Activated carbon is a very mature technology that is designed to help remove taste and odor from water through adsorption of the compounds that cause problems.

There are a variety of different types of carbon that are used industry-wide. They include wood, lignite, coal, and coconut as the most common sources for activated carbon.

Activated carbon operates through adsorption. Adsorption is a surface phenomenon and is therefore directly related to the surface area of the media. In the case of activated carbon, the surface area is related to the pore structure of the raw materials. The cost of the media is also related to the raw materials, so there are other factors that must be taken into consideration besides the total surface area.

Adsorption takes place due to intramolecular attraction between the carbon surface and the substance that is being adsorbed. The force of the attraction can be altered by increasing the density of the carbon or by reducing the distance between the carbon surface and the substance being adsorbed (typically by reducing the median pore size). As the fluid (often water) passes over and through the carbon, the attractive forces between the compounds that are the most attracted to the carbon are adsorbed onto the surface. The compounds that are the most highly attracted are typically organic compounds (which can cause taste, odor and appearance problems), volatile organic compounds (VOCs) and halocarbons such as trihalomethane (THM) compounds and other process wastes.

Once all of the surface area of the carbon has been exhausted through adsorption, the carbon can be regenerated in a number of different manners. The most common is offsite furnace re-activation which involves heating the carbon up to drive off the organic materials that are adsorbed.

The bioprocessing of biotech products consists of two major processing steps: upstream processing and downstream processing. Upstream processing refers to the culturing of cells and microorganisms to create the bulk bio-product. This processing is typically done through cell culture or fermentation. Downstream processing refers to the separation and refinement of the bulk bio-product into a form suitable for its end use. Typically, this processing includes separation, purification and sterilization.

The process of distillation has been known and used for millennia. Although it has primarily been employed as a method of producing alcoholic beverages like whisky and vodka, distillation also works as a technique of water purification. In the 1970s, distillation was a popular method of home water purification, but its use is now largely confined to science laboratories or printing industries.

The Process:
The distillation process utilizes a heat source to vaporize water. The object of distillation is to separate pure water molecules from contaminants with a higher boiling point than water. In the distillation process, water is first heated until it reaches its boiling point and begins to evaporate. The temperature is then kept at a constant. The stable temperature ensures continued water vaporization, but prohibits drinking water contaminants with a higher boiling point from evaporating. Next, the evaporated water is captured and guided through a system of tubes to another container. Finally, removed from the heat source, the steam condenses back into its original liquid form. Contaminants having a higher boiling point than water remain in the original container. This process removes most minerals, most bacteria and viruses, and any chemicals that have a higher boiling point than water from drinking water. For this reason, distillation is sometimes valued as a method of obtaining pure drinking water.

Pros and Cons:
Distillation, similarly to reverse osmosis, provides mineral-free water to be used in science laboratories or for printing purposes, as both functions require mineral-free water. It removes heavy metal materials like lead, arsenic, and mercury from water and hardening agents like calcium and phosphorous. Distillation is often used as the preferred water purification method in developing nations, or areas where the risk of waterborne disease is high, due to its unique capabilities to remove bacteria and viruses from drinking water.

Distillation has several qualities that make it undesirable for the purification of municipally treated water, especially when compared to the decontamination capacities of water filters. Although distillation processes remove mineral and bacterial drinking water contaminants, they do not remove chlorine, chlorine byproducts, or VOCs. These chemicals, which have a lower boiling point than water, are the major contaminants of municipally treated water. Most dangerous metals and bacteria are removed from water prior to its arrival at a home’s plumbing system. Thus, a distillation system, targeted at the removal of these contaminants, is unnecessary and irrelevant for most people.

Distillation, like reverse osmosis, provides mineral-free water that can be quite dangerous to the body’s system when ingested, due to its acidity. Acidic drinking water strips bones and teeth of valuable and essential mineral constituents.

Furthermore, distillation is an incredibly wasteful process. Typically, 80% of the water is discarded with the contaminants, leaving only one gallon of purified water for every five gallons treated.

The two media in a media filtration assembly are manganese greensand and anthracite. The manganese greensand acts as a form of chemical treatment that, when in contact with soluble iron in water, reduced the iron from the soluble form to an insoluble form that will precipitate out of solution. The anthracite then can filter both the precipitated iron out of the solution as well as other entrained particles that have entered the water source.

This combination of anthracite and manganese greensand together can remove a majority of particles greater than 10 microns in size. In addition, the filter can be backwashed to remove the entrained particles and iron in order to extend bed life. The manganese will eventually be exhausted and will also need to be regenerated, something which most systems are equipped to do.

Microfiltration is a form of filtration that has two common forms. One form is crossflow separation. In crossflow separation, a fluid stream runs parallel to a membrane. There is a pressure differential across the membrane. This causes some of the fluid to pass through the membrane, while the remainder continues across the membrane, cleaning it. The other form of filtration is called dead-end filtration or perpendicular filtration. In dead-end filtration, all of the fluid passes through the membrane, and all of the particles that cannot fit through the pores of the membrane are stopped.

Crossflow microfiltration is used in a number of applications, as either a prefiltration step or as a process to separate a fluid from a process stream.

Nanofiltration is a form of filtration that uses membranes to preferentially separate different fluids or ions. Nanofiltration is not as fine a filtration process as reverse osmosis, but it also does not require the same energy to perform the separation. Nanofiltration also uses a membrane that is partially permeable to perform the separation, but the membrane's pores are typically much larger than the membrane pores that are used in reverse osmosis.

Nanofiltration is most commonly used to separate a solution that has a mixture of some desirable components and some that are not desirable. An example of this is the concentration of corn syrup. The nanofiltration membrane will allow the water to pass through the membrane while holding the sugar back, concentrating the solution. As the concentration of the fluid being rejected increases, the driving force required to continue concentrating the fluid increases.

Ozone is formed as oxygen (O₂) is struck by a source of energy. The bonds that hold the O₂ together are broken and three O₂ molecules are combined to form two O₃ molecules. The ozone begins to break down fairly quickly, and as it does so, it reverts back into O₂. The bonds that hold the O atoms together are very weak, which is why ozone acts as a strong oxidant as readily as it does.

Ultrafiltration is a form of filtration that uses membranes to preferentially separate different fluids or ions. Ultrafiltration is not as fine a filtration process as nanofiltration, but it also does not require the same energy to perform the separation. Ultrafiltration also uses a membrane that is partially permeable to perform the separation, but the membrane's pores are typically much larger than the membrane pores that are used in nanofiltration.

Ultrafiltration is most commonly used to separate a solution that has a mixture of some desirable components and some that are not desirable. One of the uses that demonstrates the usefulness of ultrafiltration is electrodeposition paint recovery. In this instance the paint, composed of a resin, a pigment and water are separated into two streams that can be reused. The first stream includes the water and a small amount of the paint resin, which can be used to rinse the parts later in the process. The paint pigment is separated from that stream and can be reused in the paint bath, allowing the bath to be concentrated to a usable level.