Belews Creek Wastewater Treatment Station
FGD Wastewater Treatment for Coal & Natural Gas Power Generation
Industry: Power Generation
Application: Flue Gas Desulfurization (FGD) Wastewater Treatment
Location: Belews Lake, North Carolina
Technology: Solids Contact Clarifiers with Lift Mechanisms
Provided by: ClearStream Engineering
Facility Overview
The Belews Creek Steam Station is a two-unit coal and natural gas power plant with a combined generating capacity of 2,220 megawatts (MW). Located on Belews Lake in North Carolina, the facility is capable of co-firing up to 50% natural gas on both units, allowing flexible operation using coal, natural gas, or a combination of fuels.
During coal combustion, sulfur dioxide (SO₂) is released in the flue gas stream. When SO₂ reacts with atmospheric moisture, it contributes to acid rain, making emissions control a critical environmental requirement. To address this, the facility utilizes flue gas desulfurization (FGD) technology to remove SO₂ from exhaust gases prior to release.
FGD Process & Wastewater Challenge
The FGD system operates by spraying a limestone slurry into a reaction chamber, where calcium in the limestone reacts with sulfur dioxide in the flue gas. This chemical reaction produces calcium sulfate, commonly referred to as synthetic gypsum, as a primary byproduct.
While effective at controlling air emissions, the FGD process generates a high-strength wastewater stream containing elevated levels of dissolved solids, suspended solids, metals, and trace contaminants such as mercury. Typical untreated FGD wastewater characteristics include:
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High total suspended solids (TSS)
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Elevated chloride, sulfate, calcium, and magnesium concentrations
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Variable iron content
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Neutral to slightly alkaline pH
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Trace mercury measured in parts per billion (ppb)
Treating this complex wastewater requires robust clarification equipment capable of handling heavy lime sludge and maintaining continuous operation.
ClearStream Engineering Solution
ClearStream Engineering designed a custom solids contact clarifier system tailored specifically for FGD wastewater treatment at Belews Creek. The solution includes:
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(2) 50-foot diameter ClearStream Solids Contact Clarifiers
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Column-supported dual cage drives with lift mechanisms
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Multiple influent ports for improved hydraulic distribution
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An axial impeller to promote internal sludge recirculation
This custom configuration maximizes chemical reaction efficiency while maintaining effective solids contact and floc formation. The caged lift mechanism allows the rake arms to be raised during high-torque events, enabling the system to process dense lime sludge continuously without interruption.
Results
The engineered clarifier design delivers reliable treatment of high-strength FGD wastewater while supporting consistent operation under variable loading conditions. By combining advanced process design with rugged mechanical features, ClearStream provided a solution that meets the demanding requirements of modern power plant wastewater treatment systems.
