The MBR membrane method is becoming more and more widely used and is attracting a lot of attention for its stable and clear effluent, but its huge maintenance volume is also causing many users headaches; so to minimise the intensity of maintenance work in use, the following issues need to be taken into account during the design phase.
MBR is not a universal solution, it is a microfiltration membrane and is defined by the particle size that can be passed through; therefore, the clogging problem is the key for it, some wastewater that is easy to scale, contains more heavy metal ions, contains more oil substances and viscous substances, it is recommended not to use MBR membrane method.
1. Assemble the membranes together to form a membrane module, paying special attention to the spacing between the membranes, the effective distance between the membranes should be large enough, the effective distance should be greater than 100mm (axis distance greater than 140mm), if the membranes themselves have a high density of membrane filaments, then the effective spacing should be appropriately relaxed, the purpose of this is to keep the flushing airflow to reach the top membrane filaments smoothly, also can reduce the membrane filaments between the slab and trapped material, reduce the membrane The purpose of this is to keep the flushing airflow reaching the top membrane filament smoothly, which can also reduce the caking and retention between the membrane filaments and reduce the cleaning frequency of the membrane components.
2. The membrane can be installed horizontally or vertically, depending on the installation space; when installed horizontally, the membrane filaments should be slightly sagged, with a sag range of 10mm, or as straight as possible, while ensuring that the membrane filaments are not under tension, so that there will not be too much debris between the membrane filaments and the membrane filaments.
3. The membrane module cannot be made very large, because if the membrane module is too large, the installation density will be large, the same amount of air mixing is not enough for it, and when many packages are accumulated on the membrane, it is necessary to spray the membrane, using high pressure water gun or tap water, the installation is too dense will make it difficult for you to flush to the inner membrane, it is recommended that the processing capacity of a single membrane module should not exceed 1.5m3/hr.
1. The aeration device can be fixed at the bottom of the pool (need to do the membrane component support frame and membrane component slide into the guide), can also be done with the membrane component, each has its advantages and disadvantages, the location of the aeration tube to do careful consideration, using DN20 perforated tube, each membrane gap corresponds to a perforated tube, perforation size Φ3.2mm, perforation spacing of 100mm, adjacent to the two way tube perforation position staggered interpolation, orifice do a single row of vertical upward, the aeration tube location should be carefully considered. There are many double rows and sloping downward practices, personally I think it is not desirable, the settled sludge will not produce blockage to the orifice.
2. The size of the aeration volume is roughly estimated, according to empirical figures, according to the steam to water ratio of 24:1 can be (conventional pool depth of 3.5m), the fan exhaust pressure head selection than the highest liquid level high 0.01Mpa; fan outlet set relief valve, relief pipe caliber fully open can unload 70% of the air volume can be, the relief port on the installation of silencers, this device is used to control the DO value in the biochemical tank.
3. Each membrane module aeration is equipped with a separate adjustment valve, while the oxygenated aeration of the entire biochemical tank is controlled by a separate control valve, using a microporous oxygenated aeration device to ensure that the mixing air volume and oxygenated air volume can be flexibly adjusted.
4. The best DO control for the MBR tank is between 2.5 and 5, with a normal level of about 3ppm, and the DO will change when the level varies, and should not exceed 5.0ppm for a long time.
