The AquaStorm cloth media filters experienced the first wet weather events shortly after start-up in October and November 2017. Due to the continuous treatment capacity, no untreated overflows have occurred.
Rushville’s new tertiary/wet weather filtration system also included replacement of its existing gas chlorine disinfection system with a UV disinfection system. The UV system was installed in the existing tank, which also provided significant project cost savings.
Completion of the filtration/disinfection phase of the city’s upgrade project was achieved five years earlier than required by the state regulation agency. This project is the first AquaStorm filter installation in the nation for dual tertiary/wet weather treatment and will keep approximately 50 million gallons of raw sewage from entering the nearby Flatrock River annually.
“With the addition of the AquaStorm Filter System and new UV disinfection system, Rushville is discharging the best quality of water to our receiving stream, the Flatrock River, than in years past,” Utilities Director Les Day said.
The AquaStorm filter features a disk configuration and an outside-in flow path, which allows for three zones of solids removal. These zones are especially critical in wet weather applications due to the high solids typically associated with the first flush after wet weather events.
The top zone is the “floatable zone” where surface materials such as fats, oils and grease are allowed to collect on the water surface. Solids are removed from this zone by allowing floating material to overflow a scum weir a couple of times each day. The middle zone is the “filtration zone” where solids are removed through filtration. Here, solids deposit on the outside of the cloth media, forming a mat as filtrate flows through the media.
The buildup of solids on the media creates hydraulic resistance to flow through the media and causes the water level in the tank to rise. Once a predetermined liquid level or time setting is attained, the disks begin to rotate and the backwash pump starts, which draws filtered water from the inside of the disk through the media and removes solids from the filter media’s surface. This process fluidizes fibers to provide an efficient release of stored solids deep within the fiber. The bottom or “solids zone” permits heavier solids to settle to the bottom of the tank for intermittent removal. The solids are evacuated from the hopper through collection laterals using the solids/backwash pump. WW
Aqua-Aerobic Systems Inc. is exhibiting at WEFTEC.19, booth 2234. To learn more, visit www.aqua-aerobic.com.
