ASSESSMENT OF PHYSICOCHEMICAL CHARACTERISTICS OF WASTEWATER FROM SELECTED VEHICLE SERVICE STATIONS IN PESHAWAR

Abstract

The rapid expansion of the automotive service sector in Peshawar has intensified concerns regarding the generation and discharge of industrial wastewater, presenting substantial environmental and public health risks. This study conducted a comprehensive physicochemical characterization of effluent from six representative vehicle service stations within the city. Wastewater samples were analyzed for critical parameters pH, electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), turbidity, total hardness, calcium, total alkalinity, chloride, chemical oxygen demand (COD), five-day biological oxygen demand (BOD₅), and oil and grease (O&G) with results evaluated against Pakistan's National Environmental Quality Standards (NEQS). The findings reveal significant non-compliance, with key parameters exceeding NEQS limits by considerable margins: TSS (654.33 mg/L vs. 150 mg/L), turbidity (543.4 NTU vs. 5 NTU), chloride (858 mg/L vs. 250 mg/L), and COD (690 mg/L vs. 150 mg/L). In contrast, parameters including pH, TDS, total hardness, and BOD₅ were within permissible thresholds. The severe exceedance of TSS, turbidity, and COD indicates a high load of particulate, colloidal, and recalcitrant organic pollutants, characteristic of vehicle washing and maintenance activities. The elevated chloride levels further suggest a salinity burden that threatens soil and aquatic ecosystems. This study concludes that untreated effluent from service stations constitutes a major source of urban water pollution in Peshawar, necessitating the immediate implementation of targeted treatment interventions, such as integrated physicochemical and biological processes, to ensure regulatory compliance and safeguard water resources.