COD = (C/FW)·(RMO)·32.
Why COD is calculated?
Chemical oxygen demand (COD) is used to determine the quantity of pollution in water after wastewater treatment. The higher value of chemical oxygen demand indicates the higher organic pollution in the water sample. Only chemically digest able matter can be determined by the COD test.
How COD is measured?
COD is measured via a laboratory assay in which a sample is incubated with a strong chemical oxidant for a specified time interval and at constant temperature (usually 2 h at 150°C). The most commonly used oxidant is potassium dichromate, which is used in combination with boiling sulphuric acid.
How do you calculate BOD and COD?
The COD test should be considered an independent measure of the organic matter in a wastewater sample rather than a substitute for the BOD test.
Can I use my COD results to predict my BOD?
| Sample 1: | COD = 2,150 mg/L | BOD = 1,100 mg/L |
|---|---|---|
| Sample 3: | COD = 1,850 mg/L | BOD = 997 mg/L |
| COD ÷ BOD = 1,850 ÷ 997 = 1.86 |
What is the unit of COD?
COD is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. It is commonly expressed in mass of oxygen consumed over volume of solution, which in SI units is milligrams per liter (mg/L). A COD test can be used to easily quantify the amount of organics in water.
What is the value of COD?
The COD value indicates the amount of oxygen which is needed for the oxidation of all organic substances in water in mg/l or g/m3. The COD (Chemical Oxygen Demand) is closely related to the laboratory standard method named Dichromate-Method.
How do you calculate kg in COD?
BOD (or COD) load: Units: kg/day
This is simply done by multiplying the BOD in mg/l by the daily effluent volume in cubic metres (m3) and dividing the product by 1000.
What is COD method?
COD measures how much DO is consumed by the oxidation of organic matter and inorganic compounds such as ammonia or nitrite under controlled conditions. COD testing typically involves digestion of the water sample in a sealed vial with potassium dichromate and sulfuric acid at 150C for 2 hours.
What is BOD and COD?
Biochemical oxygen demand (BOD) is the amount of oxygen required by the microorganisms to break down the organic materials, whereas chemical oxygen demand (COD) is the amount of oxygen required to break down the organic material via oxidation.
What is COD reagent?
The most general COD determination uses potassium dichromate (K2Cr2O7) in excess in an acidic medium with the aid of silver sulfate (Ag2SO4) as a catalyst, and mercuric sulfate (HgSO4) added to remove interference of chlorides.
What is BOD formula?
Biochemical Oxygen Demand ???, ??/? = ?1 − ?2 ? When the dilution water is seeded ?????/?, = ?1 − ?2 − ?1 − ?2 ? ? Where: D1: Dissolved oxygen of diluted sample immediately after preparation, mg/L D2: Dissolved oxygen of diluted sample immediately after 5day incubation at 20⁰C, mg/L B1: Dissolved oxygen of seed control
How do you calculate BOD?
BOD measurement requires taking two samples at each site. One is tested immediately for dissolved oxygen, and the second is incubated in the dark at 20 C for 5 days and then tested for the amount of dissolved oxygen remaining.
What is the limit of COD?
The chemical oxygen demand (COD) concentration in a treated effluent, if observed to be persistently greater than 250 mg/l before disposal to any receiving body (public sewer, land for irrigation, inland surface water and marine coastal areas), such industrial units are required to identify chemicals causing the same.
What is COD analysis?
Chemical Oxygen Demand (COD) analysis is a measurement of the oxygen-depletion capacity of a water sample contaminated with organic waste matter. Specifically, it measures the equivalent amount of oxygen required to chemically oxidize organic compounds in water.
Who BOD and COD standards?
According to standards of Central Pollution Control Board, permissible value of BOD is 30 mg/l and COD is 250 mg/l.
What is COD loading rate?
The loading rate is the COD load divided by the reactor volume, but sometimes is referred as volumetric loading rate kg/m3*d. The formula is TCOD(kg/m3)*Q(m3/d)/V(m3)= TCOD load(kg/d)/V(m3)= result (kg/m3*d)
What is BOD loading rate?
Organic loading rate is defined as the application of soluble and particulate organic matter. It is typically expressed on an area basis as pounds of BOD5 per unit area per unit time, such as pounds of BOD5 per square foot per day (lb/ft2/day).
How is COD organic loading rate calculated?
How to calculate the total organic loading rate (TOLR) in terms of chemical oxygen demand (COD)? [(COD mg/lit) x (Volume m3/ year) x (1000lit)]x 10–6 .
What is the COD of water?
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. This test is based on the fact that a strong oxidizing agent, under acidic conditions, can fully oxidize almost any organic compound to carbon dioxide.
Which is greater BOD or COD?
COD is normally higher than BOD because more organic compounds can be chemically oxidised than biologically oxidised. This includes chemicals toxic to biological life, which can make COD tests very useful when testing industrial sewage as they will not be captured by BOD testing.
What is BOD in waste water?
Biological oxygen demand is often used in wastewater treatment plants as an index of the degree of organic pollution in water. Industries that discharge wastewater into municipal sanitary sewers or waterways are facing strict regulations on levels of BOD.
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