Molecules of contaminants are pulled from the water and adsorbed by a porous surface or compound. This method is useful for many uses, but it doesn’t create the ultrapure water a lab might need.


This method uses a resin that pulls ionized salts and minerals out of the water. The ionized particles are drawn to the resin, and this means that only water is left behind. This is a method that is often used in conjunction with other purification methods.


This is one of the oldest methods of purifying water. The water is heated and condenses in a pipe that brings it to a different container. This technique has been used for so long because it is highly effective for many uses.


This method uses a filter to sift through the water and keep contaminants from flowing through it. There are varying sizes of filters which allow for different levels of purification. Filters can be solid, like paper, or a media, such as sand.

Reverse Osmosis

This method uses a membrane to separate molecules and particles from water, creating the ultrapure water that many industries need. Pressure is applied to the water, which forces the water molecules through the membrane and leaves contaminants behind.


This is a method similar to filtration but uses a membrane instead of a traditional filter to ensure finer contaminants are processed out of the water.

UV Oxidation

This method exposes water to UV light, which oxidizes and destroys organic compounds in the water. This is excellent for organic contaminants, but not for inorganic materials. A unique characteristic of UV light is that a specific range of its wavelengths, those between 200 and 300 nanometers (billionths of a meter), are categorized as germicidal – meaning they are capable of inactivating microorganisms, such as bacteria, viruses, and protozoa.

Laboratory Water Purification Standards

PPT has provided numerous Type I water purification systems to labs and universities across the nation.

ASTM D1193-91 Types I, II, III, and IV

One of the most widely used sets of standards, the ASTM divides their tiered specifications for laboratory water purification and other applications into four types, starting with Type I and going to Type IV. Type IV represents the least strict standards, while Type I represents the most stringent. When it comes to most laboratories that depend on highly purified water, most systems will want to adhere to Type I standards. PPT has provided numerous Type I standard equipment to labs and universities across the nation.

CAP – 1988

Similarly to ASTM, the College of American Pathologists divides their standards into three tiers as well, starting with Type I and ending with Type III. These standards describe the purity of laboratory water purification required to work with microorganisms, with Type I being the strictest and suggested standard for cell cultures and tissue cultures, and Type II being used for mundane or routine laboratory procedures relating to immunology and other fields.