Effect of Distillery Spent-wash on Channel Bed and Groundwater Quality: Case Study of Unicol Distillery District Mirpurkhas

Abstract

The effect of treated spent wash on channel bed and groundwater qualities was investigated during 2014-15 at Unicol distillery as study area in district Mirpurkhas. For this purpose, samples of spent wash, soil/water were collected and determined for parameters related to physical and chemical properties. The impact of spent wash on channel bed and on the adjacent soils at different distances showed that highest soil EC (18.40 dS m-1) and TDS (11776 ppm) were determined for spent wash channel bed at surface soil and EC decreased with increasing distance from channel bed at sub-surface layers; while the highest overall soil pH (7.43) was observed at 450m distance at 30-45 cm soil depth. The highest total N (0.16%) and available K (0.53%) was observed at channel bed and at surface soil with highest available P (4.80%) at channel bed in sub-surface (15-30 cm) soil. The groundwater samples obtained from tube well and hand pump were also analysed for physical and chemical properties and compared with the spent wash from channel bed. The lower Na (1578.7 ppm) was determined in hand pump water samples than tube well water (2588.3 ppm); while highest (7050 ppm) in spent wash. The HCO3 was lower in tube well water (247.00 ppm) than hand pump water (430 ppm); and highest (6166.70 ppm) in spent wash. The Chloride (Cl) content was lower (2117 ppm) in hand pump water samples than tube well water (5259 ppm); and highest in spent wash (14097 ppm). The groundwater EC was lower (11.077 dS m-1) hand pump water than tube well water (17.262 dS m-1) and highest (47.090 dS m-1) in spent wash. Similarly, the lower magnesium (465.3 ppm) was determined in hand pump water samples than tube well water (553.3 ppm) and exceptionally high (1300.7 ppm) in spent wash. The SAR of hand pump water samples was lower (11.583) than tube well water (20.390) and outstandingly high (35.693) for spent wash. In case of calcium content, it was lower in tube well water (359.33 ppm) than hand pump water (593.33 ppm) and exceptionally higher in spent wash (764.33 ppm). It was concluded that soil EC and TDS were lower at farther locations from spent wash channel bed at sub-soils. The surface soil contained higher organic matter; no effect of spent wash on soil organic matter was recorded. The soil pH was relatively higher at spent wash channel bed and its adverse effects were noted upto 300-meter distance. Total N was slightly (P>0.05) higher at channel bed than distant locations, while phosphorus was significantly higher at spent wash channel bed. The available potassium was also significantly influenced by the spent wash; and P was higher at channel bed, and decreased at the farther locations adjacent to the channel bed. The EC level, Na, HCO3, Cl, Mg and Ca contents as well as SAR for spent wash samples were manifold higher than the tube well and hand pump water samples.