and bod loading 1 6kg m 3 d the result is shown in table 2 below the liquor thus treated was clear and svi was 90 table 2______________________________________ before treatment by after treatment by the activated sludge the activated sludge process process______________________________________bod 1600 ppm 40 ppm cod kmno sub 4 1200 90cod k sub 2 cr sub 2 o sub 7 2700 240iodineconsumption 130 0______________________________________ a waste liquor from a hydrosulfite production process sodium formate 12 iodine consumption 20 was diluted to 40 times and ammonium sulfate and phosphoric acid were added to the liquor the resulting liquor was subjected to an activated sludge consumption at mlss 3000 ppm the floc was broken at bod loading of 0 4 kg m 3 d and the fine sludge was carried over with the effluent bod cod and iodine consumption were as shown in table 3 below table 3______________________________________ before treatment by after treatment by the activated sludge the activated sludge process process______________________________________bod 1500 ppm 610 ppm cod kmno sub 4 1500 680cod k sub 2 cr sub 2 o sub 7 3000 1550iodineconsumption 5000 1320______________________________________ a waste liquor from a hydrosulfite production process sodium formate 12 iodine consumption 20 100l was mixed with 100l of water and 50 g of fecl 3 6h 2 o was added to the liquor the resulting liquor was fed to the top of a bubble column of 100 mm in inner.