Enhanced simultaneous nitri-denitrification in aerobic moving bed biofilm reactor containing polyurethane foam-based carrier media.

Abstract

Fluidization of carrier media for biofilm support and growth defines the moving bed biofilm reactor (MBBR) process. Major MBBR facilities apply virgin polyethylene (PE)-based circular plastic carrier media. Various carriers were studied to replace these conventional carriers, but polyurethane (PU) foam-based carrier media has not been much explored. This study evaluates the potential of PU foam carrier media in aerobic MBBR process for simultaneous nitri-denitrification (SND). Two parallel reactors loaded with conventional PE plastic (circular) and PU foam (cubical) carriers compared for their removal efficiencies of chemical oxygen demand (COD) and nitrogen contaminants from wastewater. Results indicate that average COD removal in MBBR containing PE plastic carrier media was 81%, compared to 83% in MBBR containing PU foam. Average ammonical and total nitrogen reduction was 71% and 59% for PU foam-based MBBR, compared to 60% and 42% for PE plastic-based MBBR. SND-based nitrogen removal capacity was doubled in aerobic MBBR filled with PU foam carrier media (27%), than MBBR containing PE plastic carrier media (13%). Cost economics also governs the commercial advantage for the application of PU foam-based carrier media in the MBBR process.