| It is a fact that our country is lack of water resources at present .In addition ,as a result of the over propagation of alage owing to eutrophication ,landscaping water has been seriously damaged—dissolved oxygen decreases sharply and the quality of water deteriorates rapidly even turns black and smelly. Based on above-mentioned water environmental problems, combined with the water characteristics of natural landscapingwater and reused wastewater treated by biological process, the purpose of this research work is to find out a proper treatment process and parameters with microwave/electrodeless discharge ultraviolet/ozone (MW/UV/O3) reactor to sterilize E.coli and remove alage. Then, this research could provide references for further study and practical projects. Two reactors with the volume of 1L and 85L are designed carring on small experiment and model experiment separately in this research. Four processes—microwave, ozone(ozone is produced by ozone reactor ), microwave/electrodeless discharge ultraviolet (MW/UV), microwave/ electrodeless discharge ultraviolet /ozone(MW/UV/O3) are made to study the principle of disinfection and then find out the best process. Research work includes two parts. The first is to use the MW/UV/O3 reactor totreat urban wastewater resued as landscaping water, the expetimental wastewater treated by "Biological Process" comes from the second—sedimention poll of environmental science school of one university.The indices of expetimental quality are: BOD=14.6mg/L, CODcr=31.6mg/L, TN=13.54mg/L,TP=1.34mg/L,NH3-N=8.25mg/L,KN=12.41mg/L,NO3-N=0.89mg/L,SS=8mg/L,E.coli =2.4× 106cfu/L,when compared with "Quality Standard for Recalimed Wastewater Reused as Scenic Water CJ/95—2000", all indices meet the requirements except E.coli ,sterilizing E.coli is the focus in the experiment. The second part is to utilize the MW/UV/O3 reactor to treat natural landscaping water and the main aim is to removealage, alage control efficiency is mainly described by Do concentration change. At the same time, changes of turbidity,CODMn,NH3-N, NO2-N,TP are measured, too. In model experiment,the paper also optimize several parameters about the microwave ultraviolet lamp such as the length and the diameter of the ultraviolet, the number of the ultraviolet lamp,etc. The results demonstrate that (1)MW can disinfect E.coli only when the temperature rises to some extent on sample water and it chiefly plays the role of stimulating the microwave electrodeless discharge ultraviolet ultraviolet lamp in this research. (2)Tubility has a significant influence on the effect of the disinfection of E.coli and alage for MW/UV/O3 process. (3)Ozone is a good disinfectant for E.coli and alage.(4)MW/UV/O3 process can achieve better effect than ozone and microwave/ultraviolet process.(5)In model experiment,on condition that ultraviolet intensity is 4.38 mw/cm2 and the ozone concentration is 0.202mg/L accordingly, E.coli disinfection efficiency in urbanwastewater can get to 99.99% when the flow rate is 2.04m3/h and HRT is 2.5 minutes correspondingly. And on the conditon the flow rate is 1.46m3/h and HRT is 3.5 minutes correspondingly, alage control efficiency can also reach more than 90%, other quality of sample water such as tubility,CODMn , NO2-N, all decreased to different degree. Thennical and economical analysis shows that MW/UV/O3 reactor takes the air as raw material to generate ozone, so it doesn't need adscititious ozone producer. Poessing the characteristics of long life and quick start, the electrodeless discharge ultraviolet lamp without any electrode in the research is stimulated by microwave.The investment operation cost are very low. For example, to a water body with volume 1m3, the electricity cost is 0.46 yuan RMB for urban wastewater that comes from the second—sedimention poll and 0.65 yuan RMB for landscaping water.
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