| With the development of urbanization, many rivers and lakes are polluted simultaneously by nitrogen,phosphate and recalcitrant chemicals. For this kind of water, it is difficult to get repaired by complying single physical, chemical, or biological methods.In this case,we treat the simulated and actual water with complex pollution by using integrated photocatalytic-biological internal circulating reactor.At the beginning of the research, we study the method of TiO2 sol-gel for making TiO2 film, and the effect of photocatalytic film. The results show that the best film should be coated on groundglass,for eight times, in 500 degrees Celsius.In the study of groundwater(composite polluted) treatment by TiO2 photocatalyst, we found that COD could be increasing greatly, and we get the same result in the photocatalytic treatment of water containing pyridine, which indicates that the urban river water contains the similar chemicals like pyridine. The structure of pyridine was changed after photocatalytic oxidation according to ultra violet spectrum analysis. Verified the rise of COD ,and original pyridine could not be oxidized by potassium dichromate, but it could be oxidized after photocatalytic oxidation. Experimental results suggested that there were some recalcitrant organics in urban river water with complex pollution.It can be indicated that the change of TN was relative to the change of COD. The removal rate of COD was opposite to the removal rate of TN, by using integrated photocatalytic-biological internal circulating reactor.TN and chemicals are removed at the same time by integrated photocatalytic-biological internal circulating reactor.After photocatalytic oxidation,the chemicals might be transferred into utilizable organic carbon source uses by microorganism and increase of carbon/nitrogen ratio. It is indicated that total nitrogen removal rate increased more than 30 percent by photocatalytic oxidation compared with the river treat that without photocatalysis.
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