Research On Small Environmental Protection Equipment For Catering Wastewater Treatment

With the rapid development of China's social economy,people's quality of life has been improved,the catering industry is booming,and the production of catering wastewater is increasing day by day.The food industry uses a large amount of animal and vegetable oil in the cooking process,which will produce a large amount of oily wastewater.The organic matter content of animal and vegetable oil is high,putrefy easily,can produce certain chromatism and malodorous,accordingly,research the treatment technology of meal kitchen waste water,reduce water pollution,protect environment and resource to use,have practical application value and significance.Based on the characteristics of catering wastewater generated by a catering unit in Hefei city,this paper studies and designs the wastewater treatment equipment with a higher degree of integration,which is characterized by high efficiency and small area.The wastewater treatment technology,which is suitable for the equipment,is put forward by combining grille filtration,gas-floating oil-water separation and PVDF tubular membrane separation.This paper carried out the study on the flow state and air floatation effect of the gas-water two-phase flow in the advection type air floatation pool.Through fluent Ansys simulation software,the optimized process parameters of the inlet water in the upper part of the air floatation pool,the gas content rate at 5%,the bubble diameter at0.01mm,and the length to depth ratio of the air floatation pool were obtained as1.6:1.According to the simulation results,the experimental equipment of the floating tank was established.Through experimental research,it was found that the removal effect of animal and vegetable oil and COD was the best when the dissolved gas pressure of the floating tank was 0.3 MPa,the hydraulic retention time was 15 min,the water temperature was maintained between 10 to 20?,the dissolved gas volume was 50 m L·L^-1,and the concentration of polyaluminum chloride?PAC?was 60 mg·L^-1.At the same time,the dispersion state of animal and vegetable oil in the water samples was determined by the filtration and ultraviolet spectrophotometry.The experimental results show that the main existence state of food waste water raw water of animal and plant oil for oil?51.77%?,oil?39.16%?,under the optimal air flotation separation process parameters after treatment of restaurant wastewater,in addition to the most of the oil slick and most of the dispersed oil,animal and plant oil in the food and beverage wastewater after air flotation separation of decentralized state mainly for emulsified oil and dissolve oil,emulsified oil,dispersed oil accounted for 58.14%,18.15%respectively.On this basis,PLUM-PVDF tubular membrane was applied to conduct secondary treatment after air flotation,and the orthogonal experiment determined that when the temperature was 50?,the flow rate was 1 m³/h,and the back washing time was 20 min,the removal rate of animal and vegetable oil and COD reached 78%and 65.3%,respectively.At the same time,the dispersion state of animal and vegetable oil in the water sample was determined by filtration and ultraviolet spectrophotometry.The experimental results show that membrane separation technology can effectively remove emulsified oil,floating oil and dispersed oil from catering wastewater,but has poor treatment effect on dissolved oil.Finally,by combining grillage filtration,heavy-duty floating oil-water separation and PVDF tubular membrane oil-water separation,the concentrations of animal and vegetable oil and COD after treatment were 13.6 mg·L^-1and 124.3 mg·L^-1,to achieve the integrated wastewater discharge standard?GB8978-1996?"the secondary emission standards.On the premise of ensuring the feasibility and economy,the structure design of the green,simple and environment-friendly equipment for the treatment of catering wastewater was obtained.