Aerial view of UMJA wastewater treatment plant.

RETTEW continues to bring value to municipal clients as their Engineer of Record!

UMJA recently completed a significant wastewater treatment plant upgrade by a third party. This upgrade converted the plant to meet stricter effluent ammonia and phosphorus discharge limits.

As part of the upgrade, a new headworks screening system was installed, resulting in a higher pass-through of organic material to the primary clarifier. In addition, the biological treatment system was converted from a trickling filter to a modern activated sludge-enhanced nutrient removal system.

The effluent quality has been excellent, but since the start of the year UMJA has struggled with managing their biosolids. As Engineer of Record for UMJA, RETTEW worked with them to analyze the issue and develop an innovative response. This was all conditional upon using the existing assets, as UMJA did not want to spend additional capital.

RETTEW analyzed the operation of UMJA’s aerobic sludge digester that was used to stabilize the sludge to a Class B product prior to land application. The prior batch operation was determined to be unsuitable for the new plant operation and resulted in higher biosolids costs for UMJA. RETTEW’s Energy & Environmental Engineering team designed a reconfiguration of the digestion process and allowed UMJA to achieve the required process results for Class B biosolids using one of the two of UMJA’s existing digesters.