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The COD or chemical oxygen demand determines the quantity of oxygen required to oxidize the organic matter when we make COD test we prepare a lot of things
We are using HACH For analysis COD Digestion , and we are purchasing COD Vails LR OR HR depend on the sample
I will try to explain the principle you can then modulate according to your need,
Basically it involves complete oxidation of organic species present in the sample.The simplest way to do this would be using an oxidising agent along with an acid, generally people use K2Cr2O7/H2SO4 (excess of K2Cr2O7). After adding K2Cr2O7/H2SO4to the sample, heat it to°C using a re-flexing assembly for and hour. Then allow it to cool and back titrate the solution with FAS, to do determine the unreacted dichromate, which can co-related to the organic content.
- Method 410.4
- EN ISO 8467
Many procedures depending on the laboratory equipment and analyzers, COD is mainly done on waste water streams prior to marine discharge to insure compliance of oxygen levels in such water.
COD usually determine chemical pollution in waste water, you can use Hach vials which offer wide ranges, or you can use open reflux method which is recommended by APHA. Otherwise you can test TOC (Total Organic Carbon) in drinking water to determine organic pollutants in drinking water.
Their is an standard procedure for COD analysis of drinking water recommended by APHA. It is available in net.
The COD or chemical oxygen demand determines the quantity of oxygen required to oxidize the organic matter when we make COD test we prepare alot of things
1. reagent preparation
2. sample preparation
3. sample heating
4. read at 600nm and don't forget adjust zero abs. for reagent blank.
