Research And Development Of An EAFC Based Equipment For Car Wash Wastewater Circulating Treatment

The rapid growth of the vehicle population in China causes the waterconsumption and wastewater discharge issue, which attracted extensive socialconcerns. Circulating water-treatment equipment of car washing wastewaterdemonstrated to be one of the most efficient ways to solve the problems. The result isnot optimistic though series of the laws and regulations were set down.This project combined survey, experiment, design and application researchmethods to try to research and develop a new circulating water-treatment equipmentwith obvious economic efficiency and higher promotion and application features.During the period, we need to assess the problems of existing circulatingwater-treatment equipment and put forward corresponding methods.Research suggests that three main problems such as evil-smelling of effluent, toomuch space occupied and hardly maintain strictly affect the promotion andapplication of the existing equipments,so we designed a new equipment based onEfflux Air Floatation and Coagulation technical flow process（EAFC, for short）toreclaim car-washing wastewater.In the design of EAFC equipment, traditional coagulation-air flotation isreversed. At the air flotation time, the remaining kinetic energy is utilized to create asuitable flow pattern for coagulation and flocculate process, which makes thecoagulation-flocculation and Efflux air floatation coincident. So the EAFC processeliminates the traditional coagulation-air flotation’s scraping, air dissolving, andcoagulation-flocculation’s promotion, mixing, stirring apparatus and equipments.Tests and design of no-scrub and air compression type of UV sterilization device,jar tests and the jet apparatus appointed that, after the jar test of PAFC,polyaluminium chloride, polyferric sulfate or special A+B the supernatant fluidsuperior to the standards of wastewater reclamation and reuse in color and turbidity.The inner cone angle of the nozzles of jet device has considerable impact of theapproximate efficiency, in the range of0-0.5Mpa. The flow rate and the approximateefficiency of90°inner cone angle nozzles are obviously better than nozzles of60° and120°. The pressure boost process and the callback procedure of sterilizationdevice are on the brink of the theoretical value of air compression, which can protectthe lamp from wastewater to prevent the decline of UV germicidal efficiency. In thecore of the EAFC, the mixing pipe volume is14L, the foam slag separating chamberat the top of mixing pipe is65L, the coagulation District mixing pipe outside of240L. Jet device using a90°inner cone angle nozzles, and the diameter of the nozzles is6mm, the flow rate is1m3/h, the sewage pump lift is30m.At the actual environment operation of car washing wastewater treatment, theequipment was integrated works well, there was no vicious salinities accumulated,and obtained a good contaminants removal efficiency, where the LAS, color, turbidity,CODcrremoval rate up to85%,96%,98%and77%. Achieved advantages of goodand odorless effluent quality, less covering and earthworks, and complied the runningprocess automation. All above consequents proved that the EAFC technologicaldesign is feasible and probably a higher value of application and popularization.The techno-economic analysis of the equipment indicates that the technology hasbrought certain advantages in technical, economic, environmental and socialefficiency advantages. To the research orientation aspect influencing factors,principles of EAFC and applicability merits when the EAFC make application for thewastewater treatment which was purified by coagulation-air flotation.