What are the treatment methods for catering wastewater treatment equipment?

Coagulation treatment of catering wastewater:

Contaminants in restaurant wastewater are mainly in the form of colloids. The colloid itself has both large surface free energy, large adsorption capacity, and Brownian motion characteristics, so that there are more collision opportunities between the particles, which seem to adhere to aggregate into large particles, which are then subjected to gravity. sink. However, because the colloidal particles of the same kind have the same electric charge, the electrostatic repulsion between them prevents the particles from approaching each other and polymerize into larger particles. Second, the charged colloidal particles and counter ions hydrate with the surrounding water molecules. The formation of a layer of hydration shell also hinders the polymerization of the colloidal particles. After adding an inorganic salt such as an aluminum salt, a metal ion hydrolysis and polymerization process occurs, and the adsorbed positively charged multi-nuclear ion can compress the electric double layer and lower the zeta potential, so that the large repulsion energy between the rubber particles is reduced, thereby The rubber particles are destabilized.

Organic polymers are also often used as flocculants while being treated with inorganic salt flocculants. The polymer flocculant has good bridging and adsorption, and the use of the inorganic salt flocculant can accelerate the reaction speed and improve the treatment effect. Some tests have shown that:

1 potassium aluminum sulfate + polyacrylamide as flocculant can significantly reduce the CODcr and turbidity of restaurant wastewater. The CODcr removal rate can reach 83.3%, and the turbidity removal can reach 76.9%.

2 Basic aluminum chloride, iron sulfate, aluminum chloride, ferrous sulfate, potassium aluminum sulfate, potassium aluminum sulfate + polyacrylamide 6 kinds of flocculants have better effects on flocculation treatment of restaurant wastewater. Among them, aluminum sulfate potassium + polyacrylamide treatment effect is good. The dosage of Zui Jia is: 16mL of 1g/L composite flocculant is added per 1L of water sample, and the pH value of Zui is about 9.

Biochemical treatment of catering wastewater:

Due to the BOD/COD>0.3 in the catering wastewater, it has the characteristics of good biodegradability. Under the premise of removing the oil and not affecting the subsequent biochemical reaction, the biological method can be used to treat the catering wastewater.

SBR process: Yu Jinlian used the sequencing batch activated sludge process (SBR) process to treat the catering wastewater, and investigated the relationship between sludge concentration, sludge load and treatment effect and the denitrification performance of the process. The results showed that when the influent COD concentration was 900 mg/L - 1095 mg / L, the influent oil concentration was 185 mg / L ~ 356 mg / L, the sludge load was less than 0.81 kg / kg (ss) · d, oil load Less than 0.112 kg/kg (ss). Under the condition of d, the effluent water quality can reach the secondary emission standard of GB8978-1996.

When the influent TN<30mg/L, the TN removal rate can reach more than 85%. The SBR process is an ideal process choice for catering wastewater with intermittent discharge and large changes in water quality and quantity.

Biological contact oxidation method: Fan Limei continuously treats catering wastewater by biological contact oxidation method. The filler is PVC biosphere and soft fiber filler. When the hydraulic retention time is more than 78h, the removal rate of COD, BOD and TSS of wastewater reaches 90%, and The amount of sludge produced is 1/4 less than that of activated sludge.

Membrane bioreactor: Ning Ping uses a membrane bioreactor to treat catering wastewater. The membrane bioreactor combines the degradation of microorganisms with the efficient separation of membranes, which can effectively reduce the concentration of pollutants in wastewater, and the effluent quality is better. The national "Sewage Integrated Emission Standard" GB8978-1996 first-class standard, to achieve the standard of domestic miscellaneous water.

Membrane bioreactor for treating catering wastewater:

A membrane bioreactor (MBR) is a biochemical reaction system that combines a membrane module with a bioreactor. With the development of membrane technology, the price of membrane materials has declined, and there will be a big development in the application of membranes in this century. The adaptability is strong, HRT and SRT can be controlled separately, and the advantages of pathogens and easy commercialization determine that the membrane bioreactor is a promising water treatment technology. The operating conditions and characteristics of the activated sludge mixture are important factors influencing the membrane flux of the reactor.

(1) After the catering wastewater is treated by the membrane bioreactor, the effluent water quality is good, meets the first-class standard of the comprehensive wastewater discharge standard (GB8978-96), and can also reach the water quality standard for reclaimed water;

(2) In the area where the pressure is relatively low, the membrane flux is proportional to the pressure, and in the region where the pressure is relatively high, the membrane flux is independent of the pressure. As the temperature increases, the membrane flux increases proportionally. Membrane flux is linear with sludge concentration. The film surface flow rate is not as high as possible. The membrane module operating conditions are preferably an average operating pressure P: 0.2 MPa, and a membrane surface flow rate V = 6.5 rn/s to 7.5 m/s;

(3) By contrast analysis of the new film and the contaminated film by scanning electron microscopy, it is found that the void on the surface of the film is greatly reduced after the film is contaminated, and the thickness of the gel layer is 3-4 m;

(4) When the pollution reaches a certain level (when the membrane pressure of the test is greater than 0.2 MPa), the membrane is cleaned. The cleaning conditions of the membrane are as follows: Qingshui rushing +0.2% NaCL0 (soaking 0.5h) +l% acetic acid (soaking for 0.5h), the water recoil can slightly restore the membrane permeability, and the inorganic membrane can be permeable after NaCL0 immersion. It recovered to 62%, and the acid membrane permeability can be restored to 84% or more after pickling.