Treatment Pathways to Address Current and Future Nutrient Reduction and Operation Goals

The Rochester Water Reclamation Plant is evaluating alternatives to address aging infrastructure and sequentially reducing nutrient discharges in a logical progression. Facility testing and process analysis is presented demonstrating how existing plant capacity and performance was maximized to reduce future facility needs. Three treatment pathways for reducing nutrient discharges were considered including continued parallel operations of high purity oxygen and air activated sludge systems, conversion to conventional biological nutrient removal, and conversion to aerobic granular sludge. By maximizing capacity of the existing facilities and converting to a single conventional biological nutrient removal system, previous facility planning capital and annual operating costs were reduced by 25 and 15 percent respectively. An innovative solution using advanced aeration controls and hydrocyclone wasting could further reduce costs by 25 to 30 percent when total nitrogen discharges of 10 mg/L are required.