Coagulation-flocculation studies of tannery wastewater using cationic polymers as a replacement of metal salts.
Studies were conducted to evaluate the efficiency of cationic polymers as a suitable replacement of metal salts for the treatment of a local tannery wastewater. Eleven cationic polymers of varying molecular weights (MW) and charge densities (CD) were examined using jar test apparatus. Three cationic polymers: one with MW of 4 million Dalton and CD of 55%; second with MW of 6 million Dalton and CD of 40%; and the third with MW of 8 million Dalton and CD of 40% were found suitable for tannery wastewater treatment at an optimum dose of 20 mg/L for each. Percentage removals with these three cationic polymers for turbidity, total suspended solids (TSS), total chemical oxygen demand (TCOD) and chromium lied in a range of 91-95%, 69-83%, 25-29% and 96-97%, respectively with respect to plain settled wastewater. The cost of the most suitable cationic polymer C-496 at its optimum dose was $0.09 per cubic metre of wastewater and sludge production was 35 mL/L. The results demonstrated that treatment of tannery wastewater with cationic polymers is a viable and economical option when compared with metal salts.
Haydar
Sajjad
S
Institute of Environmental Engineering and Research (IEER), University of Engineering and Technology (UET), Lahore, Pakistan. sajj@brain.net.pk
Aziz
Javed Anwar
JA
D005427:Flocculation; D008670:Metals / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
D008670:Metals; D011108:Polymers; D012492:Salts