Technologies and Costs for Removal of Arsenic From Drinking Water

two technologies. Redundancy for the lower cost components would be covered by the conservativeassumptions used in deriving the capital costs.Recommended Standards for Water Works (Great Lakes Upper Mississippi River Board ofState Public Health and Environmental Managers, 1997), often referred to as the Ten State Standards,presents a comprehensive discussion of redundancy and recommended redundant items for watertreatment facilities in those States. Systems may incur additional costs if additional redundant itemsare required by the State.3.4 COSTS FOR MULTIPLE REMOVAL PERCENTAGESCapital and O&M cost estimates are presented for the maximum achievable removal in thisdocument. Table 3-12 presents a removal technology matrix which identifies maximum removalpercentages for the technologies for which costs have been estimated. Costs for facilities requiringless than the maximum removal to meet the arsenic MCL target, can be estimated using the blendingapproach discussed in Section 3.4.2.3.4.1 Removal and Accessory CostsBoth the April 1999 and the November 1999 drafts of the Technology and Cost Documentincluded costs for accessories in Appendix D. Accessory costs included raw and finished waterpumping, and clearwell storage. Removal costs include any process item directly associated with theremoval of a particular contaminant, e.g., the ion exchange bed in ion exchange processes. Inclusionof accessory costs was not based on a recommendation of the Technical Design Panel. A detailedexamination of Section 3.11 of the November 1999 Technology and Cost Document revealed theapparent source of the accessory costs. Section 3.11 compared the costs in the November 1999Technology and Cost Document with the costs from the 1993 Technology and Cost Document(Malcolm Pirnie, 1993a) and Evaluation of Central Treatment Options as Small System ComplianceTechnologies (SAIC, 1999). There is a statement in bold at the end of Section 3.11.1 that states thatthe 1993 estimates are greater than the 1999 estimates for many technologies. It further states that thisis because the 1993 estimates included accessory costs; i.e., raw and finished water pumping andclearwell storage.3-16