Hindered and compression settling: parameter measurement and modelling

Area of Science:

• Environmental Engineering
• Chemical Engineering
• Fluid Dynamics

Background:

• The Vesilind settling velocity function is crucial for flux theory in wastewater treatment design and modeling.
• Existing methods have known shortcomings in accurately representing settling behavior across various scales and concentrations.

Purpose of the Study:

• To propose and validate new methods for determining Vesilind parameters from batch settling tests.
• To develop an extension for one-dimensional dynamic settler models to incorporate compression settling.

Main Methods:

• Extensive batch settling tests were conducted at different scales.
• Two novel methods for extracting Vesilind parameters were developed and compared to the traditional manual method.
• A modified empirical function was proposed to extend 1-D dynamic settler models.

Main Results:

• Slow stirring in settling cylinders is confirmed as essential for accurate representation of full-scale plant performance.
• The proposed methods for parameter extraction showed effectiveness.
• The extended 1-D dynamic model successfully described batch settling interfaces irrespective of layer count.

Conclusions:

• The study provides improved methods for settling velocity analysis and dynamic modeling in wastewater treatment.
• Accurate parameter determination and advanced modeling enhance the design and operational efficiency of settlers.