scholarly journals On the distribution of multicomponent mixtures over generalized exposure time in subsurface flow and reactive transport: Batch and column applications involving residence-time distributions and non-Markovian reaction kinetics

2000 ◽  
Vol 36 (10) ◽  
pp. 2895-2903 ◽  
Author(s):  
Timothy R. Ginn
Keyword(s):  
Reaction Kinetics ◽  
Residence Time ◽  
Exposure Time ◽  
Reactive Transport ◽  
Subsurface Flow ◽  
Multicomponent Mixtures ◽  
Residence Time Distributions

Flow Pattern Analysis of Constructed Wetlands Treating Landfill Leachate

1999 ◽  
Vol 40 (3) ◽  
pp. 309-315 ◽  
Author(s):  
Jonathan K. Rash ◽  
Sarah K. Liehr
Keyword(s):  
Constructed Wetlands ◽  
Vertical Mixing ◽  
Subsurface Flow ◽  
Free Water ◽  
Chemical Reactor ◽  
Operating Conditions ◽  
Conservative Tracer ◽  
Residence Time Distributions ◽  
Physical Barriers ◽  
Interior Points

Three series of tracer studies were performed on three constructed wetlands at the New Hanover County Landfill near Wilmington, North Carolina, USA. One vegetated free water surface wetland (FWS-R), one vegetated subsurface flow wetland (SSF-R), and one unvegetated control subsurface flow wetland (SSF-C) were studied. A conservative tracer, lithium chloride, was used to study the chemical reactor behavior of these wetlands under normal operating conditions. Results indicated that short-circuiting is quite common in SSF wetlands, while FWS wetlands are well-mixed and not as subject to short-circuiting. These results were obtained from and reinforced with tracer measurements at interior points in these wetlands, analysis of residence time distributions from two different formulations, and the construction of residence volume distributions. The short-circuiting in the SSF wetlands can be attributed to the following: (1) Vertical mixing is inhibited by a combination of physical barriers and density gradients caused by rainfall and runoff dilution of the upper layer; and (2) Leachate is drawn from the bottom of the wetland, causing it to further prefer a flow path along the bottom.

Residence time distributions in SX–EW equipment

1998 ◽  
Vol 54 (3-4) ◽  
pp. 235-242 ◽  
Author(s):  
Hossein Aminian ◽  
Claude Bazin ◽  
Daniel Hodouin
Keyword(s):  
Residence Time ◽  
Residence Time Distributions
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