| Combining nonthermal N2 plasma with a denitrifying biofilm reactor for PFAS-contaminated wastewater remediation |
| Author |
Chen, CT; Yang, XT; Wang, QT; Tian, Y; Demeestere, K; Nikiforov, A; Hulle, SWHV |
| Journal |
CHEMICAL ENGINEERING JOURNAL |
| Pub Year |
2024 |
| Type |
|
| Abstract |
Perfluoroalkyl and polyfluoroalkyl substances (PFAS), commonly known as 'forever chemicals', pose significant environmental threats to water bodies due to their persistence and toxicity. Traditional remediation methods are often ineffective or costly. In response, this study presents a novel two-step solution combining nonthermal nitrogen (N2) plasma degradation with a denitrifying biofilm reactor to treat PFAS-contaminated wastewater efficiently. Treatment by N2 plasma resulted into PFOA and PFDA degradation efficiencies up to 45% and 60%, respectively. The low cost of N2 gas makes N2 plasma more favorable (compared to e.g. Ar plasma) for practical applications. The biofilm reactor, inoculated with activated sludge and packed by expanded clay aggregates (ECA), could efficiently remove the inorganic nitrogen produced by N2 plasma. CH3COONa was utilized as a carbon source to supply energy for denitrifying bacteria. The total nitrogen (TN) removal efficiency was up to 90% at a C/N ratio of 4.0. Also, UV 254 (40-50%), turbidity (80-90%) and COD (80-90%) were removed in the biofilm reactor. Due to the non-biodegradability of PFAS, their removal (initially up to 60-90%) in the biofilm reactor was attributed to ad- or absorption on sludge and ECA. The bioreactor offers a cost-effective solution to the issue of secondary inorganic nitrogen pollution caused by N2-containing plasma. This is beneficial for broadening the practical use of both N2 plasma and air plasma. The two-step process is not only applicable for treating PFAS-contaminated wastewater but can also be applied to various fields suitable for N2 and air plasma applications. |
| Volume |
500 |
| SCI |
13.3 |
