Evaluation of aircraft deicing fluid as an external carbon source for denitrification

• Published in: The Science of the total environment 2024-05, Vol.925, p.171795-171795, Article 171795
• Main Authors: Sayin, Aykut, Soleimanifar, Maedeh, Rosenthal, Alex, Jezek, Roland, de Falco, Giacomo, Ramalingam, Krish, Fillos, John
• Format: Article
• Language: English
• Subjects: Circular economy; Deicing fluid; External carbon source; Nitrogen removal; Wastewater process modeling
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.171795

Water resource recovery facilities (WRRFs) performing biological nitrogen removal (BNR) often require external carbon sources for meeting nitrogen discharge permit limits. This brings an additional financial burden to the facilities considering the continuous need of these external carbon sources. This paper evaluates the utilization of airport stormwater, which in the winter season is rich in aircraft deicing fluid (ADF) as an alternative external carbon source. Denitrification and nitrification bench scale experiments were performed to assess the efficacy of external carbon sources to remove nitrogen in WRRFs. Experimental results showed that ADFs achieve denitrification rates of 0.064–0.066 d−1, higher than what achieved by a commercial carbon source, MicroC 2000A, with corresponding value of 0.058 d−1 at low temperatures, as low as 13 °C, which is considered a worst-case scenario for nitrogen removal efficiency. Furthermore, no inhibition to nitrification associated with the ADFs was observed. Subsequently a dynamic modeling study was conducted to assess the performance of ADFs as external carbon sources for denitrification and compared them to the conventional source that was being used in a full-scale BNR process. Results from the dynamic modeling study revealed that if 40 % of the spent-ADF at LaGuardia airport, New York City, could be collected with the stormwater and conveyed to a WRRF via the sewer collection system, an approximate reduction of 30 % of the commercial external carbon source could be accomplished by repurposing a waste product. This study contributes to the potential of ADF as a denitrification aid and an alternative for commercially available carbon sources with comparable nitrogen removal efficiencies. [Display omitted] •Spent-ADF can be used as an external carbon source for wastewater nitrogen removal.•SDNR of spent-ADF was slightly higher than glycerol based commercial carbon source.•Tested ADFs in bench scale BNR process did not pose any inhibition to nitrification.•Models predicted 30 % savings in commercial carbon usage by applying spent-ADF.•This study contributes to the circular economy with repurposing a waste product.