Modules Applications Bioremediation by alicejenny

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									                                                                           Title Page




Applications - 1. Bioremediation



   You will NOT be responsible for the bulk of material referenced
  in this section.


   You will be responsible for the exam for knowing the major
  features and problems involved in implementing and selecting
  bioremediation options, but not all of the details that go into a real
  decision.
                                                                                                                                                       Fate of Chemicals
                                                                                                Chemical
                                                              Not volatile                                                               volatile

                                                                                                                               no                        yes
              Water soluble                                                                                                              Evaporation
                                                                                                                                          possible ?
                                                                Water insoluble                Chemically         Chemically
                                                                                                 inert ?          reactive ?
      no                         yes
                 Water
                 available ?

                                                                         Go to Next Page                                                 yes        Site accumulation/
                                                                                                            no
                                                                                                                 Conditions favourable                    buildup
                                    Chemically          Chemically                                                  for reaction ?
                                      inert ?           reactive ?
  Accumulation on
       site
                                         no                                                     Accumulation in
                                                 Conditions favourable                                                                       Loss/
                                                    for reaction ?
                                                                                                  atmosphere
                                                                                                                                         disappearance


                                                                             Loss/
                                                                         disappearance

                          Sorbed                 Not sorbed



                           Matrix for sorption          no
              yes              available ?


                                                                                   Amenable to
                     Amenable to                                                                                       Not degradable
Not degradable                                                                     degradation
                     degradation


                  no   Conditions favourable     yes                      yes Conditions favourable
                                                                                                       no           Transport in sediment
 Accumulation on          for reaction ?                                           for reaction ?
                                                           Loss/                                                       & water (surface,
 site or transport
 with particulates                                     disappearance                                                      ground)
                                                       Biodegradation - Interactions
                                                             Biodegradation Summary




Biodegradation of a given compound is a
complex result of the interacting factors
listed in this diagram. It is a function of the
chemical structure of the compound, the
environmental conditions, the organisms
present and their quantities, the adsorption,
release and solubility of the compound, the
general bioavailability of the compound,
interactions with other compounds present
in the environment, kinetics of growth and
metabolism, threshold effects, co-metabolic
processes, acclimation effects, and others.


Some factors appear in more than one of
these columns since they involve more than
one of the columns (Biological, Chemical
and Environmental)
Remember that all of these features are inter-
related and that it is often impossible to
separate them “neatly” as we have done here
Some of the interacting factors are
summarised in the diagram.


Note: that these same features and factors have been
used in the Module on Biodegradation
                                                                            Common Hazardous Wastes




Most Common Hazardous Waste Types are:

Petroleum hydrocarbons - Major contaminants:
                   1.BTEX compounds
                     Benzene
                     Toluene
                     Ethylbenzene
                     Xylene
                   2. Aromatics
                   3 Heterocyclic aromatics

               See an example of a real service station cleanup procedure

Halogenated aliphatic compounds - Major contaminants:
                     1.Trichloroethylene
                     2.1,1,1-Trichloroethane
                     3.Tetrachloroethylene
                     4.cis-trans-1,2-Dichloroethylene
                     5.1,1-Dichloroethane

Industrial waste lagoons and wood preservation - Major contaminants:
                      1.Creosote
                      2.Polynuclear aromatics (or PAHs)
                      3.Pentachlorophenol
                      4.Nitrogen heterocyclic aromatics
                      5.Aromatics
                                                                           Gasoline




Gasoline spills are perhaps the single most common occurrence.

The major constituents of fresh gasoline are:

      Constituent                                          Percent

      Isopentane                                           10.5
      p-Xylene                                             9.6
      n-Propylbenzene                                      8.4
      2,3-Dimethylbutane                                   7.3
      n-Butane                                             6.3
      n-Pentane                                            5.9
      Toluene                                              5.5

      Total                                                53.5

As it "weathers", volatile" compounds decrease and some are biodegraded.
Typically the composition changes to:

      Constituent                                          Percent

      2, 2-Dimethylheptane                                 12.4
      Toluene                                              10.5
      2,3-Dimethylpentane                                  10.2
      n-Propylbenzene                                      8.3
      n-Heptane                                            8.0

      Total                                                49.4
                                                                        Wastes Bioremediated




