Graph no 1. C.O.D Readings
There was a drastic reduction in COD level after PVA Gel treatment was provided. After treatment the COD level of
primary clarifier influent, which was 1700 mg/lit reduced considerably. It can seen in above graph that the COD of
bioreactor outlet after 12 hrs retention time is 78 mg/lit. Analyzing above graph COD is efficiently removed in 12 hrs
retention time as compared to 6, 8, & 10 hrs retention time.