Design-Build ZLD Wastewater Treatment Plant
APS (Arizona Public Service) has been a leading provider of electricity and energy products and services to the Western United States for over a century.
With power plants located throughout the Southwestern U.S., APS provides natural-gas, coal and nuclear generated electrical power to the region.
The plant is comprised of two 2x1 combined cycle natural gas-fired units to produce a total of 1060 MW of electrical power. Critical to the planning and permitting of this facility was the source and utilization of water and the environmental impact of the station with respect to liquid emissions.
Based upon these issues, Redhawk was designed to use reclaimed municipal effluent from the nearby Palo Verde Nuclear Generating Station for its process water requirements. What is unique about this source of water is that it's supplied by several neighboring City of Phoenix municipal treatment facilities with their associated seasonable variability. The plant would also be designed to utilize well water as a contingency and achieve in either case, high-quality water for continuous re-use throughout the plant.
Design-Build Project Capabilities
APS chose proven and resilient technologies to successfully achieve the objectives of the Redhawk Power Station wastewater treatment facility. The Zero Liquid Discharge (ZLD) System had to reclaim water resources and reject waste properly as an integrated component of the power station.
To accomplish this, the HPD-designed process utilized brine evaporation and crystallization systems, which were the key elements in the overall design. The evaporator was designed to receive 450 gpm of high salinity blowdown from the cooling towers. The compressor-driven evaporator pre-concentrates the brine and produces high purity distillate for recycling to the cooling tower and service water system.
Concentrate from the evaporator is advanced to the crystallizer where the salts that form the impurities are crystallized and sent to a centrifuge for dewatering. The crystallizer is also compressor-driven and produces distillate that is combined with that of the evaporator for recycle.
