A Midwestern sugar beet processor was struggling to handle the high-strength waste that was produced as the company processed sugar beets into refined granulated sugar. Before retaining ATI’s services to design the expansion of its wastewater treatment plant (WWTP), the company’s system consisted of two flume water clarifiers, several wastewater holding lagoons, an anaerobic contact process system, an aerobic activated sludge process system, and a sludge dewatering system. During warm weather, the wastewater ponds created order issues, while during cold weather, adequate pre-acidification did not occur in the wastewater holding lagoons to maintain design flow and COD loading to the anaerobic contact process. The system discharges to a nearby river.
ATI promptly developed a plan of attack. This plan included the conversion of the existing lagoon to a covered raw wastewater holding lagoon, modifications to the aerobic portion of the WWTP to treat the lagoon wastewater, and the addition of a pre-acidification system with a new heating system, to improve the performance of the existing anaerobic portion of the WWTP during cold weather. The pre-acidification system partially pre-acidifies the wastewater and allows the anaerobic contact process to treat closer to its operational capacity during cold weather. The existing anaerobic heating system was retained.
The upgraded WWTP successfully completed its first winter of operation. Preliminary data indicated that the anaerobic system was able to process about 50% more organic load than previous winter seasons. The additional biogas is used on site in dryers.