Prior to this project, Selmer Utility Division had a level of iron in its water supply that was near and occasionally exceeded the allowable maximum contaminant level. The high iron content was successfully addressed through the employment of filter systems at each of three water treatment plants. The horizontal pressure filters that were installed virtually eliminated iron entering the distribution system, thereby providing a long-term solution to the problem.
Each filtration units provides two 2-cell pressure filters. This system allowed for redundancy in the system and lowers the flow rate required for backwash of each cell. An air wash or “simulwash” system was also provided to minimize the amount of water required for backwash, thus further reducing amount of backwash water required and minimizing the impact to the sanitary sewer system where backwash water is disposed. Each treatment plant has a design capacity of approximately 1200 gpm. TLM Associates, Inc. was retained to provide the preliminary engineering report, pre-design cost estimations, hydraulic analysis, design, construction administration, construction observation, and closeout for this project.