Application And Research Of Grease Wastewater Treatment Process

In recent years,with the rapid development of China's oil industry,various kinds of grease wastewater have been produced continuously.If such waste water is directly discharged into rivers,lakes and other water bodies without treatment,it will damage the water ecosystem and seriously affect the environment.Therefore,it is very necessary and meaningful to carry out pollution prevention and control of grease wastewater.Grease wastewater is mainly produced in the alkali processing,washing,acidification,neutralization,deacidification,deodorization and other processes of the oil and fat processing industry.This type of wastewater contains not only high concentrations of oils,but also organic substances such as phospholipids and saponins as well as acids,alkalis and salts.And solid suspensions.At present,the discharge of grease wastewater from China's oil plants is mostly intermittent,with large fluctuations in water quality and water,unstable pH values,and complex components,which can easily impact the biological treatment process.In this thesis,the actual wastewater from a certain oil processing plant in Dalian is taken as the object of study.Its COD is up to 42146mg/L,pH is about 1.61,phosphorus content is up to 3013mg/L,conductivity is about 80.1ms/cm.The experiment mainly used the "chemical phosphorus removal(pretreatment)+ UASB + biological contact oxidation" process to treat the oily wastewater generated by the oil processing enterprise.The main tasks of the experiment are:1 to study the effect of chemical phosphorus removal method and its influencing factors and to determine the optimal operating parameters.2.To study the acclimation and start-up of UASB and biological contact oxidation method,and determine the best reaction parameters and make it chemical.Phosphorus method coordination,and then make the entire process stable operation.Lime method and aluminum calcium powder pretreatment of oily wastewater shows that the lime method is superior to aluminum calcium powder method.When only lime is added to the system,the phosphorus removal efficiency can reach about 98%,and the lime dosage is 50 g/L.The effluent pH is approximately 8.1,the conductivity is approximately 39.6 ms/cm,and 25%COD can also be removed.When the pH of raw water was adjusted to 3.0,the removal rate of phosphorus could be kept above 95%and the removal rate of COD was 21.2%-27.5 under the conditions of lime dosage of 23g/L,constant speed stirring for 50min and static sink for 20min.%,the conductivity is about 50ms/cm,the effluent is stable below 9.0,does not affect the subsequent biochemical treatment.UASB and biological contact oxidation inoculation sludge was obtained from the sludge of the secondary sedimentation tank of the Chunliu River sewage treatment plant in Dalian City.UASB designed a volume load of 20 kg COD/m3 d.The sludge was inoculated for 133 days after inoculation,and the COD removal rate was Maintained at 65%?70%,the pH of the effluent is 7.0?8.5.The design load of the biological contact oxidation reactor is 2.0 kg COD/m3(filler)d.10 g/L aluminum calcium powder is added during the treatment.When the reaction time is 48 h,the effluent COD concentration is maintained at about 500 mg/L.TP When the concentration is lower than 5mg/L,the quality of the effluent meets the three-level discharge requirement of Integrated Wastewater Discharge Standard(GB8918-1996).