Debate Over Phosphorus Reduction Brews In Utah

The city of Provo, UT, may have to make a big investment in its phosphorus problem. By 2020, it must assure that every liter of discharge from its municipal treatment plants contain only 1 milligram of phosphorus, as mandated by the state’s Division of Water Quality (DWQ), according to the Daily Herald.

Currently, the plant is putting out 2 to 3 milligrams. To meet the 1 milligram goal, it will cost $12 a month per household, totaling approximately $100 million in costs, reports the Herald.

After that goal is achieved, the next step is to reduce phosphorus to a tenth of a milligram per 1 liter of discharge. The statewide cost, according to the DWQ, would be approximately $1.3 billion or about $20 a month for a Provo residence, reports the Herald.

The phosphorus levels released by the Provo wastewater treatment plant are linked to Utah Lake’s toxic algae problem. According to the DWQ, warm temperatures, calm conditions, low lake levels, and phosphorus, are causing the problem.

However, not everyone agrees that the investment is necessary. As it stands now, Provo is required to comply with Utah’s Division of Water Quality regarding levels nutrients that are discharged into Utah Lake by 2020. But the DWQ’s study on Utah Lake, which will determine the percentage of nutrient reduction needed, won’t come out for four years, according to the Herald.

“What the council and public works department finds disconcerting is the elevated level of crisis the DWQ is making over the issue before the scientific studies are completed,” reports the Herald.

At this time, the Environmental Protection Agency (EPA) has not established a numeric standard for nutrients.

LaVere B. Merritt, retired Brigham Young University professor in civil and environmental engineering, published an analysis on algae blooms and phosphorus in the lake and found that it was, “highly probable that the lake would be essentially the same quality as now even if every nutrient source were reduced to the highest degree possible — at a cost of many hundreds of millions of dollars,” reports the Herald.

In addition to the financial cost, phosphorus removal may also have a negative environmental impact. Rebecca Andrus, Provo’s water resource engineer, opposes the updates, noting that the process required to limit nutrients to the suggested levels will increase the plant’s carbon footprint.

“Treating to this higher level costs more in energy, transportation of chemicals, and other high carbon footprint impacts,” Andrus said, according to the Herald. “Additionally, treating water to the higher standards would make it more valuable for other uses rather than discharging it into the lake.”

Limiting nitrogen may also lead to more toxic algal blooms, said Andrus.

“Cyanobacteria can fix nitrogen; it pulls it out of the atmosphere. When nitrogen is limited, cyanobacteria have the competitive advantage over green algae,” she said.

The issue is still being debated. The Provo council heard concerns from the Provo wastewater treatment plant and from DWQ during a recent work session.