why is it important to determine bod value in wastewater treatment

Applications of Biological Oxygen Demand in Wastewater Treatment Wastewater treatment plants use BOD value as an index to ascertain the overall degree of organic pollution in a water source. A BOD test is typically carried out over a standard 5-day incubation period at 20°C (68°F) for the most accurate results.

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What is the importance of BOD in water quality?

Oct 30, 2018 · Wastewater treatment plants use BOD value as an index to ascertain the overall degree of organic pollution in a water source. A BOD test is typically carried out over a standard 5-day incubation period at 20°C (68°F) for the most accurate results. Generally, a higher BOD value indicates a higher level of water pollution, while a lower BOD value indicates less …

What is BOD and cod in wastewater?

Biochemical oxygen demand / biological oxygen demand is an important water quality parameter because it provides an index to assess the effect discharged wastewater will have on the receiving environment. The higher the BOD value, the greater the amount of organic matter or “food” available for oxygen consuming bacteria.

How do you calculate the BOD of a wastewater treatment plant?

Determining BOD values after five days (BOD 5) has been adopted as a compromise between a short test-period and the detection of a practically complete biological breakdown of organic materials. With domestic effluents, at 20 °C a complete degradation (= 100 % BOD) is achieved only after 20 days (BOD 20 ); however, after only 5 days, 70 % of the biologically convertible …

What is BOD5 test in wastewater treatment?

Jan 13, 2019 · The organic strength of wastewater is measured in three ways: 1) as 5-day biochemical oxygen demand (BOD5), 2) chemical oxygen demand (COD), and/or 3) total organic carbon. Typically, municipal wastewater treatment plants will use BOD5 as a measure of the organic concentration into, and through, the wastewater plant.

Why is it important to check the BOD values in the water body?

A small amount, but it is essential for life in the water. Biological oxygen demand (BOD) generally represents how much oxygen is needed to break down organic matter in water.

What is BOD and COD why it is important to determine in waste water treatment?

Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) are two of the most important parameters to characterise (measure the degree of pollution) of wastewater. BOD, the biological demand for oxygen a source of water has, is the amount of oxygen used by microorganisms to break down organic substances.Mar 1, 2018

Which is more important 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.Jan 12, 2022

What is the value of BOD of industrial sewage?

What is the value of BOD of industrial sewage in kg/day, given population equivalent as 6000 persons? Explanation: BOD of industrial sewage in kg/day = Population equivalent * Average standard BOD of domestic sewage = 6000*0.08 = 480kg/day. 6.

What is biological oxygen demand?

Biochemical Oxygen Demand or Biological Oxygen Demand, is a measurement of the amount of dissolved oxygen (DO) that is used by aerobic microorganisms when decomposing organic matter in water. BOD can be measured in real-time with our BOD sensors to improve wastewater process control and plant efficiency.

Why is biological oxygen demand important?

Biochemical oxygen demand / biological oxygen demand is an important water quality parameter because it provides an index to assess the effect discharged wastewater will have on the receiving environment. The higher the BOD value, the greater the amount of organic matter or “food” available for oxygen consuming bacteria. If the rate of DO consumption by bacteria exceeds the supply of DO from aquatic plants, algae photosynthesis or diffusing from air, unfavourable conditions occur. Depletion of DO causes stress on aquatic organisms, making the environment unsuitable for life. Further, dramatic depletion can lead to hypoxia or anoxic environments. BOD is also used extensively for wastewater treatment, as decomposition of organic waste by microorganisms is commonly used for treatment.

Is BOD used for wastewater treatment?

Further, dramatic depletion can lead to hypoxia or anoxic environments. BOD is also used extensively for wastewater treatment, as decomposition of organic waste by microorganisms is commonly used for treatment. Regulations and permitting for biochemical oxygen demand effluent will vary by country and region, such as the National Pollution Discharge ...

What is the BOD of oxygen?

BOD n (Biochemical Oxygen Demand after n days) is defined in detail in German Standard DIN 38 409-H51 1 and is associated with certain experimental conditions. It represents the quantity of oxygen which is consumed in the course of aerobic processes of decomposition of organic materials, caused by microorganisms. The BOD therefore provides information on the biologically-convertible proportion of the organic content of a sample of water. This leads to the consideration of these materials in terms of their susceptibility to oxidation by the use of oxygen. BOD is stated in mg/l of oxygen and is usually measured within a period of 5 days (BOD 5 ).

