The City of Evansville, Indiana needed to make improvements to the West Side Wastewater Treatment Plant (WWTP) to provide additional capacity for both growth and to treat wet-weather flows. Lochmueller Group used phased construction to make improvements that nearly doubled the plant’s NPDES permit capacity of 20.6 mgd.
One of the major improvements involved the addition of a new Biological Aerated Filter, which is ideal for urban WWTPs with limited space for expansion as it requires no settling tanks and no return sludge system.
The West Side project increased the average design flow from 10 mgd to 30.6 mgd. The average design peak flow for the whole plant is 39 mgd with the average design peak flow of the biofiltration process at 20 mgd. The biofiltration process is operated in parallel with the existing activated sludge system. Other improvements included:
- Replacement of fine bar screen
- Addition of inflow bypass pipe with coarse bar screen
- Replacement of influent pumps
- Replacement of aerated grit chambers with vortex grit chamber
- Addition of chlorinated spray system for aeration tanks
- Modification of plant water system