Ponding of Effluents from Fossil Fuel Steam Electric Power Plants

摘要

Control of both the suspended solids discharge and the effluent chemistry (pH, trace metal concentrations, etc.) is of primary concern for the operation of ponding facilities. To assess the operational performance of ponds, a mathematical model has been constructed based on hydraulic transport, sedimentation of solids, and chemical reactions. Due to inadequacies in previous descriptions for (chemical) adsorption and sedimentation, the features principally addressed in development of this model have been formulations of new submodels for adsorption (surface precipitation formulation) and sedimentation (including coagulation). Application of the ponding model to fly ash ponds has demonstrated the model's ability in predicting mass removals of solids and in analyzing chemical behavior. From the effort of this research project, improvements in the operations of fly ash ponds have been determined. For solids, increased removal efficiencies can be achieved by decreasing the sluicing rate, increasing the length to width ratio of the pond, and/or proper design of the pond with respect to inflows and outflows. For chemical removal, improvements in the operations of ponds are difficult to generalize and therefore are treated on a case by case basis.