How do you calculate BOD?

How do you calculate BOD?

Dissolved oxygen (D.O.) is measured by probe before and after incubation. BOD is computed based on the difference between initial and final D.O. The test uses dilution water and a known amount of sample in a 250-300 ml incubation bottle.

How do you calculate BOD in wastewater?

For example: 1.0 mL of a full strength wastewater sample added to 9.0 mL of DI water results in a 0.1 dilution of the wastewater. The DO concentration (mg/L) reduction must then be multiplied by 10 to determine the final BOD concentration.

Why is BOD typically calculated over 5 days?

The standard oxidation (or incubation) test period for BOD is 5 days at 20 degrees Celsius (°C) (BOD5). The BOD5 value has been used and reported for many applications, most commonly to indicate the effects of sewage and other organic wastes on dissolved oxygen in surface waters (see TECHNICAL NOTE).

How do you find the BOD rate constant?

The ultimate BOD allows for an accurate calculation of the Lo. where t is time, y is the BOD in mg/L at time t (L in Equation 2), Lo is the original concentration of biodegradable organic matter, and k is the rate constant. By substitution, k = 6b/a and Lo = 1/(ka3).

How do you measure BOD in water?

Measuring biochemical oxygen demand requires taking two measurements. One is measured immediately for dissolved oxygen (initial), and the second is incubated in the lab for 5 days and then tested for the amount of dissolved oxygen remaining (final).

How is BOD concentration calculated?

The concentration of BOD (in mg/l) in the influent can be used to calculate the total BOD load per day being treated. This is simply done by multiplying the BOD in mg/l by the daily effluent volume in cubic metres (m3) and dividing the product by 1000.

How is BOD measured in water?

BOD measurement requires taking two samples at each site. One is tested immediately for dissolved oxygen, and the second is incubated in the dark at 20 C for 5 days and then tested for the amount of dissolved oxygen remaining.

Why do we calculate BOD?

One water analysis that is utilized in order to better understand the effect of bacteria and other microorganisms on the amount of oxygen they consume as they decompose organic matter under aerobic (oxygen is present) is the measure of biochemical oxygen demand (BOD).

What are the limits for BOD in drinking water?

There is no specific limits prescribed for BOD in drinking water by ISI Or WHO. The presence of BOD in drinking water indicates that the water contains biodegradable organic substances.

How much oxygen is needed to determine BOD?

A general rule-of- thumb has been developed to provide sufficient accuracy in determining BOD values. This states that at least 2 mg/L of oxygen must be used over the course of the experiment , but at least 0.5 mg/L must remain in the final sample.

What is a BOD test for water?

The [BOD] of a water or wastewater sample is measured using a bioassay–a test in which organisms (biota) are used to determine (assess) the amount of a target substance. In the case of a BOD test microorganisms are used to degrade/oxidize many different compounds in the sample.