What is the difference between BOD and CBOD?
BOD results are based on DO depletion from both carbonaceous and nitrogenous actors in a wastewater sample. CBOD measures DO depletion from only carbonaceous sources. Regulators may assign either BOD or CBOD, or both, to wastewater treatment facilities. Method SM 5310B is used for both BOD and CBOD.
How do you calculate lab BOD?
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).
What reagents are required to chemically Dechlorinate a BOD sample?
Sodium sulfite is used to dechlorinate for BOD, because sodium thiosulfate has a significant oxygen demand if any excess is present.
What are the possible interferences in BOD determination?
Nitrogenous demand historically has been considered an interference in the determination of BOD, and the inclusion of ammonia in the dilution water contributes an exter- nal source of nitrogenous demand. The interference from nitrog- enous demand can now be prevented by an inhibitory chemical.
What is Nbod and CBOD?
Nitrogenous Biochemical Oxygen Demand (NBOD) refers to the difference between Biochemical Oxygen Demand (BOD) and Carbonaceous Biochemical Oxygen Demand (CBOD): NBOD = BOD – CBOD. According to Standard Methods 5210, microorganisms can facilitate the oxidation of reduced forms of nitrogen.
What is STP BOD?
Biochemical oxygen demand (BOD) is the amount of dissolved oxygen (DO) needed (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.
Why must samples containing residual chlorine be dechlorinated before preparation of BOD dilutions?
TO PREVENT INTERFERENCE FROM CHLORINE Any samples containing residual chlorine must be pretreated to remove chlorine before the test is run. This is done by adding sodium sulfite to the sample. NOTE: Those samples which are dechlorinated must be seeded for the BOD test.
Why are BOD bottles incubated in the dark?
Incubation in the dark ensures that no additional oxygen is produced in the samples from photosynthesis. After 5 days, the dissolved oxygen is measured again.