Compliance with new Effluent Limitation Guidelines promulgated under the Clean Water Act was modeled through the development of a complex GoldSim Water Balance dynamically linked to Phreeqc water chemistry.
American Electrical Power (AEP), along with many in the Power industry, is facing the need to comply with several new environmental regulations relating to water, wastewater use, treatment and discharge. As part of the Clean Water Act (CWA) under section 40 CFR Part 423, the US EPA promulgated the Effluent Limitations Guidelines and Standards for Steam Electric Power Generating Stations. In order to better understand the constituents that make-up the effluent from their plants, AEP is undertaking the development of detailed plant-wide water balance studies that link water chemistry/composition and mass balance in a dynamic approach. These models are intended to be flexible enough to evaluate various options at each of its affected plants to develop compliance within the guidelines. Thus, AEP wants to further develop and refine a GoldSim model, augmented with PHREEQC, based upon actual water quality sampling done at each plant site.
Advisian was retained to provide field sampling services, GoldSim model development and programming within C++ to dynamically link Phreeqc water chemistry modeling at each timestep. Over the course of the project, complete site walkdowns were held to identify and quantify wastewater streams leaving the plant and entering environmental discharges. Four sampling events were conducted to gain insight into analytical chemistry of each of the discharges. Complex GoldSim-Phreeqc models were then developed and calibrated to predict water chemistry through-out the series of ash ponds.
The results of the integrated water balance will allow AEP to test a variety of conditions allowing them to understand the benefit and implications of changes to process and pond configuration that will allow them to meet compliance guidelines. Overall, this will save capital dollars and benefit the environment through the discharge of cleaner waste streams.