High-Voltage Water Purification

Scientists at NASA’s Glenn Research Center have developed a unique water purification method that can be used for water recycling or point-of-use applications. Originally developed as a means to recycle water in space, this technology has applications in industrial water treatment, water recycling, and water purification for military bases, disaster sites, and regions without easy access to clean water.
Relying on only electrical energy, this technology uses plasma-generated reactive species to decompose organic contaminants, ranging from submicron particles to water soluble organics like glycol, ethanol, and industrial dyes.
Benefits
  • Environmentally friendly: Does not introduce toxic chemicals into liquids
  • Readily available: Provides clean water on-demand
  • Accessible: Accommodates large-volume, high-throughput applications and works with in-volume and in-line water feed systems
  • Simple: Operates without filters, which can often become fouled or punctured
  • Durable: Housed in a self-contained unit
  • Highly antiseptic: Attacks and destroys microbes
Applications
  • Wastewater treatment
  • Pharmaceutical and food and beverage water treatment
  • Pretreatment of contaminants
  • Point-of-use drinking water
  • Groundwater treatment
  • EPA Superfund site cleanup
  • Hydraulic fracturing water reuse
The Technology
The Glenn water purification system has application in wastewater treatment
The Glenn water purification system has application in wastewater treatment

 

Highly oxidizing water treatments, like ozonation and UV-ionization, have proven useful in removing organics from water, but they require high capital costs and high amounts of wasteful energy consumption.

Glenn’s approach to water purification uses high-voltage, nanosecond-pulsed, non-equilibrium plasma to treat water. The pulsed electrical discharge destroys micro-organisms in liquid, essentially sterilizing the water, without the use of toxic chemicals or filters. The plasma creates highly reactive OH radicals (e.g. hydroperoxl, hydrogen peroxide, super oxide O2) that break down organic contaminants into carbon dioxide and water.
The nano-pulses ensure that only enough energy is produced to destroy the contaminant without heating up the water, eliminating the need for cooling loops or downtime that is associated with other processes (such as UV-ionization).   NASA’s water purification technology relies only on electricity and can be scaled to meet a wide range of needs, from small portable units that purify drinking water in disaster relief to million-gallons-per-day industrial applications.
This technology is simple, straightforward, and low cost, with virtually no consumables nor byproducts. Furthermore, the plasma pulse technology can function as a stand-alone purification process or as an add-on to existing solutions as a polishing step.

Activated carbon is widely used for odour control

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removal at a number of stages in municipal sewage treatment. Odours can develop at a number of points in municipal waste water treatment plants where sewage is agitated or where sludge accumulates. This includes pumping stations, head works, trickling filters, digesters and at sludge handling and storage areas.

The Carbon Filtering Process is generally used for Indoor Air Purification/(quality),  (Odor) control and (emission control) Processing. Activated carbon is a general term of adsorbents that have been manufactured from a variety of carbon-based materials. Each base material results in an activated carbon with unique physical characteristics that determine its suitability for treatment applications.

The ability of activated carbon filters to remove impurities from the air is one of the reasons it is commonly used for indoor air quality, odor control and emission control systems. Carbon Filter use continues to increase as more industries and consumers consider their environmental impact.

 

History of carbon filters

Carbon filters have been used for several hundred years and are considered one of the oldest means of water purification. Historians have shown evidence that carbon filtration may have been used in ancient Egyptian cultures for medical purposes and as a purifying agent.  2000 B.C. Sanskrit text refers to filtering water through charcoal (1905 translation of “Sushruta Samhita” by Francis Evelyn Place). The first recorded use of a carbon filter to purify potable water on a large scale occurred in 19th century England.

Currently, carbon filters are used in individual homes as point-of-use water filters, groundwater remediation, landfill leachate, industrial wastewater and, occasionally, in municipal water treatment facilities. They are also used as pre-treatment devices for reverse osmosis systems and as specialized filters designed to remove chlorine-resistant cysts, such as giardia and cryptosporidium.

Activated Carbon For Filters and Water Treatment

Because of activated charcoal’s incredible adsorption ability, it is an ideal choice for air and water filters. When used appropriately, charcoal filters will effectively clean the air and water by electrostatically binding pollutants to its vast surface area.

