An increasing number of water and wastewater utilities are using green technology in an effort to help conserve water and cut down on costs. Metropolitan Industries recently provided a non-potable, effluent water reuse station to the Village of Romeoville’s South Wastewater Treatment Plant with the expectation to provide both energy efficiencies and expand the village’s green initiative.
The plant’s initial concept was to simply reduce the amount of treated water the plant was using from the village’s water supply. Their thought was that the effluent water, which was just going to waste, could be used as a non-potable water source, ideally saving a significant amount of the town’s water output for potable use, which has to be treated for consumption.
The excess water left over from the treatment plant that would typically be discharged back into the river is now disinfected, filtered and reused, supplying pressurized effluent water back to the treatment plant for non-potable uses at the plant while developing more applications to utilize the water.
The system is comprised of three stainless steel submersible turbine pumps and coarse screen in the final effluent structure. Metropolitan also provided stainless steel piping, a duplex basket strainer, flow meters, a “smart” valve system, remote access for end-users to fill their tanks without entering the control building, variable speed operation via variable frequency drives and SCADA system interface via A-B PLC control system with touchscreen operator interface to maintain a constant pressure.
The pumps operate only when demand for non-potable water exists throughout the WWTP and/or customers are filling their tanks. The variable speed control system matches demand while maintaining constant pressure, therefore saving electrical costs. Except for the pumps, the balance of equipment was all furnished and installed inside a precast, concrete building prefabricated with all mechanical, electrical, HVAC, etc., finished inside the insulated building with a split-block look and shingled roof.
The pressure control system also allows pumps to speed and slow down depending on demand. The tanker fill line has a backpressure sustaining line to prevent overflowing and over pressurizing the fill line to customers.
Since its installation in October 2013, the station is saving about 115,000 to 120,000 gallons of the treated water per day, which will add up to an average of 45 million gallons of water per year. The village water rate is over $4.00 per 1,000 gallons used, allowing this owner to save over $100,000 a year in water treatment costs. The station most often uses one pump at a time with the capability of running up to three pumps as more effluent water is used.
Fully integrated into the plant’s existing SCADA system, employees have the ability to remotely monitor the new reuse station. Since the system is new to the plant, the remote access also allows employees to view trends.
An extra measure taken by Metropolitan to prevent clogging and keep the effluent water clean was providing a basket strainer to stop small solids from getting though.
This new system is now replacing the need for the existing large non-potable break tank system and diminishing the amount of wastewater discharge to the river, creating a beneficial impact on the environment.
The village describes this project as “well thought out” and applauds Metropolitan for being so instrumental in getting the project to move forward.
The next phase, which is in planning, will allow contractors the opportunity to use the effluent water. Plans to decide how the water will be regulated for contractors to use are in progress and should be available in the near future. The plant expects the demand on effluent water used from the reuse station to increase in the coming years.