190-EIA Study of Ash Pond of a Thermal Power Plant in Jharsuguda District, Orissa, India.

Abstract

A super Thermal Power Plant is likely to come up in Jharsuguda district by the Orissa Government and an Industry under Public-Private partnership. The ash generated in the thermal Power plant will be stacked in Ash ponds in the areas earmarked for the Industry. Environmental Impact Assessment of Ash Ponds on the groundwater regime in the watershed covering the proposed plant area and Ash Pond area has been made through establishing 32 observation wells for periodical monitoring of groundwater level and groundwater quality. Bedhan river flows along one boundary of the watershed. Aquifer geometry has been determined by carrying out 50 multi-electrode resistivity imaging surveys covering ash ponds and Super Thermal Station Complex. Aquifer characteristics were estimated by carrying out pumping tests at five locations and also infiltration rates were determined through infiltration tests. The area exposes a wide spectrum of rock types. Groundwater occurs in the porous sedimentary formations and fractured igneous and metamorphic rocks in unconfined to confined conditions. The groundwater prospects indicate that the Pedi-plane shallow weathered and Lateritic plane shallow formations in the area are having a poor permeability supported by steep gradients of groundwater levels. Significantly, none of the major lineaments are found traversing the Ash pond. The Valley fill shallow formation is not extending beyond the stream on west. Hydrogeological evidence suggests that there seems to be no possibility of contaminant migration passing through the lineaments. Groundwater flow and mass transport processes models have been developed using the integrated database and predicted the likely migration of contaminants in groundwater from the ash ponds. The hydrogeological, geophysical, remote sensing, water level and water quality-monitoring database, prima fade, does not predict contamination of groundwater from the Ash Pond of the captive Power Plant. The lateral migration of TDS plume for 50 years will be in the downstream side along the stream course, which is however, falling within the boundary of assigned Ash Pond Area of the industry. As a remediation measure, it is suggested to reduce pressure of Leachate within the Ash Pond by Pumping leachate from the bottom of Ash Pond and spraying it through sprinklers to keep ash under wet condition in the Ash Pond.