Aerobic Granulation Strategy For The Treatment Of Dairy Waste Water

Dairy waste water being organically rich is suitable for biological treatment which can be carried out using indigenous microflora and also by bioaugmentation. Aerobic granulation is a highly bioactive form of bioaugmentation. In the present investigation aerobic granules were cultivated in the sequencing batch reactor with Height/Diameter ratio of 26.14 (height 91.3 cm and diameter 3.5 cm). The reactor was operated with a 24 h cycle consisting of 5 min of addition, 23 h 45 min of agitation, 5 min of settling and 5 min of withdrawal. After complete granulation and separation of biomass from the effluent, aerobic granules of size 1-5 mm were formed. Appropriate dilutions of granules yielded ten Gram positive bacterial cultures, which were designated as isolate 1 to 10. Aerobic granules were added to dairy waste water @ 1% (w/v). At volumetric exchange ratio of 50% removal efficiencies of 61.54% of BOD 3 (Biological Oxygen Demand), 61.2% of oil and grease, 90% of TSS (Total Suspended Solids) and 47.11% of TKN (Total Kjeldahl Nitrogen) was achieved. Reduction of only 10 % of BOD, 18.7 % of oil and grease, 30% of TSS and 12.8% of TKN were obtained in a free cell system.