Historically, EPA has not revised the hazardous waste toxicity characteristic regulation to reflect other MCL changes. Tested spent activated alumina has not been hazardous waste due to arsenic. In addition, EPA develops unit cost estimates to develop national cost estimates. Stakeholder comments have been incorporated into EPA's analyses, such as operating activated alumina at suboptimal pH for small systems. EPA is to specify compliance technologies for small systems to achieve compliance with the regulatory standard.
Exemptions give the system extra time to come into compliance.
Therefore, more process-control monitoring may be required for a variance technology than for a compliance technology. Working Group developed options that States can use for system-level affordability criteria. Technologies that meet the national-level criteria may not be affordable for a specific system within the size category. National Occurrence Estimate. In order to estimate compliance costs and benefits, EPA needs an estimate of the national distribution of mean arsenic concentrations in water systems, the range of arsenic within systems with multiple sources, and the number of systems with at least one source above the proposed standard.