Many people use activated charcoal filters in outdoor ponds and aquariums to keep the water clean and the marine life healthy.

Carbon filtering is a method of filtering that uses a bed of activated carbon to remove contaminants and impurities, using chemical absorption.

Each particle/granule of carbon provides a large surface area/pore structure, allowing contaminants the maximum possible exposure to the active sites within the filter media. One pound (450 g) of activated carbon contains a surface area of approximately 100 acres (40 Hectares).

Activated carbon works via a process called adsorption, whereby pollutant molecules in the fluid to be treated are trapped inside the pore structure of the carbon substrate. Carbon filtering is commonly used forwater purification, in air purifiers and industrial gas processing, for example the removal of siloxanes and hydrogen sulfide from biogas. It is also used in a number of other applications, including respirator masks, the purification of sugarcane and in the recovery of precious metals, especially gold. It is also used in cigarette filters.

Active charcoal carbon filters are most effective at removing chlorine, sediment, volatile organic compounds (VOCs), taste and odor from water. They are not effective at removing minerals, salts, and dissolved inorganic compounds.

What carbon filtration doesn’t do can be seen in the remaining three categories of the EPA contaminant list. Carbon is mentioned as a treatment for only one of the four Microbiological contaminants listed: turbidity.

It is not recommended for coliform removal or for cysts, though ironically, some of the very tight solid carbon block filters now on the market remove bacteria (though manufacturers seldom make this claim) and cysts like giardia and cryptosporidium quite handily. Multipure solid carbon blocks, in fact, were the first filtration device certified by NSF (the most prestigious independent agency that tests and certifies product performance) for removal of cryptosporidium.

Multipure and some other very tight carbon block filters remove cysts simply because of their restricted pore size. Multipure blocks are absolute 1/2 micron filters, making cryptosporidium organisms about ten times too fat to go through the holes. Thus, although other types of very tight filtration might work as well, the very dense carbon block filters now on the market are very effective against certain forms of microbiological contaminants.

 Activated Carbon for drinking water Treatment

Potable or drinking water is a commodity with stringent requirements of being safe and pure. Granular Activated Carbons (GACs) and Powder Activated Carbons (PACs) is your ideal solution in making drinking water free from taste and odor forming compounds such as MIB and geosmin, undesired colors, endocrine disrupting compounds and other micropollutants, chlorinated hydrocarbons, Trihalomethanes and other disinfection byproducts, VOCs, pesticides and their byproducts.

You can treat drinking water with the high quality, standard, and specially processed products complying with NSF 61, NSF 42, PROP 65 certifications with low dechlorination half values, superior flow characteristics, consistent particle size distributions to facilitate pressure drop and adsorption kinetics requirements, extensive pore structures with an ideal balance of both adsorption and transport pores, and high mechanical strength resulting in minimal operational and pressure drop issues. These superior features have made  granular carbon products the industry choice for Point of Use (POU) and Point of Entry (POE) water filters.

Activated Carbon for Municipality water treatment

In the treatment of municipal water, removal of organics including VOCs, inorganics and toxins inherent in the rivers, lakes, reservoirs and other surface water sources and ground water systems is essential. You can find a tailor made series of products for surface and ground water treatment in municipality water treatment systems to deliver consistent performance in removing these contaminants.

These products are also geared to adsorb hazardous pesticide and herbicide residues, chlorinated hydrocarbons, disinfectant byproducts, inhibitory compounds for biological treatment systems, non-biodegradable organic compounds, and undesired colored and smell compounds. Our carbons are effective in lowering of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Organic Content (TOC) and toxicity. In addition, the high purity of the carbon products prevents the release of contaminants that may damage sensitive membrane systems used in other in-process filtration systems. We also offer custom designed products and total purification solutions to best suit your requirement.

Activated Charcoal As A Deodorizer

Activated carbon adsorbs. The chemical process of absorption is commonly compared to a sponge soaking up water. The water is fully integrated into the sponge, not being limited to the surface area. Differently, adsorption is a process whereby molecules stick to the surface area only. As mentioned above, activated carbon has a large surface area due to being a porous material. The unwanted substance sticks to the surface area of the carbon particles.

