What is the limit of cod in drinking water?
For drinking water BOD has to be less than 5 mg/L and for treated wastewater to be disposed of in the water bodies it is 30 mg/L, 100 mg/L if treated waste water is discharged into the sewerage system in India.
What is the permissible limit of cod?
effluent into a waterbody or watercourse used or earmarked to be used for potable water supply. influent. 6….
| Parameter | Unit | Maximum permissible limit |
|---|---|---|
| Chemical Oxygen Demand (COD) | mg/l | 120 |
| Biochemical Oxygen Demand (BOD5) | mg/l | 40 |
| Chloride | mg/l | 1500 |
| Sulphate | mg/l | 1500 |
What is the range of cod?
The COD of surface water normally ranges from 5 to 20 mg l−1. The COD as standardized method has found its way into wastewater legislation.
What is BOD COD ratio?
BOD (Biochemical oxygen demand) is the pollution index of any water sample. BOD : COD (Chemical oxygen demand) ratio using the formulated seed comes in the range of 0.7-0.8 whereas that using BODSEED comes in the ratio of 0.5-0.6. The ultimate BOD (UBOD) was also performed by exceeding the 3-day dilution BOD test.
What causes high COD in wastewater?
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.
How do you treat high COD water?
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.
How do you reduce COD in wastewater?
The most important way to get rid of the sludge is to use coagulants and flocculants. The principle is to bind the sludge to one another so that a larger clumps of sludge and then be deposited in a sedimentation tank. Some chemicals commonly used as a coagulant, among others; PAC, FeCl3 (Ferric Chloride) and Alum.
Does aeration reduce cod?
Aeration should help reduce the COD in 2 ways. First it may evaporate some volatiles like hexane. Second it will add oxygen to the water speeding up any biological oxidation of the less volatile organics by the bacteria (microbial growth). It will actually increase the COD very quickly.
What is BOD of drinking water?
BOD is a measure of the amount of oxygen required to remove waste organic matter from water in the process of decomposition by aerobic bacteria (those bacteria that live only in an environment containing oxygen). BOD is used, often in wastewater-treatment plants, as an index of the degree of organic pollution in water.
What increases BOD water?
Organic loading is occurrence of excess organic matter inside water due to sewage disposal and eutrophication. This leads to an increase in biological oxygen demand (BOD) for putrefaction. Explosive multiplication of alga leads to algal bloom. These conditions result in decrease in dissolved oxygen in water.
What is a good BOD level?
A BOD level of 1-2 ppm is considered very good. There will not be much organic waste present in the water supply. A water supply with a BOD level of 3-5 ppm is considered moderately clean.
DO levels in drinking water?
Water at lower temperatures should have higher mg/L of dissolved oxygen and higher %DO while warmer, polluted waters will have lower mg/L and %DO. Healthy water should generally have dissolved oxygen concentrations above 6.5-8 mg/L and between about 80-120 %.
Is oxygen more important than water?
Adequate dissolved oxygen is necessary for good water quality. Oxygen is a necessary element to all forms of life. Biologically speaking, however, the level of oxygen is a much more important measure of water quality than feacal coliform.
How much oxygen is in tap water?
While air consists of 21% oxygen, the oxygen content in water is only 0.001%! Just how much dissolved oxygen can be found in a water supply will depend on several factors: Aeration of water – Under high pressure, relatively large quantities of oxygen dissolves in water.