FORMS OF ARSENIC IN WATER & REMOVAL CONSIDERATIONS
Holden, MA homeowners are often surprised when they get their laboratory water test results back and see they have arsenic in their water. Activities that could have left arsenic residuals include apple orchard spraying, coal ash disposal, and use of some pressure treated wood. However, arsenic in water also occurs naturally and is a colorless, tasteless, and odorless contaminant. While there are associated serious health threats with ingestion, there are effective removal methods for arsenic in well water. For detail on potential health affects, see the link at: who.int/mediacentre/factsheets.
Arsenic III and Arsenic V are the two primary forms of arsenic in water. Many Arsenic removal media have a low capacity for removing Arsenic III from the water, therefore, converting it to Arsenic V for removal is a common approach. Determining the ratio of Arsenic III versus Arsenic V in the water is, therefore, critical. This will allow the design and implementation of a water filtration system that will effectively remove it from the water. There are methods to oxidize the Arsenic III and convert it to Arsenic V for ease of removal.
Approximately 20 percent of private wells in Massachusetts produce water that exhibit unhealthy levels of naturally occurring arsenic in water. Even more wells have elevated concentrations of radon in water for which treatment is recommended. Wells that have not been properly maintained may produce water contaminated with bacteria and other contaminants. Testing well water and inspecting your well is the best way to make sure that your water is clean and safe to drink.
WATER TESTING & ANALYSIS AND OTHER FACTORS
Having a complete laboratory water test and analysis, including parameters that can negatively impact arsenic removal media, is critical to a well designed, safe water treatment system that will remove arsenic in well water. pH can significantly affect Arsenic media performance along with other competing ions such as Iron, Manganese, Hardness, Vanadium, Sulfate, Phosphate, Silica, Total Dissolved Solids, Suspended Solids and Hydrogen Sulfide. For a full article on this topic which we’ve had published in Water Technology Magazine, go to our publications section and click on the Arsenic removal article at http://publications/.
WATER USAGE MONITORING
Determining water usage is also critical to designing an effective removal system that will have the proper capacity. Key information would include well pump size, well pump flow rate, size of the incoming water line, number of residents in the home, the number of bathrooms, space availability for equipment installation, electrical availability and water discharge location or restrictions, among others.
TRACKING YOUR WATER USAGE POST INSTALLATION – IMPORTANT!
A couple of key components for consideration when designing this type of system include:
- Utilizing a meter to track flow rate and total gallons processed is critical to determine the home’s water demand.
- Gallons used readings also assist in uncovering any potential leaks in the home such as running toilets, which will unnecessarily prematurely deplete the arsenic media’s capacity.
LEAD/LAG ARSENIC FILTRATION TANKS SET-UP
Because Arsenic in well water is a tasteless, colorless and odorless contaminant, it is particularly important to have two tanks in series in case the first tank is depleted prior to scheduled service with your water treatment company. Service should be scheduled at intervals determined by the water use tracking data accumulated. This combined with appropriate water testing intervals are added safeguards to prevent Arsenic from getting into the treated water entering the home.