Removal Of Algae In Eutrophicated Water By Hydrodynamic Cavitation

Regarding controls cyanobacterical bloom in eutrophic water, the traditional technology for algae removal, including physical method, chemistry method, biological method, have shown each other some shortcomings. Some methods can't make widely available for the higher cost, or some can't meet the new requirement of environmental protection. Based on the previous researchs on the algae removal technology, a set of device for creating hydrodynamic cavitation has been built for this study. The novel cost-effective technique of hydrodynamic cavitation (HC) for rapid removel of alage species was applied to meet the demand of cleaning the eutropication water.Cavitation was a kind of fluid phenomenon. In the water power machine, the cavitation should be avoided as far as possible,in order to prevent from damages the machine. However, the collapsing cavitation bubbles generate partial extremely high temperature and pressure, lihgt, micro-jets, shock waves, and strong tublence in the liquid,which destroy the molecular bond of water and result in formation of free radicals. Hydrodynamic cavitation has been applied to decompose organic pollutants in wastewater, but no report has been published on removel algae by hydrodynamic cavitation technology up to now.The change of design parameter of hydrodynamic cavitation generator can affect the cavitation effect, but the more researches are fewer. The installs position of the hydrodynamic cavitation generator influence the rule of cavitation effect , and the cavitation effect comparison research are less between the different kind of hydrodynamic cavitation generator. In order to realize the mechanism of hydrodynamic cavitation on the physico-chemical effects and removal algae,Venturi, single hole orifice and multi-hole orifice are the major part for creating the hydrodynamic cavitation. Mainly,optimizes the hydrodynamic cavitation generator on type , the parameter of structure and their installation location which affect cavitation effect by changed area of passage of them.The degradation of chloroform was used to determine the cavitational intensityn was applied to optimize reaction conditions. Microcystic aeruginosa was then used to carry on removel processing by the HC device. the major conclusions are listed as follows: (1) It is important to optimize the reactor structure of hydrodynamic cavitation for achieving a desired effect. A reasonable geometric parameter can promote the removal of algae. Comparing the venturi and the orifice , the cavitation effect of the orifice work better. The superior cavitation effect of single hole orifice and the multi-hole orifice is close when the area of passage in the same situation.(2) When degrades the chloroform and extinguishes the microcyst algae with the same kind of cavitation generator in the different design parameter: in certain scope, ratio of the hole area and the pipeline plan area is more bigger, the cavitation phenomenon is more increasingly obvious; The total perimeter of the hole and the total overflow area ratio is more smaller, the cavitation effect is more increasingly better. Which can produce better cavitational effect of them, the taperture of single orifice is 6 mm and the multi-hole orifice is 2# ,which has 9-hole.(3) The cavitation effect generated by suction is much better than by positive pressure. The cavitation grnerator superiorly installation location in the device 1 #.(4) The hydrodynamic cavitation may play strengthens H2O2, the Fenton reagent to remove the algae the role. The aperture is the 6mm of the single-hole orifice is installing the 1# and the 9 hole 2# is installing the 3# both combination to unite the Feton reagent to kill algae 20min ,the extinguishes rate of algae is being 69.58%. But removes algae 20min using the Fenton reagent alone the extinguishes rate of algae is being only 34.69%.Compared to other methods, the hydrodynamic caviton has many advantages, such as simple reaction operator, less energy consumption, convenient operation, lower maintenance cost and readily scale up, so it is meaningful to inivestigate the regular pattern of hydrodynamic cavitation, and apply it on field of removal of algae in eutrophicated water.