Iowa Wastewater Treatment Plant Improvements

Challenge: A private client facility was increasing its production and was having difficulty meeting the total nitrogen limit.

Solution: The HR Green team completed a Facility Plan, plans, specifications, and construction observation for a private facility that had an upcoming production expansion. The design included civil, process, structural, and instrumentation and controls. These improvements included the conversion of existing concrete basins into anoxic zones for denitrification so that new tankage and aeration equipment was not required. The design conditions were a 2.41 MGD flow, 14,000 lbs per day of biochemical oxygen demand, and 5,000 lbs per day of total Kjeldahl nitrogen. This facility is now seeing total nitrogen removal greater than 79%.

The improvements related to production expansion were designed with future biological phosphorus removal in mind. The biological phosphorus removal recommendations are currently being reviewed and include the reuse of existing pumps, mixers, and tankage to meet the new biological phosphorus removal goals. All of the plant improvements are being completed within the footprint of the existing wastewater treatment plant through repurposing of existing tanks and structures

Benefit: The private client will be able to avoid building a new WWTP by simply modifying existing structures. Additionally, operational changes were implemented which significantly reduced their annual power costs without reducing treatment effectiveness.