Ionics assists Texas power plant with wastewater treatment system

Hays Energy LP, a limited partner of American National Power (ANP), is using a new water treatment system from Ionics that includes a zero liquid discharge system.

Jan. 24, 2001—Hays Energy LP, a limited partner of American National Power (ANP), is using a new water treatment system from Ionics that includes a zero liquid discharge system.

The new 1,100 MW combined cycle gas turbine power plant is located in San Marcos, Texas.

For the project, Ionics is combining several thermal and membrane-based technologies, including: a zero liquid discharge (ZLD) system using Ionics' RCC(r) brine concentrator and crystallizer technologies; ultrafiltration (UF); reverse osmosis (RO); and electrodeionization (EDI).

Ionics' water treatment technology reuses and recycles 98% of the wastewater from the plant's cooling towers and eliminates wastewater discharges into the nearby San Marcos River. All the solids from the water are concentrated into a waste that is suitable for disposal at a licensed landfill.

Bill Heins, Project Developer for the Hays Energy installation, notes, "Ionics was selected for this project because of its superior technical qualifications, experience and reputation. Approximately 90% of the integrated wastewater and ZLD systems for power plants around the world are designed by Ionics. These systems have proven to make both environmental and economic sense."

At the power plant, two wet towers dispose of waste heat by evaporation, and produce a wastewater stream, or "cooling tower blowdown." Ionics' integrated water treatment process for the Texas power plant takes the cooling tower blowdown and treats it. First, the backwashable ultrafiltration (UF) system, which utilizes NORIT UF technology, removes suspended solids from the cooling tower blowdown. Next, a filter press processes the UF system backwash, creating a solid waste. The excess liquid removed from the backwash processing system is then recycled to the UF feed.

The UF filtrate is then preconcentrated by the reverse osmosis (RO) system. Ionics' Electrodeionization (EDI) system then polishes the high quality product water produced by the RO system to produce water suitable for useage as boilerfeed makeup. The UF/RO/EDI system produces about 800,000 gallons per day of demineralized water.

The concentrate from the RO then goes to Ionics' zero liquid discharge (ZLD) system, which utilizes Ionics' RCC(r) brine concentrator and crystallizer technologies. Ionics' ZLD system treats about 1 million gallons per day of the cooling tower blowdown.

The ZLD system maximizes the recovery of high quality water for use as demineralizer makeup, and allows the cooling tower blowdown to be reduced to a dry solid suitable for disposal in a landfill.

Ionics was awarded the $10 million contract to design, engineer, supply, install and commission the integrated water and ZLD system in early 2000, and the new power plant is due to begin operating in 2001.

Commenting on the project, Arthur L. Goldstein, Ionics' Chairman and CEO, notes, "This Texas facility, like a number of recently awarded Ionics contracts, reflects the execution of the Ionics Total Water Management(r) concept. This concept involves the recognition that the water that enters, leaves and becomes part of industrial processes can be economically managed. Increasingly, power plant clients such as ANP are choosing an integrated water and wastewater treatment approach which provides for a zero liquid discharge facility and produces high quality water for reuse and recycle to the power plant."

With Ionics' state of the art water and wastewater technology, Hays Energy is incorporating a water management solution that reduces the power station's water consumption as well as contributes to environmental protection in the San Marcos area.

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