United Arab Emirates University College of Engineering Training

1
United Arab Emirates UniversityCollege of
EngineeringTraining Graduation Projects
UnitGraduation Project II

• Design of a Remediation System for a Groundwater
  Contaminated Site
• Student Name- ID-
• Akram Abdu Saif. 200101797
• Mohamed Sarhan. 200101692
• Majid Ibrahim Bin Amer. 199900404
• Date of Presentation- 31 - May- 2007
• Advisor- Dr. Mohamed M. A. Mohamed

2
General Idea

• Project Definition
• - Simulate groundwater flow and contaminant
  transport produced by a gasoline station using a
  numerical model.
• - Study the effectiveness of natural attenuation
  on the contaminant plume.
• - Perform a sensitivity analysis to study the
  influence of changing input biological parameters
  on the plume fate and migration.
• - Design a PRB remediation system for the site
  by performing several scenarios of different
  barriers dimensions and select the most effective
  and economic one.

3
Presentation Outline

• Introduction.
• Literature review.
• Groundwater equations.
• Problem description.
• Sensitivity analysis.
• Biodegradation Scenarios.
• Conclusion Recommendation.

4
Introduction
5
Introduction

• Groundwater contaminants come from two categories
  of sources point source and distributed, or non-
  point source.
• In the entire world, the hazards waste
• grow every year by a scaring numbers
• which let this problem very serious
• and blusters all the people
• who lives on the earth

6
Literature review
7
Literature review

• Natural attenuation.
• Biodegradation of contaminate in groundwater.
• Modeling groundwater biodegradation.
• Available biodegradation models and software

8
Literature review

• Natural attenuation
• Natural attenuation refers to the ability of a
  ground water system to rid itself of
  contamination resulting from a spill or wrong
  disposal of wastes
• Bacteria that naturally inhabit many ground water
  environments are able to break down chemicals to
  be virtually non-biodegradable

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Literature review

• Natural attenuation Properties
• -Natural attenuation is sometimes a preferred
  remedy strategy because it does not transfer
  pollutants from one location to another.
• -natural attenuation is not always a completely
  effective remedy by itself. In cases where the
  contamination is spreading more quickly than it
  can break down.
• -At many sites natural bacteria in the soil and
  groundwater will use petroleum compounds as their
  primary source of energy or food
• -Natural attenuation could be an effective mean
  of achieving cleanup goals, particularly when
  these goals are based on site-specific risk
  reduction

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Literature review

• Biodegradation of contaminate in groundwater
• -Naturally biodegradation means degradation of
  organic compounds by indigenous microbes without
  artificial enhancement
• -Application of naturally occurring
  biodegradation as a remediation technique
  requires that a site be evaluated to ensure site
  conditions are appropriate and that a monitoring
  plan be developed.

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Literature review

• The term biodegradation may refer to complete
  mineralization of the organic contaminants to
  carbon dioxide, water, inorganic compounds, and
  cell protein, or to transformation of organic
  contaminants to other organic compounds.
• Biodegradation of organic constituents is
  accomplished by enzymes produced by micro
  organisms.

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Literature review

• Characterization of a site for evaluation of
  naturally occurring
• biodegradation potential should be part of the
  initial site investigation.
• Naturally occurring biodegradation is considered
  to be a remedial action, and its suitability to a
  given site should be considered during evaluation
  of possible remedial action options and selection
  of an overall site remedial action plan.

13
Literature review

• Characterization of a site for evaluation of
  naturally occurring
• biodegradation potential should be part of the
  initial site investigation.
• Naturally occurring biodegradation is considered
  to be a remedial action, and its suitability to a
  given site should be considered during evaluation
  of possible remedial action options and selection
  of an overall site remedial action plan.

14
Literature review

• Permeable Reactive Barriers (PRB)
• A permeable reactive barrier (PRB) is defined as
  an in situ method for remediation contaminated
  groundwater that combines a passive chemical or
  biological treatment zone with subsurface fluid
  flow management
• In situ bioremediation has been one of the most
  promising techniques for remediation of petroleum
  contaminated sites however design of in situ
  bioremediation under specific one-site conditions
  may remain to be challenging issue, due mainly to
  difficulties in gaining insight into the complex
  source and medium conditions in subsurface
  systems.

15
Available biodegradation models and software

• There is many Program Software describe our
  project but at end we build our project depend
  on
• 1- Excel simulation program (Monod kinetics)
  simulated by Dr. Mohammed to describe bacteria
  growth.
• 2- Surfer Program.
• 3-METABIOTRANS the main program.

