1. Water inlet standard for MBR membrane.
The effect of MBR membrane to purify sewage is very powerful, but it is not all types of sewage can be purified, it is there a certain use standard, so, before the use of MBR membrane, what is its inlet standard?
1. Feed water source: suitable for various water sources, the standard sludge concentration is 15000ppm.
2. PH (Running): 1 12.
3. Cleaning: 1 12 (3g-tips, 4g-tips products can reach 14).
4. Temperature (°C) 5 45.
5. Filtration transmembrane pressure (mpa) 005。
6. Backwash transmembrane pressure (mpa) 005
7. Feed particle size: <2mm, the pool where the membrane is located should not contain sharp objects that damage the membrane, such as branches, plastic sheets, sand particles, etc.
8. Oil content in the feed: <2mg l, otherwise degreasing pretreatment must be carried out first.
9. Hardness: depending on the pH value and scaling tendency.
10. Theoretical oxygen demand refers to the theoretical value required for the complete oxidation of hydrocarbons in organic matter.
11. Biochemical oxygen demand, under aerobic conditions, due to the regulation of microorganisms, the oxygen demand of organic matter is degraded.
12. Organic matter, the amount of organic matter that is reduced in a water sample oxidized by chemical methods. It refers to the oxygen equivalent of substances (usually organic matter) that can be oxidized by strong oxidants in wastewater, wastewater treated with a wide outflow of wastewater and polluted water.
13. Organic carbon refers to the total carbon content in dissolved and suspended solids.
2. Requirements for the inlet water quality of MBR ultrafiltration membrane.
What are the requirements for water quality of MBR ultrafiltration membranes?Different types of impurities in different raw water are different, and in the case of complex water quality, we require pretreatment of raw water to prevent impurities from damaging the MBR membrane. Let's talk about the requirements for the quality of the influent water of the MBR membrane and the related treatment methods.
1. Oils and fats.
When the raw water contains grease substances, the grease will cover the surface of the filter membrane, clog the membrane pores, and cause irreversible contamination of the filter membrane. Oils and fats can be analyzed as n-hexane extracts and then separated into animal and vegetable oils and mineral oils. When the grease in the raw water is too high, it is necessary to carry out degreasing treatment, and the methods of degreasing treatment include natural floatation method and pressurized air flotation method.
Animal and vegetable oils: The content of animal and vegetable oils should be less than 50mgl. Animal and vegetable oils can generally be degraded by activated sludge, and by maintaining a high MLSS concentration, the clogging of the membrane surface can be controlled to a certain extent, but when the n-hexane extract exceeds 50mg, the oil will adhere to the membrane surface, and clogging may occur, so pretreatment is recommended.
Mineral oil: The mineral oil content should be less than 3mgl. Mineral oil is difficult to dissolve and will have a worse effect on the filter membrane than animal and vegetable oils, so special care should be taken when mineral oil is mixed in.
2. Defoamer. When the sludge foams and you need to put a defoamer, please use a high-grade ethanol, ether, vinegar defoamer, and do not use a silica gel-based defoamer. Silicon-based defoamers are easy to be adsorbed to the surface of the membrane, which will pollute the membrane, and this pollution is irreversible, so it is strictly forbidden to use silicon series defoamers.
If a silicon defoamer is used, the defoamer will adsorb on the film surface, which will accelerate the rise of the pressure difference between the films. The adsorption of silicon-based defoamers leads to an irreversible loss of membrane flux.
3. Biochemical treatment.
In the case of membrane module filtration, biochemical treatment of the raw water must be carried out beforehand. When the membrane module is directly used for the source without biochemical treatment, the untreated organic matter in the raw water will adhere to the membrane surface, accelerating the rise of the pressure difference between the membranes and causing the module to clog quickly.