MBR(Membrane Bio-Reactor) s COD(chemical oxygen demand) have important effects on entire system.We design our wavelet transformation and LSSVM(Least Squares Support Vector Machine) method based on CODs nonlinear characteristic.First
we use Mallat deconstruction and reconstruction arithmetic to get trend and random time series
and then we use LSSVM to predict separately.Finally we combine every time series to get final result.Through simulation