Which of the following options is used to estimate the BOD of wastewater?

Measurement of oxygen consumption

The correct answer is Option (4)- Measurement of oxygen consumption

(1) Measurement of total organic matter: This option refers to measuring the total amount of organic matter present in the wastewater. While it provides information about the overall organic content, it does not specifically indicate the biodegradability or oxygen demand of the organic matter.

(2)Measurement of biodegradable organic matter: This option involves measuring the amount of organic matter in the wastewater that is capable of being decomposed by microorganisms. It provides a more specific indication of the organic matter that can contribute to oxygen consumption during microbial decomposition. BOD is closely related to the measurement of biodegradable organic matter.

(3) Measurement of oxygen evolution: This option involves measuring the amount of oxygen released or evolved during a specific process. While oxygen evolution can be relevant in certain contexts, it is not directly associated with the estimation of BOD in wastewater.

(4) Measurement of oxygen consumption: It is correct .This option refers to measuring the amount of oxygen consumed by microorganisms during the decomposition of organic matter in wastewater. BOD is determined by analyzing the difference in dissolved oxygen levels before and after a specific incubation period. The higher the oxygen consumption, the higher the BOD, indicating a greater amount of biodegradable organic matter in the wastewater.

In summary, the most accurate method for estimating BOD in wastewater is by measuring the oxygen consumption, as it directly reflects the oxygen demand associated with the decomposition of organic matter by microorganisms.