Study On Hydraulic Optimal Design Of Constructed Wetland

Constructed wetland technology is a kind of low-cost and high-efficiency ecosystem engineering for wastewater treatment and water reuse, which factor about hydraulics has a great effects towards the system's management. However, nowadays, there are few researches on the interior mechanism of the constructed wetland system, especially the ones relevant to the hydraulics. According to the reality that the construction and design of the wetland always depends on traditional experienced formula, which, in a certain extent, has a bad influence to the efficiency of the refine function of the constructed wetland, the author work comprehensively on the important problems on hydraulics and optimal design of constructed wetland, then finds the new-style ways to optimal design.After summarizes researches of wetlands both in and outside the nation, the researches indicate that relative to other styles of constructed wetland system, the IVCW has superiorities on sewage management, sanitation condition and occupied land area as well. Moreover, these researches also analyze the effects on wastewater treatment, which causes by the factors of hydraulics including pollutants loading rate, hydraulic retention time and system of depth etc. The paper further discusses the problems about hydraulic retention time and clogging by the data of the experiments. Finally, these researches get the value of the important parameter(rate constant "k") of frist reaction kinetics model in the IVCW , and then, this paper introduce three significant but less research mathematical models of constructed wetland,including Monod reaction kinetics model model, Ergun flow model, discrete flow model. With the data that taken by the medium scale plot of Integrated Vertical-flow Constructed Wetland (IVCW) systems, we can see clearly that has a favorable on forecast and application.In the end, based on the traditional design methods, the author would like to put forward these three calculating models in optimal design different styles of constructed wetland. Monod reaction kinetics model, Ergun flow model are mainly introduced in application of subsurface flow wetlands and discrete flow model are mainly introduced in application of the IVCW. Then the paper summarizes the differences of steps and methods between the IVCW and other traditional designs, which gives a reference to optimal design and design methods for the future.Through studies above, the author tries to provide scientific basis and technological parameters for design and management of constructed wetland and to promote the appropriate application and development of the constructed wetland wastewater treatment technology in China.