Challenge
Evoqua Water Technologies was contacted by a leading global engineering, consulting and construction company, to provide wastewater treatment assistance during the final stages of commissioning at a power generation facility located in the southeast US. The station is a 665 megawatt generator which utilizes pulverized coal boiler technology along with advanced emission controls, thereby making it one of the cleanest coal-fired plants in the US.
The plant’s existing wastewater treatment system for the coal pile run-off pond was designed for a rate of approximately 100 gpm. During the final stages of commissioning, the site experienced heavy rains which impacted the runoff pond level. The increased volume posed a problem for the existing system and its ability to maintain and/or lower the pond level. Further, significant concerns were raised regarding total suspended solids (TSS) which were measured to be over 1000 ppm versus a discharge limit of 50 ppm.
Solution
In order to meet the customer’s commissioning schedule, while also delivering a compliant solution, Evoqua's response was to use our mobile clarification system. Evoqua mobile clarification is a self-contained, trailer mounted system capable of treating highly turbid water (up to 1000 NTU).
The solution Evoqua provided allowed a rapid reduction in pond level in a manner that maintained compliance with discharge permit levels, achieving water quality of <20 NTU and ~10 ppm TSS. Flow rates were increased to 300-500 gpm and the pond level was safely reduced to an acceptable operating level over a 4 week period.
In addition to providing the treatment system, Evoqua's scope of supply also included system installation, testing and commissioning and training of staff. An annual service and operations contract provides scheduled media exchanges, service and troubleshooting support, including operations and maintenance of the system for one year by a Department of Public Health certified water treatment operator.
Results
Based on a verbal release from the consulting engineer on May 12, Evoqua was able to deliver the mobile clarification equipment to the site by May 14 and to complete the ancillary equipment assembly by May 17. The availability of Evoqua mobile clarification treatment system and the ability to deliver the equipment quickly allowed the customer to meet their commissioning schedule.
Evoqua's mobile treatment services provided a temporary solution which permitted the customer to resolve the challenge quickly and without the requirement of additional capital investment.
