Improvement of ammonia oxidation in wastewater using rockwool as a carrier in wastewater treatment
2008
Shimizu, K.(Tsukuba Univ., Ibaraki (Japan)) | Okano, K. | Yang, Y. | Utsumi, M. | Zhang, Z. | Sugiura, N.
Improvement of microbial ammonia oxidation method using a rockwool as a carrier in wastewater treatment was examined through batch and continuous operation. In batch operation, a nitrifying bacterium, Nitrosomonas europaea (NBRC 14298), and phosphorus and iron-complexes were highly attached to the rockwool. In continuous operation, the operation with rockwool (RW) was shortened the hydraulic retention time (HRT) from 20 h to 10 h, and the maximum ammonia removal ratio was 87.5%. The average of ammonia removal ratio was performed 73.1%, 78.2% at 20 h and 10 h, respectively, at aeration rate of 3000 ml/min. The ammonia oxidation rate was 22.3 mg-N/l-carrier/h when the ammonia loading rate was 25.5 mg-N/l-carrier/h. Quantitative PCR results revealed that around 10E15 cells/l-carrier were immobilized to the RW. Therefore, the RW could retain a large number of nitrifying bacteria improve the degree of nitrification and have widely application.
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