biodegradation of effluents from dairy plant by bacterial isolates

micro flora of the effluents from a dairy factory in tehran(pegah dairy processing plant) were isolated and screened for their ability to reduce the organic matter content and cod of the effluents. 10 bacteria were selected due to  reduction in cod content from the 4th to 6th day of incubation at 30 °c and  ph =11. highest cod reduction were obtained by two isolates, bp3 and bp4, 70.7 % and 69.5 %,, respectively (the initial cod concentration was 3000 mg/l and reduced to 880 and 920 mg/l).after optimization of the condition for test organisms, big reductions in cod, carbohydrate, fat and protein content of the effluents were observed by bp3 up to 84.70 %, 98 %, 45.30 % and 53 %, respectively .the mixture of bp3 and bp4 did not show the good results as the bp3 alone .therefore, bp3 has been selected as the most efficient microorganism for the system.theoverallefficiency of the system willbe increased if it is added toanaerobic activatedsludge tank.