Finishing & Environmental
Concentration alone tells you nothing about plant sizing. Load is concentration times flow.
— kg/day
Oxygen demand the plant must handle daily
A BOD/COD ratio below about 0.3 means the effluent resists biological treatment, so chemical or advanced oxidation stages become unavoidable.
Effluent Treatment Plant COD & BOD Load Estimator — free, with the formula and a worked example, at Textile School.