ABSTRACT

Background and objective: Milk and dairy industries wastewater are considered the most polluted effluents, and if discharged without treatment into the environment, can cause serious environmental problems.  In this study, effects of aeration time and lime coagulant on SBR efficiency were investigated.

Materials and Method: Two Parallel reactors with a volume of  20 L was used. The examination was conducted in three steps. During these steps , effects of conventional aeration time, long aeration time and use of lime coagulant aim after 7h aerated on SBR performance were investigated, respectively.

Results and discussion: The results were shown an increase of aeration period can be effected on increase removal rate of COD, BOD NH4-N, and TP, respectively. And also this is indicated suitable efficiency for the removal of COD , BOD, NH4-N were created with a duty cycle 24h and aeration time of 7 h. Application of SBR system with the aeration time of 7h and injection of lime coagulant aim in the loading rate of 0.6 kg BOD/m3.day, provided the essential standards for the disposal of effluent into the water reservoirs.

Conclusion: Optimized SBR process can be provided to reach  better effluent standards in less time in milk and dairy industries and also reduce time can decreases of operation costs.