Seasonal and Spatial Variations in Biochemical and Chemical Oxygen Demand of Untreated Sewage in Sironj Tehsil, District Vidisha, India

- In this study, untreated sewage from five suburban sites in Sironj Tehsil, district- Vidisha, India, was evaluated for seasonal and spatial variations in Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) in 2024. The APHA 5210 B and 5220 D procedures for BOD and COD, respectively, were used to analyse 100 sewage samples from Kahra Bazar, Kathali, Bhawani Nagar, Katra Mohalla, and Hajipur. Due to runoff-driven organic matter, the BOD ranged from 159.16 to 186.96 mg/L, with Bhawani Nagar recording the highest value (186.96 mg/L) during the monsoon season (mean 180.98 mg/L). Bhawani Nagar had the highest COD (571.32 mg/L), which ranged from 337.15 to 571.32 mg/L and peaked during the monsoon (mean 511.21 mg/L). The seasons with the lowest BOD (mean 161.35 mg/L) and COD (mean 358.09 mg/L) were winter. Statistical analysis showed site-specific influences on COD (F(4,80)=8.63, p<0.001) and significant seasonal effects on both BOD (F(3,80)=36.90, p<0.001) and COD (F(3,80)=114.14, p<0.001). According to these results, there are moderate to high levels of organic pollution, which means that to prevent oxygen depletion during monsoon peaks, biological treatment with increased aeration is required. These findings support the need for customised wastewater management plans in Sironj and are consistent with those of similar Indian cities. Key Words: Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Sewage analysis, Seasonal variation, Sironj Tehsil, Organic pollution, Wastewater treatment