Chemical compounds and Wastes that have been bioremediated




           Acetone                  Industrial wastes
           Acrylonitrile            Isopropyl acetate
           Animal fats and grease   Methanol
           Anthracene               Methylene chloride
           Benzene                  Methylethyl ketone
           Benzopyrene              Methylmethacrylate
           t-Butanol                2-Methylnaphthalene
           Butylcellosolve          Monochlorobenzene
           Chrysene                 Naphthalene
           Coal tar                 Pentadecane
           Crude oil                Petroleum hydrocarbons
           2,4-D                    (miscellaneous)
           1,2-Dichloroethane       Phenanthrene
           Diesel fuel              Phenols
           Dodecane                 Polynuclear aromatic hydrocarbons
           Ethylacrylate            (PAHs)
           Ethylbenzene             Pyrenes
           Ethylene glycol          Stoddard solvent
           Fatty amines             Styrene
           Fluoranthene             Tetrahydrofuran
           Gasoline                 Toluene
           Hexadecane               Trichloroethylene (TCE)
           Hexane                   1-Tridecene
                                    Xylene
                                                                                              Overview


Overview
Bioremediation is the application of microorganisms or microbial processes or products to remove or
degrade contaminants from an area.


A more rigorous definition is:




      Bioremediation is the intentional use of biological degradation procedures to
      remove or reduce the concentration of environmental pollutants from sites where
      they have been released. The concentrations of pollutants are reduced to levels
      considered acceptable to site owners and/or regulatory agencies.




A bioremediation project or program should consider many aspects of the site, the contamination, the
microorganisms, the environment, the goals and regulatory limits on contaminants set by the
appropriate agencies (MoEE, EPA, etc.) and features that would impact on the successful outcome of
the project.
                        Soil Bioremediation Site Map




One way to look at this is through
a "flow diagram" of items and
features that should be examined.
                                                                                                        Questions




There are two basic questions to be answered before bioremediation starts:


1.    Where will the contaminants be metabolized - and what factors will determine this ?

      The possible types of bioremediation activities fall into two main categories: ex-situ and in-situ.

             In-situ bioremediation occurs in the soil. groundwater or other environment without removal
             of the contaminated material. In contrast,

              ex-situ bioremediation entails the removal of all or part of the contaminated material for
             treatment.

2. How aggressive will the site remediation be - and what factors will determine this ?


      Intrinsic bioremediation is passive - it relies on the capacity of microorganisms or other organisms
      in the system to metabolize, remove, reduce or inactivate the pollutants. It is by definition "in-situ".


      Another type is Engineered Bioremediation where the operators take an active role in promoting
      or carrying out the bioremediation process. This can be either in-situ or ex-situ. Some processes
      originally designed to carry out remediation through chemical or physical means are now known to,
      at least partially, involve bioremediation processes. Typical of these is bioventing where air is passed
      through a soil or groundwater to volatilize contaminants. It is now thought that the microbial activities
      in the volume being treated is enhanced by this process.
Process Diagram
Chemical Class                                                         Biodegradability*            Mobility   Occurrence   Partitioning      Prospects for
                                                                       Aerobic/Nitrate              (**)       (***)        characteristics   Bioremediation
                                                                       Reducing/                                            (****)            (1999
                                                                       Anaerobic


Hydrocarbons -BTEX                                                     A1, N2, AN2                  H          F            M                 Established


Hydrocarbons -Low MW;gasoline, #2 Fuel oil                             A1, N3, AN2                  M          F            M                 Established


Hydrocarbons -High MW: oil, PAH                                        A2, N4, AN4                  L          C            S                 Emerging

Hydrocarbons -Creosote                                                 A1, N2, AN4                  L          I            S                 Emerging

Oxygenated hydrocarbons - Low Mol Wt alcohols, ketones,                A1, N5, AN3                  H          C            W                 Established
esters, ethers

Halogenated aliphatics -Highly Chlorinated                             A4, A3, N5, AN2              M          F            M                 Emerging

Halogenated aliphatics -Less Chlorinated                               A2, A3, N5, AN2              H          F            M                 Emerging

Halogenated Aromatics - Highly Chlorinated                             A4, A2, N5, AN2              L          C            S                 Emerging

Halogenated Aromatics - Less Chlorinated                               A2, A3, N2, AN2              M          C            M                 Emerging