What is the dilution method?

There are two standard procedures, which are equivalent to each other under given conditions: the first is the dilution method to DIN 38409-H51 and gives the so-called dilution BOD n over a period of n days. This is in most cases an officially-approved procedure. It is cumbersome and includes an optimization for test conditions required for the decomposition process at 20 °C. The oxygen content is measured directly in the water itself.

What is a BOD value?

BOD values are generally determined and evaluated in association with other parameters (e.g., COD, DOC, POC, TOC) and this makes them more useful in formulating predictions. For example, if we consider a comparison of the measured BOD value with the COD value:

What does a high BOD mean?

In general, the following assertions may be made: • a high BOD indicates a high content of easily degradable, organic material in the sample. • a low BOD indicates a low volume of organic materials, substances which are difficult to break down or other measuring problems (see below)

How long is a BOD graph?

However, in some countries a testing period of 7 days is performed. A so-called BOD-Graph can be drawn up, in which BOD values are shown in graphical form over a given period of time. A slight deviation from the kinetic described above occurs, caused by fluctuations in the rate of breakdown.

What are the conditions for determining BOD?

The conditions for determining BOD are so defined that the quantity alone of the organic materials contained in a sample limits the growth of microorganisms - i.e., the greater the number of organic nutrients present, the greater the material-exchange activity of the bacteria and , therefore, the resultant BOD.

How does biodegradation occur in water?

Biodegradation of materials present in water occurs in two phases. The breakdown of carbons begins practically immediately . In the second phase, nitrification occurs, which also involves the consumption of oxygen. There are two groups of nitrifying bacteria, which catalyse the synthesis in a close relationship.

How long does it take to complete the Bod5 test?

Due to the length of time required to complete the BOD5 test (five days), BOD results provide historical data only and do not facilitate rapid water quality assessment for optimal process control. The often highly variable chemical composition ...

What is BOD5 in wastewater?

Typically, municipal wastewater treatment plants will use BOD5 as a measure of the organic concentration into, and through, the wastewater plant. Industrial wastewater systems will more often use COD to measure the organic concentration moving through the treatment plant. In my experience, I see TOC being used much less often (rarely) ...

What is the purpose of a wastewater test?

The test measures only the approximate amount of oxygen that will be required (absorbed or consumed) by a wastewater when it is exposed to air or oxygen for an extended period of time. Toxic substances in the wastewater inhibit or even prevent bacterial growth and, therefore, oxidation of the organic matter.

What is the BOD5 test?

The BOD5 test measures the oxygen consumed by microorganisms as they oxidize (consume or eat) the soluble organic matter in the wastewater. But the BOD5 test is a somewhat unreliable means of determining the amount of organic matter present in water. The test measures only the approximate amount of oxygen that will be required ...

How long does it take to test for organics in wastewater?

The often highly variable chemical composition and strength of industrial wastewater requires a much more rapid method for measuring the organic concentration, hence the use of the two hour COD test or, in some plants, the 30 minute TOC analysis.

How much COD is in water?

The COD in industrial water may be 50 – 2,000 mgO 2 /L, although it may reach 5,000, depending on the type of industry. The main difference between BOD and COD is that COD measures all organic material, while BOD only measures organic material which is or can be biologically degraded.

What is COD in water?

COD, the chemical demand for oxygen a source of water has, is the amount of oxygen required to break down organic substances chemically and convert them to CO 2 and H 2 O. It is also expressed in mgO 2 /L, and the higher the COD, the more polluted the water is.

What is the biological demand for oxygen in water?

BOD, the biological demand for oxygen a source of water has, is the amount of oxygen used by microorganisms to break down organic substances. These are usually bacteria (aerobic or anaerobic), yeasts and plankton contained in the water. It is a measure of the degree of contamination and is expressed in mgO 2 /L.

How is Bod5 measured?

It is measured via a delicate and time-consuming biological process, which depends on temperature. The standard measurement is performed at 20°C for 5 days and is called BOD5. The period of 5 days was chosen, as this is the average time it takes a British river to reach the sea. In general terms, the greater the pollution, the higher the BOD.

Is the COD greater than the BOD?

