What is the unit of Chemical Oxygen Demand?

What is the unit of Chemical Oxygen Demand?

The chemical oxygen demand (COD) test is commonly used to indirectly measure the amount of organic compounds in liquid waste. It is expressed in milligrams/grams per liter, which indicates the mass of oxygen consumed per liter of solution. Older references may express the units as parts per million (ppm).

How is COD oxygen demand calculated?

There is a formula for calculating COD. Consider the formula for COD calculation: (a – b) X C X 8,000 / the volume of the sample in mL. Let “a” represent the titrant used for your sample expressed in mL. Let “b” represent the titrant used for your blank sample in mL.

Is COD equal to BOD?

the standard ratio BOD:COD is as 0.6:1.0 (BOD is about 60%of COD) in standard raw communal wastewater in Europe.

What is COD and BOD?

The biochemical oxygen demand (BOD) represents the amount of dissolved oxygen (DO) consumed by biological organisms when they decompose organic matter in water. The chemical oxygen demand (COD) is the amount of oxygen consumed when the water sample is chemically oxidised.

What does COD mean in wastewater?

Chemical oxygen demand
5 Chemical oxygen demand (COD) The COD is the estimate of oxygen required for the portion of organic matter in wastewater that is subjected to oxidation and also the amount of oxygen consumed by organic matter from boiling acid potassium dichromate solution.

Why Sulphuric acid is used in COD?

COD samples are prepared with a closed-reflux digestion followed by analysis. Concentrated sulfuric acid (H2SO4) provides the primary digestion catalyst. The secondary catalyst, Silver Sulfate (AgSO4), assists oxidization of straight-chain hydrocarbons such diesel fuel and motor oil.

What is the difference between Do and COD?

The BOD test involves taking an initial dissolved oxygen (DO) reading and a second reading after five days of incubation at 20°C. COD analysis on the other hand is a measurement of the oxygen-depletion capacity of a water sample contaminated with organic waste matter.

What is a good COD level?

Influent COD in normal domestic sewage is therefore generally 600 – 900 mg/l and it is then treated to at least 75 -100 mg/l before discharge to minimise pollution potential.

What increases the BOD of water?

Increase in the dissolved oxygen concentration.