Research On Environmental Protection Equipment Technology Of Catering Oil-water Separation And Purification Treatment

With the continuous increase in the discharge of oily wastewater from catering,the pollution caused by it has become more and more serious,and it has caused great harm to the natural environment and human health.Therefore,it is of practical application value and significance to study the treatment technology of oily wastewater from catering,improve the level of urban environmental management,and promote the recycling of resources.The treatment technology of restaurant oil-water separation and purification was researched,combining traditional treatment technology and super-wetting materials,and proposes a composite treatment process of air flotation,super-hydrophilic copper mesh and super-hydrophobic copper mesh.Based on the principle of air flotation,air flotation oil-water separation tests were carried out;oil-water separation was simulated using simulation software,and the oil removal process parameters were optimized through orthogonal tests and verified through experiments with oil-water separation devices with super hydrophilic copper mesh and super hydrophobic copper mesh.On this basis,an industrial-type restaurant oil-water separation and purification treatment equipment was designed.Firstly,the air flotation process parameters were optimized through experiments on the influencing factors of air flotation.Based on the principle of air flotation,a pressuring dissolved air flotation tank was set up and experiments were conducted on the factors of dissolved air pressure,air flotation time and coagulant dosage to study the influence of the removal effect of animal and vegetable oils and COD in restaurant oily wastewater.The concentration of animal and vegetable oil in the water sample was 54.5 mg/L and the concentration of COD was 363 mg/L.The effect of air flotation on oil-water separation and purification was good.Next,the oil-water separation effect of the super hydrophilic copper mesh was simulated using the fluid dynamics software Fluent.Based on the Wenzel model and the Cassie model,a two-dimensional superhydrophilic copper mesh groove structure was established to simulate the flow field conditions of oil and water droplets touching the surface of the superhydrophilic copper mesh,and to analyse the influence of velocity,copper mesh pore size and oil contact angle on oil-water separation and purification.The simulation results show that the oil and water flow velocity increases,the copper mesh aperture increases and the oil contact angle on the surface of the super hydrophilic copper mesh decreases,the oil barrier performance of the super hydrophilic copper mesh decreases.The optimized process parameters were determined by orthogonal tests with a velocity of 0.1 m/s,a copper mesh aperture of30 μm and an oil contact angle of 150 °.Applying this combination of process parameters,an oil removal rate of 95.7% was obtained.Secondly,superhydrophilic and superhydrophobic copper meshes were prepared by solution etching and low surface energy material modification,respectively,to design a model oil-water separation device and to perform oil-water separation experiments.The copper mesh was etched with a mixture of sodium hydroxide and sodium persulphate to produce a superhydrophilic copper mesh,and the surface of the mesh was modified with a perfluorinated aoi triethoxysilane reagent on top of the mixed solution etching to obtain a superhydrophobic copper mesh.The surface morphology and the wettability of the copper mesh were characterised and compared before and after treatment,both the superhydrophilic and superhydrophobic copper mesh surfaces developed a rough structure and affected their surface wettability.On this basis,a model of a continuous and efficient oil-water separation unit was designed to treat air-floated wastewater using 500 mesh superhydrophilic and superhydrophobic copper mesh.The concentration of animal and vegetable oil in the treated wastewater from a single oil-water separation unit was 1.98 mg/L and the oil removal rate was 96.4%,which was close to the numerical simulation results and proved that the numerical simulation experiment was reasonable and feasible.The concentration of animal and vegetable oil in the wastewater treated by the three tandem oil-water separation units was 0.34 mg/L,and the oil removal rate reached99.4%,which was better than that of the single oil-water separation unit.The concentration of animal and vegetable oil in the oil-water separation purified water reached the primary discharge standard of the Comprehensive Discharge Standard of Wastewater(GB8978-1996).Finally,the combination of spiral solid-liquid separation,air flotation treatment and super hydrophilic copper mesh + super hydrophobic copper mesh combination treatment improves the effect of restaurant oil-water separation and purification treatment,and designs an economic and feasible industrial-type restaurant oil-water separation and purification treatment equipment.In summary,this paper investigates the restaurant oil and water separation and purification treatment technology and provides an air flotation + super hydrophilic copper mesh and super hydrophobic copper mesh combination treatment process.Combining theoretical research,finite element numerical simulation and experimental techniques,the process parameters of restaurant oil and water separation and purification are optimized to improve the oil removal effect and reduce environmental pollution,which is of great significance in urban environmental management and ecological protection.