Applied Research Of Uncertain Analysis Method On Water Pollution Control Of Lake In The City

Lakes of China are famous for their extensive distribution, various types, and compl icated causes of formation. But in the past 20 years, with the aggravation of the human activity, the lakes'water environmental pollution questions are outstanding day by day, among which eutrophication causes people's attention more and more. Comparing large-scale shallow lake, the research to the medium and small-scale shallow lake in the city is very weak. The urban lake is regarded as the important component of the infrastructure, which is very important to the ecological construction of the city. Improving the water environment of urban lake must deepen on the deep and rational planning. Water environmental program is the important way and means to coordinate the relation between economic development of human society and water environmental protection. The research of uncertain methods in water environment start on 1960s and uncertain research launched rapidly. This paper firstly analyzes several kinds of uncertain information in this system: random information, fuzzy information, grey information and unknown information. The complicated information with two kinds or the above-mentioned information of more than two kinds is called blind information. Analyzed from angle of system, the system of lake water body is the system full of more uncertain factors complicated system. Because lakes water body is influenced by hydrology process and uncertain emission, randomness, fuzzy and greyness often appear at the same time or across. Therefore it will inevitably have greater discrepancy with single type information handled. Then the question of water environmental system should be studied and discussed from the coexist of various uncertainty. Because each parameter has uncertainty and the uncertainty of information often is not unitary, to forecast the consistence of P should be handled by the theory of blind number. Four kinds of mathematics theories have been put forward: random method, fuzzy method, grey theory and unknown mathematics. Comprised the advantages and the suitable scope, blind number theory is chosen to handle the uncertainty in lakes water environment. Water environmental capacity and the incorporate dirty ability with water body are the key problem in water resource plan. This paper gives classifications, definition, average; operational rule and BM model of blind number theory in detail. For convenience, according to application condition, Dillion model is chosen to forecast the environmental capacity of P. The parameters, lakes area, average depth of water and lake water replacement rate , detained coefficient in this model, change in the grey interval of each, and each internal has its own confidence level. So the quantities mentioned above not only have grayness, also unknown character, shown by blind number. According to the arithmetic of blind number and worth theory, the average value and reliability of environmental capacity of P could be got. This paper discusses the index of cost and benefit and the reliability index of program scheme. Suppose lakes incorporate dirty quantity is v, the difference of environmental capacity and incorporate dirty quantity is C = w-v. When C<0, water quality exceeds standard Set up additionally r '= ∑?ijij,(αβ)-r In type, αi, βj is the reliability of a i, b j. r ' is the index of reliability.