Polyurethane Foams for Domestic Sewage Treatment

Area of Science:

• Environmental Engineering
• Wastewater Treatment Technologies
• Material Science

Background:

• Domestic sewage often presents challenges in treatment due to high ammonium nitrogen and low carbon to nitrogen (C/N) ratios.
• Conventional treatment methods may be less effective under such specific wastewater conditions.
• Polyurethane foams (PUF) are explored as potential filter media for wastewater treatment.

Purpose of the Study:

• To evaluate the efficacy of polyurethane foams (PUF) as a filter medium in foam-sand filters for direct domestic sewage treatment.
• To compare the performance of novel polyurethane foams (NF) and waste polyurethane foams (WF) for this application.
• To assess the physical, chemical, and morphological properties of PUF relevant to wastewater treatment.

Main Methods:

• Foam-sand filters were constructed using two segments filled with novel foams (NF) and waste foams (WF).
• Characterization of foams included assessment of hydrophobic properties, cell structure (diameter, porosity, surface area), and physical properties.
• Application-related properties like water absorption, biomass adsorption, and regeneration potential were evaluated.
• Scanning Electron Microscopy (SEM) was used to analyze cell morphology and microorganism immobilization.

Main Results:

• Waste foams (WF) demonstrated suitability as an innovative biomass carrier for treating domestic sewage with a low C/N ratio.
• SEM analysis revealed microorganism immobilization through multi-cellular structures and single cells attached to the foam surfaces.
• Foam-sand filters utilizing WF layers (0.50-1.53 mm diameter, 53.0-63.5% porosity) created favorable conditions for active microorganism development.

Conclusions:

• Waste polyurethane foams (WF) are a promising and sustainable material for enhancing foam-sand filters in domestic sewage treatment, particularly for challenging wastewater compositions.
• The porous structure and surface properties of WF effectively support microbial community development and biomass adsorption.
• This study highlights the potential of repurposing waste foams for effective wastewater treatment applications.