Looking for engineered nanoparticles (ENPs) in wastewater treatment systems: Qualification and quantification aspects

Area of Science:

• Environmental Science
• Analytical Chemistry
• Nanotechnology

Background:

• Existing methods for engineered nanoparticle (ENP) analysis are limited to low organic loads and controlled lab settings.
• Current techniques primarily focus on single ENP types.
• There's a need for robust methods to analyze ENPs in complex environmental matrices like wastewater.

Purpose of the Study:

• To develop and validate a rationalized method for quantifying and identifying ENPs in high-organic-load wastewaters.
• To assess the presence and concentration of specific ENPs in municipal wastewater and sludge.
• To determine the removal efficiency of ENPs during wastewater treatment processes.

Main Methods:

• Sample pretreatment using dialysis for desalting and low-temperature oxidation for organic removal.
• Scanning Electron Microscopy (SEM) mapping for nanoparticle identification.
• Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES) for quantification.
• Analysis of wastewater and sludge from municipal wastewater treatment plants (WWTPs).

Main Results:

• Successful identification and quantification of nano-size titanium and zinc oxides in WWTP samples.
• Established concentration profiles for ENPs within the studied WWTPs.
• Achieved 80% removal of titanium and 68% removal of zinc by sludge particulates.
• Calculated mass flux to estimate daily ENP flow through the system.

Conclusions:

• The developed method is effective for analyzing ENPs in complex wastewater matrices.
• Significant removal of titanium and zinc oxides occurs during wastewater treatment.
• The study provides crucial data on ENP fate and transport in WWTPs.