Technologies and Costs for Removal of Arsenic From Drinking Water

Manufacturer and laboratory data suggest greater than 95 percent removal of arsenate by ROsystems, and slightly less (75 percent) removal of arsenite. Field studies indicate that greater than 50percent removal is possible, but data are inconclusive much beyond those levels.5.4.1 Cost EstimatesThe EPA document, Cost Evaluation of Small System Compliance Options - Point-of Useand Point-of-Entry Treatment Units (Cadmus Group, 1998), was used to estimate POE and POU ROtreatment costs. Costs are presented in Figures 5-1 and 5-2 for total capital costs and annual O&Mcosts for POU RO treatment, respectively. The cost curves are based on the following assumptions:# Average household - 3 individuals, 1 gallon each per day, 1,095 gallons per year.# Annual treatment - 1,095 gallons (POU), 109,500 gallons (POE).# Minimally skilled labor - $14.50 per hour (population less than 3,300 individuals).# Skilled labor - $28.00 per hour (population greater than 3,300 individuals).# Life of unit - 5 years (POU), 10 years (POE).# Duration of cost study - 10 years (therefore, two POU devices per household).# Cost of water meter and automatic shut-off valve included.# No shipping and handling costs required.# Volume discount schedule - retail for single unit, 10 percent discount for 10 or moreunits, 15 percent discount on more than 100 units.# Installation time - 1 hour unskilled labor (POU), 3 hours, skilled labor (POE).# O&M costs include maintenance, replacement of pre-filters and membrane cartridges,laboratory sampling and analysis, and administrative costs.POE RO is not considered a compliance technology because it could create corrosion controlproblems. Furthermore, water recovery would not be any higher than observed for central ROtreatment, so concerns regarding water quantity that arise with central treatment would also apply toPOE treatment. Therefore, POE RO treatment option is not considered in the final rule.5-7