ASSESSMENT OF SINGLE-WALLED CARBON NANOTUBES ON ACTIVATED SLUDGE WASTEWATER TREATMENT PROCESS

This paper evaluated the impact of 95% purified single-walled carbon nanotubes (SWCNTs) on the activated sludge wastewater treatment process through a batch-scale study. We found that the SWCNTs adsorbed 22% of the soluble COD (sCOD, chemical oxygen demand). One-way ANOVA analysis revealed that only four experimental parameters, i.e., surface charge, sCOD, mixed liquor suspended solids (MLSS) and sludge volume index (SVI) were significantly impacted by the addition of SWCNTs. Other parameters such as pH, dissolved oxygen (DO), specific resistance to filtration (SRF), and relative hydrophobicity were not significantly impacted. Further data analysis demonstrated that better sCOD removal was achieved in the SWCNTs-added reactors than that in the control reactors (80% vs. 62%). The addition of the SWCNTs also improved sludge settleability and made the surface of the activated sludge flocs less negatively charged. Overall the SWCNTs showed positive impacts on the reactor performance and sludge properties.