Arsenic Removal
Inorganic arsenic (arseniite and arsenate) can be removed by MetalEase-ALF. The process is very pH sensitive and capacity decreases rapidly when the pH is below 5.5 or above 6.0. Arsenite is not removed nearly as well as arsenate; therefore, prechlorination to convert arsenite to arsenate may be required. Arsenic removal is also affected by temperature and by the TDS of the feedwater. Increasing temperature increases capacity while increasing TDS decreases capacity.

Equilibrium capacity for arsenate (1,000 ppm TDS, 25ºC, 1 mg/L As) is approximately 0.66 lbs/cu.ft. Operating capacity to a 10% leakage end point is approximately 10% of the equilibrium capacity. Regeneration can be accomplished by using 3 to 4 lbs/cu.ft. of 2 to 4% sodium hydroxide, over 20 to 30 minutes, followed by nuetralization with acid to a pH of 5 to 6.

Lead Removal
Dissolved lead is adsorbed by MetalEase-ALF and is not normally regenerable. Capacity for lead is at least 0.4 lbs/cu.ft. while maintaining greater than 98% lead removal. This process is not dramatically affected by flow rate, temperature, or TDS. However, pH should be maintained above 6.0 as lead removal drops under acidic conditions, and below 10 as lead precipitates under basic conditions.

Fluoride Removal
Fluoride is removed by MetalEase-ALF by a chemical reaction with the media. The process is flow and pH sensitive. The best results are obtained when the flow is limited to about 1 gpm/cu.ft. and the pH is held at 5.5. Higher flows and higher or lower pH causes a significant loss of capacity. The best capacity obtainable is approximately 0.2 lbs/cu.ft. Leakage of fluoride is generally less than 0.1 mg/L to breakthrough.

Regeneration can be accomplished using 3 to 4 lbs/cu.ft. of 2 to 4% sodium hydroxide over 20 to 30 minutes, followed by neutralization with acid to a pH of 5 to 6.