The Brownwood Texas Project
Wastewater Treatment Plant with Bosman Fine Bubble Aeration
The population of brownwood is approximately 19,000.
Brownwood is home to Howard Payne University and a Kohler manufacturing facility.
And Growing Steadily...
the brownwood wastewater treatment plant was in need of a cost effective improvement.
Their Problem.
The wastewater treatment plant is rated for a maximum 4,54 MGD, and is currently running an average of around 2.5 MGD. he plant contained some equipment in the neighborhood of 30 years old, and was chiefly comprised of an equalization basin used at high flows, a bar screen and aerated grit basin at the headworks, primary clarification, two Carrousel reactors, two secondary clarifiers, chlorine contact, tertiary sand filters, and dechlorination. The plant used aerobic digesters and dewaters waste sludge using a belt filter press.
Looking for Alternatives.
The owner and the engineer were looking for a cost-effective way to improve the plants performance. They settled on PB Equipment, Inc. Bosman Plate Aerator system to upgrade the existing Carrousel basins. The modified basins make use of only 248 plate aerators total in the two basins, and are now capable of treating the entire 4.54 MGD flow at the elevated BOD levels. An added benefit of using the Bosman Plate Aerators is that four duty 100 HP PD blowers would replace the four existing 125 HP mixers, providing a substantial power savings.
Brownwoods Challenges.
The Carrousel reactors consist of two basins running in parallel. This unit is 20 years old and was already overloaded due to a higher concentration of influent BOD. 250 mg/L, which is over twice the 118 mg/L for which it was designed. The Carrousel provided mixing and oxygenation from four 125 HP mixers. One on each end of the two basins. Even at half the design daily flow rate, the plant suffered from very low DO concentrations. Especially during the very hot summer months west Texas suffers from. Additionally, the owner desired to take the primary clarifiers off line, which would add to the basins load.
The Solution.
Adding the new innovative design converted the aeration basins to plug flow and made use of an anoxic zone to provide nutrient removal in the basins. Five 100 HP blowers will be provided: four will be service with one standby in conformance with Texas state regulations. Additionally, the blowers are equipped with variable frequency drives with basin DO monitoring to provide additional power savings above stated data plate ratings. Controls also incorporate the required aerator relax cycles daily to help maintain the membrane efficiency high by cleaning the membrane.
True Results.
Readings indicated attainable basin dissolved oxygen levels of 7% or higher, which is 3 1/2 times better than before the improvements. Overall plant process is improved with the ability to introduce sufficient D.O. for the MLSS and nitrification. The access walkways and handrails are cleaner and safer with the absence of the constant splashing and aerosols that form a coating on many of the plants surfaces. The replacement of the old surface aeration with the new PB Equipment, Inc. Plate Aeration system effectively doubles the current capacity of the plant for less horsepower than previously used.