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Groundwater equations
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Groundwater equations

• Groundwater flow equations
• Contaminate transport equations
• Biodegradation equations
• Modeling Biodegradations
• Model descriptions

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Groundwater equations

• Aquifer a unit of porous material capable of
  storing and transmitting appreciable quantities
  of water.
• A confined aquifer a unit of porous material
  between two impermeable layers.
• unconfined aquifer Aquifer has impermeable layer
  from bottom and the water table as its upper
  boundary.

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Groundwater equations

• General form of the governing equation for
  groundwater flow in an aquifer-
• Where

20
Groundwater equations

• Where
• h head.
• Tx and Ty components of transmissivity.
• S storage coefficient.
• R sink/source term.
• Kz vertical hydraulic.
• hsource is the head in the source reservoir.

21
Groundwater equations

• To apply govering equation on unconfind aquifer
  the assumtion is-
• Flow lines are horizontal and equipotential lines
  are vertical.
• The horizontal hydraulic gradient is equal to the
  slope of the free surface and is invariant with
  depth.

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Groundwater equations

• 1- Advection The movement of the contaminant
  with the groundwater flow.
• 2- Diffusion spreading due to concentration
  gradients and random motion.
• 3- Dispersion-
• a- mechanical dispersion mixing of the
  contaminant resulting from movement through
  complex pore structures.
• b- Hydrodynamic dispersion adds the factor
  of molecular diffusion to the effects of
  mechanical dispersion.

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Groundwater equations

• The governing transport equation in 2-D is-
• Where
• C concentration of solute
• Vx, Vy seepage velocity
• Dx, Dy coefficient of dispersion
• C0 solute concentration in source or sink fluid
• Rk Reaction rate
• n effective porosity.
• W source or sink term.

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Groundwater equations

• Main expressions utilized in modeling
  biodegradation is
• 1- Instantaeous reaction kinetics.
• 2- First-order decay kinetics.
• 3- Monod kinetics.

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Groundwater equations

• 1- Instantaneous reaction kinetics.
• The expressions used in this modeling is -
• Where
• CR is the change in contaminant concentration
  due to biodegradation.
• O is the concentration of oxygen.
• F is the utilization factor, or the ratio of
  oxygen to contaminant consumed.

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Groundwater equations

• 2- First-order decay kinetics
• The expressions used in this modeling is -
• Where
• C is the biodegraded concentration of the
  chemical
• Co is the starting or initial concentration.
• k decay rate.

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Groundwater equations

• 3- Monod kinetics
• The expressions used in this modeling is -
• C is contaminant concentration.
• M is the microbial concentration.
• is maximum contaminant utilization rate per
  unit mass microorganisms.
• Kc is contaminant half saturation constant.
• t is the time interval.

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Modeling Biodegradations

• The equations that used in modeling-

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Modeling Biodegradations

• Where
• C is the contaminant concentration.
• O is the oxygen concentration.
• D is a dispersion tensor.
• V is the ground water velocity.
• Rc is the retardation coefficient for the
  contaminant.
• M is the concentration of microbes in solution.
  
• maximum contaminant utilization rate
  per unit mass of microorganisms.
• Y the microbial yield coefficient.
• Kc is the half saturation constant for the
  contaminant.
• Ko is the half saturation constant for oxygen.
  
• F is the ratio of oxygen to hydrocarbon
  consumed.
• b is the microbial decay rate.

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Model descriptions

• Model use in this study is called METABIOTRANS
  (Mohammed, 2001)
• simulates the transport of multiple solutes in
  anisotropic, heterogeneous saturated aquifers.

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Model descriptions

• METABIOTRANS has the following features
• 1- Multi-component aqueous advective and
  dispersive transport in saturated groundwater
  aquifers.
• 2- Simulates 1-D, 2-D, and 3-D problems.
• 3- Biodegradation/biotransformation using Monod
  kinetics.
• 4- Simulation of heterogeneous and/or anisotropic
  porous media.
• 5- Biotransformation by multi-bacterial-species.

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Model descriptions

• The data file that we need to prepare
  METABIOTRANS -
• Problem dimensions 1, 2 or 3-D.
• Nodes data node number and its corresponding
  Cartesian coordination.
• Elements data number of each element and the
  corresponding nodal numbers.
• Materials data the different aquifer material
  properties at each element.

