Abstract
The effect of anoxic/anaerobic condition on filamentous bulking of activated sludge is studied experimentally using completely mixed reactor and sequencing batch reactor activated sludge process. These laboratory scale processes were fed with synthetic wastewater by modifying operational schedule with timer. And aeration was performed after feeding substrate in a cycle. As result the following conclusions can be made from this study.
1) In completely mixed reactor process, the anoxic/anaerobic condition has no effect on controlling growth of Sphaerotilus natans. Regardless of anoxic/anaerobic and aerobic conditions, starvation period ratio defined by the auther (1981) has effect on growth of filamentous microorganisms. And filamentous bulking is proved to be controlled in the case in which its ratio is held over 6.
2) In sequencing batch reactor process, Sphaerotilus natans is found in the case of low COD-SS loading and over pH 6, and Type 1863 or free bacteria is found in the case of high COD-SS loading because of accumulation of metabolic substances such as organic acids in anaerobic stage, but growth of these are not influenced by pH value.
