Nearly Three Years of Successful UV Disinfection At Poughkeepsies’ Water Treatment Facility, NY

It is now nearly three years since Poughkeepsies’ Water Treatment Facility in New York state installed six Aquionics UV disinfection systems for drinking water treatment. In that time the closed chamber, medium pressure systems have been performing beyond expectations.


“We get approximately 5,000 hours of lamp life per UV system, but a few lamps have run for as long as 11,000 hours, which is excellent” commented Paul Lill, the facility’s plant manager. “This means we only have to change the lamps about once a year while also reducing our running costs – always an important consideration.”

Poughkeepsies’ Water Treatment Facility serves a community of nearly 80,000, drawing water from the Hudson River to meet an average daily demand of 10.5MGD.  Prior to installing the Aquionics equipment in March of 2005, chlorination was used in open settling basins, followed by filtration. This process required substantial chemical usage and produced significant disinfection byproducts.

With the addition of the Aquionics UV treatment equipment the amount of chlorine required for primary disinfection was significantly reduced, with a corresponding lowering of disinfection byproducts by up to 20%. Secondary, residual disinfection is provided by chloramines. The resulting disinfection levels complied with the new guidelines of the Surface Water Treatment Rule issued by the EPA.

The six Aquionics UV systems are situated downstream of the filters and operate in parallel.  The medium pressure, closed channel design disinfects with far fewer lamps and with a much smaller footprint than comparable low pressure systems. Each chamber is fitted with UV monitors to measure actual UV fluence and dose for record keeping. With the addition of an optional online transmittance monitor, real time transmittance values are used to automatically adjust the dose pacing of the UV system.

“We originally considered alternative disinfection technologies to meet our goals,” explained Lill. “The units’ lower relative cost, their compact size which fits into our existing facility and the technical merit were all deciding factors in choosing Aquionics equipment.”

To keep maintenance low, the systems are equipped with automatic cleaning mechanisms which keep the UV lamp sleeves free of organic deposits. When the lamps need replacing, it is a simple operation that is carried out by on-site staff.

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