PCBS - Highly Chlorinated                                              A4, N5, AN2                  L          I            S                 Emerging

PCBs -Less Chlorinated                                                 A2, A1, N5, AN4              L          I            S                 Emerging

Nitro Aromatics                                                        A2, N5, AN2                  M          C            M                 Emerging


  * Numeric rating under A (aerobic), N (nitrate reducing) or AN (anaerobic) biodegradability is:
                       1=readily mineralized as growth substrate
                       2=biodegradable under narrow range of conditions
                       3=metabolized via co-metabolism when second substrate is available
                       4=resistant
                       5=insufficient data
  ** Mobility is rated as:
                       H=highly mobile
                       M=moderately mobile
                       L=least mobile
  *** Frequency of Occurrence is rated by surveys in groundwater as:
                       F=frequent
                       C=common
                       I=infrequent
  ****Partitioning Reactions are rated as:
                       S=strong sorptive capacity
                       M=moderate characteristics
                       W=weak characteristics
                                                                                                                                                            Prospects
                                                                                  Summary


  Summary of Table


 Generally, compounds susceptible to bioremediation show the following
characteristics:

 Water soluble, have a simple molecular structure, are not sorbed, are non-
toxic, and serve as substrates for growth for many aerobic organisms.

 Compounds resistant to microbial metabolism are: insoluble (or slightly
soluble) in water, have strong sorptive reactions, are toxic and do not support
microbial growth

 Only a few (mainly petroleum hydrocarbon derived) chemicals have
established processes and are accepted widely as suitable candidates for
bioremediation.

 Others have an "emerging" status where more information is being gathered
and more tests are under way
                                                                                                    Generic process


An overview of the "generic" process that is commonly used to plan and initiate a
     bioremediation in a contaminated site shows that a number of decisions have to made
     at the various stages.


Strategy for Implementing a Bioremediation Project

1.    Preliminary Site Investigation to determine site geochemistry, environmental characteristics, soil
      conditions, hydrology, hydrogeology, concentration and distribution of contaminants.

2.    Propose intrinsic microbial reactions that can and have affected concentration and distribution of
      contaminants

3.    Detailed site investigation to confirm these proposals.

4.    Use information from steps above to decide if intrinsic or engineered bioremediation processes
      could be used to remediate site to required conditions. This is done in relation to the regulations
      applying to the site and to the proposed use for the site.

5.    Implement intrinsic or engineered program OR investigate alternative remediation options

6.    Monitor site for efficacy of program

7.    Modify program on the basis of on-going analyses and any other developments

8.    Terminate program when "clean-up" goals are reached - completely document the entire process

      If bioremediation is a viable option at Step 4 above, then further more complicated
      decisions can be made on which type of bioremediation should be employed:
                    Intrinsic
                    Bioremediation




Can Intrinsic
Bioremediation be
used ?

This flow diagram can
be used to find out.
                                                                          Remediation Technologies




LIST OF ALL REMEDIATION TECHNOLOGIES - those in blue are bioremediation or have elements that
include bioremediation activities. See the WWW site for details


            ACID EXTRACTION
            ADSORPTION/ABSORPTION - IN SITU
            AIR SPARGING
            BIOREMEDIATION - IN SITU GROUNDWATER
            BIOREMEDIATION - IN SITU LAGOON
            BIOREMEDIATION - IN SITU SOIL
            BIOREMEDIATION - NOT OTHERWISE SPECIFIED
            BIOREMEDIATION - SLURRY PHASE
            BIOREMEDIATION - SOLID PHASE
            BIOVENTING
            CHEMICAL TREATMENT - DECHLORINATION
            CHEMICAL TREATMENT - IN SITU GROUNDWATER
            CHEMICAL TREATMENT - OTHER
            CHEMICAL TREATMENT - OXIDATION/REDUCTION
            DELIVERY/EXTRACTION SYSTEMS
            DUAL PHASE EXTRACTION
            ELECTRICAL SEPARATION
            ELECTRO-THERMAL GASIFICATION - IN SITU
            MAGNETIC SEPARATION
            MATERIALS HANDLING/PHYSICAL SEPARATION
            OFF-GAS TREATMENT
            PNEUMATIC FRACTURING
            PYROLYSIS
            SLAGGING
            SOIL FLUSHING - IN SITU
            SOIL VAPOR EXTRACTION
            SOIL WASHING
            SOLVENT EXTRACTION
            SURFACTANT ENHANCED RECOVERY - IN SITU
            THERMAL DESORPTION
            THERMALLY ENHANCED RECOVERY - IN SITU
            VITRIFICATION
                                                                    Site




