Chemical Oxygen Demand Discussion

Tchobanoglous and schroeder 1985.

Chemical oxygen demand discussion. While the bod test is performed by using a population of bacteria and other microorganisms to attempt to duplicate what would happen in a natural stream over a period of five days the cod test uses a strong chemical oxidizing agent potassium dichromate or potassium permanganate to chemically oxidize the organic material in the. Most applications of cod determine the amount of organic pollutants found in surface water e g. The chemical oxygen demand cod test is used widely to estimate the amount of organic matter in wastewater. Biochemical oxygen demand or bod measures the amount of oxygen consumed by microorganisms in decomposing organic matter in stream water.

It is a measurement of the oxygen equivalent of the materials present in the wastewater that are subject to oxidation by a strong chemical oxidant in this case dichromate. With this test you can measure virtually all organic compounds that can be digested by a digestion reagent. It is commonly expressed in mass of oxygen consumed over volume of solution which in si units is milligrams per liter mg l. Bod also measures the chemical oxidation of inorganic matter i e the extraction of oxygen from water via chemical reaction.

The test for biochemical oxygen demand bod is a bioassay procedure that measures the oxygen consumed by bacteria. Chemical oxygen demand is an aggregate property of water and no cas registry number is appropriate. The first low range is applicable to natural and treated waters at concentrations from 15 to 150 mg l cod. Oxygen demand is a measure of the amount of oxidizable substances in a water sample that can lower do concentrations nemerow 1974.

The chemical oxygen demand or cod is a measurement of the amount of material that can be oxidized combined with oxygen in the presence of a strong chemical oxidizing agent. In environmental chemistry the chemical oxygen demand cod is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. Of organic compounds in water. Conclusion in environmental chemistry the chemical oxygen demand cod test is commonly used to indirectly measure the amount.

Lakes and rivers making cod a useful measure of water quality. Measured as biochemical or chemical oxygen demand. It is commonly expressed in mass of oxygen consumed over volume of solution which in si units is milligrams per litre mg l. Chemical oxygen demand cod is a second method of estimating how much oxygen would be depleted from a body of receiving water as a result of bacterial action.

Chemical oxygen demand cod is an indirect measurement of the amount of organic matter in a sample.