Experimental Research On The Treatment Of Carwash Water In Kunming City By Coagulation United Technology

The third industry has developed rapidly in Kunming, especially for car washing industry. With the development of the industry, the water consumption and the volume of wastewater are growing. Car washing wastewater contains varieties of pollutants, such as mud, detergent, etc. If it is discharged into municipal pipe network directly, the urban of drainage facilities and sewage treatment facilities will be aggravated. Consequently, the study about the treatment of car washing wastewater have practical sense in improving urban water environment.At present car washing shop has the characteristic of dispersive and a small amount of water in Kunming city, so most of them discharge the wastewater into municipal sewers directly after the process of sedimentation. By continuous water quality monitoring, statistics show that effluent of sedimentation can not fulfill discharge requirement. Therefore the paper debate on the treatment of car washing wastewater to provide models and reference for engineering practice. The study contains following five parts: ①The optimum conditions about treatment of car washing wastewater with PAC and the preliminary analysis of adsorption mechanism; ②The effect about treatment of car washing wastewater with single or mixed coagulant and the comparison between them; ③The removal efficiency by combining PAC with coagulant and their best combination;④The effect on③fter Bringing in H2O2 and influencing factors;⑤ Adopting different combinations to treat car washing wastewater and comparing iheir superior and inferior.The study shows following results. ①When adding 1.6g/L PAC, reacting 45min, elimination rate of COD and anionic surfactant exceed 70%,85% respectively. The adsorption of PAC about reducing substances is in accord with Freundlich model, and about detergent chemicals is in accord with Langmuir model. ②The addition of coagulant has an positive effect on removal of turbidity. When adding A12(SO4)3340mg/L, elimination rate of turbidity is 99.11%; When adding PFS 340mg/L,260mg/L, elimination rate is 99.00%; When AI2(SO4)3and PFS are mixed with a mass ratio of 1:3, adding 280mg/L, elimination rate is 99.27%. In terms of elimination rate of COD and LAS, compared with Al2(SO4)3, improve 8% and 9%; compared with PFS, improve 3% and 3%; ③When combining PAC with coagulant, adding PAC after coagulant in 60s can get a good result.④Adding H2O2 have a positive effect on removal of COD no effect on LAS. When adding H2O25 mg/L before coagulant, removal of COD perfect best. ⑤ Removal efficiency of COD and LAS exist difference by PAC, A12(SO4)3-PFS, PAC+A12(SO4)3- PFS and H2O2+PAC+A12(SO4)3-PFS. From good to bad, ranking as H2O2+PAC+A12(SO4)3-PFS, PAC+A12(SO4)3-PFS, PAC, A12(SO4)3-PFS. ⑥ Adding the filtering process on the basis of "H2O2+Al2(SO4)3-PFS+PAC", the index of COD, LAS, chromaticity and turbidity are depressed to 22 mg/L,0.24 mg/L, three times,2.3 NTU respectively, up to the water quality standard ("water quality standard of living of mixed water "-GJ25.1-89), and under different filter speed and different filter material layer thickness has a certain influence on the removal of LAS.The paper through the experimental study, concentrations using the four indexes of the "H2O2+A12 (SO4) 3-PFS+PAC+filter" technology, to a large extent reduce of the COD, Las, chroma, turbidity, water quality reached reuse water quality standards, and provided a reference for the engineering practice.