Donohue, the City of Rushville, Indiana, and generator contractor Bowen received a 2018 Merit Award for engineering excellence from the American Council of Engineering Companies (ACEC) of Indiana. The award was made in recognition of the Cloth-Media Disk Filters for CSO Treatment project completed for Rushville Utilities. 

This project included a new and innovative application of cloth-media disk filters (CMDFs) for combined sewer overflow (CSO) treatment followed by ultraviolet (UV) disinfection. This is the first completed project in the U.S. to use CMDFs combined with UV disinfection for CSO treatment. 

The CMDFs were also designed to filter the secondary clarifier effluent and, with the addition of alum, are capable of achieving a total phosphorus effluent discharge below 0.3 mg/l. The combined WWTP secondary effluent and treated CSO flow was designed to meet the plant’s discharge permit limits. With the new UF disinfection system, the average monthly e. coli colony count for filtered plant effluent is less than 1. 

Existing underutilized or abandoned structures were repurposed to house the new treatment processes, avoiding the need to construct costly new structures. In addition, the new system was designed and constructed as a guaranteed savings project to minimize ratepayer impacts.

This successful project allowed Rushville Utilities to meet their CSO compliance schedule five years in advance and future lower phosphorus discharge limits three years in advance.

Pictured above (left to right): Tracy Williams (Donohue), Les Day (City of Rushville Utilities), Mayor Pavey (City of Rushville), Matt Meyer (Bowen), Steve Gress (Donohue), Steve Nutt (Bowen), and Ryan Vevang (Donohue).