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Teacher Incharge: Engr. Gul-E-Hina

(Lecturer, IEER)

Estimation of Organic Compounds

Lecture 3

By: Engr. Gul-E-Hina

Bio degardation

Organic Matter

Reaction End Products

Active Bacterial cells

Energy Production

Synthesis

Endogenous Metabolism

Organic Matter

Reaction End Products

Active Bacterial cells

O2+

CO2+ H2O

Cell debris

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Estimation of organic content in IWW

•BOD

•COD

•TOC

•ThOD

Estimation of Organic Content in IWW

•BOD:

BOD5 is the quantity of oxygen required for the stabilization of oxidizable organic matter present over 5 days of incubation at 20ᵒC.

BOD5 test measure the biodegrable organic carbon and under curtained conditions the oxidizable nitrogen present in the waste.

Typical BOD Curve BOD Curve

First Order of Kinetics:𝑑𝐿

𝑑𝑡𝛼 𝐿

𝑑𝐿

𝑑𝑡= −𝐾𝐿

𝑑𝐿

𝐿= −𝐾𝑡

𝐿𝑜

𝐿𝑑𝐿

𝐿= −𝐾

0

𝑡

𝑑𝑡

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𝐿𝑡 = 𝐿𝑜𝑒−𝐾𝑡

BOD Curve

𝑊ℎ𝑒𝑟𝑒 ,

Lt=BOD Remaining at any time “t”

Lo= Ultimate BOD

K=Reaction Rate coefficient

𝑦𝑡 = 𝐿𝑜(1 − 𝑒−𝐾𝑡)

𝑊ℎ𝑒𝑟𝑒 ,

Yt=BOD Exerted at any time “t”

Lo= Ultimate BOD

K=Reaction Rate coefficient

Bacterial Growth Curve

LogLog

Reaction Occurring in a BOD Bottle

•BOD is a sum of :

1. Oxygen used for synthesis of a microbial

cells using the organic matter

2. Endogenous Respiration

Reaction Occurring in a BOD Bottle