Application of Biological Aerated Filters to Meet NPDES Ammonia Limits for Small Communities

Principal Investigator:

Say-Kee Ong, skong@iastate.edu (other projects)

Other Authors: Jeonghyub Ha

Project Status: In Progress

Start Date: 07/16/2001
End Date: 07/15/2003


Research Objective: In the state of Iowa, there are over 100 aerated lagoons that do not meet NPDES discharge limits for ammonia over the winter months. Similar problems are experienced by other states such as Minnesota, Nebraska and Wisconsin with their aerated lagoon facilities. Various state agencies are studying alternative treatment technologies and, eventually, may require these facilities to comply with their discharge limits.

The objectives of this project are to investigate the application of biological aerated filters (BAFs) for nitrification at low temperatures and to provide a preliminary assessment of its feasibility for small communities to meet their NPDES limits. In addition, the objective to this study is to develop a single stage reactor containing both an anoxic and oxic zone for nutrient removal. BAFs is a compact system and can be used as an add-on to existing facilities or used as a secondary treatment at small community’s wastewater treatment facilities. BAF is a popular treatment system in Europe but rarely used in the US.

Research Plan: The proposed research will study the impact of low temperature, recirculation ratios, organic and hydraulic loading rates on nitrification. In addition, the study will evaluate different easily available media (sand, lava rock and plastic rings) for BAFs. Experimental results showed that BAF has the potential in reducing ammonia concentrations to acceptable levels and assist small community treatment facilities meet their NPDES limits for ammonia.

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