Treating Iron & Manganese

Background
In June 2009, the Stewart County Water Co. selected and began working with AdEdge Technologies to assist with the design and implementation of an iron and manganese treatment system to serve the water supply for Stewart County in Louvale, Ga. The site has one existing groundwater supply well that provides drinking water for approximately 225 connections with high levels of manganese and iron that exceed the secondary drinking water standard maximum contaminant levels (MCLs) and resulted in poor water quality being served to the community. The well produces approximately 45,000 gal per day during a typical eight hours of well pump operation. The treatment system was designed for 100 gal per minute (gpm) with an approximate iron concentration of 1.16 mg/L and manganese levels of up to 0.05 mg/L. AdEdge assisted Stewart County Water Department with the necessary drawings, submittals and technical documents for obtaining the necessary permits to install and operate the new treatment system.

Treatment System
AdEdge recommended an AD26 oxidation/filtration treatment system to reduce these parameters to below MCLs. The proposed integrated AdEdge AD26 iron and manganese treatment system for Stewart County included a pH adjustment module, (existing) pre-chlorination module and backwash recycle module with integrated controls. The system consisted of a skid-mounted model AD26-3660CS-S-2-AVH in parallel configuration, with a programmable logic controller module that regulates the automated control valves. System features also include differential pressure switch, central control panel and local gauges, flow sensors and totalizers, including sample ports for a complete functioning package. Each vessel contains the catalytically active AD26 manganese dioxide media. In addition to the treatment system, the integrated water treatment system includes a soda ash feed injected prior to the filtration system to raise the raw water pH, which is less than 5.5 to approximately 7.5 for enhancing contaminant removal. The treatment system also features a zero-discharge backwash recycle module consisting of a backwash recycle pump skid and control panel, bag filter and a vertical polyethylene storage tank that allows nearly 99% reuse of the backwash water, eliminating the need for discharge permits.

System Performance
The system was successfully started up and commenced operation in December 2009. The system throughput is based on a utilization of approximately seven to eight hours per day, with approximately 100 gpm (7 gpm/sq ft) being consistently treated for high manganese and iron levels that exceed the MCLs. To date, the system’s performance is excellent and consistently achieving MCLs (greater than 9% removal) for these contaminants with no downtime. Independent testing provided by Professional Water Services, Albany, Ga., indicates nondetect levels of iron and manganese in the effluent of the treatment system.

Company Information