Application of Ceramic Membrane Separation Technology in Edible Oil Wastewater Treatment

1、 The Introduction of Membrane Filtration Technology

Membrane filtration is a hot technology in the treatment of industrial wastewater at home and abroad. Compared with other filtration and separation technologies, membrane filtration technology has the advantages of low energy consumption, high separation efficiency, strong work reliability, small equipment area and high degree of automation. Membrane filtration technology is used to treat all kinds of oily wastewater, which does not consume chemical agents and generate new pollution during normal operation. Polyacrylonitrile membrane, polysulfone membrane and cellulose acetate membrane were used earlier in China to treat oily wastewater LJ. However, these membranes are all organic membranes, which have disadvantages such as poor chemical stability, easy aging, short service life (only 2-3 years), high replacement cost, poor resistance to high temperature, acid, alkali and organic solvents, limited application scope and operating conditions. At present, there has been a trend of using inorganic ceramic membrane to treat various oily wastewater at home and abroad. Compared with the organic membrane, the inorganic membrane is resistant to high temperature, acid, alkali and corrosion of organic matter, has high mechanical strength, long service life (more than 5 years), narrow pore size distribution, high oil cut-off rate and good operation stability. When the composition and concentration of oily emulsion sewage change, it has little impact on the quality of permeate. In addition, the membrane bioreactor (MBR) formed by combining the inorganic ceramic membrane module and the wastewater biochemical treatment device has also shown good treatment effect in the treatment of oily wastewater, and has become a new development direction of oily wastewater treatment.

2、The principle of inorganic ceramic membrane filtration technology for treating oily wastewater

The treatment of oily wastewater by inorganic membrane filtration is to make use of the surface tension of oil under a certain pressure, so that oil droplets and suspended solids larger than the membrane pore diameter are intercepted by the membrane pore. Inorganic membrane is a kind of polar membrane, which has strong hydrophilic and oleophobic properties and can form a gel layer in the filtration process. Therefore, in the actual filtration, oil droplets that are far smaller than the pore diameter of the membrane can often be intercepted, making the permeation concentration of oil very low. The oil in the wastewater is continuously concentrated in the circulating tank, and the small molecular substances and water molecules dissolved in water become permeate through the membrane pores. The oil content in the permeate is very low, usually less than 1% l4j of the treated wastewater.

3、The Characteristics of Inorganic Membrane Filtration Technology

a. Filtration mode: the working modes of Inorganic Ceramic Membrane Filter for filtering oily wastewater include whole process filtration (cross flow filtration) and cross flow filtration (tangential flow filtration)

b. Inorganic Membrane Filtration features simple operation and easy automation

c. The on-line instantaneous recoil technology can reduce the membrane surface pollution and prolong the service life and cycle

d. The membrane flux is large, and the filtration area is correspondingly reduced. The equipment occupies less land, requiring only 2-3m2