Glyphosate, the active ingredient in Roundup weed killer, has been found in water supplies all over the world, and many people are looking for ways to remove it from their water. If your water is contaminated with glyphosate, you may be wondering if activated carbon filters can remove it.
Activated carbon is very effective at removing the herbicide glyphosate from drinking water. The US EPA considers it a benchmark technology for evaluating other treatment methods. It is possible to reduce the concentration of glyphosate to drinking water limits with a well-designed carbon filter system.
In this blog post, we will review activated carbon, how well it works to remove glyphosate, and what your carbon filter system needs to protect you and your family from this herbicide.
What is Glyphosate
Glyphosate is a broad-spectrum herbicide used to control weeds in both agricultural and nonagricultural settings. It is sold under the trade names Roundup and Rodeo. This herbicide is applied to the leaves of plants to kill both grasses and broadleaf plants.
Glyphosate is also used to control aquatic plants. Products containing glyphosate are sold in various formulations, including as liquid concentrate, solid, and ready-to-use liquid. It can be used in agricultural, residential, and commercial settings using a wide range of application methods.
The substance was first registered for use in the United States in 1974, and it has since become one of the most widely used herbicides in the country.
Products that contain glyphosate
There are more than 750 glyphosate-containing products on the market in the United States. The following herbicides contain glyphosate:
- Roundup – made by Monsanto
- Rodeo Aquatic Herbicide – made by DowDuPont
- Eraser – made by Martin’s
- GroundClear – made by Ortho
- RM43 Total Vegetation Control – made by Ragan & Massey
- Ranger Pro Herbicide – made by Monsanto
How does glyphosate get in my water
Glyphosate, the popular weed killer ingredient found in many brands of Roundup products can get into our drinking water through runoff from farms and fields where it’s being used as an herbicide.
This powerful chemical seeps into soils where glyphosates tend to bind with soil particles. Adsorption to soil inhibits its mobility, but this contaminant still finds its way to our water supply through soil erosion or careless application of the chemical.
Glyphosate is a very soluble chemical that remains in the environment for long periods of time. It has been found to persist more than three hundred days if it is not exposed to sunlight.
Because glyphosate lasts so long in the environment, it is more likely to be ingested by people and animals. When a city or individual property draws water from those sources for its drinking water supply, consumers can be exposed to this herbicide.
Health concerns with Glyphosate
Glyphosate, the active ingredient in Roundup, has been the focus of much research. The EPA has stated that glyphosate does not present any risks to human health from current uses. They also noted that glyphosate is not an endocrine disruptor.
The EPA found no indication children are more sensitive than adults when exposed at similar levels. Finally, EPA found no indication that glyphosate causes human cancer.
The World Health Organization’s International Agency for Research on Cancer convened a panel of experts in 2015 to review available medical research on glyphosate. They concluded that glyphosate is “probably carcinogenic”. The state of California has declared that glyphosate causes cancer.
Drinking water standard for Glyphosate
The United States regulates the levels of glyphosate in drinking water under the Safe Drinking Water Act. The EPA established an MCL of 700 parts per billion (ppb) for glyphosate.
Beyond the federal drinking water standard, several states established stricter standards. Minnesota established a standard of 500 ppb for glyphosate. Wisconsin set their limit for drinking water at 10 milligrams per liter (mg/L), which is equal to 10,000 ppb.
Activated carbon adsorption is an effective and reliable water treatment process. It is considered a best available control technology by the USEPA and is a benchmark for other water treatment methods.
Carbon filters are widely used in residential and commercial water treatment systems to remove a variety of contaminants including taste and odor, chlorination byproducts, VOCs, and THMs.
Read my comprehensive Carbon Design Guide for a detailed explanation of this treatment technology.
How carbon adsorption works
Adsorption is a physical process where contaminants are removed from water by binding to the surface of the carbon media. Adsorption is different than absorption. Adsorption, which is how carbon filters work, is a physical attraction that attracts a contaminant to the surface of the carbon.
Absorption is a bulk process where the substance is taken into (absorbed) the media like a sponge. Adsorption onto activated carbon works because most organic molecules have a natural affinity for carbon. This means they will stick to the surface of the carbon. To increase the surface area available for adsorption, thousands of tiny pores are created by “activating” the carbon.
Carbon filter components
Carbon filters for residential applications are very simple. They include either a vessel filled with activated carbon (for whole-house systems) or a cartridge that contains carbon (point-of-use filters).
Granular activated carbon, also known as GAC, is the most commonly used type of carbon. GAC looks like the gravel in an aquarium. Some carbon filters include a particle pre-filter to remove sediment and suspended particles. This protects the carbon from fouling and extends the life of the media.
