WATER-PURIFICATION BY FLUIDIZED-BED TECHNIQUE

Composite samples of wastewater obtained from a Nigerian institution were clarified with a 10% solution of commercial alum and then filtered through a sand bed. The optimum dosage for the clarification was 400 mg l** minus 1. Considerable reductions in colour, turbidity, suspended solids (SS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), detergents of alkyl benzene sulphonate (ABS) base and total coliform bacteria were achieved in the samples. The samples were further purified by adsorption of their impurities by powered activated carbon (PAC) in a fluidized bed. The purification was done by two modes: fluidization with no beads added and fluidization with beads added. With 200 mg l** minus 1 PAC and fluidization for 10 min, 92. 8% COD reduction was achieved with no beads added while 98. 5% COD reduction was achieved with 4% (v/v) glass beads added.