Client: Portage Area Sewer Authority
Year Completed: 2010
Project Cost: $10,200,000
The Portage Area Sewer Authority provides regional wastewater service for 5,800 residents. The original contact stabilization treatment plant had hydraulic capacity limitations because of excessive sewer system inflow/infiltration. Gwin, Dobson & Foreman designed upgrades to the wastewater treatment plant that included a raw sewage lift station, headworks, aerated grit chamber, equalization storage, ICEAS process treatment system and UV disinfection.
The project included the following:
- Expansion of treatment plant capacity from 1.0 MGD to 2.0 MGD (average) and 6.0 MGD (peak).
- New headworks facility including flow diversion channels, gates and auger screening system.
- New aerated grit chamber with aeration system, grit classifier and grit storage.
- New raw sewage lift station with five (5) 1,300 GPM raw sewage submersible pumps for a total station capacity of 9.4 MGD.
- Conversion of existing contact stabilization tanks to equalization storage (0.6 MG) including coarse bubble aeration system, flow diversion box, level control and painting of steel structure.
- New suspended growth biological reactors for organic treatment and biological nutrient removal. The Intermittent Cycle Extended Aeration System (ICEAS) uses continuous activated sludge aeration technology for organic removal and nitrification. An intermittent anoxic mixing cycle provides denitrification. Settling is achieved by an articulated decant mechanism. All physical and biological processes occur in a single reactor. Aerobic sludge digestion and storage are an
integral component. - New aeration system including centrifugal blowers, fine bubble diffusers and aeration piping.
- New energy efficient sludge dewatering system consisting of a rotary screw press with
polymer feed system. - Channel-type ultraviolet disinfection system with effluent channel and outfall.
- Instrumentation and control system (SCADA) for monitoring and operation of treatment system.
The $10.2 million project places the Authority in regulatory compliance. The increased capacity prevents system overflows and surcharging while providing future service area expansion. The new process has enhanced organic and nutrient removal capabilities. GD&F designed the original treatment facility in the mid-1970’s and became the Authority consulting engineer in 1979.