Challenge
With new federal regulations for flue gas waste and coal combustion residuals (CCR) in effect, energy companies transitioning from coal-fired to gas-fired power generation began to reclaim CCR storage ponds. A power company located in the southeastern U.S. needed a treatment solution that would reduce arsenic and total suspended solids (TSS) in the impounded water, yielding discharge water to comply with the plant’s NPDES permit for release into the environment. The company was in need of a solution to handle feed water with a widely varying TSS concentration, including pH adjustment of treated water. Evoqua Water Technologies had the expertise and technology to meet the power company's needs providing a solution to dewater and decommission aging water impoundments.
Solution
Evoqua was awarded the contract to deliver its superior technology and significant knowledge in pond remediation which included personnel, supplies, and services to maintain the project. A ballasted floc clarification system was implemented to enhance floc formation and increase settling speed. This process is streamlined to operate and produces high-quality effluent faster and in less space than traditional clarification, ultra-filtration, or media filtration.
The system was up and running as of late January 2016 and Evoqua will manage the system for the 12-month duration of the project. TSS, arsenic levels, and pH will be monitored and maintained within permit limits as the ponds are drained and made ready for reuse.
Results
As market and regulatory trends lead the industry focus and prioritize cleanup, advanced water treatment solutions such as Evoqua’s ballasted floc clarification technology will be ready to respond. With this advanced clarification technology, Evoqua was able to meet site-specific NPDES discharge requirements for suspended solids, arsenic, and pH.