Study On Biological Grid Device And Mechanism Of Nitrogen And Carbon Removal

China's major waters are polluted increasingly serious, and watersource shortage problem is getting more and more serious. Eutrophication of water bodies take place in almost all the major cities, there are black and odor waters, with a serious impact on the urban landscape, and also with threats to the health of residents. More people focus on polluted water restoration. There are some methods, such as physical, chemical and biological repair methods, which are used to deal with polluted water. In this study, a biological grid device was built to restore polluted landscape water. Biological grid is a new ecological remediation device which assembles combination package, plants,animals into one unit, and which can assemble a great deal of biomass. By microbial decomposition and conversion, as well as plants absorbtion, biological grid can in-situ deal with polluted water efficiently.The plants growing in the biological grid were canna, celery and white hold, and aquatic animals were snails and loaches, and the microbial carriers were combination package.The surface areas of Canna indica's roots in the ecological grid device are 39.4 m², and the surface areas of third class roots are 21.7 times larger than sub-system roots. Roots and combination package interlace, which supplements each other in function and becomes relationship of ecological symbiosis. Combination of plant roots and package forms a fixed spatial structure which can not only fix plants but also provide habitats for aquatic animals.The amounts of heterotrophic bacteria, nitrate bacteria, nitrite bacteria on the root in biological grids are 2-3 times larger than those on package. The amount of denitrifying bacteria on the package in biological grids is 22 times larger than that on roots. Functions such as organic nitrogen decomposition, ammonification and nitrification reactions are mainly carried on the root system, denitrification takes place mainly in the package. Dissolved oxygen soon decreases to 1.5 mg·L^-1 after 24h biological grids running, with TN removal rate 17%. Under micro-oxygen status, nitrification and denitrification could act in the same time and removal rate of TN could rise to 69% after 72h treatment. The N conversions are carried on different places in biological grid.Biological grid have wide adaptability to different natural waters. Eutrophic Suining River water, diluted black-odor and high concentrations of artificial wastewater were delt with biological grid. After 120h treatment, water comprehensive indexs had decreased 11.75 and 13.3 respectively. Removal rates of COD, TP, NH₄⁺-N and TN were 68.0%-80.4%,61.6%-94.9%, 83.4%-92.9% and 77.5%-90.9% respectively. Physical structure of the biological grid was multiform, convenient to transportation and easy to handle, and having a role of flexible Landscaping.