On controlling pH

The paper summarises a recent investigation to find out what contribution could be made to pH regulation by modern algorithms for online estimation and/or adaptive control. Topics discussed include a mathematical model to account for nonlinearity; full-scale trials using selftuning controllers; a specially developed nonlinear estimator; use of resulting estimates to drive a suboptimal `cautious¿¿ control law; and a specialpurpose CAD package. It is concluded that pH regulation is amenable to good engineering practice, and that whether or not this should include modern algorithms is a problem-specific question which can be answered using the CAD package.