Phosphorus limit must be met by 2003

by Melissa Wilson

SBJ Staff

The Clean Water Commission of the Missouri Department of Natural Resources implemented a new rule July 14 requiring area wastewater treatment plants that drain into Table Rock Lake to limit their phosphorus output to 0.5 milligrams per liter of water.

Lake Taneycomo already has a phosphorus limit in place, according to Bruce Martin, regional director of the division of environmental quality for the Department of Natural Resources.

Existing plants will have four years to reach the 0.5 milligram per liter level, while plants beginning operation after July 14 must be immediately compliant with the new level, according to Ed Sears, chief of the water section for the DNR.

Bob Schaefer, assistant director of Springfield Public Works, said the city has been working on phosphorus removal for a few years and will have no problem meeting the 2003 deadline for the 0.5 milligram per liter limit.

"We didn't wait for the rule to be approved to begin working on phosphorus removal. It would have been on a tight schedule if we had waited," Schaefer said.

Schaefer also served on a citizens' advisory committee to the DNR to study the phosphorus issue and make recommendations about what level of the nutrient, which causes algae to thrive, would be tolerated.

A 1-milligram-per-liter level, which can be reached less expensively than the 0.5 milligram per liter level through a biological removal process, had previously been discussed by the DNR.

"The sources of the phosphorus and the amount of it already present in Table Rock, and what would happen if the area continued to grow all were deciding factors in the 0.5 milligram per liter level recommendation by the advisory committee to the DNR," Schaefer said.

Removal of the phosphorus to the 0.5 milligram level involves a process in which chemical polymers are added to the treatment process and a solid is formed. The Springfield wastewater treatment plant's phosphorus removal is now at the 1-milligram level in about 30 percent of its wastewater, and it needs to complete the second phase of the installation of the phosphorus-removal system, according to Schaefer.

"We still need to install the biological and chemical equipment to handle the other 70 percent of the flow," Schaefer said.

The Springfield wastewater treatment plant is undergoing a $27 million expansion, which will be complete by the end of 2000. The expansion will be paid for through savings and a recently-approved sewer rate increase.

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