PROCESS BASED WATER FOOTPRINT ASSESSMENT IN SELECTED LEATHER GOODS MANUFACTURING INDUSTRY OF SIALKOT, PAKISTAN

Abstract

Sialkot is considered as one of the largest Leather producing city in Pakistan. The manufactured Leather and Leather products are also imported to many countries. There are many researches have done on Leather tanneries in order to identify the health risks, water risks and solution to these problems have proposed. This research work involves the calculation of Water Footprint which tells about the amount of water uses in the reprocessing of wet blue hide which referred as BWF, and also the amount of fresh water required to dilute pollutants in the sludge before discharging it into water body and this is referred as GWF. Water is normally used in five processes which are Wet Wash, Rechroming, Neutralizing, Re-tanning and Finishing. Finishing processes generally carried out in Spray Plant where further desired dye is given to dry Leather. By using their process chart sheet, input of water for each process has calculated and The BWF was 134.604 liters which was calculated by adding the total DWC i.e; 108.644 liters and virtual water content i.e; 25.96 liters. For GWF, water samples have collected in bottles from the drums. The waste water as a result of those processes was then analyzed for heavy metals i.e As, Cr, Cd, Cu and Pb, BOD and COD. Then GWF has calculated for those pollutants which exceed the permissible limit of NEQs. In the analysis of waste water samples As, BOD, COD and Cr exceeds the permissible limit of NEQs so calculated GWF for As, BOD, COD and Cr was 1mg/l, 113.37mg/l, 100.2mg/l and 100.8380mg/l respectively. GWF tells about the fresh water required for the dilution of those contaminants before discharging it into canal. In addition to extracting fresh/ raw water for re-processing of wet blue hide, fresh water will also have to be extracted to reduce pollutants in the waste water before discharging it into the water body. Blue Water Footprint and Gray Water Footprint have calculated separately to better understand the detailed water consumption on daily basis.