Description: Matching mixing and oxygen needs: Optimizing a severely mixing-limited aeration...
Insufficient DO in aeration systems prevent the successful degradation of organic matter and create conditions for the proliferation of filamentous bacteria. Sufficient air addition not only satisfies the needs of the bacteria, it also maintains solids in suspension. This is important because, without enough air, solids settle to the bottom of the basin and can decompose, releasing pollutants into...
PublisherWater Environment Federation
Word count303
Description: Matching mixing and oxygen needs: Optimizing a severely mixing-limited aeration...
The 90.8-ML/d (24-mgd) Muncie activated sludge WRRF serves approximately 31,000 population equivalents. Following fine screens and grit removal, the flow enters two 42.7-m-diameter (140-ft-diameter) primary clarifiers to settle out heavy organic material. Primary effluent is then combined with return activated sludge (RAS) and mixed liquor is conveyed to aeration basins for oxygen transfer and...
PublisherWater Environment Federation
Word count239
Description: Matching mixing and oxygen needs: Optimizing a severely mixing-limited aeration...
“We’d run our belt presses during the day shift, and as the filtrate came back through the facility as a recycle stream it would knock our DO levels down throughout the day,” said John Barlow, Muncie superintendent. “Our operators would have to constantly turn up the blowers by hand and then adjust the individual header valves. But by the time the afternoon shift came on...
PublisherWater Environment Federation
Word count274
Description: Matching mixing and oxygen needs: Optimizing a severely mixing-limited aeration...
The upgrade to the Muncie facility’s existing aeration system brought in an energy-efficient turbo blower, membrane disc aeration diffusers, and an automated control system. The automated control system included instruments, control valves, and a biological process control panel including a programmable logic controller (PLC) and human–machine interface (HMI).
PublisherWater Environment Federation
Word count244
Description: Matching mixing and oxygen needs: Optimizing a severely mixing-limited aeration...
To support real-time monitoring and control, a suite of instruments were installed in the basins, including calibration-free fluorescent DO probes and ion selective electrode sensors, which measure ammonium, nitrate, and potassium. One ion selective probe was installed per bank (4) and one DO probe was installed in each of the three passes of the four banks (12 DO probes total).
PublisherWater Environment Federation
Word count423
Description: Matching mixing and oxygen needs: Optimizing a severely mixing-limited aeration...
There often is a balance between the risk of using an alternative novel approach versus the safety of a tried and trusted existing one, but the key is always in having enough knowledge and understanding of the facility targets and alternative processes to choose the most appropriate option. After a short trial in a single basin to address the mixing limitations that were resulting in higher DO...
PublisherWater Environment Federation
Word count367
Description: Matching mixing and oxygen needs: Optimizing a severely mixing-limited aeration...
“We initially struggled to have our DO levels close to where we wanted them to be but still get enough mixing in the tanks so that they didn’t become settling tanks, but our controller’s new pulse program took care of that,” Barlow said. “We now save more than $5000 per month with the new aeration system, and that’s with our low, grandfathered electrical rate....
PublisherWater Environment Federation
Word count155
Description: Matching mixing and oxygen needs: Optimizing a severely mixing-limited aeration...
Fundamental to energy efficiency and optimal performance of any activated sludge process is the ability to vary the oxygen supplied to meet changes in flow and BOD loading. This can be challenging in mixing-limited environments. But through automation and taking the novel approach of adopting a sequenced pulsed aeration mode of operation, the Muncie Water Pollution Control Facility has met this...
PublisherWater Environment Federation
Word count124