find out the ratio
of BOD to COD to know the treatability of wastewater.
Now, let's see what is BOD and COD; and what is their relevance
with reference to wastewater treatment.
**Biochemical oxygen demand (BOD)**
The strength of wastewater is judged by BOD. This is defined as the
amount of oxygen required by bacteria while stabilizing the
organics in wastewater under aerobic conditions, at a particular
time and temperature. This can be referred as BOD5, which accounts
for 70% of the total BOD. The measurement of BOD is based on the
principle: determination of dissolved oxygen content of
water/wastewater on the first day and dissolved oxygen content on
the fifth day ('5' in BOD5 indicates this). The difference in
dissolved oxygen concentrations between first day and fifth day is
expressed as BOD of wastewater.
**What does COD of wastewater mean?**
Chemical oxygen demand (COD) reflects the concentration of organic
compounds present in wastewater. This measures the total quantity
of oxygen required for oxidation of organics into carbon dioxide
and water. The oxidation of organics in wastewater is carried out
by the action of strong oxidizing agents. Generally, acidified
potassium dichromate is used as an oxidizing agent for the
determination of COD. Silver sulfate is used as the catalyst for
the oxidation of organics in wastewater during the determination of
COD. Mercuric sulfate is added to control the interference of
chloride in the estimation of COD. The method consists of adding a
known concentration of potassium dichromate (added with silver
sulfate and mercuric sulfate) into wastewater containing organic
compounds to be oxidized in the heating condition. After oxidation,
the excess potassium dichromate is back titrated with ferrous
ammonium sulfate.
**Importance of COD**
Estimation of COD expresses the total concentration of organics
present in the wastewater. This measures approximately the
theoretical oxygen demand of wastewater. The determination accounts
for about 95% of the organic concentration in wastewater. This
forms about 1.43 times the BOD of wastewater. BOD to COD ratio
reveals the treatability of wastewater. If the ratio of BOD/COD is
above 0.5, the wastewater is considered to be highly biodegradable.
If the ratio is less than 0.3, the wastewater is deemed to undergo
a chemical treatment before the routine biological treatment.
With this mandatory information, you will be able to choose the
exact right wastewater treatment plant that suits your need.
of BOD to COD to know the treatability of wastewater.
Now, let's see what is BOD and COD; and what is their relevance
with reference to wastewater treatment.
**Biochemical oxygen demand (BOD)**
The strength of wastewater is judged by BOD. This is defined as the
amount of oxygen required by bacteria while stabilizing the
organics in wastewater under aerobic conditions, at a particular
time and temperature. This can be referred as BOD5, which accounts
for 70% of the total BOD. The measurement of BOD is based on the
principle: determination of dissolved oxygen content of
water/wastewater on the first day and dissolved oxygen content on
the fifth day ('5' in BOD5 indicates this). The difference in
dissolved oxygen concentrations between first day and fifth day is
expressed as BOD of wastewater.
**What does COD of wastewater mean?**
Chemical oxygen demand (COD) reflects the concentration of organic
compounds present in wastewater. This measures the total quantity
of oxygen required for oxidation of organics into carbon dioxide
and water. The oxidation of organics in wastewater is carried out
by the action of strong oxidizing agents. Generally, acidified
potassium dichromate is used as an oxidizing agent for the
determination of COD. Silver sulfate is used as the catalyst for
the oxidation of organics in wastewater during the determination of
COD. Mercuric sulfate is added to control the interference of
chloride in the estimation of COD. The method consists of adding a
known concentration of potassium dichromate (added with silver
sulfate and mercuric sulfate) into wastewater containing organic
compounds to be oxidized in the heating condition. After oxidation,
the excess potassium dichromate is back titrated with ferrous
ammonium sulfate.
**Importance of COD**
Estimation of COD expresses the total concentration of organics
present in the wastewater. This measures approximately the
theoretical oxygen demand of wastewater. The determination accounts
for about 95% of the organic concentration in wastewater. This
forms about 1.43 times the BOD of wastewater. BOD to COD ratio
reveals the treatability of wastewater. If the ratio of BOD/COD is
above 0.5, the wastewater is considered to be highly biodegradable.
If the ratio is less than 0.3, the wastewater is deemed to undergo
a chemical treatment before the routine biological treatment.
With this mandatory information, you will be able to choose the
exact right wastewater treatment plant that suits your need.
Saleem Asraf Syed Imdaadullah
Mobile : 9899300371
311/22,Zakir Nagar,New Delhi-110025
email: saleemasraf@gmail.com
BLOG: http://saleemindia.blogspot.com
Mobile : 9899300371
311/22,Zakir Nagar,New Delhi-110025
email: saleemasraf@gmail.com
BLOG: http://saleemindia.blogspot.com
For an all natural, bacterial solution to the reduction of BOD and COD, one should try the products from Custom Biologicals, Inc. Check out www.wastewaterodor.com for more info, it performed very well for our treatment plant.
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ReplyDeletereally wonderful article on Wastewater Treatment
ReplyDeleteThanks for the sharing nice information.......
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