Phosphorus in Utah Lake targeted

The hope of the Timpanogos Special Services District used to be in a crop of bug-eating bugs — but not anymore.

Now the waste-treatment plant is turning to a different microorganism that's designed to combat phosphorus, a rising star on the list of Utah Lake spoilers that's raising statewide concerns and focusing attention on waste-treatment plants.

No mandates have required the district to alter its previous plans — which were almost a year in the making — but the hint that a biological phosphorus removal program might one day be necessary made the district change its mind.

"If we don't do it now, then my guess is that it would cost a lot more money to do it later," said Timpanogos Special Services District engineer Larry Bowen.

The district had chosen to add an army of insects to cannibalize waste as part of the plant's long-planned expansion. The goal was to reduce the amount of sludge that came through the plant — thus minimizing the often criticized foul smell that sometimes lingers in the area.

But a recently published study by the Utah Division of Water Quality says waste treatment plants are responsible for dumping 76 percent of Utah Lake's phosphorus into the water, which is bad because phosphorus facilitates the overgrowth of a harmful blue-green algae.

The study suggests that waste treatment plants should implement biological phosphorus removal plans to reduce the amount of phosphorus flowing into the lake, but a lack of conclusive data has made the division stop short of setting an exact limit on how much phosphorus is acceptable.

Nevertheless, a cannibalizing system would not necessarily reduce the plant's phosphorus output, so Bowen suggested the district change plans at a board meeting a week ago. With a biological removal system in place, Bowen says he thinks the plant will only emit one milligram of phosphorus per liter of water, as opposed to the three or four milligrams of phosphorus per liter now being released.

"Eventually, we're going to get a limit," Bowen said. "We're still not sure (what the limit will be) — the state can't give us definitive numbers because they don't know what they will be. But we're trying to read between the lines and make a decision with the information that's available to us."