Coagulants destabilise colloids by four distinct mechanisms. Which one dominates depends on dose, pH and the coagulant, and it determines the floc you get and the clarifier that follows.
The physical chemistry behind every coagulant dose, from zeta potential to the Camp number.
DAF, clarification and chemical conditioning systems for solids and oil removal.
Dissolved air flotation for coagulated solids, fats and oils.
Coagulation removes colloidal turbidity by two distinct mechanisms, and knowing which one your plant relies on changes the coagulant, the dose and the pH you should target. At low coagulant doses, dissolved metal-hydroxide species adsorb onto negatively charged colloids and neutralise their surface charge, letting them collide and aggregate. At higher doses the coagulant precipitates as a voluminous hydroxide floc that physically enmeshes particles as it settles — the ‘sweep’ regime that dominates most municipal clarifier and DAF designs. Reynolds & Bauhm use jar testing to identify which regime gives the best, most economical result for your water, then size the rapid-mix and dosing system around it.
Cationic hydrolysis products adsorb onto negative colloids and neutralise their charge at low dose and near-neutral pH.
At higher dose, metal-hydroxide precipitate forms and physically enmeshes colloids as it settles, the dominant mechanism in many plants.
High-molecular-weight polymers adsorb across several particles, bridging them into large, strong flocs.
Low doses neutralise; higher doses sweep. The dose-response defines the operating window.
pH sets coagulant speciation and hydroxide solubility, and therefore the active mechanism.
Rapid mixing disperses coagulant before hydrolysis completes, fixing whether neutralisation or sweep prevails.
Bridged flocs are large and strong; sweep flocs are voluminous; neutralised flocs are dense but small.
Floc character is matched to the downstream process, settling, flotation or filtration.
Sweep coagulation maximises removal but produces more hydroxide sludge, a key trade-off.
Reynolds & Bauhm delivers this scope as part of an integrated, single-point engagement matched to your project, programme and regulatory regime.
Our expertise spans multiple industries with sector-specific water treatment solutions.