| The rapid development of modern industry accelerates the steps of chemical wastewater discharge, which causes the water pollution, the shortage of water resources and even great threat to human health. The development of water treatment technology has a long way to go. Hydrodynamic cavitation, as an advanced water treatment technology, is being studied and discussed by many scholars at home and abroad. The experiment in this paper, using the circular orifices plates, was based on hydraulic cavitation device which was designed out independently. P-Nitrophenol (P-NP) solution was treated and analyzed as a kind of simulate wastewater under different orifice velocity (including maximum velocity, minimum velocity and middle velocity), cavitation number, initial concentration (of the wastewater), initial pH value, cycle time and different types (including orifice number, size and arrangement) of circular orifices plates. The relationship between these factors and P-NP degradation was researched out. Plus, in the corresponding conditions, Methylene Blue (MB), whose concentration before and after were determined and analyzed by spectrophotometer, was used to capture hydroxyl radical. And pressure characteristics were analyzed on five measuring points in cavitation segment through the YE6263pressure data acquisition system. Finally, the actual chemical industry wastewater was treated and researched. The initial COD between227.63-398.35mg/L can make a best degradation effect on wastewater with four types of plates. There was the best removal efficiency of COD due to venturi tube when the initial COD was between284.54～398.35mg/L. |
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