The United States Environmental Protection Agency (USEPA)’s announcement that it will revise the effluent limitation guidelines for steam electric power generating units could affect not only how power plants use water, but also how they discharge it. The revised guidelines may lower discharge limits for various contaminants in flue gas desulfurization (FGD) wastewater including mercury, selenium, arsenic, and nitrate/nitrite. Although the specific details of the guidelines are unknown at present, the power industry is evaluating various technologies that may address the new effluent limitation guidelines and promote water conservation. Moreover, the power industry is looking for avenues to increase water usage efficiency, reuse and recycle throughout its plant processes. Final rule approval is expected by the middle of 2014 and new regulations are expected to be implemented between 2017 and 2022 through 5-year NPDES permit cycles. discharge limits for various contaminants including arsenic, mercury, selenium, and nitrate/nitrite [1]. These pollutant limits may be below the levels achievable today with conventional treatment [2]. A growing interest exists in zero liquid discharge (ZLD) facilities and processes in power plant operations. Potentially stringent discharge limits along with water conservation and reuse efforts are two of the major drivers to achieve ZLD. Potential pollutant levels are so low that ZLD may be the best option, if not an outright requirement [1]. Thermal ZLD systems have been the subject of increased interest and discussion lately. They employ evaporating processes such as ponds, evaporators and crystallizers, or spray dryers to produce a reusable water stream and a solid residue (i.e. waste). Evaporators and crystallizers have been employed in the power industry for a number of years. However, typical A growing interest exists in zero liquid discharge (ZLD) facilities and processes in power plant operations. Potentially stringent discharge limits along with water conservation and reuse efforts are two of the major drivers to achieve ZLD. Potential pollutant levels are so low that ZLD may be the best option, if not an outright requirement. A key disadvantage of thermal ZLD is its high capital cost. One way to reduce this cost is to pre-treat the liquid stream using innovative membrane technologies and reverse osmosis (RO).

The Water Research Center (WRC) is located at Georgia Power Company's (GPC) Plant Bowen near Cartersville, Georgia outside of Atlanta. Operated by Southern Research Institute, the WRC is an industry resource providing independent performance evaluations of technologies to address water withdrawal, consumption, usage efficiency, treatment, recovery, and reuse throughout the power generation process. The WRC was designed to focus on current and potential future regulatory constraints relevant to the power industry. Technology evaluations at the WRC are centered around seven primary focus areas: 1) Cooling Water & Advanced Cooling Systems, 2) Wastewater Treatment, 3) Zero Liquid Discharge, 4) Solid Landfill, 5) Moisture Recovery, 6) Carbon Technology Effects, and 7) Water Balance Modeling. Testing at the WRC began in 2012 and how the Center was designed as an industry resource for water-based technology R&D, along with updates on select projects underway at the WRC are reviewed.

The safe disposal of FGD brines is a new environmental challenge facing the coal-fired power industry. Due to the removal of heavy metals from coal combustion flue gas in wet FGD units, the purge brines from these units contain significant concentrations of arsenic, cadmium, chromium, mercury, and selenium. The USEPA is currently revising the Steam Electric Power Generation Effluent Guidelines, where it is expected that discharge limits for metals could be made much more stringent. In addition, the new regulations could limit co-mingling of wastewater streams (such as FGD purge brines and cooling tower blowdown). Treatment of FGD purge brines has gained traction in the industry due to being the main source of the discharge of metals in power plant waters. Among various treatment options for FGD brines, zero liquid discharge (ZLD) approaches are gaining significant interest from the industry because traditional physical, chemical or biological treatments may be cost prohibitive and unreliable to meet the new limits. ZLD transforms the challenge presented by the brines from wastewater treatment to a solid waste disposal issue.

The United States Environmental Protection Agency (USEPA) possibly will revise the effluent limitation guidelines for steam electric power generating units. The revised guidelines may lower discharge limits for various contaminants in flue gas desulfurization (FGD) wastewater including mercury, selenium, arsenic, and nitrate/nitrite. At the Water Research Center, the power industry is evaluating various technologies that may address the new effluent limitation guidelines and promote water conservation. Stringent discharge limits along with water conservation and reuse efforts are two of the major drivers to achieve Zero Liquid Discharge (ZLD). Potential pollutant levels are so low that ZLD may be the best option, if not an outright requirement. A key disadvantage of thermal ZLD is its high capital cost. One way to reduce this cost is to pre-treat the liquid stream using innovative membrane technologies and reverse osmosis (RO).