Water Color Monitor / Measurement:

Hazen, Platinum Cobalt (Pt/Co), Apha

Background

A commonly used color scale to evaluate the pollution levels in both water and waste water is the Platinum-Cobalt (Pt/Co), Hazen or Apha color scale. Pt-Co units can be abbreviated as PCU.

Additional application areas for the Pt-Co/Apha-/Hazen color scale include polymer additives, resin solutions, and solvents such as hexane, glycerol, methanol, mineral oils etc.

This test method is specific to the color yellow and is based on dilutions of a standard platinum cobalt solutions as defined by:

- ASTM D 1209 Standard Method for Color of Clear Liquids (Platinum-Cobalt Scale)

- BS 5339:76 (1993) Measurement of Color on Hazen Units /Platinum-Cobalt Scale

- DIN 53409 Bestimmung der Hazen-Farbzahl (APHA-Verfahren)

- DIN ISO 6271 Einstufung der Farbe nach der Platin Cobalt Skala

As a guide, liquids with a color of <15 PCU are generally not detectable, while tea has a color of about 2500 PCU. While there is no health based guideline limit for drinking water, an aesthetic limit has been set to minimize consumer concern at < 15 PCU.