# How do you calculate theoretical oxygen demand?

1. Write balanced reaction for the carbonaceous oxygen demand. CH2(NH2)COOH + 1.5O2 → NH3 + 2CO2 + H2O.
2. Write balanced reactions for the nitrogenous oxygen demand. NH3 + 1.5O2 → HNO2 + H2O. HNO2 + 0.5O2 → HNO3
3. Determine the ThOD. ThOD = (1.5 + 2) mol O2/mol glycine.

## What is the difference between ThOD and COD?

COD/TOC = 32/12 = 2.66 ThOD (Theoretical oxygen demand): If the type of organic matter and its concentration present in the system is known then the amount of oxygen required for its decomposition can be computed theoretically and is termed as ThOD. COD (Chemical oxygen demand):

## What is theoretical oxygen demand of glucose?

The correct option is C 533.33. When chemical formula and concentrations of different organic compounds is known, then theoretically calculating the oxygen required to completely oxidize the organic matter using balanced chemical equation is called as theoretical oxygen demand. Given, concentration of glucose= 500 mg/L.

## What is 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.

## What is the difference between CBOD and Nbod?

The major difference between CBOD and NBOD is that there are two classes of bacteria believed to be responsible for the oxidation of reduced nitrogen. The BOD5 value of Sewage samples collected from Covenant University oxidation pond was therefore measured and the samples examined for the presence of Escherichia coli.

## What is the difference between BOD and Ultimate BOD?

Generally, BOD is standardized by the measurement of oxygen consumption in 5 days (BOD5). But, determination of the ultimate biochemical oxygen demand (BODu), which is taken 28 days and the reaction rate constant (k) are necessary to understand the organic strength of the wastewater.

## Which is higher BOD or COD?

COD is always higher than BOD because chemical oxidation is easier than biological oxidation.

## Why do we measure BOD and COD?

Answer: Both COD and BOD test methods aim to give an indication of the amount of pollution in a water sample. COD is the amount of oxygen required to chemically breakdown the pollutants whereas BOD is the amount of oxygen required to do this biologically through micro-organisms.

## Why is BOD measured for 5 days?

BOD occurs in 2 general stages. While calculating the oxygen demand, the carbonaceous stage is taken into account. This stage is almost completed in 5 days, which means that most of the organic content of the sewage is oxidized under aerobic conditions in 5 days. Hence ,BOD for 5 days is calculated.

## What does BOD measure in wastewater treatment?

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).

## What is ultimate BOD?

The ultimate BOD best expresses the concentration of degradable organic matter based on the total oxygen required to oxidize it. However, it does not indicate how rapidly oxygen will be depleted in receiving water. Oxygen depletion is related to both the ultimate BOD and the BOD rate constant (K).

## What causes high BOD in wastewater?

Sources: BOD represents the amount of organic matter in a water supply; therefore, it increases when decaying plants, human or animal waste, and other organic compounds are added to water.

## Why do we perform BOD?

Biochemical oxygen demand, or BOD, is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period.

## What is the difference between BOD and BOD5?

BOD technically stands for Biological Oxygen Demand BOD5 means the test has been run for 5 days. C-BOD means only the Carbonaceous Biochemical Oxygen Demand N-BOD means Nitrogenous Biochemical Oxygen Demand BOD5 typically includes C-BOD and N-BOD unless one or the other is inhibited.

## Can CBOD be higher than BOD?

The BOD5 value should always be higher than or equal to the cBOD5, since the nitrification inhibitor is intended to prevent NOD, which is in excess of the oxygen demand exerted by heterotrophic oxidation of organic compounds.

## How many types of BOD are present?

There are two forms of soluble BOD: nitrogenous and carbonaceous. Nitrogenous BOD consists of ammonium ions and nitrite ions.

## What does Nbod mean?

What is NBOD? 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.

## How do you measure BOD in water samples?

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.

## How do you calculate BOD at different temperatures?

The standard BOD test is conducted at 20°C. To convert a measured BOD value at 20°C to a different temperature, a temperature coefficient, θ, is used. The equivalent 30°C BOD is 1.7244 higher than the standard 20°C BOD.

## Does BOD increase with temperature?

The BOD removal rate in the bioreactor increased when the temperature increased from 20 degrees C to 30 degrees C, 40 degrees C, and 50 degrees C, but it decreased when the temperature increased from 50 degrees C to 60 degrees C. Higher temperature enhanced the endogenous respiration of microbes in the bioreactor.

## Who limits COD in water?

According to standards of Central Pollution Control Board, permissible value of BOD is 30 mg/l and COD is 250 mg/l.

## What is meant by BOD of sample water is 80 MGL?

BOD- Biochemical Oxygen Demand is the amount of dissolved oxygen in a water body, required by microorganisms for the aerobic breakdown of organic matter in the water. Higher the value of BOD more is the amount of organic matter available for aerobic bacteria. this corresponds to the greater degree of pollution.

## What is BOD value of water?

BOD values range widely; generally, pristine waters have a value below 1 mg l−1, moderately polluted waters 2–8 mg l−1, and treated municipal sewage 20 mg l−1. Standards for the discharge of effluent from WWTPs have the range 20–30 mg l−1 and require a minimum flow in receiving waters to ensure sufficient dilution.

## What is the optimum value of BOD?

Statement 1: The value of the parameter “Biochemical oxygen demand (BOD)” is important for survival of aquatic life. Statement 2: The optimum value of BOD is. 5 ppm .