Arsenic in water occurs naturally and is a tasteless, odorless and colorless contaminant. Other activities that could have left residuals include apple orchard spraying, coal ash disposal, and use of some pressure treated wood. While there are serious health threats associated with ingestion, there are effective methods for removal. For detail on potential health affects, see the link at: http://www.who.int/mediacentre.
FORMS OF ARSENIC IN WATER
The primary forms of Arsenic in water are AS III and AS V. Many arsenic removal media have a low capacity for removing AS III from the water, therefore converting it to AS V (which is easier to remove) is a common approach. Determining the ratio of AS III versus AS V in water is critical as this will allow the design and implementation of a water treatment system that will effectively remove it. There are methods to oxidize the AS III and convert it to AS V for ease of removal.
WATER TEST & ANALYSIS
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 the arsenic in water. pH can significantly affect media performance along with other competing ions such as Iron, Manganese, Hardness, Vanadium, Sulfate, Phosphate, Silica, Total Dissolved Solids, Suspended Solids and Hydrogen Sulfide.
WATER USAGE MONITORING
Determining water usage is also critical to designing an effective arsenic in water 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 WATER USE AFTER SYSTEM INSTALLATION IS 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 TANK DESIGNED FOR ADDED SAFETY
Because Arsenic in 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.