the parks and recreation department integrates effluent water into its irrigation plans, the city’s water bill probably won’t change.

“It’s still a good thing,” Klamm said. “The city has to buy water, and the amount probably won’t change. But the city also spends money treating and pumping water. The parks and rec department has had to use water we’ve treated for drinking purposes to water all the flowers and trees. It’ll just be a little water every day that we won’t have to treat and pump.”