City of Gardiner

Maine Avenue CSO Storage Tank & Screen Upgrade & Collection System Evaluation

Gardiner, ME

Project Summary

The Maine Avenue Pump Station (MAPS) in Gardiner pumps approximately 85% of the City’s wastewater flow. MAPS was constructed in the late 1970s and the pumps were again upgraded in the mid-1990s. The pump station was originally designed with a 2” bar rack for removing inorganic matter from the wastewater flow prior to pumping. The 2” bar rack required excessive maintenance from a lean wastewater operations staff. And, with the increase in use of ‘flushable wipes’, which pass through the existing bar rack, the City had been experiencing an increase in pump clogging. Furthermore, during periods of high flow, the lower level of the pump station could flood, presenting a safety hazard for operators. 

Hoyle Tanner completed the evaluation of CSO storage, retention and treatment alternatives, mechanical screening improvement alternatives, preliminary engineering, and final design, permitting, environmental impact assessment and assisted with funding procurement for this project. The selected screening alternative includes a long multi-rake bar screen that transports screenings to the upper level of the pump station to a washer/compactor unit to remove inorganics and excess water, for ease of disposal.  A CSO storage basin was sized and designed by others.    


  • Alternatives Development & Analysis 
  • Preliminary Design 
  • Permitting 
  • Funding Assistance 
  • Final Design 
  • Bid Process Administration 
  • Construction Administration 
  • Construction Observation 

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