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Model descriptions

• 5. Boundary conditions
• Flow boundary conditions
• Specified head.
• Specified flow.
• Transport boundary conditions
• Specified solute concentration.
• Specified solute flux.
• 6. Initial conditions for transport equation.
• 7.Injection/discharge data
• a- Number if injection/discharge wells.
• b- Time functions

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Model descriptions

• 8.Solutes data
• a-Number of solutes.
• b- Chemical properties for each solute.
• 9. Bacterial species data
• a- Number of bacterial species.
• b- Solutes that are being utilized by each
  bacterial species.
• c- Growth parameters for each bacterial species.

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Problem description
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Problem description

• 1- Conceptual Model
• Site Area 100 X 50 m2
• Contamination source Area 10 x 5 m2
• Drinking well is located 80 m from the
  contamination source.

Co 100 mg/l Mo 0.001 mg/l Vx 0.5 m/day
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Problem description

• 2- Grid Design
• Elements of 0.5 X 0.5 m2
• of Elements 20000
• of nodes 20301
• Numbering the Nodes
• Numbering the Elements

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Problem description

• 3- Input data-
• Three Groups-
• 1- Physical aquifer properties Kx, Ky, ?l, ?t,
  ?, and Vx.
• 2- Transport properties
• 3- Microbial properties µmax, B, Yc, Kc, Mo

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Problem description
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METABIOTRANS Input file
41
Sensitivity analysis
42
Sensitivity analysis

• The major objective of this part is to show
  the sensitivity of model outputs (concentrations
  of contaminant and microorganisms and contaminant
  biodegraded mass)

43
Sensitivity analysis

• First The affect of adding bacteria to the site.

44
Sensitivity analysis
the effect of adding bacteria to the site" _at_ 30
days
the effect of adding bacteria to the site" _at_ 60
days
the effect of adding bacteria to the site" _at_ 100
days
The effect of natural attenuation is very clear
in the Figure 4.8 a, b and c in the trailing edge
of the plume??????
Run 2------ Run 1???????????
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Sensitivity analysis

• Second The affect of µmax B-

46
Sensitivity analysis

• Figure 4.4 (a) "the effect of increasing ? max on
  the biodegraded mass of the contaminant.

Figure 4.4 (b) "the effect of increasing ? max on
the bacterial growth.
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Sensitivity analysis
Increasing ? max 0.1 0.4 on the degradation
rate _at_ 30 days.
Increasing ? max 0.1 0.4 on the degradation
rate _at_ 60 days.
Increasing ? max 0.1 0.4 on the degradation
rate _at_ 100 days.
What did happen in the interval 20 40
days??????
Run 2------ Run 4???????????
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Sensitivity analysis
Figure 4.5 (b) "the effect of increasing B on the
growth rate of the bacteria.
Figure 4.5 (a) "the effect of increasing B on the
biodegraded mass of the contaminant.
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Sensitivity analysis
increasing B from 0.01 0.04 on the degradation
rate _at_ 30 days
increasing B from 0.01 0.04 on the degradation
rate _at_ 60 days
increasing B from 0.01 0.04 on the degradation
rate _at_ 100 days
The effect can be ignored
Run 2------ Run 6???????????
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Sensitivity analysis

• Third The affect of Yc Kc-

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Sensitivity analysis
Figure 4.6 (a) the effect of increasing Yc on
the biodegraded mass of the contaminant.
Figure 4.6 (b) "the effect of increasing Yc on
the growth rate of the bacteria.
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Sensitivity analysis
Figure 4.7 (a) "the effect of increasing Kc on
the biodegraded mass of the contaminant.
Figure 4.7 (b) "the effect of increasing Kc on
the growth rate of the bacteria.
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Biodegradation Scenarios
54
Biodegradation Scenarios

• Permeable reactive barriers (PRB).

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Biodegradation Scenarios
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Biodegradation Scenarios
the effect of increasing PRB width on the
biodegraded mass of the contaminant.
the effect of increasing PRB width on the growth
rate of the bacteria
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Biodegradation Scenarios
Run 1 ------ Run 12???????????
Run 1 ------ Run 13???????????
Run 1 ------ Run 14???????????
Run 1 ------ Run 15???????????
Concentration of the contaminant after 100 days
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Biodegradation Scenarios
Concentration of bacteria after 100 days
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Conclusion Recommendation
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Conclusion Recommendation

• For the site presented in this study, it is
  recommended to use a microbial with a value of
  max equal to or more than 0.2. The best
  remediation scenario simulated produced PRB
  located 30 from the left edge of the study area
  with width in the direction of flow equal to 25 m
  and a length in the vertical direction of the
  plume path equal to the length of the plume.
  Based on results, this design will be the most
  economical way to protect the well from being
  contaminated

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The END

• Thanks for listening