Meeting MCLs

In January 2008, AdEdge Technologies , Inc. was selected by Nationwide MHP to supply a turnkey arsenic, iron and manganese treatment system for the Highland Hills MHP in Highland, Mich. The system consists of multiple wells that combine to serve potable water to 306 connections and a population of 765.

Several options were considered based on the need to remove the 1 mg/L iron and arsenic from 13 parts per billion (ppb) to below the new maximum contaminant level (MCL) of 10 ppb. An AdEdge AD26 oxidation/filtration system was selected as the best overall approach to simultaneously remove both contaminants while having a small footprint to fit into the existing building space.

Work was closely coordinated with Atwell-Hicks, the site’s engineer. All appropriate permitting documents were prepared and submitted to the Michigan Department of Environmental Quality for approval and the permit was granted in March 2008. The AdEdge scope of work included system design, supply, installation, piping and sewer tie-ins and electrical. The packaged system uses an NSF 61-certified manganese dioxide media (AD26) that is excellent for co-contaminant removal. The technology was selected based on overall cost, the small footprint and simplicity of operation. The raw water quality of the combined wells is shown to the right.

The arsenic treatment train consists of two skid-mounted triplex packaged treatment systems with six vessels in parallel to treat up to 450 gal per minute (gpm). A design filtration rate of 8.5 gpm/sq ft is nearly 3 times higher than conventional greensand filtration, offering high-efficiency removal with smaller vessels and lower cost. The automated system, equipped with a PLC, automated butterfly valves and control panel, is integrated with chlorine addition and monitoring for process control and disinfection purposes. The system is pre-engineered, pre-piped and skid mounted for ease of installation and operation.

A continuous free chlorine monitor on the system allows the operator to maintain desired disinfection residual in the distribution system. The technology has been deployed successfully on many wells with high arsenic, iron and manganese levels to date and also on three full-scale U.S. Environmental Protection Agency (EPA) arsenic demonstration projects.

The system was officially started up in July 2008. Since operations began, the system has consistently met all the EPA MCLs for arsenic, iron and manganese. Arsenic in the treated water has been recorded consistently below detection (less than 2 ppb).