Storm water treatment with nano-coated mesh
School of Chemical, Biological, and Environmental Engineering
L. Cach, C. Glasscock, M. Schneider, A. Tahayeri
Overview
Modeling Strategy
Field Scale
Puralytics has developed a photocatalytic mesh that
degrades certain organics, coliforms, and metals from water.
This technology has potential applications for on-site
industrial storm water treatment to reduce environmental
contamination.
Data are analyzed in MATLAB using the method of leastsquares and the following equations to find rate-constants k
and k’.
𝑑𝐶
𝑦𝐴
= −𝑘′ ∙ 𝐶 ∙
𝑑𝑡
𝑉
The overall rate coefficient k” is dependent on k (a function
of UVA intensity) and k’ (a generic correlation coefficient).
ft
𝑘′ = 𝑓(𝐼) ∙ 𝑘
6 ft
Figure 1. Schematic of Lily Pad application to degrade contaminants (red
dots) by photocatalysis.
A predictive mathematical model is needed for the Lily Pad
technology to transition from drinking water purification to
storm water treatment. MATLAB analysis of experimental
data will determine rate constants for use in the model.
2 ft
Variable
C
Description
Contaminant concentration
Units
mg/L
k
Rate constant
m/h
I
Y
UVA intensity
Fractional surface coverage
W m2
A
V
Surface area
Volume
m2
m3
Field scale tests were run in two model pond
configurations: one circle and one trench both 1-foot in
depth. Surfaces were covered with varying amounts of
1-square foot Lily Pads.
Lab Scale
UVA light
Lily Pad
Lab experiments allow for testing variables such as light
intensity, temperature, and mixing. These parameters are
difficult to control in field scale.
Figure 3. Concentration of Kroger blue dye in a
12 ft3 trench with varying fractional surface
coverage. Experiments were exposed to different
ranges of UVA intensity.
Figure 4. Concentration of Kroger blue dye in a
28 ft3 circular pond with varying fractional
surface coverage. Experiments were exposed to
different ranges of UVA intensity.
Figure 6. Modeling predictions (from lab scale data) compared with field
scale results for the trench . Corrected predictions account for different
mixing conditions in the field scale.
Future Work
Future work will evaluate the effects of trench depth and
mixing on rate and analyze additional contaminants,
including methamphetamine (quality control), caffeine,
Diuron, and coliforms.
Figure 5. Concentration of Kroger blue dye in a
28 ft3 circular pond and 12 ft3 trench with
approximately 40% surface coverage. UVA
intensity is shown for the experimental time.
Figure 2. Concentration of PurBlue dye in 3 L bucket for
two idential trials. Both tests used approximately 44%
coverage, light intensity of 12 w/m2, and constant mixing.
Acknowledgments
Figure 6. Concentration of Kroger Blue 1 in a 28
ft3 circular pond and 12 ft3 trench with
approximately 60 - 70% surface coverage. UVA
intensity is shown for the experimental time.
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Field samples from the 83%
coverage trial of the trench.
Dr. Christine Kelly, Project Sponsor
Dr. Tom Hawkins, Puralytics
George Jendrzejewski, Puralytics
Dr. Jennifer Field, Environmental Chemist
Dr. Todd Jarvis
Oak Creek Center for Urban Horticulture
Dr. Phil Harding