Water Purification -

Private Well Water Treatment by Activated carbons

PRIVATE WELL WATER

IN CONNECTICUT

Publication Date: May 2018

Publication #1: Granular Activated Carbon

Treatment of Private Well Water

Introduction

Granular activated carbon (GAC) is a type of water treatment commonly used to remove chemical contaminants and for taste and odor control. GAC filters come in a variety of types and sizes and can be used to treat the water at a single tap or all the water in your home. As with all treatment types, GAC units must be operated and maintained properly to ensure the water supplying your home remains safe.

GAC can be used to remove or reduce:

Unwanted tastes and odors
Radon
Organic chemicals
Pesticides and Herbicides
Chlorine
Per- and Polyfluoroalkyl Substances (PFAS)

GAC is not considered effective to remove or reduce:

Microorganisms (i.e. bacteria, viruses) Some metals

Nitrates

How Granular Activated Carbon Treatment Works

GAC media is an effective adsorbent because it is highly porous and provides a large surface area for contaminants to adsorb onto. GAC media is made by heating a carbon source such as coal, coconut shells, wood or peat. GAC media is placed inside a filter tank. When untreated water passes through, certain contaminants are attracted to the media and become adsorbed by its surface, becoming trapped in its pores.

The effectiveness of any GAC filter unit will depend on the type of GAC media installed, the concentration and type of contaminants in the water, and the size of the GAC filter.

Types of Units

GAC filters come in both whole house (also known as point-of- entry (POE)) units and point-of-use (POU) units, which refers to the location where the treatment unit is installed.

Produced by The State of Connecticut Department of Public Health Environmental Health Section, Private Well Program 410 Capitol Avenue, MS#11PWP, PO Box 340308, Hartford, CT 06134 Phone: 860-509-8401 Fax: 860-509-7295

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POU units treat water only at a specific tap ; usually the kitchen sink to treat the water you drink and cook with. POU units can be pour through units, faucet mount units, in-line devices, or line bypass units:

Pour-through GAC units: Untreated water is poured into the top of the pitcher, then passes through a small carbon filter. Treated water is collected at the base of the pitcher. These units are not connected to the water supply and usually sit on counter tops. Pour-through devices only treat small quantities of water at a given time, and are not recommended for removal of organic chemicals.

Faucet mount units are attached to the faucet or placed on the counter with connections to the faucet. Some of these units may be equipped with a bypass option to selectively filter water (usually for cooking and drinking) which helps to prolong the life of the carbon cartridge. Faucet-mount units are typically not recommended for removal of organic chemicals. Certain faucet mount units may be effective at reducing lead in water. Always consult with manufacturer’s specifications to determine effectiveness against specific contaminanants in your water.

The line-bypass unit is attached to the cold water plumbing beneath the kitchen sink and has a separate faucet installed that provides treated water for uses such as cooking and drinking. The regular tap delivers untreated water. This design may increase the life expectancy of the carbon by allowing a choice of either treated or untreated water.

The in-line device is installed beneath the kitchen sink on the cold water plumbing to treat water for uses such as drinking or cooking. If both hot and cold water come from a single faucet, the treated cold water can mix with the untreated hot water. Treated water is provided only when using cold water for uses such as drinking and cooking.

Whole House Treatment (POE) GAC units are typically installed where the water line enters your house and will treat all the water in your household plumbing.

Whole house treatment or POE is recommended for treatment of most volatile organic compounds (VOCs), pesticides, herbicides or chemicals. Whole house treatment also prevents the inhalation of hazardous vapors for those contaminants that can easily vaporize from water into air, such as radon and VOCs. Whole house treatment also prevents skin absorption from bathing and showering from chemicals such as VOCs, pesticides and herbicides.

Unit Effectiveness

The effectiveness of a GAC unit depends on the time of contact between the carbon and the untreated water. The longer the contact time, the better the adsorption of contaminants onto the GAC filter media. Over time, channels can form within the GAC filter media, which may allow some untreated water to pass through the filter media through these channels. Since treatment depends on the GAC media adsorbing the chemical contaminants, these channels decrease the effectiveness of the GAC filter unit.

Some types of GAC filters are better at treating for certain contaminants than others. Discuss your options with a GAC product distributor or water treatment company. Always confirm that the treatment unit you are choosing has been tested to meet manufacturer’s claims.