Therefore, for a given water sample, the COD is always greater than the BOD, and the second result (COD), as the complete chemical oxidation of the sample, can be considered to include the first. BOD and COD are related and maintain their relationship for each type of water.

Is the Bod/COD relationship the same for different types of water?

The relationship is not the same for different types of water; however, industrial water of the same type has a similar BOD/COD relationship. By providing more information and being quicker to obtain, the COD is becoming the reference standard in the field.

What does high BOD mean?

High levels of BOD indicate an elevated concentration of biodegradable material present in the wastewater and can be caused by the introduction of pollutants such as fecal waste or fertilizer runoff. It can also be elevated by organic waste, whether by domestic or industrial sources. When these levels are elevated, ...

What happens if nitrates are not removed from wastewater?

If large amounts of nitrates and/or phosphates are not removed from wastewater and these nutrients are discharged into local environments, they can increase the BOD and lead to extensive weed growth, algae, and phytoplankton.

What happens when water levels are elevated?

When these levels are elevated, this can deplete the oxygen needed by other aquatic organisms to live, leading to algal blooms, fish kills, and harmful changes to the aquatic ecosystem where the wastewater is discharged.

Why are metals in wastewater so toxic?

They are particularly damaging because they don’t break down and tend to accumulate, causing toxic environs . Some of the more common metals found in wastewater are outlined below along with their potential effect on humans and the environment.

Why treat wastewater?

Treating your wastewater to recycle/reuse it can be especially helpful in areas with low water resources (for example, California that is currently experiencing a drought). In addition to conserving water, this can help your facility save on connection fees that might be extremely high due to the shortages. Your wastewater treatment options, in ...

What happens when a body of water is deoxygenated?

This can lead to eutrophication, or the deoxygenation in a body of water, killing the organisms and potentially leading to hypoxia or environmental dead zones. They can enter the wastewater stream a variety of ways, including human and food waste, detergents, and pesticides.

What diseases can be spread from industrial wastewater?

When domestic or industrial wastewater contains these harmful pathogens and is not treated, it can spread illnesses and diseases such as cholera, dysentery, salmonellosis, hepatitis A, botulism, and giardiasis, to name a few.

What are the health effects of wastewater?

Untreated, the chemical compounds and pathogens in wastewater can harm the health of animals, plants and birds that live in or near the water. It can also contaminate crops and drinking water, affecting human health.

Why is wastewater treatment important?

Wastewater treatment is fundamental to protect the health of many different ecosystems. Wastewater, properly treated, is a source of water for many purposes. Good wastewater treatment allows the maximum amount of water to be reused instead of going to waste.

Can water be reused?

All communities, especially areas with water scarcity, need to ensure they have good water treatment processes in place so that treated water can either be reused or returned to the water cycle, but never wasted. Wastewater can include contaminants from both residential and commercial use.

Is water a natural resource?

Essential for life, clean water is one of the most important natural resources on the planet. Wastewater, which is basically used water, is also a valuable resource, especially with recurring droughts and water shortages in many areas of the world.

What is wastewater treatment?

Wastewater treatment is a process that coverts wastewater from its unusable state into an effluent that can be either returned to the water cycle with minimal environmental issues or reused for another purpose.

Why is wastewater treatment important?

Why Waste Water Treatment is So Important. All around the world, it’s common practice to pump enormous volumes of wastewater into rivers, oceans and streams. This has extremely negative effects on the environment, fisheries, animals, and that’s not to mention it’s an aptly named ‘waste’ of water too.

What is wastewater in mining?

To put it simply, wastewater is any form of water that has been contaminated by a commercial or domestic process. This includes water that was used for sewerage and water that’s a by-product of large-scale industries such as mining and manufacturing.

Which country is the most developed in South America?

Uruguay, which happens to be one of the most developed countries in South America, has announced that it will be spending $100m over the next year on new treatment plants, and Indonesia will have help from Australia to solve water management problems that it has had in the past.

Does Sweden have waste?

In fact, Sweden actually ran out of its own waste and it now imports over 700,000 tonnes of waste from other countries. Less than 1% of their waste ends up at the dump and their wastewater is purified to the extent of being potable.

Is water a resource?

Water is one of our most important resources and it’s being squandered. There are multiple ways to treat wastewater, and the better the process, the higher the percentage that it can be reused before it gets dumped into the ocean.