TTK University of Applied Sciences. What the BOD to COD ratio shows is the measure of wastewater susceptibility to biodegradation: the lower is the ratio, the more refractory matter it contains. In your case, the water is not really biodegradable as it is.
What does the ratio of BOD to COD indicate?
The BOD to COD ratio is an indicator of the proportion of biologically degradable organic matter to total organic matter. Wastewater can be considered readily biodegradable if it has a ratio value between 0.4 and 0.8 (Metcalf and Eddy, 1985; Al-Momani, et al., 2002).
How do you treat water with low BOD COD ratio?
Increasing biodegradability of a low BOD/COD ratio could be carried out by addition of organic chemicals which have high BOD/COD ratio such as glucose, methanol and acetic acid. Or, mixing the low biodegradable wastewater with high biodegradable wastewater would increase biodegradability of the low BOD/COD ratio.
Is there any correlation between COD and BOD?
COD typically correlates to BOD, which is one of the reasons the method was initially developed. It has been found to be a very useful tool in municipal wastewater treatment process monitoring and modeling, and to aid in process control.
What does low COD mean?
A Low concentration of Dissolved Oxygen is harmful life forms which oxygen to live. Therefore it’s best to reduce COD levels, thus increasing DO concentrations, in wastewater before releasing it. How to Reduce COD in Wastewater. Luckily, there are several ways to reduce COD.
What is the ratio of BOD and COD in treated wastewater?
The ratio between BOD to COD is variable with season and geographical location. generally it is 0.4 – 0.45 in summer and increases 0.3 – 0.35 in winter. Depend on the type of your wastewater can vary from 0.6 to 0.8, this rate can be consider biodegradable (biological treatment is recommended).
What does high COD to BOD ratio of an organic pollutant represents?
A high COD to BOD ratio means that the organic pollutant has very less organic matter which can be oxidized by the pollutant. This ratio is generally greater than 1 but can be equal to 1 if the sample has only biodegradable organics.
Does chlorine reduce BOD?
BOD reduction: Chlorine accomplishes BOD reduction by oxidation of organic compounds present in wastewaters. 4. Oxidation of metal ions: Metal ions which are in reduced state are oxidized by chlorine (e.g., ferrous to ferric ion and manganous to manganic ions).
What should be the COD of drinking water?
According to standards of Central Pollution Control Board, permissible value of BOD is 30 mg/l and COD is 250 mg/l. Hope this helps, it mentions standards for India relating to different uses.
Does BOD COD water analysis?
BOD analysis is similar in function to chemical oxygen demand (COD) analysis, in that both measure the amount of organic compounds in water. However, COD analysis is less specific, since it measures everything that can be chemically oxidized, rather than just levels of biologically oxidized organic matter.
What is COD and its significance?
COD is a measure of the oxygen equivalent of the organic matter in a water sample that is susceptible to oxidation by a strong chemical oxidant. COD is widely used as a measure of the susceptibility to oxidation of the organic and inorganic materials present in water bodies and in the municipal and industrial wastes.
How does COD affect water quality?
When treated wastewater is discharged into the environment, it can introduce pollution in the form of organic content to receiving waters. High levels of wastewater COD indicate concentrations of organics that can deplete dissolved oxygen in the water, leading to negative environmental and regulatory consequences.
Why is COD higher than BOD in wastewater?
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
What is a 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 the ratio of COD BOD for fresh water?
For fresher water, as both BOD and COD should be negligible, hence the ratio can be equal to 1.
What is the permissible limit of COD for industrial effluent?
250 mg/l
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 does high BOD indicate?
The dissolved oxygen readings are usually in parts per million (ppm). Higher BOD indicates more oxygen is required, which is less for oxygen-demanding species to feed on, and signifies lower water quality. Inversely, low BOD means less oxygen is being removed from water, so water is generally purer.
Which of the following indicates that the water body has been used for waste disposal?
Explanation: High concentrations of chlorides indicate that the water body has been used for waste disposal.
Can chlorine increase BOD?
Chlorine dosages above 10 mg l−1 resulted in increased BOD and COD levels of the effluent, with chlorine dosages above 30 mg l−1 resulted in almost double the original BOD and COD values.
Is chlorination used for COD removal?
The existing pollution level of the water bodies from the textile wastewater will be significantly reduced by using chlorine and compounds of chlorine. It act as an oxidising agents but to remove COD treatment with H2O2 will be a good alternative.
Can chlorine reduce COD?
Chemically, Chlorination or hydrogen peroxide would reduce the COD. Biologically you could use the conventional activated sludge process, which is an aerobic biological process.
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