In order for GAC filtration to be most effective, it is important to follow manufacturer’s maintenance requirements. Filter media should be replaced over time as needed. Consult with your water treatment company installing the GAC treatment unit or the manufacturer to determine maintenance requirements.

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Backwash Wastewater Generated

Treatment backwash is sometimes necessary to lift the GAC filter media and reduce sediment from it.

This process may help eliminate any channels that may have formed in the filter media.

If you have an on-site septic system, water treatment wastewater must be discharged in accordance with criteria established in the CT Department of Public Health, 2018 On-site Disposal Regulations and Technical Standards for Subsurface Sewage Disposal Systems.

Contact CT Department of Energy and Environmental Protection if you are connected to municipal sewer and the WPCA does not allow discharge of treatment backwash water to the sewer.

Maintenance

Water treatment equipment will not perform satisfactorily unless it is maintained in accordance with manufacturer’s recommendations for maintenance, cleaning and part replacement. It is recommended that you keep a record of equipment maintenance and repairs.

GAC filter units need to have the GAC media inside changed regularly. For small point of use specialty units, the entire cartridge filter is normally replaced. POE GAC filters are often used in line with a pre-treatment filter to remove sediment and iron particles that can clog the carbon filter. If installed, pre-treatment filters will also need to be replaced periodically.

GAC filter media eventually becomes saturated and can no longer adsorb contaminants. This is called ‘breakthrough’. When this occurs, the GAC filter media can no longer remove contaminants from the water. If left for too long after this point, contaminant concentration levels in the water supplying your house could actually be higher than the untreated water entering the GAC filter. Two GAC filters may be placed in series to prevent breakthrough contaminants from reaching your home’s water supply. Changing the filter media on a regular basis will also help to prevent breakthrough from occurring.

GAC maintenance frequency will vary based on the size of the filter unit, household water usage, contaminant concentration levels, and overall water quality. Water quality testing can help determine when GAC media needs to be replaced. A water meter installed at the filter may be helpful in determining when carbon replacement is necessary. Refer to the two sections below for more information.

GAC media can sometimes provide a medium for bacterial growth, reducing the effectiveness of the filter. If bacterial growth coats your GAC media it may also enter your household plumbing system. If test results indicate bacteria is present in the water, replacement of the GAC filter media and disinfection of your well water and household plumbing may be needed. Use of GAC media infused with an antibacterial coating to help prevent bacterial growth may also be considered.

Depending on the types and concentrations of the contaminant being removed, GAC filter media may require special waste handling and disposal. Ask your water treatment company beforehand about disposal costs, disposal requirements and whether alternative treatment methods should be considered before making a decision to install a GAC treatment system.

Alternative options may include use of bottled water, installing a new well in another location that is not contaminated, or connecting to a public water system when available and feasible. Using bottled water for drinking and cooking may be an option, however, when contaminant levels are high, or, pose a risk during bathing and showering, whole house GAC treatment may be the best option. In many cases use of bottled water can serve as a viable temporary solution until a long term solution has been made.

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GAC Unit Installation and Water Testing Considerations

Always confirm with your water treatment installer that your GAC unit is installed according to manufacturer’s specifications. Retain a copy of your GAC unit manufacturer’s specifications for reference and follow any required maintenance protocols. Confirm with your water treatment installer that all State and Local requirements will be met during its installation.

After installation, test both the untreated water (raw water from the well) and treated water (water after GAC treatment) at a state certified laboratory. Compare the results of the treated and untreated water to determine if the GAC unit is properly removing contaminants. Test untreated and treated water annually or more frequently if high levels of contaminants are present in the untreated water. Frequent testing will help you determine how well your treatment system is working and whether maintenance or replacement of components may be necessary.

It is a good idea to install sample taps before (pre) and after (post) GAC filtration. Periodic testing both pre and post filter will help determine when the filter media needs to be changed and to ensure that breakthrough hasn’t occurred. Installing a water meter and recording water meter readings when new filter GAC media is added can also help determine about how many gallons the GAC filter treated before service was needed. You can then use this number to estimate approximately how many gallons the GAC filter can treat before it is no longer effective and how often you should test water quality after filtration to determine if breakthrough has occurred.

