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Innovative Biological Water Treatment for the Removal of Elevated Ammonia
Citation:
Lytle, D. A., C. White, D. Williams, L. Koch, AND E. Nauman. Innovative Biological Water Treatment for the Removal of Elevated Ammonia. Journal AWWA. American Water Works Association, Denver, CO, 105(9):E524-E539, (2013).
Impact/Purpose:
The objective of this work was to demonstrate the effectiveness of an innovative and simple biological water treatment approach to remove more than 3 mg N/L ammonia and iron from the water through a pilot study conducted at a water utility in Iowa. The study also identified operating parameters necessary to meet the desired goal of complete ammonia and iron removal, and discuss the design of a full-scale system with the same goals. Study results will benefit a range of systems across the United States by providing guidance on the design and operation of biological treatment systems for ammonia removal.
Description:
The objective of this work was to demonstrate the effectiveness of an innovative and simple biological water treatment approach for removing 3.3 mg N/L ammonia and iron from water using a pilot study conducted at a utility in Iowa. Biological water treatment can be an effective approach to addressing low ammonia levels, however, providing adequate oxygen to address source water ammonia levels greater than 1.5 mg N/L is challenging. The treatment consisted of a biological “contactor” combined with aeration, followed in series with a dual granular media. Orthophosphate was necessary to satisfy biological nutrient requirements and maintaining near-saturated dissolved oxygen levels throughout the contactor was important. The pilot demonstrated that a contactor and filter operated at loading rates of 2.2 gpm/ft2 and 2.0 gpm/ft2, respectively, met desired finished water quality objectives. The contactor alone was able to completely biologically oxidize all of the ammonia to nitrate. Contactor maintenance was minimal.
