Clearfield Municipal Authority
Permitted Design Flow: 4.5 MGD. Maximum Flow: 25 MGD
Target Effluent Concentrations: 6.0 mg/L TN, 0.80 mg/L TP
Bassett Engineering partnered with Gwin, Dobson & Foreman to evaluate, design and upgrade the Wastewater Treatment Plant that serves Clearfield Borough and Lawrence Township. The permitted design flow for the WWTP is 4.5 MGD with a design maximum day flow of 25 MGD.
An entirely new liquid treatment process is being built in order to reduce annual effluent loadings to 6.0 mg/L Total Nitrogen and 0.8 mg/L Total Phosphorus. The Hybrid Bardenpho with Step Feed Process was designed with the flexibility to operate other processes including the Modified Ludzack-Ettinger, Virginia Initiative Plant, Johannesburg, and A2O. Step Feed will divert peak flows to the last aerated zone for contact stabilization, allowing a maximum daily flow of 25 million gallons per day.
BioWin process modeling used five years of actual flow and loading data. Two weeks of intensive testing were conducted to supplement and collaborate this historic data.
High-efficiency grit removal and influent screening are being added. Three new biological reactors are being built, each with baffle walls, anoxic and oxic zones, submersible mixers, fine bubble diffusers, mixed liquor and nitrate recycle pumps. High-speed Turbine aeration blowers are also being provided. Carbon can be fed to enhance denitrification and caustic soda could be fed to raise pH.
The Clarifiers are being optimized to remove nutrients, including chemical enhancements (polymer and alum feeds) to prevent solids washouts during peak flows.
Treatment buildings, clarifiers, and sludge pumping are being built. The sludge handling processes are being modified to minimize the amount of nutrients being recycled to the main treatment process. Sidestream treatment of sludge recycle flows will be implemented.
The NRT Upgrade design includes a fully automated computer process control system that will allow either flow-paced or instrument-based process control of D.O., pH, ORP, ammonia, and Nitrate; plus Mixed Liquor, Nitrate, and RAS pumping.