If you have two GAC filters installed in series, sample taps can be installed pre, mid and post GAC filtration. Periodic testing can be performed pre, mid and post filtration to determine when service is needed or if breakthrough has occurred. Once the mid -stream water quality sample indicates that the GAC filter media should be changed, the second GAC filter is often times swapped to the front position and a filter with new GAC media is moved to the second filter position.

Questions to Ask Before you Buy

Before purchasing a water treatment device, have your water tested at a state certified laboratory to determine the contaminants present and their concentrations. This will help you determine if GAC is an effective treatment method for the water quality parameters identified through the test results. See Publication #19: Questions to Ask When Purchasing Water Treatment Equipment, for more information.

For More Information:

Please contact the Connecticut DPH, Private Well Program at 860-509-8401.

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How does carbon filtering work ?

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

Each particle, or granule, of carbon provides a large surface area, or pore structure, allowing contaminants the maximum possible exposure to the active sites within the filter media. One gram of activated carbon has a surface area in excess of 3,000 m2 (32,000 sq ft).

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 for water purification, air filtering 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 and in the EVAP used in cars.

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

Typical particle sizes that can be removed by carbon filters range from 0.5 to 50 micrometres. The particle size will be used as part of the filter description. The efficacy of a carbon filter is also based upon the flow rate regulation. When the water is allowed to flow through the filter at a slower rate, the contaminants are exposed to the filter media for a longer amount of time.

Hydrogen production

For small-scale production of hydrogen, water purifiers are installed to prevent formation of minerals on the surface of the electrodes and to remove organics and chlorine from utility water. First the water passes through a 20 micrometer interference (mesh or screen filter) filter to remove sand and dust particles, second, a charcoal filter (activated carbon) to remove organics and chlorine, third stage, a de-ionizing filter to remove metallic ions.^{[citation needed]} A test can be done before and after the filter for proper functioning on barium, calcium, potassium, magnesium, sodium, and silicon.

What is activated carbon used for ?

Activated charcoal is a sponge-like substance that is made from different carbon-containing substances of natural origin. Activated Charcoal is charcoal that has been treated with oxygen. The treatment results in a highly porous charcoal. It is made at very high temperatures and as a result, activated charcoal is a substance which is almost one hundred percent composed of carbon.

The chemical composition of charcoal is very similar to graphite. Useful properties of activated charcoal can be contributed to the huge number of pores and hence activated charcoal exhibits very high absorbent and catalytic properties.

Activated carbon is used in methane and hydrogen storage, air purification, decaffeination, gold purification, metal extraction, water purification, medicine, sewage treatment, air filters in gas masks and respirators, filters in compressed air, teeth whitening, and many other applications.

Activated carbon industrial application

One major industrial application involves use of activated carbon in metal finishing for purification of electroplating solutions. For example, it is the main purification technique for removing organic impurities from bright nickel plating solutions. A variety of organic chemicals are added to plating solutions for improving their deposit qualities and for enhancing properties like brightness, smoothness, ductility, etc. Due to passage of direct current and electrolytic reactions of anodic oxidation and cathodic reduction, organic additives generate unwanted breakdown products in solution. Their excessive build up can adversely affect plating quality and physical properties of deposited metal. Activated carbon treatment removes such impurities and restores plating performance to the desired level.

Medical uses

Activated charcoal for medical use

Activated carbon is used to treat poisonings and overdoses following oral ingestion. Tablets or capsules of activated carbon are used in many countries as an over-the-counter drug to treat diarrhea, indigestion, and flatulence.

However, activated charcoal shows no effect of intestinal gas and diarrhea, and is, ordinarily, medically ineffective if poisoning resulted from ingestion of corrosive agents such as alkalis and strong acids, iron, boric acid, lithium, petroleum products, or alcohol. Activated carbon will not prevent these chemicals from being absorbed into the human body.

It is particularly ineffective against poisonings of strong acids or alkali, cyanide, iron, lithium, arsenic, methanol, ethanol or ethylene glycol.

Incorrect application (e.g. into the lungs) results in pulmonary aspiration, which can sometimes be fatal if immediate medical treatment is not initiated.

