d) Determination of the chemical oxygen demand
(COD)
Measurement by spectrophotometry UV-VIS [6].
e) Measurement of the NTK (Nitrogen Kjeldahl)
5 ml of the sample are place in the flask of Kjeldhal.
Add 7, 5 g of catalyst (CuSO4 + K2SO4). Add 10 ml of
H2SO4.
f) Measurement of the biochemical oxygen demand
(BOD)