What is the difference between BOD and COD which one is better and why?

BOD measures the amount of oxygen required by the aerobic organisms to decompose organic matter and COD measures the oxygen required to decompose organic and inorganic constituents present in the wastewater by chemical reaction. Hence, the value of COD is greater than BOD.

What is difference between DO and BOD?

Hint: DO are dissolved oxygen and BOD are biochemical oxygen are certain parameters by which one can find out the degree of water pollution or the concentration of readily biodegradable organic matter in the water bodies.

What is the COD and BOD?

The biochemical oxygen demand (BOD) represents the amount of dissolved oxygen (DO) consumed by biological organisms when they decompose organic matter in water. The chemical oxygen demand (COD) is the amount of oxygen consumed when the water sample is chemically oxidised.

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.

Why is COD always higher than BOD?

All Answers (29) always COD is higher about 5 times than BOD because its comprises both Organic and inorganic Pollutants while BOD is only for Organic Pollutants. Dear brother, Simply BOD indicates the biodegradable organic matter (OM) while COD represents both biodegradable and non-biodegradable OM in water.

What is COD in drinking water?

The chemical oxygen demand (COD) is a measure of water and wastewater quality. The COD test is often used to monitor water treatment plant efficiency. This test is based on the fact that a strong oxidizing agent, under acidic conditions, can fully oxidize almost any organic compound to carbon dioxide.

What is BOD explain?

Biochemical oxygen demand (BOD) represents the amount of oxygen consumed by bacteria and other microorganisms while they decompose organic matter under aerobic (oxygen is present) conditions at a specified temperature.

What is BOD formula?

Formulation of BOD Equation ‘Oxygen Equivalent of Organic Matter Present’ is nothing but the BOD remaining. The rate of change of BOD directly varies with BOD remaining at that point in time (Lt) So, dLt/dt ∝ Lt. Integrating both the sides from interval Lo to Lt in time interval 0 to t, Lt = Lo x e^(-kt)

Why is COD higher than BOD?

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

What if COD is high in water?

When the COD levels are higher, there is a greater demand for oxygen. This means that there is likely more oxidizable organic material in water with high COD levels. This also means that there are reduced Dissolved Oxygen (DO) concentrations in wastewater with high COD levels.

What is BOD limit?

According to WHO for drinking water BOD limit is less than < 5.0 mg/l at this limit BOD will not cause any harmful impacts on human body, wastewater sewage must has BOD around 80 ppm and COD 200 ppm for discharge in see”.

What is COD in wastewater?

5 Chemical oxygen demand (COD) The COD is the estimate of oxygen required for the portion of organic matter in wastewater that is subjected to oxidation and also the amount of oxygen consumed by organic matter from boiling acid potassium dichromate solution.

How COD is calculated?

There is a formula for calculating COD. Consider the formula for COD calculation: (a – b) X C X 8,000 / the volume of the sample in mL. Let “a” represent the titrant used for your sample expressed in mL. Let “b” represent the titrant used for your blank sample in mL.

Does chlorine reduce BOD?

BOD reduction: Chlorine accomplishes BOD reduction by oxidation of organic compounds present in wastewaters. 4. Oxidation of metal ions: Metal ions which are in reduced state are oxidized by chlorine (e.g., ferrous to ferric ion and manganous to manganic ions).

How is COD removed from wastewater?

You can reduce COD and BOD by adding hydrogen peroxide to the wastewater solution. The hydrogen peroxide will chemically attack the organics in the wastewater, degrading them and reducing the measured COD and BOD.

What is the limit of COD?

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

What is the range of COD?

The COD of surface water normally ranges from 5 to 20 mg l−1. The COD as standardized method has found its way into wastewater legislation.

Why is chlorine added to wastewater 7?

Answer. Nearly every wastewater treatment facility uses chlorination to disinfect wastewater before the water is sent back out into the environment. The primary goal of chlorination is to disinfect the wastewater and remove any harmful pathogens that are present in the water.

Why BOD is greater than cod?

In some cases, the total BOD (includes both nitrogeneous and carboneceous portions) can exceed the COD depending upon the nature of the waste. Because, microbes in total BOD analysis can oxidize reduced form of nitrogen as reflected in NBOD whereas potassium dichoromate used in COD is ineffective for oxidizing nitrogen.

What is the difference between cod and BOD?

COD and BOD can be indicated as mg/L or ppm (parts per million).

Both parameters measure the amount of oxygen needed to oxidize pollutants in water.

Also,both measurements indicate the intensity of water pollution.

Furthermore,both BOD and COD are critical in wastewater for determining the amount of waste in the water.

What are the advantages of cod over BOD?

– Biochemical Oxygen Demand. – Measurement of Biochemical Oxygen Demand (Bod) Title: Laboratory 2: Measurement of Biochemical Oxygen Demand ( BOD ) Objective To determine the amount of oxygen necessary for biological oxidation of wastewater – Chemical Oxygen Demand. – Chemical Oxygen Demand. – Dissolved Oxygen. – Oxygen.

What is the difference between BOD, COD or TOC?

COD should always measure higher than TOC and then BOD. COD or Chemical Oxygen Demand is the total measurement of all chemicals in the water that can be oxidized. TOC or Total Organic Carbon is the measurement of organic carbons. BOD- Biochemical Oxygen Demand is supposed to measure the amount of food (or organic carbons) that bacteria can oxidize.