Decantation is a process used to separate a mixture. It usually involves removing the liquid portion of a substance while leaving behind the sediment. This process is used in a variety of instances. Red wine is a common example of a substance that is decanted. Wastewater may also be processed using this method.
Insoluble matter is something that does not dissolve in a liquid. Instead, it tends to float and will generally settle if the substance is left at rest. The purpose of decantation is to separate the liquid from this type of matter.
This is done because in many cases the insoluble matter is undesired. In the case of wine, decantation leaves only the liquid, so a person does not have to be concerned with sediment when her glass is agitated. In a case such as wastewater treatment, it removes solids that cannot be broken down or treated along with the liquid waste.
The process of decantation is fairly simple, although some skill and practice may be required if it is done manually. There usually must be a minimum of two containers. One should have the substance that needs to be decanted. The other will be used to collect the liquid.
The substance can be poured from one container to the other. This should be done in such a manner that the insoluble material does not leave the first container. In most cases, a choice will have to be made. Either a small portion of the liquid will need to be sacrificed or a small amount of sediment will need to be permitted in the liquid. It can be extremely difficult, if not impossible, to manually decant all of a liquid.
Decantation is sometimes mistakenly used interchangeably with the word “filtration.” These two processes both accomplish similar goals. They are, however, not the same.
One of the greatest differences is that filtration utilizes a filter, or barrier material, that catches the sediment. With decantation, filters are not used. This means that filtration can be more effective because almost all of the liquid can be recovered.
Another difference is that some degree of settling is generally necessary to decant if the sediment is to be successfully separated. With filtration, however, since there is a barrier, it does not matter if the sediment and liquid are mixed together. This means filtration may not only be easier, but it can also be performed faster.