Many carbon filters, especially whole-house systems, include a bypass valve to allow the flow of water when the vessel is being serviced. Pressure gauges are often installed on the inlet and discharge side of the filter to allow you to monitor the amount of fouling that has occ
Types of granular activated carbon
Carbon is formed by converting organic materials like wood and coal into charcoal. The charcoal is then activating by exposing it to high temperature steam.
1 – Coal-based carbon
Most of the activated carbon used in water treatment is made from coal. The two main types use in carbon are bituminous coals and lignite coal. Coal-based carbon is very hard with pore sizes that make it ideal for removing many of the contaminants found in drinking water.
2 – Coconut shell carbon
Coconut shall carbon is highly prized for its ability to purify air and to remove difficult contaminants like PFAS and lead. This carbon is made from coconut husks. Coconut shell carbon is more expensive than coal-based carbon, but it lasts longer and is more effective at removing certain types of contaminants.
3 – Catalytic carbon
Catalytic carbon is activated carbon that has been modified through the addition of iron-hydroxide or through an enhanced activation process. It has several advantages over conventional carbon including a higher affinity for chlorine and chloramines.
How Well Does Carbon Filtration Remove Glyphosate
Activated carbon is an effective treatment method to remove glyphosate from drinking water. The US EPA considers carbon adsorption a best available control method for treating glyphosate-contaminated water.
The removal of glyphosate by activated carbon is affected by many factors including:
- the type of carbon
- contact time
- glyphosate concentration
- water temperature
Glyphosate has a strong affinity for carbon, which means it will bind to the surface of the media. The adsorption process is rapid and can achieve very high removal rates.
How much glyphosate can carbon remove
Activated carbon performs very well with glyphosate. A recent study determined the maximum removal capacity with coconut shell activated carbon is 98.45%.
Activated bio-carbon produced from rice husk and wood biochar have both been shown to be highly effective at removing pollutants, with removal efficiency rates of 82% and 100%, respectively.
In general, the adsorption capacity of glyphosate reduces significantly as the pH increases. The ideal pH range is between 4.0 and 5.0 SU.
Carbon filter requirements for good PFAS removal
Carbon filtration is very effective at removing glyphosate. Removal rates approaching 100% can be achieved with a properly designed system.
It is also important for the carbon filter to be well maintained. A carbon treatment system must have the following design components to effectively remove glyphosate to drinking water standards:
- Adequate amount of carbon: A whole-house carbon filter needs a minimum of 100 pounds of activated carbon. If your system has less carbon, glyphosate can breakthrough and expose you to this dangerous herbicide.
- Two carbon vessels plumbed in series: To ensure you get 100% removal, you need two carbon filters plumbed in series. The first filter does the heavy lifting and removes most of the glyphosate. The second carbon unit is for polishing and removes any glyphosate that isn’t removed by the first filter.
- Pre-treatment filter to remove suspended solids: Fouling of the carbon bed can cause channeling, which results in blockage of pores inside the carbon. A sediment filter of high quality is a necessity to remove any and all solids as well as turbidity.
- Post-treatment filter to remove carbon fines: A particle filter is needed to remove carbon fines that might contain adsorbed glyphosate.
- Flow meter: A flow meter is required to track the amount of water treated. Carbon has a finite ability to remove glyphosate, and the volume of water treated is a good estimate of the remaining treatment capacity.
- Sample ports: To verify that the carbon is effectively treating glyphosate, you should sample your drinking water once a month. Collect a sample between the two carbon filters to know when breakthrough occurs so you can change the carbon.
Factors to Consider with Carbon Filters
If you are considering a carbon filter for your home, there are some factors you should keep in mind before making a decision.
A carbon filter can be installed as a point-of-use (POU) unit or as a whole-house system. Whole-house systems are also known as point-of-entry (POE) systems.
POU systems are less expensive to install, but they only treat water at the sink where they are installed. Whole-house systems are more expensive to install, but they will treat all of the water in your home. Typical installation costs for POE carbon filtration are between $1,300 to $5,000.
The biggest cost is the labor to install the filter. If you’re handy, you can install the system yourself. An under-sink carbon filter can be installed for less than $100. However, a filter this small would not remove all of the radon from your water.
Carbon filters require maintenance to keep them operating properly. The primary maintenance is replacement of spent carbon – spent carbon is media that has no remaining adsorption capacity.
Small, under-sink filters need to be replaced every few months. Large whole-house filters can last for 6 months to as long as 2 years before they need to be replaced. Often, the carbon will become fouled with sediment or biological growth which would require replacing it more frequently.
