The method of oil-water separation:
1. Filtration method
The filtration method is to pass the waste water through a device with perforations or through a filter layer composed of a certain granular medium, and use its interception, screening, inertial collision and other functions to remove the suspended solids and oil in the waste water and other harmful substances.
2. Gravity separation method
Gravity separation is a typical primary treatment method, which utilizes the density difference between oil and water and the incompatibility of oil and water to separate oil droplets, suspended solids and water in a static or flowing state. The oil droplets dispersed in the water slowly float and layer under the action of buoyancy. The floating speed of the oil droplets depends on the size of the oil droplets, the density difference between the oil and the water, the flow state and the viscosity of the fluid. The relationship between them can be described by laws such as Stokes and Newton.
3. Centrifugal separation
Centrifugal separation method is to rotate the container containing oily wastewater at high speed to form a centrifugal force field. Due to the different densities of solid particles, oil droplets and wastewater, the centrifugal force received is also different, so as to remove solid particles and oil droplets from wastewater.
4. Flotation method
Flotation method, also known as air flotation method, is a water treatment technology that is being researched and promoted continuously at home and abroad. The method is to introduce air or other gas into the water to generate fine air bubbles, so that some small suspended oil droplets and solid particles in the water are attached to the air bubbles, and float to the water surface together with the air bubbles to form scum (oil-containing foam layer), and then use an appropriate The oil skimmer skims the oil.
5. Biological oxidation method
Biological oxidation is a method of purifying wastewater by using the biochemical action of microorganisms. Oil is a hydrocarbon organic matter that can be broken down into carbon dioxide and water by life activities such as metabolism by microorganisms. The organic matter in the oily wastewater is mostly in the dissolved and emulsified state, and the BOD5 is high, which is beneficial to the biological oxidation.
6. Chemical method
The chemical method, also known as the chemical method, is a method of adding chemicals to convert the pollutants in the wastewater into harmless substances by chemical action, so that the wastewater can be purified. Commonly used chemical methods are neutralization, precipitation, coagulation, redox and so on. Coagulation is mainly used for oily wastewater. The coagulation method is to add a certain proportion of flocculant to the oily wastewater. After hydrolysis in the water, a positively charged micelle and a negatively charged emulsified oil are formed to generate electrical neutralization, the oil particles aggregate, the particle size becomes larger, and flocculation is formed at the same time. The oil-like substance adsorbs fine oil droplets, and then separates oil and water by means of sedimentation or air flotation.
Post time: Mar-31-2022