Activated Charcoal is a powerful tool for emergency cleansing of the gastrointestinal tract, perhaps the most effective remedy known today. It can be used in cases of poisoning from virtually any toxic substance. Activated charcoal reduces the absorption of poisonous substances up to 60%.

One teaspoon of activated charcoal has a surface area of approximately 10 000 square feet. It adsorbs and helps eliminate toxins, heavy metals, chemicals, pharmaceutical drugs, morphine, pesticides from your body.

Activated carbons can be also use to whiten tooth

Benefits of Activated Charcoal and Its Uses:

Poisoning by various chemical substances, drugs, toxic heavy metals, alkaloids
Overall body detoxification
Food poisoning
Treating stomach pain caused by excess gas, diarrhea, or indigestion.
Body odor and bad breath
Hepatitis: chronic and acute viral
Withdrawal syndrome (as a rule, is used for drinking, not for drug addiction)
Intoxication caused by chemotherapy or radiotherapy
Various skin ailments
Inflammation
Helps lower cholesterol, triglycerides and lipids found in the blood.

Analytical chemistry applications

Activated carbon, in 50% w/w combination with celite, is used as stationary phase in low-pressure chromatographic separation of carbohydrates (mono-, di-trisaccharides) using ethanol solutions (5–50%) as mobile phase in analytical or preparative protocols.

Environmental applications

Activated carbon is usually used in water filtration systems. In this illustration, the activated carbon is in the fourth level (counted from bottom).

Carbon adsorption has numerous applications in removing pollutants from air or water streams both in the field and in industrial processes such as:

Spill cleanup
Groundwater remediation
Drinking water filtration
Air purification
Volatile organic compounds capture from painting, dry cleaning, gasoline dispensing operations, and other processes.

During early implementation of the 1974 Safe Drinking Water Act in the US, EPA officials developed a rule that proposed requiring drinking water treatment systems to use granular activated carbon. Because of its high cost, the so-called GAC rule encountered strong opposition across the country from the water supply industry, including the largest water utilities in California. Hence, the agency set aside the rule. Activated carbon filtration is an effective water treatment method due to its multi-functional nature. There are specific types of activated carbon filtration methods and equipment that are indicated – depending upon the contaminants involved.

Activated carbon is also used for the measurement of radon concentration in air.

Agriculture uses

Activated carbon (charcoal) is an allowed substance used by organic farmers in both livestock production and wine making. In livestock production it is used as a pesticide, animal feed additive, processing aid, nonagricultural ingredient and disinfectant. In organic winemaking, activated carbon is allowed for use as a processing agent to adsorb brown color pigments from white grape concentrates.

Activated carbon has been used as a purification agent since ancient Egypt and India. It was introduced to the modern world via the sugar refineries of 1800s Europe, and its use quickly swept the globe. Rapidly evolving technology has led to its expansion ever since, and today activated carbon plays a key role in a vast number of industries, from wastewater treatment to pharmaceutical manufacturing. It is also used in agriculture to improve crop yields.

activated carbon adsorbs and removes targeted compounds along its vast surface area. Although it has been used in modern agriculture for only a decade or so, research shows that activated carbon can boost agriculture in several important ways.

Seed Protection

Fungicides and herbicides are absolutely essential to modern agriculture, preventing harmful species from taking over and destroying crops. Unfortunately, these products can also be damaging to newly planted seeds. When mixed with fertilizer or used to coat vulnerable seeds, activated carbon can ensure the survival of the vast majority of seeds. The surface chemistry of the activated carbon can even be manipulated to ensure the best pH for different types of seeds. In some cases, activated carbon can also be mixed into the soil to protect fields from accidental spills of fungicides or herbicides.

Time-Release Nutrient Delivery

Although most popular applications of activated carbon involve removing toxic or noxious compounds, activated carbon’s tremendous storage abilities also allow it to deliver helpful compounds on a timed basis. For agriculture, activated carbon can store nutrients that are essential to plant health and then release them over time. For example, activated carbon can be impregnated with ethylene, the naturally occurring hormone that causes plants to ripen. The ethylene can then be delivered to help all of the fruits in a crop ripen at the same time.