Gasoline Station Bioremediation




 The gas station at Phillip and Columbia Street was sold to a new
 company and any soil and groundwater contamination of the site
 due to its previous operation by Sunoco had to be removed.
                                                          Excavation and Tank
                                                               Removal
                                                            Tank Removal
The old gasoline tanks were
removed and holes bored to
detect gasoline and then a
deeper excavation was done
to the groundwater level to
check for this contamination




                               The water surface showed visible
                               signs of oil contamination.
                                                    Drilling
                                             Soil Removal




             The soil that was contaminated was
             excavated and removed to a secure
             landfill site
             To remove, or at least reduce, the
             contamination of the groundwater
             below the soil, holes were drilled
             and pipes were installed around the
             edge of the contaminated zone




These pipes had perforated
sections spanning the soil
and groundwater regions
and going a few feet below
the water table
The larger pipes
surrounded the
contaminated areas and
were all then joined to the
vacuum pumping systems
                                                     Pumping

 Gasoline removal
The pipes were joined together at the surface and
pumps were attached to these pipes.
The pumping systems pumped a mixture of
groundwater, pure gasoline product floating on the
surface of the groundwater and soluble products
from gasoline that had entered the groundwater.
These soluble products would have included
benzene, ethylbenzene, toluene and xylenes.
The mixture of gasoline, soluble products from
gasoline products and water was pumped into a
tanker truck on the property and disposed of after
separation into the two phases of water and
gasoline. The water would have contained the
water-soluble components.
                                                                                   Tanker Truck (storage)
   Site Diagram




                                                                                            Fuel
                        Old Gasoline Pumps (removed)


                                                             Old Garage Building




                                                                                            Water
Columbia




           Collection                                                                 Pump and
                                        Old Storage Tanks (removed)                   fuel/water
           Wells
                                                                                      Separator




                                            Phillip Street
Cross Sectional Diagram
                                                   To Separation and Collection



                                                                Pump

                              Excavation

                                                                    Soil




                       Free gasoline product




                        Groundwater




            Cross Sectional Diagram of excavation and wells
Final Operations

 Pumping continued for some months until most of the free product and soluble
components had been removed from the immediate vicinity of the site. Pumping also
ensured that no more migration of the soluble components in the groundwater could
occur. A negative gradient was established during pumping so that surrounding
contaminated water flowed into the site and not away from it.


 Pumping would have to have been continued for many years if ALL of the soluble
components in the groundwater needed removal through this “pump & treat”
methodology.

 The residual soluble components were assumed to have been remediated through
biological mechanisms in the groundwater.


 In this particular case, bioremediation was used as a final cleanup operation, but
the bulk of the materials were removed via the pump and treat method. This is often
referred to as “polishing” – that is, removal of the residual, low levels of soluble
components through bioremediation activities performed by indigenous
microorganisms




                                                                           End
         Bioventing




US-EPA
Bioventing
                  Hill Air Force Base, Utah Bioventing




Total Petroleum
Hydrocarbons
and BTEX
reduced by an
average 75%
Definition of Land Treatment
       Land Treatment

Land treatment involves use of natural biological, chemical and physical processes
in the soil to transform organic contaminants of concern. Biological activity
apparently accounts for most of the transformation of organic contaminants in soil,
although physical and chemical mechanisms may provide significant loss
pathways for some compounds under some conditions.

Degradation by ultraviolet light may serve as a loss pathway for certain
hydrophobic compounds at the soil surface.

Volatilization of some low molecular weight compounds also takes place at the soil
surface and provides a significant loss pathway for such compounds. Certain
chemical reactions such as hydrolysis can play an important role in transformation
of some compounds.

Humification, the addition of compounds to the humic materials in soil, can be an
important route of transformation for some polynuclear aromatic compounds. The
relative importance of these processes varies widely for different compounds under
different circumstances.

