Related Experiment Video
Updated: Jul 4, 2026
15:19
Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor
Published on: October 15, 2015
Modeling the liquid flow in up-flow anaerobic sludge blanket reactors
W L Bolle1, J van Breugel, G C van Eybergen
1Dow Chemical Nederland BV, Terneuzen, The Netherlands.
Biotechnology and Bioengineering
|November 1, 1986
Summary
Fluid flow models for wastewater treatment in upflow anaerobic sludge blanket (UASB) reactors were tested. Optimal sludge bed height minimizes short-circuiting, improving reactor efficiency.
Area of Science:
- Environmental Engineering
- Biotechnology
- Chemical Engineering
Background:
- Upflow anaerobic sludge blanket (UASB) reactors are crucial for wastewater treatment.
- Understanding fluid dynamics is key to optimizing UASB reactor performance.
Purpose of the Study:
- To model and analyze fluid flow patterns within a large-scale UASB reactor.
- To identify key parameters influencing flow dynamics and reactor efficiency.
Main Methods:
- Stimulus-response experiments using an Li(+) tracer.
- Development and validation of fluid flow models for a 30-m(3) UASB reactor.
- Analysis of sludge bed, sludge blanket, and settler regions.
Main Results:
- The sludge bed and blanket function as perfectly mixed reactors with short-circuiting.
- The settler volume acts as a plug-flow region.
- Short-circuiting flows are minimized at a sludge bed height of 3.5-4 m, contrary to other findings.
- Superficial gas velocity significantly influences short-circuiting flows.
Conclusions:
- Two parameters, short-circuiting flows over the sludge bed and blanket, are sufficient to describe UASB reactor fluid dynamics.
- Optimal sludge bed height is critical for minimizing short-circuiting and maximizing efficiency.
- Findings provide valuable insights for designing and operating efficient UASB wastewater treatment systems.
Related Concept Videos
01:23Steady, Laminar Flow in Circular Tubes
Hagen-Poiseuille flow describes a viscous fluid's steady, incompressible flow through a cylindrical tube with a constant radius R. This flow profile is often applied to understand fluid transport in narrow channels, such as capillaries. It serves as a foundational example of laminar flow. In this model, cylindrical coordinates (r,θ,z) are used to describe the radial (r), angular (θ), and axial (z) dimensions within the tube. For Hagen-Poiseuille flow, the velocity profile is purely axial,...
01:30Typical Model Studies
Fluid mechanics model studies often utilize scaled-down systems to predict fluid behavior in full-scale environments, such as river flows, dam spillways, and structures interacting with open surfaces. Maintaining Froude number similarity in river models is crucial, as it replicates surface flow features like wave patterns and velocities.
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...
01:24Rapidly Varying Flow
Rapidly varying flow (RVF) in open channels is characterized by abrupt changes in flow depth over a short distance, with the rate of depth change relative to distance often approaching unity. These flows are inherently complex due to their transient and multi-dimensional nature, making exact analysis difficult. However, approximate solutions using simplified models provide valuable insights into their behavior.Key Features of Rapidly Varying FlowRVF is commonly observed in scenarios involving...
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...
01:25Design Example: Flow of Oil Through Circular Pipes
Understanding fluid flow behavior through pipes is critical in fluid mechanics, especially in applications like oil transportation through pipelines. Hagen-Poiseuille's law provides an exact solution derived from the Navier-Stokes equations for steady, incompressible, and laminar flow within a circular pipe. Hagen-Poiseuille's law helps determine the necessary pressure drop across a pipeline section by determining parameters like pipe length, radius, oil viscosity, and the desired volumetric...