COD And BOD Full Form
What is the full form of COD And BOD?
- Chemical Oxygen Demand (COD)
- Biological Oxygen Demand (BOD)
The two main distinctive qualities that show the strength of sewage is chemical oxygen demand (COD) and biological oxygen demand (BOD). Both variables assess the wastewaters' ability to demand oxygen. The amount of oxygen that bacteria need to consume to decompose organic materials is known as the biochemical oxygen demand (BOD). The quantity of oxygen needed to oxidize the organic material, in contrast, is known as the chemical oxygen demand, or COD.
| Biological Oxygen Demand (BOD) | Chemical Oxygen Demand (COD) |
| It is the quantity of oxygen needed by bacteria to break down organic materials in an aerobic environment. | It is the overall amount of oxygen needed to chemically oxidise organic materials and break them down. |
| A sealed water sample must be exposed to a certain temperature range for five days in order to be determined. | It can be discovered by exposing a water sample to a potent oxidizer for a certain amount of time at a predetermined temperature. |
| In treatment plants, it is employed to handle waste loadings. | In treatment plants, it is employed to determine how much oxidisable contaminants are present in water bodies. |
The standard method for assessing the relative "strength" of a wastewater sample is to conduct analytical tests that try to quantify the amount of organic (i.e., carbon-containing) matter present (often expressed in mg/L (milligrams per litre) or ppm (parts per million) ). To ascertain the gross amount of organic matter (i.e., concentrations > 1.0 mg/L) in wastewater, four standard laboratory procedures are employed today:
1. BOD (biochemical oxygen demand)
2. COD (chemical oxygen demand)
3. TOC (total organic carbon)
4. O&G (oil and grease)
Biochemical Oxygen Demand (BOD)
- To determine the amount of organic matter in wastewater samples, the traditional and most popular test is BOD.
- BOD is founded on the idea that aerobic biological decomposition by microorganisms will continue as long as there is enough oxygen available until all waste has been eaten.
- Since the BOD test is based on an accurate measurement of DO (dissolved oxygen) at the start and end of a five-day period during which the sample is kept in the dark, incubated conditions (i.e., 20°C(Celsius) or 68°F(Fahrenheit)), it is often referred to as the "BOD5" test.
- The test's five-day completion window is one of its intrinsic drawbacks.
Chemical Oxygen Demand (COD)
- The COD test, which only takes a few hours to perform compared to the 5-day BOD test, is the most often used alternative test to BOD for determining the concentration of organic matter in wastewater samples.
- It is a test of the quantity of oxygen needed for chemical oxidation with a strong oxidising agent, like potassium dichromate, to oxidize organic materials in a sample of sewage.
- The difference between COD and BOD is that BOD measures the quantity of organic matter that can be biologically oxidized, whereas COD measures the amount that can be chemically oxidized.
TOC (total organic carbon)
- A measure of the total quantity of carbon in organic molecules in pure water and aqueous systems are called total organic carbon (TOC).
- Organizations and labs use the respected analytical technique of TOC to assess how well a solution fits their processes.
O&G (oil and grease)
The amount of non-volatile hydrocarbons (also known as petroleum derivatives), vegetable oils, animal fats, waxes, soaps, greases, and associated materials in a sample is determined by oil and grease testing.