For a whole-house carbon unit, you have to remove the carbon from the filter vessel. This is difficult to do and, most people hire a specialty company to do this.
How often do I need to change the carbon
You need to replace the carbon when it becomes spent. This is the point where the media can no longer remove the contaminant from your water. For a typical residential system, a carbon filter has a service life of 6 months to 1 year. If your carbon becomes fouled with solids or biological growth, you may have to replace it sooner than this.
How much do replacement filters cost
POU carbon filters have a carbon cartridge that is replaced when the media is spent. The cost of an under-sink carbon cartridge is $30 to $350, depending on the size of the unit.
Whole house carbon filters require removing the spent carbon and adding fresh media to the vessel. The cost for this service is $1.40 top $4.50 per pound. A typical whole-house carbon system contains between 100 and 400 pounds of carbon – the cost for this service varies from $140 to more than $2,000.
Whole-house versus under-sink
You have two options when it comes to carbon filtration – whole-house and under-sink. Whole-house systems treat all of the water entering your home. They are more expensive to install, but they provide clean, safe water to every faucet and shower in your house.
Under-sink systems are less expensive to install, but they only treat the water at the sink where they are installed.
If you are planning to install a carbon filter for your home, you should look for NSF certification. The NSF certification mark means that the water filter has been tested for safety and to verify the manufacturer’s claims. Here are the NSF certifications that apply to caron filters:
- NSF/ANSI 42: Certified to reduce aesthetic impurities such as chlorine and taste/odor.
- NSF/ANSI 53: Certified to reduce a contaminant with a health effect. Health effects are set in this standard as regulated by the U.S. Environmental Protection Agency (EPA) and Health Canada.
- NSF/ANSI 401: Certified for emerging contaminants.
Test Your Drinking Water for Glyphosate (Roundup)
Other Treatment Methods that Remove Glyphosate
The EPA has been studying a variety of technologies to determine which
Reverse osmosis to remove glyphosate
Reverse osmosis, also known as RO, is a water purification technology that removes glyphosate drinking water very well. RO uses a semipermeable membrane to remove ions, molecules, and larger particles from drinking water.
In reverse osmosis, an external pressure is used to overcome the natural osmotic pressure. In this process, water is forced through a semi-permeable membrane and contaminants such as glyphosate are retained.
Clean water is collected on the other side of the membrane. The concentrated waste solution, known as brine, is disposed of down your drain.
Reverse osmosis systems come in a variety of sizes. Home RO units are typically small, under-sink systems. Larger commercial whole-house units can purify all of the water that you use. Reverse osmosis is an effective way to remove glyphosate from drinking water. Read my article on treating glyphosate with reverse osmosis.
Distillation for glyphosate removal
Distillation is very effective for removing glyphosate from drinking water. It works by boiling the water to evaporate it. The steam is collected and condensed.
Contaminants like glyphosate that have higher boiling points than water are left behind in the chamber. The remaining material is washed away when you clean the unit. Distillation is a reliable and effective way to remove glyphosate from water.
Nanofiltration to remove glyphosate
Nano filtration is a water purification technology that uses a membrane with very small pores to remove contaminants from water. Nano filtration systems can be used for both drinking water and wastewater treatment.
Nano filtration membranes have pores that are 0.001 microns in size. This is 60,000 times smaller than a human hair. The small pores allow water to pass through, but they trap contaminants such as glyphosate. Nano filtration is an effective way to remove glyphosate from water.
Does reverse osmosis remove glyphosate?
Reverse osmosis is very effective at removing glyphosate from drinking water.
Does boiling water remove glyphosate?
Boiling does not remove glyphosate or other herbicides from drinking water. In reality, boiling will actually enhance the concentration of these poisons, making them more hazardous.
Does a water softener remove glyphosate?
Water softeners do not remove glyphosate from water. This technology uses ion exchange resin, which is meant to treat hardness. Glyphosate is not removed by water softeners.
Do refrigerator filters remove PFAS?
Refrigerator filters use activated carbon to remove chlorine and taste from your water. This carbon can remove a small amount of glyphosate from water. However, they do not remove all of this herbicide and should not be relied on for treating your drinking water.
Do Brita filters remove glyphosate?
Brita filters are not specifically designed to remove glyphosate, but they do have the ability reduce your exposure by removing some of this herbicide from water. However, they are not designed to purify water and should not be used to treat the water you drink. Read my article on Britia filters and glyphosate.
Each of the water purification technologies mentioned above are effective at removing glyphosate from drinking water. If you are concerned about your exposure to this herbicide, it is best to use a combination of these technologies to ensure that all of it is removed.