How do you make COD standard solution?

Preparation of a COD standard solution: Dissolve 0.851 g of potassium hydrogen phthalate in a calibrated or conformity-checked 100-ml volumetric flask and make up to the mark with dilution solution. The stock solution prepared according to this procedure has a concentration of 10 000 mg/l COD and 20 g/l Cl-.

Is standard for COD analysis?

Dichromate, the oxidizing agent for COD determination, does not oxidize ammonia into nitrate, so nitrification is not included in the standard COD test. The International Organization for Standardization describes a standard method for measuring chemical oxygen demand in ISO 6060 [1].

How COD is calculated?

Chemical oxygen demand, or COD, is a test that measures the amount of organic compounds in water. 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.

What is the limitation of COD?

One of the main limitations of the COD test is its inability to differentiate between biodegradable and biologically inert organic matter on its own. The use of chemicals such as chromium and strong acids produce hazardous liquid waste, which requires careful disposal.

How do you make COD digestion solution?

a. Standard potassium dichromate digestion solution, 0.01667M: Add to about 500 mL distilled water 4.903 g K2Cr2O7, primary standard grade, previously dried at 150°C for 2 h, 167 mL conc H2SO4, and 33.3 g HgSO4. Dissolve, cool to room temperature, and dilute to 1000 mL.

How do you make COD reagent?

Dissolve 10 gm Silver sulfate (Ag2SO4) in 500 ml concentrated sulfuric acid and make up the solution to 1000 ml swirl the flask to mix well. Allow standing the solution for 24 hours before use.

IS 10500 drinking water standard?

This standard specifies the acceptable limits and the permissible limits in the absence of alternate source. It is recommended that the acceptable limit is to be implemented as values in excess of those mentioned under ‘Acceptable’ render the water not suitable.

What is the Indian standard for COD in drinking water?

BIS Standards Set for drinking water quality

What is COD level in water?

Chemical oxygen demand (COD) is the amount of dissolved oxygen that must be present in water to oxidize chemical organic materials, like petroleum. COD is used to gauge the short-term impact wastewater effluents will have on the oxygen levels of receiving waters.

What is a COD test?

Application Overview. The chemical oxygen demand (COD) is a measure of water and wastewater quality. The COD test is often used to monitor water treatment plant efficiency. The COD is the amount of oxygen consumed to chemically oxidize organic water contaminants to inorganic end products.

What is the acceptable range of COD in drinking water?

250 mg/l
Ltd. According to standards of Central Pollution Control Board, permissible value of BOD is 30 mg/l and COD is 250 mg/l.

What is 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 is COD analysis in chemistry?

In a COD analysis, hazardous wastes of mercury, hexavalent chromium, sulfuric acid, silver, and acids are generated. Methods 5220C and D reduce these waste problems but may be less accurate and less representative (5220A.2). 1. Selection of Method

How can I determine COD values of >50 mg O2 /L?

Determine COD values of >50 mg O 2 /L by using procedures 5220B.4 a, C.4, or D.4. Use procedure 5220B.4 b to determine, with lesser accuracy, COD values from 5 to 50 mg O 2 /L.

What is chemical oxygen demand (COD)?

Chemical oxygen demand (COD) is defined as the amount of a specified oxidant that reacts with the sample under controlled conditions. The quantity of oxidant consumed is expressed in terms of its oxygen equivalence.