5 Ways to Reduce COD in wastewater

Jopari Yusuf
Dec 9, 2015 · 4 min read

How to Reduce COD in Water

See the post on the original source at : http://on-water.us

Hello, Nice to see you again here, on a great website that discuss the secret of water and wastewater treatment world, namely On-Water.Us. This time we will discuss together about how to reduce the value of COD in waste water.
For you who don’t have any clue about what it is COD and where are the source of COD was, I suggest you to read the following article below:
Previous article: List of Sources COD You Need to Know.

Let us go to the point

How to Reduce the Chemical Oxygen Demand value (COD) in wastewater?

1. COD Reducement using Precipitation Process (Coagulation)
in the previous article, we will find that most of the COD is sourced from the TSS or no dissolved solids commonly called sludge. The most important way to get rid of the sludge is to use coagulants and flocculants.
The principle is to bind the sludge to one another so that a larger clumps of sludge and then be deposited in a sedimentation tank.
Some chemicals commonly used as a coagulant, among others; PAC, FeCl3 (Ferric Chloride) and Alum.
This deposition process, will greatly affect the value of COD. Especially in wastewater with a high enough amount of TSS. For additional information for the 1 mg / L TSS you can get a drop of up to 10 mg / L COD.
COD reduction process in order to become more perfect, it is advisable to give more concern to the process of mixing and sedimentation. Due without proper mixing process, the precipitation reaction that occurs will be less than perfect.

2. Microbiology Process for COD Reducement
COD reduction process by the method of using bacteria or microorganisms, devoted to COD derived from organic matter with a high content of biodegradable. This process is done in two main ways, namely aeration and anaerobic.
In the aeration process, COD reduceed by making the bacteria can break down organic compounds in water. These bacteria are called heterotrophic bacteria break down organic compounds due to the use of oxygen. This process is usually used in waste water with a COD of less than 3000 mg / L.
In the process of anaerobic bacteria work in a room with minimal oxygen content. This process is also called fermentation, in which bacteria break down autotrop working with organic compounds from wastewater with three stages of one of them is by taking oxygen from organic compounds.
The anaerobic process is suitable for waste water with BOD levels over 2000 mg / L.
Before deciding whether to take this method, it is important for you to understand what types of wastewater that you face. Because microbiological process is only suitable for wastewater with organic contents. You can determine this by looking at the comparison between COD and BOD.

Some processes similar to this is the process of using MBR, SBR or SMBR
3. Reduce COD with Oxidator
Some chemicals, can help you to reduce the COD of waste water. Chlorine, Hydrogen peroxide and Ozone will mengoksdiasikan chemicals in the water so that the automatic COD value will go down. But of course you should limit dose usage of oxidator, because oxidator possess sufficient berhaya especially for living organisms.
COD reduction technique is suitable for waste have COD values derived from non-biodegradable waste such as Phenol, surfactants, etc.

Recomended to Read : Is there any Correlation between COD and BOD?

4. COD Reducing process by Fenton Reaction
Fenton reaction is a reaction that has been widely known is able to reduce the COD value. The principle is the formation of free radicals that are created from the reaction between Fenton reagent is FeSO4 with Hydrogen peroxide.
Fenton reaction is what will be the forerunner of the birth of AOP system.

5. Advanced Oxidation Process, The latest COD Reducing Method
AOP is the latest technology that is able to reduce the COD value of the wastewater. Even of COD with a value above 100 thousand though.
AOP was created from the added refinement of Fenton reaction in the presence of ozone injection so adding reproduce free hydroxyl finally able to oxidize chemicals in water.
Excess AOP process is very fast reaction speed. If the processing by microbiological reduction in COD can take days. Then the AOP process only takes a matter of hours or even minutes.
Another plus is also located in the area used for this system is very small is compared with other systems.
Moreover, this process does not require a lot of chemicals to be added in the wastewater.

6. Process Filtration and Adsorption with Activated Carbon
The latter method is widely used in the finishing process or post treatment after primary treatment process. Usually used as an activated carbon filter. Activated carbon will absorb organic substances, ozone or chlorine substances remaining on the processing results. So safe effluent to be discharged into the environment.
Filtration using activated carbon is also commonly used in water treatment processes to remove odors, and reduce the chemicals in the water.

Similiar To This : TSS Removal Process

Hopefully this article can give you an idea on how to reduce the value of COD in waste water. Lastly, I would like to remind you that COD is not a substance but a parameter that accumulates from substances that require oxidation process. It is necessary for a deeper understanding of what contributes to the COD value in the wastewater you.

PS: If you are interested in learning more about the world of wastewater treatment. I suggest you to have some books below:

Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight. Watch
Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox. Explore
Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month. Upgrade