COD Full Form

The COD full form is Chemical Oxygen Demand is an ideal measurement technique adopted to check the amount of oxygen required to break down organic matter in a reaction. It is popularly used in treating wastewater by analyzing the amount of oxidized pollutants the water body contains. For a better insight into COD, continue reading this article.

What is the Full Form of COD?

The full form of COD is chemical oxygen demand. It measures the amount of oxygen susceptible to oxidation in any solution. In environmental chemistry, a COD test converts the organic matter into carbon dioxide unlike a BOD test or biological oxygen demand, where only oxidation of biological reaction of carbon is conducted. 

When treating water bodies, this measurement method helps in offering an accurate estimation of total oxygen depleted from water as a result of bacterial outgrowth. During a chemical oxygen demand test, potassium dichromate or potassium permanganate is used for carrying out the processes of chemical oxidation of organic material in wastewater. COD is generally expressed as the mass of oxygen over the volume of solution and is represented in milligrams per litre (mg/L)

An Overview of COD

As discussed above COD plays a vital role in the arena of environment chemistry, whereby the amount of oxygen required for breaking down organic material is measured using it. Earlier, COD tests were conducted by recording the changes in the colour of permanganate solution in water. In laboratories, measurement processes are conducted by incubating a sample with any strong chemical oxidant for a time interval by ensuring to keep the temperature constant. 

COD's use in wastewater treatment holds potential value because of its quality and accuracy parameters. Furthermore, treating a water body with a COD requires 3 hours to offer you with accurate information that adds to its popularity.

Explore below the expected combined oxygen demand in natural watts and sewages.

Guide on COD Procedures

COD, the full form of which is chemical oxygen demand, is conducted by experts in labs with artificial incubators. Below are some of the procedures involved in measuring the volume of oxygen in a sample that is available for oxidation.

• Gather the water samples in containers in an appropriate volume based on the tests and demand of the analysis.
• Label the COD vial properly for the samples.
• Next, turn the COD reactor and make sure the temperature is set to 150 degrees Celsius.
• Mix and shake the sample.
• After the reactor is set at the perfect temperature. Start placing vials that contain the water samples and set the time for 2 hours.
• After 2 hours, use a spectrophotometer to a specific wavelength and now, check the absorbance.

Well, it is suggested that the COD test involves a certain level of risk in terms of environmental sustainability and any man-made hazards, so it is vital to carry out the process under expert supervision. 

Calculating Process of COD

COD, the full form of which is chemical oxygen demand, is carried out in labs with the help of a mathematical calculation. This test resorts to the process of decomposing pollutants in water samples following boiling water in a solution of potassium dichromate. In case, COD is high, it proves that the water sample contains excessive levels of pollutants that can be harmful to consume.

To calculate COD, use the following formula:

COD = (a-b) X C X 8,000/volume of sample in mL

In this formula:

• a represent titrant in a sample
• b symbolises the total titrant used in a blank sample
• c refers to the normality of ferrous ammonium sulfate

How is COD Different from BOD?

COD and BOD both are popular parameters used when treating a water sample. BOD, the full form of which is biological oxygen demand, analyses the amount of oxygen bacteria require to break down organic material while COD is concerned with total oxygen required for breaking down organic material during oxidation. Let's explore some other differentiating facts that make both these measuring parameters an ideal choice among environmentalists.

Significance and Challenges of COD Tests

COD is regarded as the most suitable method for evaluating the quality of water. Most wastewater treatment projects conduct combined oxygen demand tests to ensure how much of the water contains inorganic oxidants that might pose a threat to human health. For a better understanding of its significance, let's explore some of the top benefits of this method.

Benefits of COD:

• COD is perhaps the most popular, fastest and most accurate monitoring method used for analysing water samples’ quality that helps in improving wastewater treatment projects' efficiency.
• In any sample, the presence of chemical oxygen demand oxidant never comes under the influence of toxic materials
• Unlike BOD, this method is less time-consuming and offers accurate results.
• It is also used for quantifying biodegradable content in wastewater effluent ratio between biological oxygen demand and chemical oxygen demand.

Challenges of COD:

Although chemical oxygen demand (COD full form) has been approved by scientists and environmentalists, a certain level of challenges is commonplace when using this measuring procedure.

• When conducting the test, the personnel involved have to be careful as disposal of the harmful chemical can prove hazardous.
• It can give inaccurate results in cases whereby the river or other water samples are clean or non-contaminated.
• Inconsistency and confusion can distress the test organisers as unless data is available, environmental damage can occur.
• Limited scope for creating natural conditions because the testing is conducted in an artificial incubation that uses strong oxidizing agents.

So, after going through the article, you might have gained adequate insight into chemical oxygen demand and its implication in eating a wastewater plant. Using this measuring method can prove beneficial if a proper natural environment can be created during the tests.