Views:7 Author:Site Editor Publish Time: 2019-11-26 Origin:Site
Shanghai CM Environmental Technology Co., Ltd.
Project Analysis / Treatment of Membrane Pollution in Domestic Sewage Treatment Project
MBR membranes are widely used in many fields. The key is to select high quality membrane products. However, the operation and maintenance of MBR membranes are also very important. MBR membrane in municipal wastewater, printing and dyeing wastewater, slaughter wastewater and other sewage treatment applications encountered different situations, today we use actual cases to talk about domestic sewage treatment projects, may encounter membrane pollution problems.
The total water volume of a domestic sewage treatment project in Nanjing is 1600 m3/day.
A2O+denitrification filter+MBR process is adopted.
Serious membrane fouling occurred in the field during operation, which manifested in the decrease of water production and the increase of transmembrane pressure difference.
It was found that the SV30 value in the membrane tank reached 84%, and there was a large amount of activated sludge between the membrane filaments of two adjacent curtain membrane organizers. The coagulation anaerobic condition of these activated sludges can not be achieved by conventional backwashing and flushing to restore the membrane flux and reduce the transmembrane pressure difference.
After field research, it is decided that the existing membrane curtain should be cleaned off-line.
In view of this membrane component pollution incident, our technicians put forward the following suggestions on the project site:
1. To reduce the sludge concentration of the system, the maximum tolerant sludge concentration of HPR-MBR series membrane products is 12 g/L. In order to improve the membrane efficiency, it is suggested to reduce the sludge concentration of the membrane pond to 6-9 g/L. At the same time, it is suggested to add an on-line sludge concentration meter in the membrane pond to facilitate monitoring the operation status of the membrane module.
2. To adjust the return flow of the system, HPR-MBR series membrane products belong to the category of microfiltration membrane. During the operation, the membrane module will continuously concentrate the wastewater in the membrane tank. If the return flow of the system is too small, it will cause the sludge concentration in the membrane tank to be too high. It is suggested that the reflux flow rate of membrane tank reflux pump should be controlled at
200-400% of the system water yield, so as to facilitate the adjustment of sludge concentration in the system.
3. Reviewing the air scrubbing volume of MBR membrane system, the aeration purpose of MBR membrane system is not to increase dissolved oxygen in the membrane pond, but to shake the contaminants attached to the membrane surface. Therefore, the aeration volume of MBR membrane system is higher than that of biochemical system, and the ratio of conventional aeration volume to water yield is about 15:1.
The cleaning schemes mentioned above are for reference only.