Related Experiment Video
Updated: Jul 4, 2026
09:21
Methods for Characterizing the Co-development of Biofilm and Habitat Heterogeneity
Published on: March 11, 2015
Some fluidization characteristics of biological beds
S W Hermanowicz1, J J Ganczarczyk
1Department of Civil Engineering, University of Toronto, Toronto, Ontario M5S 1A4, Canada.
Biotechnology and Bioengineering
|May 1, 1983
Summary
Biofilm coatings increase particle drag in fluidization. Researchers developed a new drag coefficient formula and improved fluidized bed porosity calculations, aiding bioreactor design.
Area of Science:
- Fluid mechanics
- Biotechnology
- Chemical engineering
Background:
- Understanding particle behavior in fluidization is crucial for industrial processes.
- Biofilm coatings alter particle properties, impacting fluid dynamics.
- Accurate modeling of fluidized beds is essential for process optimization.
Purpose of the Study:
- To investigate the terminal velocity and drag force of nitrifying biofilm-coated particles.
- To propose a new formula for the drag coefficient of biocoated particles.
- To adapt and apply the Zaki-Richardson method for fluidized bed porosity calculations.
Main Methods:
- Experimental determination of free-fall terminal velocity for coated and uncoated particles.
- Estimation of biofilm wet density.
- Modification and application of the Zaki-Richardson method for porosity analysis.
Main Results:
- Biocoated particles exhibit greater drag force compared to uncoated particles.
- The wet density of the nitrifying biofilm was determined to be 1.14 g/cm³.
- The modified Zaki-Richardson method successfully calculated fluidized bed porosity.
Conclusions:
- Biofilm presence significantly influences particle drag in fluid dynamics.
- The proposed drag coefficient formula enhances the understanding of biocoated particle behavior.
- The adapted Zaki-Richardson method provides a viable approach for fluidized bed characterization.
Related Concept Videos
01:30Biological Treatment of Effluent and Waste Water
Biological wastewater treatment relies on the metabolic activity of microorganisms to remove pollutants from sewage. In modern treatment systems, this process is organized into sequential stages that progressively reduce solid material, dissolved organic matter, and microbial contamination. Each stage plays a distinct role in improving water quality and preparing the effluent for safe discharge or reuse.Primary and Secondary TreatmentPrimary treatment is a physical process that removes large...
01:18Bioreactor Controls-II
In aerobic fermentations, oxygen is vital for microbial growth and metabolite production. Since air comprises only about 20% oxygen and the gas is poorly soluble in water—just 9 ppm at 20°C—supplying sufficient oxygen becomes a critical challenge, especially in high-demand processes like yeast growth or citric acid production. Even a fully saturated broth may offer only a few seconds of oxygen availability.To address this, sterile or scrubbed air is introduced into the fermentor via a sparger...
01:29Bioreactor Design and Operational System
Bioreactors are engineered vessels designed to cultivate microorganisms under controlled conditions for industrial bioprocessing. They maintain sterility and allow precise regulation of pH, temperature, oxygen, and nutrient levels to optimize microbial growth and metabolite production. Bioreactors range from small laboratory units of 1 liter to industrial systems holding up to 500,000 liters, though only about 75% of their volume is actively used for fermentation. The remaining headspace...
01:20Capillary Beds
Capillary beds are networks of tiny blood vessels that play a crucial role in the circulatory system. These beds are where the exchange of gases, nutrients, and waste products occurs between the blood and surrounding tissues. Each capillary bed consists of numerous capillaries, which are the smallest blood vessels in the body, typically only one cell-thick. This thinness allows for the efficient diffusion of substances.
Capillaries connect arterioles, small branches of arteries, to venules,...
Capillaries connect arterioles, small branches of arteries, to venules,...
01:20Characteristics of Fluids
When a force is applied parallel to the top surface of a solid, it resists the applied force due to the internal frictional forces between the layers of the solid known as shearing resistance. However, when the force is removed, the shearing forces restore the original shape of the solid. Other deformation forces also cause temporary changes in shape if the forces are not beyond a threshold magnitude. Solids tend to retain their shape, making the study of their rest and motion easier. Beyond...
01:28Bioreactor Controls-I
Maintaining optimal conditions within fermenters is essential for maximizing microbial productivity and ensuring process efficiency. This lesson focuses on key parameters—temperature, foam, pH, carbon dioxide, oxygen, and pressure—and their precise measurement and control strategies in fermentation systems.Temperature ControlTemperature regulation is critical due to the exothermic nature of many fermentation processes. In small laboratory fermenters, temperature is commonly monitored using...