Assessment of water-quality parameters of groundwater contaminated by fly ash leachate near Koradi Thermal Power Plant, Nagpur

Thermal power generating industries affect the surrounding environment in various ways. Fly ash escapes along with flue gases and can be found in undesirable quantities in soil and water sources in the region. The water quality of an area must be evaluated regularly to ensure the quality of potable water. The present study evaluates the pre-monsoon and post-monsoon concentrations of several important physico-chemical parameters and heavy-metal contents of groundwater samples collected from sites near the Koradi Thermal Power Plant, a major source of power generation in the Nagpur Region. The maximum amount of total dissolved solids observed during the two seasons studied were 1571 mg/l and 1591 mg/l which is within the desirable limit implying that fly ash contamination did not affect this water quality parameter. The total hardness of samples from GW-3, GW-5 and GW-9 were 844 mg/l, 775 mg/l and 675 mg/l during pre-monsoon season, while GW-3 and GW-5 along with GW-4 continued to show high levels of total hardness at 1015 mg/l, 741 mg/l and 650 mg/l, respectively. These values are higher than the permissible limit due to the high levels of ions of bicarbonate, calcium, sodium and sulphate derived from fly ash leachate. Statistical analysis showed that sulphides, total hardness, electrical conductivity and total dissolved solids were the significant water quality parameters of the region. The evaluation of the parameters found that the three water sources (GW-3, GW-5 and GW-9) out of 10 are the most affected groundwater sources of fly ash pollution.