Work out activated carbon dose instantly with clear inputs, formula shown and shareable results.
Carbon requirement is the mass of contaminant to remove divided by the carbon's adsorption capacity at the equilibrium concentration, taken from a Freundlich isotherm. Capacity falls steeply as the target outlet concentration falls, so demanding very low residuals raises carbon use disproportionately.
Carbon requirement
Carbon (kg/day) = flow x (inlet - outlet concentration) / adsorption capacity
Dose
Dose (mg/L) = carbon (kg/day) x 1000 / flow (m3/day)
From isotherm testing on the actual water, because natural organic matter competes for sites and can reduce capacity for the target compound by an order of magnitude compared with clean water.
Powdered carbon suits intermittent taste and odour episodes and is dosed and discarded. Granular carbon in fixed beds suits continuous duty and can be reactivated, giving lower cost per unit removed at high loading.