Rheological characterisation of concentrated domestic slurry

Area of Science:

• Environmental Engineering
• Fluid Mechanics
• Sanitation Science

Background:

• Transport systems are critical in new sanitation infrastructure, linking waste sources to treatment facilities.
• Understanding the rheological properties of concentrated domestic slurry is essential for designing efficient waste collection and transport systems.

Purpose of the Study:

• To investigate the rheological properties of concentrated domestic slurries, specifically black water and black water with ground kitchen waste.
• To model these properties using the Herschel-Bulkley model and analyze the effects of concentration and temperature.

Main Methods:

• Collected slurry samples from a pilot sanitation system in the Netherlands.
• Utilized a narrow gap rotating rheometer to obtain rheograms.
• Modeled slurry rheology using the Herschel-Bulkley model and an Arrhenius-type relation for temperature effects.

Main Results:

• For black water, yield stress and consistency index increased with concentration, while the behavior index decreased.
• Slurry viscosity decreased with increasing temperature for both black water and the mixture.
• Black water with ground kitchen waste exhibited higher viscosity than black water due to larger particles.

Conclusions:

• The Herschel-Bulkley model effectively describes the rheological behavior of concentrated domestic slurries.
• Concentration and temperature significantly influence slurry viscosity, with implications for transport system design.
• The proposed method aids in estimating rheological model parameters for optimized sanitation system engineering.