Disinfection vs. Sterilization
Disinfection and sterilization are both decontamination processes.

To begin with, decontamination through disinfection or sterilization is used to reduce specific contaminants, such as bacteria, viruses or any other type of microorganism that may be present in a fluid or on the surfaces of a water treatment system.

Disinfection refers to the removal or destruction of microorganisms that may pose a risk to human health. Normally, the term disinfection should only refer to the use of chemicals. However, it is common to speak of disinfection when referring to other techniques for destroying microorganisms. For example, when the fluid is heated to kill pathogens, it is often referred to as thermal disinfection, but the real term would be pasteurization.

Sterilization, on the other hand, consists of the extraction or destruction of all life forms in the fluid.

Whether used continuously or intermittently, disinfection or sterilization can be done in several different ways. Among the methods, there are three main groups: physical, chemical and thermal. 

Thermal sterilization or disinfection obviously consists of increasing the internal temperature of the system and/or the fluid in it in order to eliminate the micro-organisms on the surfaces or in the fluid. The temperature reached, the duration of time and the way the heat is propagated - for example in steam - will have an impact on the effectiveness of the treatment.

Secondly, not only is there a wide variety of chemicals that can be used, but they can also be used in a variety of ways to achieve disinfection or sterilization. The most common chemicals are chlorine and its derivatives and ozone. 

Finally, UV irradiation is typically the only physical method of water disinfection or sterilization. 

To elaborate more on the subject, we invite you to consult these articles: 

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What is a pharmacopoeia?
Pharmacopoeia is a reference book used to identify drugs and their manufacturing methods.