6    DETERMINATION OF INHIBITORY
CONCENTRATIONS OF THE SURFACTANT AFFF ON
BIOLOGICAL NITRIFICATION PROCESS AND
PASS-THROUGH TOXICITY
M. Erten-Unal, Assistant Professor
G. C. Schafran, Associate Professor
Sudhanva Paranjape, Edwin Garcia-Cardona, and Han Yan, Graduate Students
Old Dominion University Department of Civil and Environmental Engineering, KDH 135,
Norfolk, VA, 23529-0241
Fred Williams
Naval Research Laboratory
David Cotnoir and Ken Clark
NAVFAC LANTDIV
Douglas Kirk
NAS Oceana
ABSTRACT
This chapter will evaluate the impact of the surfactant AFFF to a biological nutrient removal
process and determine whether pass-through toxicity occurs in the effluent of a biological
process receiving AFFF wastewater. A bench-scale study has been conducted to investigate the
potential inhibitory effects of untreated AFFF wastewater to a BNR process.
INTRODUCTION
The U.S. Navy utilizes a surfactant in firefighting water that improves the ability to control petroleum-based fires. The surfactant, which is widely used by the Navy including facilities in the
Hampton Roads region, is currently manufactured by up to five companies and is commonly referred to as AFFF (aqueous film-forming foam) conforming to military specifications mil-F-
24385F. The AFFF chemical makeup is proprietary and likely varies among manufacturers. The
U.S. Navy is exploring a number of options that include disposal of the firefighting water to
wastewater collections systems where the components of AFFF wastewater would be transported
to a wastewater treatment facility and removed biologically.
Current disposal of firefighting water that includes AFFF wastewater has been limited by concerns for the environmental/toxic effects associated with AFFF. Disposal of the firefighting foam
to sanitary sewers has been considered as an option; however, concern for the potential toxic or
inhibitory effects associated with AFFF wastewater have generally led to a ban from introduction
of AFFF to wastewater collection systems.
Present concerns over inhibitory effects of AFFF wastewater have resulted in the prohibition of
its disposal to the Hampton Roads Sanitation District (HRSD) collection system where it would
eventually enter one of the biological wastewater treatment plants operated by the District. HRSD
is particularly concerned with how AFFF wastewater might interfere with biological nutrient removal (BNR) processes at its Virginia Initiative Plant (VIP). The VIP plant incorporates biological nitrogen, phosphorous, and organic matter (BOD/COD) removal through a sequential series of
anaerobic, anoxic, and oxic reactors. Nitrogen removal occurs through microbially-mediated nitrification and denitrification and phosphorous removal occurs through enhanced uptake by poly P
bacteria. It is well known that the nitrification and denitrification processes can be inhibited in the
52nd Purdue Industrial Waste Conference Proceedings, 1997, Ann Arbor Press, Chelsea. Michigan 48118. Printed in
U.S.A.
47