Internal Adaptive-Model Control of Wastewater pH

Control of a highly nonlinear, multi-acid plus common ion salt wastewater flow-through pH neutralization process is simulated with an Internal Adaptive-Model Controller (IAMC). The reduced phenomenological model of the "expert" controller considers the wastewater as a single fictitious acid of unknown concentration and of unknown Gibbs free energy of dissociation. Measurable process information is used to parameterize the two-coefficient model which is then used to predict a base flow rate setpoint for conventional PI flow control. IAMC control simulation over a wide range of wastewater composition and upsets indicate rapid and effective control even without the blending volume required in conventional pH control schemes.