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1.3 Effects of Ammonia <br />Many groundwater sources throughout the United States have elevated levels of ammonia due to natural <br />processes, agricultural runoff or animal feeding operations. Although ammonia is not currently regulated by <br />the EPA, elevated levels of ammonia will pose operational and health concerns if nitrification takes place <br />in the distribution system. Nitrification is the conversion of ammonia to nitrite and nitrate, which can lead to <br />potential corrosion issues, taste and odor concerns, and ultimately, elevated nitrite and nitrate levels <br />throughout the distribution system. Nitrite and nitrate are regulated under the PDWS since they are known <br />to have significant effects on human health. <br />Ammonia is typically treated with the formation of monochloramine and breakpoint chlorination, which <br />results in the removal of ammonia by a chemical reaction with chlorine. Other conventional methods to treat <br />ammonia include advanced oxidation, air stripping, or reverse osmosis. Similar to treating manganese, <br />ammonia can be removed from water biologically. Biological ammonia removal relies on naturally occurring <br />microorganisms to convert ammonia to nitrite and nitrate. Biological ammonia removal at the treatment <br />plant eliminates the likelihood of nitrification taking place in the distribution system and potentially lowers <br />the chlorine dosages needed to maintain adequate free chlorine residuals in the treated water. <br />1.4 Goals and Objectives <br />The main objective of this pilot study is to evaluate whether ammonia, iron and manganese can be removed <br />biologically without the use of prechlorination and potassium or sodium permanganate. Another main <br />objective of this study is to obtain data that can be used to design, construct, and operate a gravity filtration <br />water treatment plant utilizing biological filtration in Lino Lakes. <br />The specific goals of this pilot study are described below: <br />1. Evaluate if biological filtration can meet the treatment goals set in this study; <br />2. Compare the biological filtration efficiency of various types of filter media; <br />3. Evaluate the duration of the biological acclimation process; <br />4. Evaluate the dissolved oxygen concentration needed to enhance biological filtration; <br />5. Establish a backwash procedure that effectively cleans the biological filters; <br />6. Evaluate the filter runtime of each filter media type; <br />7. Determine if nutrients are needed to enhance the performance of biological filtration; <br />8. Evaluate whether microorganisms remain effective in colder water temperatures; <br />9. Evaluate the performance of the biological filters following a backwash; and <br />10. Evaluate the performance of the biological filters following a period of shutdown. <br />Water Treatment Pilot Study Report <br />Biological Removal of Ammonia, Iron and Manganese at Well House No. 6 <br />City of Lino Lakes, MN <br />WSB Project No. 0 18601 -000 Page 3 <br />