Comparative assessment of physico-chemical parameters of waste water effluents from different industries in Lahore, Pakistan

摘要

The magnitude of wastewater generation in Lahore city is increasing due to urbanization and industrialization. Wastewater is being thrown directly into rivers and canals without proper treatment. This study examines the physico-chemical characteristics of wastewater which is being discharged from different industries in Lahore. Samples were collected from the outlet of five industries before they discharge into Hudyra drain. Physical characteristics of wastewater were analyzed based on TDS and TSS concentration. TDS and TSS concentration was measured in the laboratory using Evaporation and Gravimetric method respectively. Chemical characteristics of wastewater were analyzed based on pH, BOD, COD, and metal concentration. pH value of wastewater collected from five sampling stations was measured using pH meter. Biological oxygen demand was determined using respirometric method and Lovibond meter while COD was determined using the Open reflux method and Back titration. The concentration of heavy metals (Cr, Hg, Ba, Fe, Mn, Cl-, B) was measured by using ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometry). All parameters after analysis were compared with standard of Punjab Environmental Quality Standard (PEQS). Experimental results show that the quality of wastewater varies from site to site and at some sampling stations values of water quality parameters exceeded maximum permissible limit of PEQS. Pearson correlation matrix for physico-chemical parameters at all sampling sites was developed to identify the possible relationships between concentrations of these parameters. The increasing level of physico-chemical parameters above permissible limit clearly shows that such type of wastewater if directly discharged into fresh water bodied may contaminate ground as well as surface water.