Chemical treatment lives or dies on speciation and rate. Reaction-kinetics and equilibrium modelling predicts what species exist at a given pH, how fast reactions proceed, and the dose and contact time needed — for coagulation, oxidation, disinfection, softening and scale control.
The questions this modelling discipline answers
Equilibrium models compute the species present at any pH and alkalinity — carbonate system, metal hydroxides, ammonia/bisulphide, free vs combined chlorine — the basis for dose and pH-correction design.
Rate laws predict how quickly iron and manganese oxidise, how coagulant hydrolyses, or how an advanced-oxidation radical attacks a target — setting the contact time and reactor volume.
The CT concept (concentration × time) sizes disinfection for the required log-removal, accounting for demand, decay and the organism’s resistance.
Saturation indices (LSI, S&DSI) and ion-pairing models predict scaling and corrosion tendency, driving antiscalant, softening and remineralisation decisions.
Two questions govern every chemical step: what is present, and how fast does it react. Equilibrium modelling answers the first — solving the simultaneous mass-action and charge-balance equations to give the species distribution at a given pH, temperature and alkalinity (why manganese needs a higher pH than iron, why free chlorine collapses to chloramine with ammonia present). Kinetic modelling answers the second — applying rate laws (often first- or second-order) to size the contact time and reactor for oxidation, coagulant hydrolysis or an AOP. Disinfection ties them together through CT, and saturation indices extend the equilibrium picture to scaling and corrosion. Modelling these explicitly — rather than dosing to a rule of thumb — is what makes a chemical design both effective and economical.
Reynolds & Bauhm applies the right modelling discipline to the question — from a steady-state flowsheet to a calibrated digital twin — so design and operating decisions are made on evidence, not assumption.
Our expertise spans multiple industries with sector-specific water treatment solutions.