Study on gray water treatment using cement kiln dust and chemical coagulants

The optimum dose for cement kiln dust (CKD), lime, Ferric chloride, alum required 60, 40, 40, 60 mg/L to bring down the turbidity of grey water from 29.3 to 3 NTU. Ferric chloride and Lime reduced the grey water COD 50 mg/L at 40–60 mg/L of dose. The aerobic migrating column reactor (AMCR) performance showed that CKD and lime at 60 and 40 mg/L to reduce the turbidity less than 1.3 and 0.6 NTU. Whereas, from lime and ferric chloride 3.5 and 4.5 NTU at 30 hr operation of AMCR. The efficacy of disinfection was found highest with CKD 105, ferric chloride 254, alum 505 and lime 525 CFU /100 mL. In addition, the shapes of sweep flocs showed from CKD 590 mm compared to alum 320, ferric chloride 210 and lime 460 mm, resultant for TS and COD removal was found 96 and 76% at 60 mg/L of CKD.