Skip to main content

difference-between-cod-bod-do-environmental-engineering

Difference Between COD, BOD and DO in Environmental Engineering

In environmental engineering, the quality of water and wastewater is often evaluated using three important parameters: Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), and Chemical Oxygen Demand (COD).

These parameters help engineers determine the level of pollution in water bodies and the amount of oxygen required to break down organic matter.

1. Dissolved Oxygen (DO)

Dissolved Oxygen (DO) is the amount of oxygen dissolved in water. Aquatic organisms such as fish and microorganisms need dissolved oxygen to survive.

DO is usually measured in mg/L (milligrams per liter). Higher DO values indicate better water quality.

Importance of DO

  • Essential for aquatic life
  • Indicates health of rivers and lakes
  • Helps determine pollution level in water

2. Biochemical Oxygen Demand (BOD)

Biochemical Oxygen Demand (BOD) is the amount of oxygen required by microorganisms to break down organic matter present in water under aerobic conditions.

BOD is generally measured over 5 days at 20°C and expressed in mg/L.

Importance of BOD

  • Measures biodegradable organic pollution
  • Used in wastewater treatment design
  • Higher BOD indicates higher pollution

3. Chemical Oxygen Demand (COD)

Chemical Oxygen Demand (COD) is the amount of oxygen required to chemically oxidize organic and inorganic substances present in water.

COD is measured using strong chemical oxidizing agents such as potassium dichromate.

Importance of COD

  • Measures total organic pollution
  • Faster test compared to BOD
  • Used to assess wastewater strength

Difference Between COD, BOD and DO

Parameter Full Form Meaning Importance
DO Dissolved Oxygen Amount of oxygen dissolved in water Indicates water quality and supports aquatic life
BOD Biochemical Oxygen Demand Oxygen required by microorganisms to decompose organic matter Indicates biodegradable pollution
COD Chemical Oxygen Demand Oxygen required to chemically oxidize organic matter Indicates total pollution in water

Key Points

  • DO shows the oxygen available in water.
  • BOD shows oxygen needed by microorganisms.
  • COD shows oxygen needed for chemical oxidation of pollutants.
  • High BOD and COD values usually mean polluted water.

Conclusion

DO, BOD, and COD are essential parameters used in water quality analysis and wastewater treatment. These measurements help environmental engineers monitor pollution levels and design effective water treatment systems.

Comments

Post a Comment

Popular posts from this blog

Write the assumptions made in theory of bending: strength of materials

The assumptions made in theory of bending The following are the assumptions made in theory of bending: 1. The material of beam is homogeneous and isotropic. (Isotropic means having the properties same in all directions.)  2. The beam is straight before loading.  3. The beam is of uniform cross section throughout its length. 4. Transverse sections, which are plane before loading, remains plane even after loading.  5. The material is elastic and Hooke's law is applicable. 6. The effect of shear is neglected. Therefore the analysis is meant for pure bending. 7. The modulus of elasticity, E has same value in tension and compression.  8. Each layer is free to expand or contract having no influence in the neighbouring layers for their extension or contraction. 9. The beam is initially straight and all longitudinal filament bend into circular arcs with a common centre of curvature.
Post a Comment
Read more

Why engineering is different from other professions

 Why engineering is different from other professions ? Engineering is a unique profession that sets itself apart from others in many ways. From its focus on problem-solving to its emphasis on innovation, engineering is a field that requires a unique set of skills and knowledge. One of the key differences between engineering and other professions is the focus on problem-solving. Engineers are trained to identify problems and develop solutions to address them. This requires a deep understanding of the underlying principles and concepts that govern the systems and processes they are working on. Another key difference is the emphasis on innovation. Engineers are constantly looking for ways to improve upon existing systems and processes or develop new ones altogether. This requires a willingness to take risks, experiment, and think outside the box. Engineering is also unique in its interdisciplinary nature. Engineers often work across multiple disciplines, such as physics, mathematics, ...
Post a Comment
Read more

Fluid mechanics and hydraulic diploma, BE, B tech

Fluids mechanics and hydraulic Fluid mechanics is the branch of physics and engineering that deals with the study of fluids (both liquids and gases) at rest or in motion. It focuses on understanding the behavior of fluids and the forces acting upon them. Hydraulic engineering, on the other hand, is a specific application of fluid mechanics that deals with the use and control of fluids, particularly water, in engineering projects and systems. Fluid mechanics involves studying properties of fluids, such as density, pressure, viscosity, and flow velocity. The fundamental principles governing fluid behavior include: 1. Fluid statics: Examining fluids at rest and understanding concepts such as pressure, buoyancy, and hydrostatic forces. 2. Fluid dynamics: Investigating fluids in motion, including the flow patterns and forces associated with fluid flow, such as drag, lift, and viscosity effects. Applications of fluid mechanics and hydraulics can be found in various engineering disciplines, i...
Post a Comment
Read more