Question: Is High COD Good Or Bad?

How do you lower COD levels in water?

Advanced Oxidation Processes(AOP) such as using H2O2/UV, O3/UV, Fenton’s reagent( H2O2+FeSO4 ), etc.Coagulation(e.g.

Alum, Cationic polymers ),Flocculation(e.g.

Chitosan, Isinglass, Polyelectrolyte) and Sedimentation.Adsorption using Activated Charcoal.ElectroFlocculation.More items….

What is BOD formula?

BOD = biochemical oxygen demand, mg/L. When seed is added, seed control tests must be done to determine the amount of oxygen depleted by the seed. Calculation of BOD includes a correction factor for seed as expressed by Equation 2.

What happen if cod is high?

Higher COD levels mean a greater amount of oxidizable organic material in the sample, which will reduce dissolved oxygen (DO) levels. A reduction in DO can lead to anaerobic conditions, which is deleterious to higher aquatic life forms.

How do you reduce cod?

Reduce COD with Oxidator Some chemicals, can help you to reduce the COD of waste water. Chlorine, Hydrogen peroxide and Ozone will mengoksdiasikan chemicals in the water so that the automatic COD value will go down.

What is COD BOD ratio?

Interrelationship between BOD, COD and TOC. Typical values for the ratio of BOD/COD for untreated municipal wastewater are in the range from 0.3 to 0.8 (see in table 3). If the BOD/COD ratio for untreated wastewater is 0.5 or greater, the waste is considered to be easily treatable by biological means.

Which is more 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.

Which is better COD or BOD?

COD is the amount of oxygen required to chemically breakdown the pollutants whereas BOD is the amount of oxygen required to do this biologically through micro-organisms. There is a strong correlation between COD and BOD, however COD analysis is a much faster and more accurate method.

Why is COD higher than BOD?

The COD test uses a chemical (potassium dichromate in a 50% sulfuric acid solution) that “oxidizes” both organic (predominate) and inorganic substances in a wastewater sample, which results in a higher COD concentration than BOD concentration for the same wastewater sample since only organic compounds are consumed …

Why is cod so important?

In wastewater treatment, the Chemical Oxygen Demand (COD) is an important measurement for the amount of oxygen that is required to break down pollutants (organic substances) in water. The chemical oxygen demand can be measured using different methods, direct or indirect.

What is the limit of cod?

250 mg/lThe 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.

How is cod 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 cod used for?

Cod is popular as a food with a mild flavour and a dense, flaky, white flesh. Cod livers are processed to make cod liver oil, an important source of vitamin A, vitamin D, vitamin E, and omega-3 fatty acids (EPA and DHA). Young Atlantic cod or haddock prepared in strips for cooking is called scrod.

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.

What causes high COD?

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 a good COD level?

It depends more on the BOD and nitrogen content. The COD load can be high – up to 850 mg/g d.w. but if the COD load are moderate toxic and if BOD content reach at least 10% of COD it can work. Be aware of the nitrogen, during degradation ammonia and nitrite levels can reach toxic levels.

What is the COD of drinking water?

The COD is the amount of oxygen consumed to chemically oxidize organic water contaminants to inorganic end products. The COD is often measured using a strong oxidant (e.g. potassium dichromate, potassium iodate, potassium permanganate) under acidic conditions.

What is difference between BOD and COD?

The main difference between BOD and COD is that BOD is the amount of oxygen which is consumed by bacteria while decomposing organic matter under aerobic conditions whereas COD is the amount of oxygen required for the chemical oxidation of total organic matter in water.

Why do we use h2so4 in cod?

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. Heat from the digestion block (150° C) also acts as a catalyst.

Why potassium dichromate is used in cod?

Currently, most COD tests use potassium dichromate as the oxidant. … During the digestion, it’s necessary to have excess oxidant; this ensures complete oxidation of the sample. As a result, it’s important to determine the quantity of excess oxidant. The two most common methods for this are titration and colorimetry.