Maintaining Plant Operations to Meet Permit Limits While Conducting Major Aeration and RAS System Replacements

The City of Richmond Department of Public Utilities began implementation of its Nutrient Reduction Program (NRP) in 2005. This program is in response to a law passed in March 2005 requiring municipalities to upgrade treatment facilities to comply with the waste load allocation for total nitrogen and total phosphorus. The NRP consists of major upgrades to existing processes and construction of new facilities. A significant portion of the NRP at the City of Richmond, VA WWTP (Richmond WWTP) is reliability upgrades for the activated sludge system. Although massive aeration and return activated sludge upgrades will provide an increased measure of reliability when they are completed, the Richmond WWTP must also consistently meet the prescribed permit limits during construction. This paper presents the challenges faced by the City of Richmond for meeting permit during construction and the proposed sequence of construction that will help them achieve their treatment goals.