Study On Rainwater Treatment And Water Quality Guarantee Technology Based On Integrated Device

In recent years,with the rapid development of urbanization in our country,water resource shortage has become more and more serious in urban city.Plenty of rainfall in flood season resulted in frequent urban water logging.Taking advantage of the renewable resource—rainwater,can effectively improve the above situation.Compared with other types of rainwater,urban roof-runoff has the advantages of low pollutants concentration,good water quality,simple processing technology,and low processing cost.Therefore,the research about the treatment and reuse of the typical Roof-runoff in Chongqing has high practical value.Water quality of rainwater runoff from three typical kinds of roofs in Chongqing including asphalt roofing,green roofing and PC-canopy was analyzed.It was found that the initial rain runoff was seriously polluted.After 6mm abandon flow,the rain-water quality parameters are as follows: pH between 6-8,SS between 45-85mg/L,turbidity between 8-30 NUT,COD between 80-120mg/L,BOD5 between 6-10mg/L,TN between 7—10mg/L,TP between 0.8—1.1mg/L.Due to the low biodegradability(BOD5/COD ?0.2)and low SS concentration,the rain-water can be processed by physicochemical technology.According to the roof runoff water quality and its requirements for reuse,Coagulation—Sedimentation—Filtration—Activated Carbon Adsorption was applied to the integrated water treatment device which is composed of blend unit,flocculation unit,sedimentation unit,and filter cloth unit.The results showed that the removal rate of the pollutants are turbidity at 99.6%,SS at 98.11%,COD at 81.16%,BOD5 at 69.85%,TN at 52.31%,TP at 93.94% respectively.The quality of the effluent from the device meet the standard in ?The reuse of urban recycling water—Water quality standard for urban miscellaneous water consumption(GB/T 18920-2002)?and?The reuse of urban recycling water-Water quality standard for scenic environment use(GB/T 18921-2002)?.The technical-economic indicator about the device and the storage period of the rain were calculated.The results showed that the equipment investment is 16606.00 RMB,the operation cost is 0.65 RMB/m3,and processing cycle about rainwater is 25 days.