Herbicide Catalyst

Activated carbon is a powerful catalyst for oxidation, and can be used for this purpose in the production of herbicides. It is important to choose a powdered activated carbon (PAC) with strong characteristics of filtration and sedimentation. When specifically prepared for this purpose, PAC can help to create a highly effective herbicide.

Purification and Decolorization

Like any other chemical product, agrochemicals need to be pure and clean to create the desired results. Colorization also matters in consumer preferences, with homogeneously colored products being seen as more desirable. Activated carbon is used in the agrochemical industry to remove unwanted compounds and create the pure, decolorized products that consumers deserve.

Agriculture is a relative newcomer to the list of industries that have been revolutionized by the use of activated carbon. Yet research shows that it works across a wide range of agricultural applications. Activated carbon comes in many types and forms, each with its own unique characteristics. For the best results, it is important to consult with an activated carbon expert who can help you sort through the options and select just the right product to meet your needs.

Are you interested in purchasing activated carbon for a specific application? Do you require expert guidance in choosing the right impregnation for your needs? With more than 70 years of experience in the activated carbon industry, Oxbow Activated Carbon is proud to provide the most diverse line of activated carbon products on the market today. We provide both standard and custom impregnations, spent carbon disposal and reactivation, and numerous other specialized services. We pride ourselves on our individualized customer service, and we look forward to becoming your one-stop shop for all your activated carbon needs.

Distilled alcoholic beverage purification

Activated carbon filters (AC filters) can be used to filter vodka and whiskey of organic impurities which can affect color, taste, and odor. Passing an organically impure vodka through an activated carbon filter at the proper flow rate will result in vodka with an identical alcohol content and significantly increased organic purity, as judged by odor and taste.^{[citation needed]}

Fuel storage

Research is being done testing various activated carbons’ ability to store natural gas^[2]^[1] and hydrogen gas.^[1]^[2] The porous material acts like a sponge for different types of gases. The gas is attracted to the carbon material via Van der Waals forces. Some carbons have been able to achieve bonding energies of 5–10 kJ per mol. The gas may then be desorbed when subjected to higher temperatures and either combusted to do work or in the case of hydrogen gas extracted for use in a hydrogen fuel cell. Gas storage in activated carbons is an appealing gas storage method because the gas can be stored in a low pressure, low mass, low volume environment that would be much more feasible than bulky on-board pressure tanks in vehicles. The United States Department of Energy has specified certain goals to be achieved in the area of research and development of nano-porous carbon materials. All of the goals are yet to be satisfied but numerous institutions, including the ALL-CRAFT program,^[1]^[2]^[13]are continuing to conduct work in this promising field.

Gas purification

Filters with activated carbon are usually used in compressed air and gas purification to remove oil vapors, odor, and other hydrocarbons from the air. The most common designs use a 1-stage or 2 stage filtration principle in which activated carbon is embedded inside the filter media.

Activated carbon filters are used to retain radioactive gases within the air vacuumed from a nuclear boiling water reactor turbine condenser. The large charcoal beds adsorb these gases and retain them while they rapidly decay to non-radioactive solid species. The solids are trapped in the charcoal particles, while the filtered air passes through.

Chemical purification

Activated carbon is commonly used on the laboratory scale to purify solutions of organic molecules containing unwanted colored organic impurities.

Filtration over activated carbon is used in large scale fine chemical and pharmaceutical processes for the same purpose. The carbon is either mixed with the solution then filtered off or immobilized in a filter.

Mercury scrubbing

Activated carbon, often infused with sulfur^[14] or iodine, is widely used to trap mercury emissions from coal-fired power stations, medical incinerators, and from natural gas at the wellhead. This carbon is a special product costing more than US$4.00 per kg.

Since it is often not recycled, the mercury-laden activated carbon presents a disposal dilemma. If the activated carbon contains less than 260 ppm mercury, United States federal regulations allow it to be stabilized (for example, trapped in concrete) for landfilling. However, waste containing greater than 260 ppm is considered to be in the high-mercury subcategory and is banned from landfilling (Land-Ban Rule). This material is now accumulating in warehouses and in deep abandoned mines at an estimated rate of 100 tons per year.

The problem of disposal of mercury-laden activated carbon is not unique to the United States. In the Netherlands, this mercury is largely recovered and the activated carbon is disposed of by complete burning, forming carbon dioxide (CO2).

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

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.