Illinois River Quality Improves
Data Shows Cities Doing Better Job At Reducing Phosphorus
By Scott F. Davis
The Morning News • sda-@nwaonline.net

ROGERS — Samples from the Illinois River show municipal wastewater plants in Northwest Arkansas are improving at removing phosphorus from their discharges into streams, a scientist said Tuesday.

Marc Nelson, supervisor of the Arkansas Water Resource Center’s water quality laboratory, said preliminary data show a “four-fold reduction” in pounds of total phosphorus in 2003, compared to 2002. The lower base-flow phosphorus concentration — about 0.16 parts per million — is still quite a bit higher than the 0.037 limit in Oklahoma’s water standards.

Nelson said 0.037 is unattainable even during base flow, unless sewage plant discharges are completely eliminated, which is not a realistic scenario, he said. Base flow is a river’s normal flow and does not include runoff from rain. High levels of phosphorus promote excessive algae bloom, which can cause taste and odor problems in drinking water.

The four cities upstream of the sampling site — Fayetteville, Springdale, Rogers and Prairie Grove — decreased the total amount of phosphorus in their discharges by 80 percent from 2003 to 2002, Nelson told officials at the Northwest District meeting of the Arkansas Water Works Association.

The big drop came from Springdale — decreasing from 7.5 parts per million in 2002 to 1.5 parts per million in 2003. Springdale is now achieving phosphorus levels comparable to those from the Fayetteville and Rogers utilities, officials said. Springdale’s discharge has been below 0.7 part per million for the past five months, said Rene Langston, executive director of the Springdale Water Utility.

The three big cities are now achieving phosphorus levels below 1 part per million in stream discharges, as required in a deal reached with Oklahoma last year. Nelson said the cities should consider splitting the $50,000 annual cost to continue the testing so they can show they are improving water
quality.

The center had been collecting base flow and extensive storm flow sampling data for eight years from the monitoring site south of Siloam Springs at the Arkansas 59 bridge until this year, when funding for testing at the site dried up, Nelson said. “It would be a reasonable thing for cities to take up that testing,” Nelson said.

“Data is extremely important. If we are basing (policy) decisions on poor data, we’re shooting ourselves in the foot,” Nelson said. “The bottom line is good information allows you to use your money more efficiently.” Langston said he is not sure whether the cities should pay to continue the center’s testing. He suggested the cities should consult with state regulatory agency officials in Arkansas and Oklahoma to determine an appropriate, agreed-upon testing methodology before paying for more testing.

Springdale officials have reduced phosphorus by making expensive operational changes to the city’s wastewater, including adding aluminum sulfate to the treated water and hauling more raw sludge to a landfill, he said. Local industries have cooperated by reducing the amount of phosphorus that they send to the plant, he added.

“We’re operating on the outer limits (of phosphorus reduction) … It’s a struggle doing that every month,” he said. Langston cautioned the utility can’t guarantee these levels until the plant expansion is complete next summer.