Located in western Pennsylvania just south of the New York border, Bradford is a town of about 8,000 residents. In 2019, the Bradford Sanitary Authority upgraded their wastewater facility to expand its capacity.
Bradford’s wastewater treatment plant
0.14
hp/1,000 FT3 mixing efficiency,
$55,000
annual energy savings
Challenge
They also constructed new aerobic digesters to remove pathogens and condition sludge and added reed beds to de-water and compost sludge. Prior to the upgrade, the plant stabilized their sludge with lime and sent it through two belt filter presses.
Solution
EnviroMix’s BioCycle-D Optimized Aerobic Digestion Process was selected as the best technology for the aerobic digesters based on the energy cost savings as well as the ability to effectively mix up to 3.5% solids, which would not be possible with diffused aeration alone.
BioCycle-D offered the plant energy cost savings of over $55,000 per year versus diffused aeration and blowers, yielding a payback period of approximately five years. BioCycle-D operates on the principle of alternating between aerobic and anoxic conditions and using real-time data to optimize digestion and save energy. By decoupling aeration from mixing, plants satisfy oxygen demand and achieve significant energy savings.
BioMix Compressed Gas Mixing is integrated seamlessly with the fine bubble diffused aeration system to decouple aeration from mixing.
The Bradford plant has both a conventional activated sludge process and a sequencing batch reactor (SBR) process that waste to the BioCycle-D aerobic digesters. So, the aerobic digesters currently receive sludge from three different sources: primary sludge (8-10%), waste activated sludge (WAS) from the conventional system, and WAS from the SBRs. Bradford operates the digesters independently, letting one fill and then switching to the second.
Results
BioCycle-D’s ease of operation and maintenance make it a great solution for the small staff at Bradford. Donnie Hayden, Bradford’s operations manager, estimates his staff only spends 6-8 hours a month maintaining the BioCycle-D system — checking the compressors, checking the blowers, and cleaning the instruments. Hayden commented, “The maintenance is very low. You pretty much set it, observe it, and leave it be.”
The Master Control Panel controls the BioMix system as well as the blowers through online instrumentation.
Along with the significant reduction in energy costs and maintenance, the BioCycle-D process eliminates the need to add chemicals. Hayden’s staff no longer has to deal with the mess of adding lime to the sludge.
As a customizable solution, EnviroMix’s BioCycle-D Optimized Aerobic Digestion Process allows plants to optimize their aerobic digesters for Class B stabilization, energy use, chemical consumption, nutrient recycle loads, and disposal costs.