The invention discloses an SMOTE_Bagging integrated 
sewage treatment fault diagnosis method based on a weighted 
extreme learning machine, the method comprises the following steps that (1) the defect items of samples with incomplete attributes in 
sewage data are supplemented with an averaging method and normalized to be in an interval of [0,1]; (2) the number of base classifiers and the optimal parameters of hidden nodes of the base classifiers are set; (3) independent 
oversampling is performed to the training sample corresponding to each base classifier with an improved SMOTE 
algorithm aimingat each base classifier, and the base classifiers are trained; (4) the output weight of each classifier is determined on the basis of a G-mean method; (5) integration is performed to all base classifiers after training, and a final integration classifier is obtained. According to the SMOTE_Bagging integrated 
sewage treatment fault diagnosis method based on the weighted 
extreme learning machine, the diversity among the base classifiers is improved while the unbalancedness of sewage data is effectively reduced, the classification accuracy of 
sewage treatment fault classes is improved, and further the whole performance of fault diagnosis in the 
sewage treatment process is effectively improved.