Treatment Of Oil Wastewater By Combination Of Chemical Precipitation And IC Reactor

In recent years,my country’s oil and fat industry has developed rapidly,and more and more oil and fat wastewater is produced.If such wastewater is not treated before being discharged,it will harm the surrounding environment,so the treatment of oil and fat wastewater is particularly important.Earlier,most researchers used aerobic biological methods to treat grease wastewater.In recent years,anaerobic process has been widely used in the treatment of grease wastewater due to its obvious advantages such as good effect,good stability and strong impact load capacity.However,in the process of wastewater treatment,anaerobic biological treatment technology also reveals many problems,many researchers through experiments to improve the anaerobic biological treatment of oil and grease wastewater technology.This article briefly describes the water environment at home and abroad,and details the sources,characteristics and treatment methods of grease wastewater.Highlights the struvite precipitation method in the chemical precipitation method and the IC reactor in the biological method.The main equipment used in this experiment is a precision stirrer and an IC reactor.In this experiment,the chemical precipitation method and the IC reactor designed by ourselves were used to treat the grease wastewater from a grain processing factory in Dalian.The best conditions for the treatment of grease wastewater by chemical precipitation method were determined by changing the ratio of calcium and magnesium,the stirring rate,the stirring time,the p H,the ratio of magnesium and phosphorus,and the temperature.Then,the chemical precipitation experiment effluent is used as the IC reactor inlet water,and the optimal conditions for the treatment of grease wastewater by the IC reactor are determined by changing the p H,wastewater/activated sludge ratio,reaction time,circulation flow rate,iron powder content,and iron-carbon ratio.The conclusions drawn are:(1)Chemical precipitation is used to treat grease wastewater.Phosphorus and ammonia nitrogen in grease wastewater are mainly removed by chemical precipitation.In this chemical experiment,the removal rates of COD,phosphorus and ammonia nitrogen have reached more than 90%.Before treatment,the COD concentration in the wastewater is 3.00×10~4mg/L,the phosphate concentration is 3.6×10~3mg/L,the ammonia nitrogen concentration is 6.48×10~3mg/L,and the COD concentration is about 1.8×10~3mg/L after the chemical precipitation experiment The concentration of phosphorus is around 10mg/L,and the concentration of ammonia nitrogen is around 60mg/L.(2)The IC reactor treats grease wastewater.The reactor is a combination of internal and external circulation,which enhances the buffering and impact resistance of the reactor,so the p H control can be performed in the early stage of the reaction.After the chemical precipitation effluent is processed by the IC reactor,the COD concentration drops to 2.85×10~2mg/L,the phosphate concentration is as low as 3.79mg/L,the ammonia nitrogen concentration is 53.27mg/L,and the removal rates of the three are 83.69%and 49.33%,23.89%.(3)Combined process to treat grease wastewater.Separate chemical precipitation and biological methods can treat pollutants in wastewater,Through productive research,the overall treatment effect of chemical precipitation+IC reactor combined process for treating oil and grease wastewater was investigated,and reasonable parameters were obtained.After the combined treatment of the two processes,the removal rates of COD,phosphate and ammonia nitrogen have reached more than 99%and the effluent concentration has reached the third level standard of"Comprehensive Wastewater Discharge Standard"(GB8978-1996).In actual engineering,there are some necessary pretreatments before chemical precipitation,and some subsequent treatments after the IC reactor,so that all impurities in the effluent can reach the national effluent standard.