With a large crop to store for processing, and a warmer than normal winter, the cooperative saw challenges at its 12 remote storage sites, Sagar Sunkavalli, environmental engineer and the cooperative’s manager of environmental affairs, told the Renville County Board of Commissioners on Tuesday.
Overall, the cooperative managed to meet its environmental obligations under terms of a consent decree and a federal water discharge permit that was approved in December after 11 years of negotiations, according to the engineer’s presentation. The annual report is a requirement as part of an agreement allowing the cooperative to discharge its treated wastes into County Ditch 45, or Sacred Heart Creek.
Fifteen years of monitoring by the cooperative has shown that its discharges have not adversely affected aquatic life in the system, according to Sunkavalli.
The cooperative and its member growers harvested 3.6 million tons of sugar beets in 2020, and were able to slice 3.2 million tons as part of the 2020-21 campaign, according to the report. That’s in contrast to the previous year, when wet and cold conditions made it impossible to harvest all of the crop. The cooperative had harvested 2.81 million tons of beets, and sliced 2.61 million tons in the 2019-20 campaign.
Sunkavalli said the warm weather conditions caused storage “challenges” at the Bird Island and Buffalo Lake sites. The cooperative acted proactively to close valves to prevent the runoff of juice from the sites. Further, the cooperative hauled 1.25 million gallons of water from those sites to the Renville factory for wastewater treatment.
“It comes at a big cost,” said Sunkavalli, “but we felt it was the right thing to do.”
The wastewater plant discharged 387 million gallons of water into County Ditch 45 through the campaign, which continued to May. The factory was able to apply 146 million gallons on land through irrigation.
The factory’s treatment process experienced ammonia exceedances on some occasions in September 2020, but did not exceed the monthly allowed total. In February, there were also instances of elevated levels for total suspended solids.
Through the campaign, the cooperative was able to continue a trend toward reduced amounts of dissolved minerals in its discharges. It also made continued progress toward reducing the amount of high-strength effluent needing treatment per ton of beets processed.
The cooperative also continued to see high participation by growers in its cover crop program. The practice reduces phosphorus runoff and earns the cooperative phosphorus credits. Growers have been planting 90,000 to 100,000 acres of cover crops each spring, or nearly double the target amount for the program.
Sunkavalli said this year’s hot and dry weather is presenting new challenges. The drought has lowered water levels in its treatment ponds, and a lack of wind has meant less dilution of the hydrogen sulfide that the ponds emit as organic matter decomposes. The factory is also monitoring the ponds to meet requirements that they maintain a minimum of two feet of water. In previous years, the challenge has generally been the opposite, as the ponds swelled due to high levels of precipitation.
The permit issued to the cooperative last year by the Minnesota Pollution Control Agency allowed it to increase its daily discharges into County Ditch 45 from September to April from 2.3 million gallons to 2.6 million gallons a day, contingent on county approval. The permit also allows the cooperative — also contingent on county approval — to extend its discharge period to April 30 or when the water temperature in Sacred Heart reaches 13 degrees Celsius, whichever comes first.
Last year, the Renville County Board of Commissioners approved the increase in daily discharges but acted to prevent the cooperative from extending the discharge into April after hearing concerns from landowners along the system.
Sunkavalli told the commissioners that the cooperative will be asking the county to reconsider the denial. He said the cooperative is confident that it can discharge into April without adversely affecting the drainage systems of farms along the creek, and that it would quickly act to stop discharges if they posed a potential of doing so.