Demonstration of Magnetic activated sludge process for water treatment with zero emission of excess sludge

磁活性污泥法（MAS）是一种高效处理废水的工艺。采用简单的方法，在活性污泥中接种Fe_3O_4，制备磁性活性污泥。污泥对磁铁矿的吸引力很高。磁性活性污泥被磁性鼓/盘吸引，并被磁性装置的刮刀分离。分离出的污泥再次返回曝气池进行活性参与。因此，MAS工艺可以维持反应池中高浓度的微生物，用于有机污染物的生物降解。该过程可以通过反应器罐中微生物的细胞生长和衰变来有效地操作。因此，MAS工艺可以减少污水净化过程中剩余污泥的排放。对苯酚、聚乙烯醇、洗涤剂、内分泌干扰物等多种有机污染物进行了室内试验。实验室规模的实验被认为是成功的生物降解这些污染物没有剩余污泥的生产。MAS工艺正在以城市污水为对象进行中试应用。在中试装置中，MAS工艺也被发现是成功的城市污水净化约500天的实验没有剩余污泥撤出。在此期间，约16 m^3的污水在约8 m^3的曝气池中连续处理。该<Cr>工艺对COD_2的去除率可达90%左右。并与传统的活性污泥法进行了比较。此外，MAS工艺通过间歇曝气进行顺序硝化反硝化，可去除污水中总氮的70%。悬浮的磁铁矿和溶解的铁离子没有观察到的过程中的流出物。

Magnetic activated sludge (MAS) process was developed for the efficient treatment of wastewater. Magnetic activated sludge was prepared simply by seeding magnetite (Fe_3O_4) to the activated sludge. High affinity of attraction of magnetite by the sludge was observed. The developed magnetic activated sludge was attracted by the magnetic drum/disk and was separated by the scraper of the magnetic apparatus. The separated sludge returned again to the aeration tank for their active participation. Therefore, the MAS process could maintain high concentration of microorganisms in the reactor tank for biodegradation of organic pollutants. This process might be efficiently operated by the cell growth and decay of the microorganisms in the reactor tank. Therefore, the MAS process could cut excess sludge emission during wastewater purification. Bench-scale experiment was carried on various kinds of organic pollutants viz. phenol, polyvinyl alcohol, detergent, and endocrine disruptor. The bench-scale experiment was found to be successful for the biodegradation of those pollutants without excess sludge production. The pilot scale application of MAS process is under experiment using municipal sewage. In the pilot plant, the MAS process was also found to be successful for the purification of municipal sewage about 500 days of experiment without withdrawal of excess sludge. During this period, about 16 m^3 of sewage was continuously treated in about 8 m^3 of aeration tank. About 90% COD_<Cr>, removal was achieved by this process. The performance is compared to conventional activated sludge process. In addition, the MAS process could remove 70% of total nitrogen in the sewage by sequential nitrification and denitrification through intermittent aeration. Suspended magnetite and dissolved iron ions were not observed in the effluent from the process.