Study On The Characteristics And Control Of Membrane Biofouling Of RO

The key to the reverse osmosis system running efficiently is that avoiding the pollution of membrane. Among several pollutions of reverse osmosis, the bio-fouling is one of the main reasons which cause the system running trouble.Based on the analysis of reverse osmosis's pretreatment system for the feeding water as surface water, groundwater, tap water and reclaimed water, the test shows that the surface water and reclaimed water, with high content of organic matters and microorganism, will cause larger harm to reverse osmosis's bio-fouling. But the reasonable and effective pretreatment is the key to prevent reverse osmosis's bio-fouling. Various experiments indicate that the ultra filtration can effectively remove the colloids and suspended solids in source water. The SDI value of effluent water can be controlled in a low level, which is generally below 2. Combined with bactericidal treatment, it can effectively prevent reverse osmosis system from bio-fouling. By the measuring and analysis of CODMn, TOC and UV254 ,the relative relationship of CODMn, TOC and UV254 in the production of pure-water is obtained in this dissertation which shows that UV254, CODMn and TOC have a well linear relationship. UV254 measuring is easy, quick and exact, which is the replaceable parameter for organic matters in water. It is reasonable to use UV254 as the controlling indicators for organic matters of influence of reverse osmosis. It also can be used as the controlling indicators for membrane bio-fouling in the prophase. When the bio-fouling membrane was anatomized, it shows that the bio-fouling membrane are meshy and coupling, whose primary ingredients are organics matter such as albumin, benzene ring, hydroxyl acid, fatty acid and so on, as well as microorganisms such as cocci, bacilli, leaf mold, alga and so on. The test of cleaning the RO membrane's bio-fouling substance shows that adopting alkali-acid-sterilization the cleaning method is the best method. The author used 0.2%NaOH→0.2%HCl→1% formaldehyde solution to clean the membrane. The technique has more popularizing and application values.