Study And Application On Optimum Design Model For Activated Sludge System Processes

It's not only a developmenting trend of engineering design method, but also a physical necessity of structured design development that the system theory and optimization method being introduced into technical disign for traditional activated-sludge process. Based on generally evaluating current research status on optimized design for activated-sludge process system, a whole optimized-disign model was established firstly in China which is for one of the activated-sludge process~A2/O and whose crresponding optimized-solvtion method was advanced. Under Matlab circumstance the optimizated-design program(ODP) was developped. All above works represent some exploring and creative effort to upgrade level and efficiency for design of activated-sludge process.According to development of the activated-sludge process and the mechanism theories of IAWQ-ASM, a whole frame model, a systematic mathematics model and an expense target function model were established in this paper, which were used for one of nitrogen and phosphor removal activated-sludge process-A2/O. Then above three models were integrated into a mathematical optimized programming problem and its solution. Practical cases research indicated that if the set of design model was adopted to optimized scheme design, total expense would be less 10% than traditional design method. Application of the optimized-method to engineering designing not only ensure organic integrality of biological treatment systems, but also increase designing efficiency and veracity.Aim at the mathematical characteristics of highly nonlinear, multi-variable, multi-restriction and multi-dimension of the optimized design model, an optimized solution strategy was put forward in which SQP(Sequence Quadic Programming) was adopted. This solution method can obtain the best searching orientation and searching step in solution searching zone and greatly reduce iteration times, then efficiently overcome many shortages of other common optimized methods, such as GRG,CM and PM in searching solution for large scale nonlinear restricting optimizing problem, and can increas efficiency and stability of optimizing process conveniencely.For the first time, Matlab language was applied in this paper to programme for system model and SQP arithmetic in optimized-designing method. Matlab's mighty calculation function and optimization function can provide excellent languagsecompilation flat for solution to the optimized-design problem of nitrogen and phosphor removal activated-sludge proces. As a calculation language in engineering domain, application prospect of Matlab to water pollution control.field would be wider.Through sensitivity analysis for design parameters in practical cases research, quantitative analysis results were obtained that uncertainty of the parameters could impact on the system's integral performance. The conclusion can guide experimenter or designer to estimate the key parameter reasonably. At the same time, according to sensitivity of the parameter, corresponding experiments plan could be established and waste of resources would be avoided.The Matlab optimized design program established in this paper could be generally used and expandable. When a design process is not exactly coincident to the concept model described in this paper, nothing but reaction and matter balance between different functions units need to be established, then through matter balance relation of node control the function module would be connected with whole system. For the optimized design program, what need to be, done is only to increase, delete or modify restricting condition or to adjust composing of the target function, a large quantity of repetition to set up the model and program could be avoided.The study indicate that it is theoretically feasible that applying the optimized model of nitrogen and phosphor removal activated-sludge process established in the paper to municipal wastewater treatment plant designing and calculating; and it is valuable to continue study the optimized design program-ODP based o...