Assessment of Water Pollution in the Kharun River and Evaluation of a 50 MLD SBR-Based Sewage Treatment Plant as a Future intervention for Pollution Mitigation in Raipur, Chhattisgarh

Abstract

The Kharun River is an important surface-water resource in Chhattisgarh and passes through areas influenced by agricultural activities, urban development, domestic wastewater discharge, religious activities and industrialization. The present study proposes an integrated assessment of Kharun River water quality using a Water Quality Index (WQI) approach combined with a preliminary design of a sewage treatment plant (STP) for pollution control. Water-quality assessment is structured around ten sampling stations representing upstream, agricultural, religious, residential, urban, industrial and downstream conditions. Monthly sampling over a 12-month period provides a framework of 120 observations. The selected parameters include pH, electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), turbidity, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), chloride, sulphate, nitrate, phosphate, hardness, alkalinity and iron. In addition to river-water assessment, a 50 million litres per day (MLD) Sequencing Batch Reactor (SBR)-based STP is proposed for treatment of domestic sewage entering the river system. The preliminary design considers an average sewage flow of 50,000 m³/day and a peak flow of 100,000 m³/day. Based on an assumed raw sewage BOD concentration of 250 mg/L, the estimated BOD load is 12,500 kg/day. Approximately 28,000 m³ of total SBR working volume is proposed, divided into five parallel basins.   Keywords - Kharun River; Water Quality Index; WQI; sewage treatment; Sequencing Batch Reactor; SBR; BOD.