What is the COD value of drinking water?
The concentrations of COD observed in surface waters range from 20 mg/l O2 or less in unpolluted waters to greater than 200 mg/l O2 in waters receiving effluents. Industrial wastewaters may have COD values ranging from 100 mg/l O2 to 60,000 mg/ O2.
What is good COD level?
BMS have recorded average ratios of 2-3 mg/l COD to 1 mg/l BOD over its 30 years of business. 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 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.
What is cod limit?
In General for India, the permissible limit to discharge is COD, less than 250 mg/L and BOD is less than 30 mg/L.
Why is COD higher than BOD?
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 a high COD level?
Higher COD levels mean a greater amount of oxidizable organic material in the sample, which will reduce dissolved oxygen (DO) levels. The COD test is often used as an alternate to BOD due to shorter length of testing time.
Is high COD good or bad?
COD is an indicative measurement of the amount of oxygen that can be consumed by reactions in a measured solution. COD detection can be used to easily quantify the amount of organics in water. The higher the COD value, the more serious the pollution of organic matter by water.
How do you treat high COD?
One way to reduce COD in water is to use coagulants and flocculants to bind sludge together. Once they are bound into big enough masses that they can be easily filtered out and deposited into a sedimentation tank for removal. This method does however rely on the use of chemicals, and requires high reoccurring cost.
What causes high COD in water?
High COD/BOD levels in stormwater runoff are cause by the residual food and beverage waste from cans/bottles, antifreeze, and emulsified oils from industrial food processing and agricultural activities. As most forms of COD are water soluble, this pollutant spreads easily via stormwater to waterways.
What is COD & BOD in water?
COD or Chemical Oxygen Demand is the total measurement of all chemicals (organics & in-organics) in the water / waste water; BOD is a measure of, the amount of oxygen that require for the bacteria to degrade the organic components present in water / waste water.
How do you test cod in water?
What test methods are typically used to determine COD at water and wastewater laboratories? The most common test method is the colorimetric analysis after oxidizing the COD with acid and using indicator compounds, such as hexavalent dichromate.
How do you reduce BOD and COD?
BOD and COD Removal Hydrogen Peroxide (H2O2) Hydrogen peroxide (H2O2) has been used to reduce the BOD and COD of industrial wastewaters for many years.
What happens if BOD is high?
The greater the BOD, the more rapidly oxygen is depleted in the stream. This means less oxygen is available to higher forms of aquatic life. The consequences of high BOD are the same as those for low dissolved oxygen: aquatic organisms become stressed, suffocate, and die.
What COD means?
Cash on delivery
Is Cod a bad word?
Other definitions for cod (2 of 4) Slang: Vulgar.
What is a cod sperm?
Sacs of cod milt are most accurately likened to pork brains, yet with a lighter, finer texture. The Japanese call it shirako, kiku, or tachi. Harvested from fish such as cod, anglerfish, monkfish, and sometimes fugu, most types of the seminal fluid are in season during winter.
What is cod and its importance?
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 BOD COD and do?
BOD is the amount of oxygen that will be consumed by bacteria or other aerobic microorganisms while decomposing organic matter under aerobic conditions. COD measures the amount of oxygen that will be consumed by the chemical breakdown, or oxidation (degeneration) of organic pollutants in water.
What does COD mean in wastewater?
Chemical oxygen demand