Enhanced coagulation: a viable option to advance treatment technologies in the South African context
Laboratory and full-scale experiments were conducted for enhancing the coagulation of stabilised surface waters with high organic content by permanganate preoxidation. It was indicated that permanganate preoxidation enhanced both the processes of coagulation and filtration of selected surface waters, River Songhua water, Qitaihe Reservoir water and Ba Reservoir water. Permanganate preoxidation is especially effective for enhancing the coagulation of very stable surface waters with relatively high organic content. Experimental results showed that the manganese dioxide produced in situ during permanganate preoxidation played an important role in enhancing the coagulation and filtration processes. The experimental results suggested that manganese dioxide may adsorb naturally occurring organic materials through surface bonding to form bigger particulates, thus increasing the floc density and improving the removal of organic particulates and possibly the inorganic fine particles. Manganese dioxide was shown to adsorb humic acid and enhance its removal by filtration.