Side stream type membrane bioreactor process
First Claim
1. A side stream type membrane bioreactor process of circulating in-tank water inside a bioreactor into a separation membrane placed outside the bioreactor, thereby taking out filtered water, wherein a backwash effluent containing foulant that is generated by backwashing the separation membrane is subjected to ozone treatment, and further the treated effluent is returned to the bioreactor.
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Accused Products
Abstract
The invention provides a side stream type membrane bioreactor process which does not cause an excessive fall in the MLSS concentration in a bioreactor, does not require any additional effluent treatment facility for discharging backwash effluent, and can further ensure the stability of the membrane filtration performance of a separation membrane. According to the invention, in a side stream type membrane bioreactor process, a backwash effluent containing foulants that are generated by backwashing a separation membrane is collected in a backwash effluent tank, and subjected to ozone treatment, and the resultant is returned to a bioreactor. By this ozone treatment, the foulants close to the membrane pore size of the separation membrane are made fine or are made into a state be easily taken into activated sludge flocs. Therefore, even when the treated effluent is returned to the bioreactor, the membrane filtration performance of the separation membrane is not deteriorated.
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Citations
7 Claims
- 1. A side stream type membrane bioreactor process of circulating in-tank water inside a bioreactor into a separation membrane placed outside the bioreactor, thereby taking out filtered water, wherein a backwash effluent containing foulant that is generated by backwashing the separation membrane is subjected to ozone treatment, and further the treated effluent is returned to the bioreactor.
Specification