Adsorptive Media to Remove Arsenic from Drinking Water
What is adsorptive media?
Adsorptive media is granular material through which water passes. Depending on the nature of the media, certain substances present in the water will “stick” to the surface of the media by adsorption and treated water will pass through.
There are many types of adsorptive media available that can remove a variety of substances from water. For arsenic removal, two common types of adsorptive media are activated alumina and iron oxide.
Are there differences between iron oxide and activated alumina?
Activated alumina and iron oxide media have different properties and can behave differently under varying conditions. You should consult with a professional to determine which will work best for your situation.
Where should the adsorptive media treatment unit be installed?
Adsorptive media treatment units can be installed either at the point-of-entry (POE) or at the point-of-use (POU). See the Arsenic in Drinking Water – General Information Fact Sheet for an explanation of POE and POU.
Is the adsorptive media treatment unit affected by raw water quality?
Raw water quality can affect the performance of adsorptive media treatment units. Therefore, it is important to ensure that your raw water quality will be compatible with the media that you choose otherwise additional treatment may be required.
How effective is the adsorptive media treatment unit in removing arsenic?
Adsorptive media units are capable of removing arsenic. Some systems may be capable of reducing arsenic by 95%. Removal efficiencies are dependent on your raw water quality and the type of media used. Consequently pre-treatment may also be required.
How practical or difficult is the adsorptive media treatment unit to operate and maintain?
Adsorptive media treatment units are simple to operate and to maintain. Periodically the cartridge may require backwashing to remove any accumulation of sediment. Upon exhaustion of the adsorptive media, it must be replaced. This replacement frequency will vary depending on the concentration of the arsenic in the water and the volume of water treated.
Like any piece of water treatment equipment, it is important to follow the manufacturer’s instructions for maintenance.
How much does an adsorptive media treatment unit cost?
A point-of-entry adsorptive media treatment system will cost between $1,500 to $3,000 depending on the size of system selected. An under the counter point-of-use adsorptive media treatment system will cost in the range of $300 to $400.
How much does it cost to operate and maintain the adsorptive media unit?
Ongoing operational costs associated with adsorptive media treatment units would be the replacement of the adsorptive media. This will be dependent on the unit’s manufacturer. This may cost in the range of $50 to $500 depending on the size of the system.
What happens to the substances that are taken from the water and how much wastewater is created by the adsorptive media treatment unit?
Substances removed from the water remain on the surface of the media. Once the media requires replacement, the exhausted media can be disposed of as non-hazardous waste.
Backwash water from point-of-use adsorptive media treatment units may be discharged to a septic system. However, the backwash water from larger point-of-entry adsorptive media treatment units should not be discharged to a septic system unless a professional engineer with expertise in on-site services has confirmed that it is acceptable to do so.
Does the adsorptive media treatment unit remove other contaminants from water supplies?
The adsorptive media unit can remove other substances in the water, depending on the type of media used. In some cases, other substances present in the water may reduce the removal efficiency for arsenic. As an example, excessive iron may foul or plug the adsorption media.
Are there any manufacturers that make a better unit?
Nova Scotia Environment and Labour does not recommend specific brands of treatment devices, however the department strongly recommends that consumers use devices that have a mark or label indicating that the device has been certified as meeting the appropriate NSF Standard.
Where can I get the adsorptive media treatment unit?
Units are available from water treatment companies in Nova Scotia. For more information check the Yellow Pages under the heading Water Treatment for a list of water treatment dealers.
How can I find out more information?
For more information contact the Nova Scotia Environment and Labour office nearest you at 1-877-9ENVIRO (1-877-936-8476).
