The Minnesota Environmental Initiative named the cooperative among its finalists this year for water quality awards for its phosphorus reduction program. More than 80 percent of the cooperative’s growers now plant a spring cover crop to reduce soil erosion that carries phosphorus into waterways. Last year, the use of cover crops by its growers is estimated to have kept 16,000 pounds of phosphorus from reaching the Minnesota River, where the nutrient feeds algae blooms.
The information was part of the annual report made Tuesday by Louis Knieper, environmental compliance director for the cooperative, to the Renville County Board of Commissioners. The Renville-based company is required to report on water quality compliance annually as part of its permit to discharge treated wastewater into County Ditch 45, which becomes Sacred Heart Creek.
Ten years of monitoring data on the lower reaches of the creek show that the discharges from the sugar processing facility have not adversely affected aquatic life in its waters, according to Knieper. The abundance and biodiversity of aquatic organisms has not been impacted. The creek’s biodiversity indices are among the best for Renville County tributaries to the Minnesota River.
Knieper reported no significant water quality violations for the previous year, but did report progress in a number of areas. Last year saw the plant process 2.437 million tons of sugarbeets, a smaller harvest than previous years. The wastewater treatment plant treated and discharged 301 million gallons of water as part of the campaign from Sept. 1, 2014, through Feb. 5.
The company installed new filters that have captured and recycled a much larger share of the “sluice’’ of organic materials that otherwise went into the large holding ponds on the plant site. Along with capturing and recycling enough sugars to pay for the filter system in a one-a-half-year span, the filters greatly reduced the organic materials that feed organisms in the ponds and cause foul-smelling hydrogen sulfide emissions. Knieper said the plant reported fewer hydrogen sulfide emission violations last year than previous years.
The company is also recycling more of its treated water for use on site, and by so doing reducing the amount of groundwater it needs. The recycling process reduced groundwater usage by 138 million gallons.
The reduction means the company has less water to remove from its ponds during the growing season. It relies on spray irrigation and discharges into the ditch to draw down the ponds prior to the next campaign.
The company has also seen progress in efforts to reduce the salt or mineral content of its discharged wastewater. To further reduce the salinity at this point would require a costly lime-softening water treatment system—estimated to cost $35 million a few years ago—to remove potassium and other minerals, he said.
Knieper said the plant also conducted emission tests on its coal-fired boiler system, and found that the mercury discharge was below the emission standard in the state of 5 pounds a year per stack. The company would have to install costly equipment to reduce mercury emissions, or convert to natural gas, if it exceeded the 5-pound standard.
The cooperative remains in negotiations with the Minnesota Pollution Control Agency over a new water permit. Its permit expired in 2009, but the cooperative operates under the terms of a modified permit application made in 2012.
Source: www.wctrib.com