Archived
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Location
Lexington, Kentucky
Start Date
5-5-2026 1:00 PM
End Date
5-5-2026 1:30 PM
Description
The water management issues created by ash pond closure are complex and can create technology selection and operational management challenges. Ash dewatering activities produce highly variable effluents, depending on ash composition, aging, and dewatering and stormwater management techniques. Effluent limitations can also be highly variable, depending upon the size of the receiving body and the anticipated composition of the effluent stream. The user often faces competing risks: installing an unnecessarily complex and expensive treatment plant, being limited on closure activities by limitations in water treatment capabilities, or both. This paper presents several lessons learned from assessing ash closure water management requirements at three TVA power stations: • Prudent water management planning can positively influence resulting effluent limitations. In many states, imposition of water-quality-based effluent limitations are influenced by the predicted effluent concentrations. • A robust data set is required to properly predict effluent loadings and associated treatment requirements. Treatment contractors base their proposals on the range of influent concentrations provided to them. • Ongoing system monitoring and timely communication with the dewatering contractor can prevent system upsets and resulting discharge exceedances. Many exceedances can be avoided by timely changes in influent feed. • Treatment chemistry can be manipulated to improve performance when needed. For example, the presence of iron and manganese can positively impact removal of many heavy metals. • Identifying the impacts of algae and other biological factors on surface impoundment chemistry facilitates pH control.
Document Type
Presentation
Archival?
Archival
Included in
Energy Systems Commons, Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Mining Engineering Commons, Oil, Gas, and Energy Commons, Structural Materials Commons, Sustainability Commons
Lessons Learned from Managing Ash Pond Closure Waters
Lexington, Kentucky
The water management issues created by ash pond closure are complex and can create technology selection and operational management challenges. Ash dewatering activities produce highly variable effluents, depending on ash composition, aging, and dewatering and stormwater management techniques. Effluent limitations can also be highly variable, depending upon the size of the receiving body and the anticipated composition of the effluent stream. The user often faces competing risks: installing an unnecessarily complex and expensive treatment plant, being limited on closure activities by limitations in water treatment capabilities, or both. This paper presents several lessons learned from assessing ash closure water management requirements at three TVA power stations: • Prudent water management planning can positively influence resulting effluent limitations. In many states, imposition of water-quality-based effluent limitations are influenced by the predicted effluent concentrations. • A robust data set is required to properly predict effluent loadings and associated treatment requirements. Treatment contractors base their proposals on the range of influent concentrations provided to them. • Ongoing system monitoring and timely communication with the dewatering contractor can prevent system upsets and resulting discharge exceedances. Many exceedances can be avoided by timely changes in influent feed. • Treatment chemistry can be manipulated to improve performance when needed. For example, the presence of iron and manganese can positively impact removal of many heavy metals. • Identifying the impacts of algae and other biological factors on surface impoundment chemistry facilitates pH control.
