Chowunikirachi chimagwiritsa ntchito njira yokhazikika ya dichromate oxidation. Nthawi ndi nthawi chimakoka chitsanzo cha madzi, chimawonjezera kuchuluka kolondola kwa potassium dichromate (K₂Cr₂O₇) oxidant ndi concentrated sulfuric acid (H₂SO₄) ndi silver sulfate (Ag₂SO₄) ngati chothandizira, ndikutentha chisakanizocho kuti chifulumizitse oxidation. Pambuyo pa kugaya, dichromate yotsalayo imayesedwa kudzera mu colorimetry kapena potentiometric titration. Chidachi chimawerengera kuchuluka kwa COD kutengera momwe oxidant imagwiritsidwira ntchito. Mitundu yapamwamba imaphatikiza ma reactors ogaya chakudya, makina ozizira, ndi ma module osamalira zinyalala kuti akhale otetezeka komanso olondola.