Study On Treatment And Reuse Of Waste Water From Passenger Car

Car cleaning not only consumes a lot of water resources,but also needs to use a certain amount of foam cleaning agent to effectively remove the dirt on the surface of the body.The cleaning wastewater usually contains a lot of sediment and some organic compounds,which will lead to water pollution if it discharge to the environment directly.The wastewater treatment and reuse can save water as well as produce some economic benefits.The wastewater treatment process of traditional car wash has a series of problems such as high investment cost,large required site,complicated operations and high running cost.In this paper,the daily washing wastewater of some automobile beauty shops in Wuhan city of Hubei was studied.After the relevant water quality analysis,a treatment for the raw water established containing the pretreatment(grid and advection sedimentation tank),coagulation sedimentation,ultrafiltration treatment(sand filter,activated carbon filter,security filter and ultrafiltration membrane).This treatment can achieve the reuse of car washing wastewater with low cost and high efficiency.The main conclusions are as follows:(1)The water quality analysis were carried out for the car washing wastewater.Based on the CODcr and LAS of the wastewater,coagulation sedimentation,ultrafiltration membrane method were applied for car washing wastewater treatment.(2)According to the data of waste water used in car washing,the grid and tank sizes in advection sedimentation were calculated.The pretreatment can effectively intercept solid debris and reduce the turbidity,CODcr,LAS and color value of the car washing wastewater;(3)In the coagulation sedimentation step,the optimal coagulant was PAC(polyaluminium chloride)and the coagulant was PAM(polyacrylamide).The optimum reaction conditions are as follows: coagulation reaction temperature 25 ℃,pH value 7,PAC dosage 20 mg / L,PAM dosing The amount of 1mg / L,rapid mixing 5min,slow stirring 10 min,static time 20 min.Through the coagulation sedimentation step,the turbidity and CODcr concentration of the wastewater were effectively reduced,providing a reliable guarantee for the subsequent processing.(4)According to the quality requirements of the recycle water,considering with actual process and the operating cost,quartz sand was used as a filter to complete the sand filter column filling,filter porosity 0.42.The best configuration of the activated carbon is 6g / L,regardless of the use of renewable.The filter is made of PP filter with a diameter of 10μm.The ultrafiltration membrane cartridge with relative molecular weight of > 10000 is used for the ultrafiltration filter.The outer tube is made of stainless steel 304,and the filter is processed by mechanical pump.Sludge can be dealt with vacuum filtration or plate and frame filter to further filter and landfill.