Using Existing Facility to Maximize the Wet Weather Treatment Capacity of the Akron, Oh Water Reclamation Facility: Optimizing Existing Secondary Clarifiers

The City of Akron, Ohio must expand the secondary treatment capacity of its Water Reclamation Facility from 416,000 m3/day (110 mgd) to 644,000 m3/day (170 mgd) as one component of an overall combined sewer overflow abatement program. Preliminary process analysis indicated that providing step-feed modifications to the aeration basins and modifications to the shallow secondary clarifiers could significantly increase the wet weather secondary treatment capacity. Secondary treatment train Unit 6 was modified to provide step-feed capabilities, and its secondary clarifiers were modified with baffles, improved center wells, and energy dissipating inlets in various combinations. Testing of the upgraded clarifiers along with actual wet weather events indicates the increase in capacity to 492,000 m3/day (130 mgd) required with only the modified Unit 6 was achieved, subject to final stress testing and a report on revising the Water Reclamation Facility’s control measures. Higher capacities may be possible.