Challenge
The Village of Libertyville, Ill., installed a Hydro-Clear® sand filter system from Evoqua Water Technologies in 1977. Since that time, the Village has benefited from the system, making only minor repairs throughout the years. While the system was still operational and successfully meeting discharge limits, the 27-year-old system was beyond its life cycle.
The Libertyville WWTP has a daily capacity of 4.0 MGD and serves a population of about 21,000 people.
Solution
To avoid the risk of a major breakdown that could have had detrimental effects on the plant and therefore the environment, the Village chose to rehab the filters in June, 2004, before such an event could take place.
Routine customer service visits and a close relationship with Evoqua Water Technologies' led the Village to upgrade their existing Hydro-Clear filter system to a new one.
Rehabilitation of the six-celled CC-37 model filter included installing new underdrain modules, reinforced fiberglass grating, stainless steel mesh and new hold-down hardware. New flip-up, stainless steel splash plates were also installed, in addition to a new PLC-controlled system with touch-screen operator interface.
The entire process took approximately six months to complete, with only two months from plant shut down to re-start.
" It is always nice to start off with new equipment to work with because the risk of equipment breakdowns and maintenance are reduced. The new touch-screen interface makes controlling and observing filter operations so much more convenient for the plant operators. "
Results
The new Libertyville filter system has been operational for a little over six months, and is running like new. Minor repair incidents have been cut dramatically, and concerns over major failure have been eliminated.
“It is always nice to start off with new equipment to work with because the risk of equipment breakdowns and maintenance are reduced,” says Todd Edmark, Village of Libertyville WWTP Superintendent. “The new touch-screen interface makes controlling and observing filter operations so much more convenient for the plant operators.”
The Hydro-Clear filter was developed specifically for wastewater applications; it is not an adaptation of a potable water filter. Hydro-Clear filters feature a unique underdrain system and a shallow bed of single-media, fine-grained sand. These innovations permit the filter surface to be “pulsed” or regenerated periodically, prolonging filter runs and keeping the filter online, despite unpredictable changes in solids loading and characteristics. The filter can be backwashed efficiently with significantly less power and water than is required with other types of filters.
By being proactive in rehabilitating the filter system, the Village will continue to comply with its discharge requirements, and can expect many more years of trouble-free service from the Hydro-Clear filter system.
“The plant operators are more at ease, knowing that most of the equipment related to the sand filter operation is fresh and should last, hopefully, as long or longer than the original installation,” says Edmark.
Evoqua Water Technologies has over 600 Hydro-Clear installations dating back to the 1970s and 1980s.