One of the common utilizations of this porous carbon is to filter gas. Not as in fuel, but the gaseous substances that are either naturally produced or expelled from various machinery. Take, for example, air filters. Air is technically a gas, and when the air contains impure elements, a purifier in the form of a filter will help remove these impurities. In a slightly different form, the activated charcoal will perform the same function with water—a use common in fish tanks.

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Yet one of the long-standing functions of activated charcoal is oral ingestion. Companies make pills that contain activated charcoal which dissolve in the stomach, allowing the granular carbon to remove toxins. You can find a ton of claims on the Internet about the magic that taking a dose of activated charcoal performs, many of which aren’t medically confirmed, however, it is common for hospitals to use activated charcoal for this use. It is widely known to be safe to ingest and acts as a poultice.

Another use gaining momentum is using activated carbon as a teeth stain removal device. Your teeth’s health is important, and the way activated charcoal works also helps to bind plaque, making it an effective whitening tool. Put some of it on your toothbrush with liquid water. It will be weird to brush with at first—seeing the black get smeared on your teeth will feel counterproductive. However, it will rinse off your teeth easily enough and you’ll love the results. Just be careful to avoid staining your sink—keep soap handy to quickly clean up any messes which ensue. Many people swear by this method to whiten their teeth, and its use on teeth as a cleaner and whitener goes back for centuries.

One of the things that using active charcoal as a filter does is the loss of odors in gasses. Odors, and any other prone elements of the gas, get trapped in the activated charcoal through a process called adsorption. Through adsorption the particles bind to the surface of the activated charcoal—which is why it is imperative that activated charcoal actually be activated; the greater the available surface, the better the grade it gets for trapping.

It is effective enough that there are underpants available for purchase which make use of activated charcoal for moments of flatulence. Let’s face it—suspension of flatulence detection would do everyone a world of good. If only they could make activated underwear for dogs and cats; the media would have a field day!

 

Where is Activated Carbons Used ?

Activated carbon is the major adsorbent in global adsorbent market occupying more than 65% of the volume market share due to its high adsorption capacity and large surface area. Activated carbon is mainly divided into three types; powdered, granular and extruded. It has become the preferred option for use in potable water purification, waste water treatment, aquariums, swimming pools and sewage water treatment as well as air and gas filtration. These applications are gaining popularity due to increasing pollution levels, health concerns and stringent government regulations.

Apart from this, activated carbon is used for decolorization and deodorization of food and beverages; and purifies vitamins antibiotics and active pharma ingredients in pharmaceutical industry and 1medical applications. Some of the other applications of activated carbon include control gas emissions in automobiles; personal protection in defense sector; gold and precious metal recovery; and as catalyst in removal of mercaptan in oil refineries.

Scarcity of raw material and increasing concerns over supply chain, the activated carbon market is currently facing pricing issues; however, the market for activated carbon is on rise due to its extensive use in liquid phase and gas phase applications.

Activated Charcoal Applications:

  • industrial/pharmaceutical/chemical/military/agricultural/environmental – adsorption of unwanted chemicals
  • neutralize toxic compounds
  • medical
  • food purification
  • metalurgy
  • carrier for chemical catalysts
  • soil enrichment
  • greenhouse gas reduction
  • soundwave/microwave/radiowave capture

activated carbon

Activated Charcoal Uses:

  • Air filters in gas masks, filter masks, air compressors.
  • Food coloring
  • Gas purification
  • Gold purification
  • Medicine: liver and kidney dialysis machines, laser surgery, breast cancer surgery, stomach decontamination from drug/food poisoning, wound dressing…
  • Metal extraction
  • Metal finishing – the purification of electroplating solutions, as in bright nickel-plating solutions.
  • Nuclear Biological Chemical (NBC) suits
  • Nuclear power plants
  • Recycling solvents
  • Rye grass seed industry
  • Sewage treatment
  • Snow avalanche control – helping to melt snow
  • Soil enhancement
  • Sound systems – “cleaning” out bad background noise
  • Toxic soil cleanup from chemical spills or accumulation of chemical spraying
  • Volatile organic compounds capture: from painting, dry cleaning, gasoline dispensing operations, and other processes.
  • Water purification: aquariums, swimming pools, domestic & municipal water systems, recycling precious water on the orbiting space station (cost $10,000/liter)
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