Borough of Sayreville
During the study phase for the new water treatment plant, Borough Engineer David J. Samuel invited water treatment equipment manufacturers to participate in a pilot study to determine the most efficient and effective methods for treating the various sources of raw water available to the Borough. After pilot testing various equipment on the Duhernal, lagoon and well waters, Krofta Technologies equipment was selected, primarily based on its ability to effectively treat even the highest iron concentrations of over 20 ppm and its relatively small footprint compared with other systems.
The process piloted by Krofta consists of two levels of treatment. The initial part of the process is a Dissolved Air Flotation (DAF) clarifier. In this equipment, the iron is coagulated through the addition of chemicals and fine air bubbles, floating the iron and other impurities to the top of the water surface where it can be easily removed. This process significantly reduces heavy concentrations of iron present in the Duhernal water to prevent over-loading of the downstream sand filtration unit.
The second level of treatment is a combination DAF and sand filtration unit, or Sandfloat. Water flows downward by gravity through the seven foot deep circular tank, through a DAF section on top that further reduces the contaminants loading and then through the gravity sand filter section at the bottom of the tank. The Sand Filter is comprised of 23 cells, which can be backwashed individually. This permits one cell to be backwashed while the other 22 cells remain in operation treating water. In this manner, a cell is being backwashed every 10 12 minutes and each cell gets backwashed every 4-5 hours.
Influent facilities were designed to connect with the existing plant's three raw water sources. Support facilities were provided for the Krofta equipment, including chemical storage and feed equipment, recycle pumping arrangements, a sludge pump station and associated piping. The intermediate pump station draws water from the Sandfloat gravity filters and pumps it through the granular activated carbon units, which act as polishing filters, to a 3 million gallon on-site storage tank. A high-lift pump station was included to transfer water from the tank to the distribution system. The first filtrate water, which is discharged prior to a sand filter cell being returned service and the backwash water from the carbon filters will be stored in an equalization basin and recycled back into the head of the process to minimize waste. The use of stainless steel was maximized throughout the plant to minimize long-term maintenance requirements. The overall system was designed to provide 7 million gallons of potable water per day (MGD) to the residents of Sayreville. Full redundancy was provided through the installation of two complete treatment process trains. The facility was also designed to be expandable to a total capacity of as much as 21 mgd.
Support facilities designed into the treatment plant include an emergency generator that can provide power to the entire plant and also be utilized through coordinate with the electric utility for load shedding to reduce Sayreville's power costs. State of the art low-harmonics variable speed drives are on the largest motors to reduce electrical starting and operational costs. A computer and PLC based supervisory, control and data acquisition system (SCADA) provides automated process control, operation and monitoring of the entire process from a single computer terminal or from an off-site computer and unmanned operation of the entire plant. Designed into the plant are modern laboratory facilities, ample office and meeting space and updated employee facilities such as locker rooms and kitchen and meal area