Treatment of dairy wastewater by immobilized microbial technology using polyurethane foam as carrier

The development of dairy industry is accompanied by large volumes of wastewater production, which is threaten to human's health and the biosphere. In this study, synthetic dairy wastewater was treated by immobilized microbial technology using polyurethane foam as carrier. Batch experiments were conducted to determine the effects of different operational parameters, and an up-flow immobilized microbial reactor was built to investigate long-term performance of the system. Batch experiments showed that COD, TN and NH3-N dropped from 1932, 51.33 and 51.42 mg·L-1 to 75.3, 5.17 and 4.54 mg·L-1 after 48 h, respectively, at the optimum conditions (25 °C, pH 6.0). Besides, the reactor can remove 97.33% of COD, 96.46% of TN and 99.55% of NH3-N with HRT of 24 h, which the average volume load was 1.93 kg COD·(m3·d)-1. The analysis of microbial community determined that dominant bacteria at genus level were Acinetobacter, Fusibacter, Nannocystis and norank _f_NS9_marine_group.