 This video is brought to you by the Environmental Protection Agency. The use of any trade names or commercial products does not constitute an endorsement on the part of the Environmental Protection Agency. The arsenic rule has identified activated alumina, an adsorptive media process, as a best available technology for arsenic removal, in addition to a number of other treatment processes. In recent years, adsorptive media processes using ferric-based media, such as granular ferric hydroxide, have been demonstrated to provide arsenic removal. This video will present information on two types of treatment systems. Iron-based adsorptive media and iron-enhanced activated alumina media. Iron-based adsorptive media is being used at one of EPA's arsenic treatment technology demonstration sites. Even though iron-based adsorptive media was not listed as a best available technology in the arsenic rule, recent research and performance of these systems have proven excellent arsenic removal. The trade name of the media at this demonstration site is Bayoxide AD33, and the treatment plant was placed online in June of 2004. The source water is this well that produces 44 gallons per minute and operates 12 hours per day. The arsenic-influent concentration is approximately 50 micrograms per liter, and the pH is around 7. The treatment system consists of, one, chlorination to oxidize all arsenic to arsenic 5 to achieve optimal removal of arsenic. Two, a 50 micron bag filter to remove sediment. And three, these two vessels with Bayoxide AD33 media that can be operated in either series or parallel. When operating in series, water flows through the first vessel, and the treated water from the first vessel goes on to the second vessel. The advantage of operating in series is that the second vessel can act as a finishing column or guard column in the event the first vessel is no longer providing adequate treatment. When operated in parallel, influent water is typically split equally between the two vessels. This particular treatment system has been able to consistently reduce arsenic levels to non-detectable levels in the treated water. The media has not required replacement since installation in June of 2004. The media needs to be backwashed periodically to remove particles trapped in the media. The backwash water is discharged to this holding tank to allow settling of solids. After sufficient settling has occurred, the supernatant is recycled back through the entire treatment process. This method of residuals handling is cost effective and has worked well with this media. One important point about this system is that a pressure loss occurs as water passes through these treatment vessels. As a result, the existing well pump and treatment system can only provide 32 gallons per minute of treated water, which is less than the 44 gallons per minute production rate prior to treatment installation. Another EPA arsenic treatment technology demonstration site is using iron-enhanced activated alumina. Activated alumina is a best available technology listed in the arsenic rule. The source water is this well that produces 36 gallons per minute and operates 24 hours per day. The arsenic-influent concentration is approximately 30 micrograms per liter and the pH is around 7.7. The treatment system consists of 1. pH adjustment using sulfuric acid. 2. chlorination. And 3. these two vessels with iron-enhanced activated alumina media that are operated in series. pH adjustment is practiced to enhance arsenic removal by this particular media. Initially, the pH was adjusted from the natural source water pH of 7.7 to 7.2. However, further pH reduction was conducted to obtain a pH of 6.9 to achieve better arsenic removal. Chlorination is practiced to oxidize all arsenic to arsenic 5 to achieve optimal removal of arsenic, although the source water arsenic is predominantly in the oxidized state of arsenic 5. This treatment system has been able to consistently reduce arsenic levels to non-detectable levels in the treated water. The media has been replaced once since installation in June of 2004. The media needs to be backwashed periodically and the backwash water is discharged to this holding tank to allow settling of solids. After sufficient settling has occurred, the supernatant is recycled back through a cartridge filter and then back into the treatment vessels. For more information on these and other EPA arsenic treatment technology demonstration sites, you can visit EPA's website at the address shown on the screen.