The land treatment concept serves as the basis for design and operation of soil
bioremediation technologies at a large number of waste sites requiring cleanup.
Land Treatment

Land treatment techniques for bioremediation purposes most often are used for
treatment of contaminated soil, but certain petroleum waste sludges have long
been applied to soil for treatment. Ideally, the contaminated soil can be treated in
place (in situ). Often, however, the soil must be excavated and moved to a location
better suited to control of the land treatment process (ex situ).

In situ land treatment is limited by the depth of soil that can be effectively treated.
In many soils, effective oxygen diffusion sufficient for desirable rates of
bioremediation extends to a range of only a few inches to about 12 inches into the
soil, although depths of 2 feet and greater have been effectively treated in some
cases.

Ex situ treatment generally involves applications of lifts of contaminated soil to a
prepared bed reactor. This reactor is usually lined with clay and/or plastic liners,
provided with irrigation, drainage, and soil water monitoring systems, and
surrounded with a berm. The lifts of contaminated soil are usually placed on a bed
of relatively porous, noncontaminated soil.
Land Treatment
Land Treatment
Phytoremediation


    Phytoremediation is the use of higher plants to
    bioremediate contamination in soil, water, or
    sediments. Variations of phytoremediation that have been
    used in the past include wetlands to treat
    municipal sewage or neutralize acidic mine drainage.

    Currently, phytoremediation is proposed for
    remediation of both organic and inorganic contaminants
    in soil, sediments and water.
Plants may transport oxygen into the subsurface; lower the water table by transpiration,
thereby pulling oxygen into the soil from the atmosphere; and increase hydraulic
                                                                             Phytoremediation

conductivity of the soil as roots produce channels in soil.

Flood-tolerant and wetland plants are especially efficient at transporting oxygen into the
subsurface. These processes are thought to enhance aerobic
biodegradation by increasing oxygen in the subsurface.

As plants transpire, the movement of water through the plant also carries along
dissolved components. Dissolved contaminants such as chlorinated solvents can be
removed from the soil in the transpiration stream and emitted to the atmosphere
through the plant leaves. This type of "remediation" could be undesirable
Composting
  Historically, composting has been used to degrade solid waste materials such as
  leaf litter, sewage sludge, and food wastes. More recently, composting has been
  investigated as a remediation technology for hazardous wastes . Laboratory and
  field-scale work has been conducted to determine the fate of polycyclic aromatic
  hydrocarbons and explosives in the composting environment.

  Composting is not generally employed to treat heavy metals or other inorganics,
  although it may be applicable to inorganic cyanides. Other studies have indicated
  that composting is potentially effective in degrading or transforming petroleum
  hydrocarbons and pesticides to environmentally acceptable or less mobile
  compounds.
Biopiles



Biopile systems offer the potential for cost-effective treatment of contaminated
soils. Like composting, biopiles provide favorable environments for indigenous
microorganisms to degrade contaminants present in the soil matrix. Although
similar to compost piles, these systems differ in that lesser quantities of
bulking agents are used in biopile units.

Air is supplied to the biopile system through a system of piping and pumps
that either forces air into the pile under positive pressure or draws air through
the pile under negative pressure (1). Depending on the contaminants in the
soil, conditions are established in the biopile to favor either anaerobic or
aerobic microorganisms. In some cases, exogenous microbes, such as fungi,
may be added to the biopile to enhance contaminant degradation.
Biopiles
Treatment of Hazardous Waste Constituents in Soil by
Lignin-Degrading Fungi

 The diversity of fungi and their remarkable ability to degrade complex
 and persistent natural materials such as lignin exemplify the host of
 useful features (1) found with these organisms. In contrast to bacteria,
 fungi are able to extend the location of their biomass through hyphal
 growth in search of growth substrates. Lignin-degrading fungi have
 been investigated for their enzymatic activity to degrade aromatic
 organic chemicals, which are structurally related to the composition of
 lignin.

 Enzymes involved in lignin breakdown are extracellular and have low
 substrate specificity. Fungi can thoroughly colonize soil and show
 exceptional tolerance to high concentrations of toxic pollutants.
 Chemical structural similarities and expected reactivities between
 lignin and organic pollutants have fostered the consideration of these
 fungi as potential pollutant degraders.
Fungi
Slurry Bioreactors
A slurry bioreactor may be defined as a containment vessel and apparatus
used to create a threephase (solid, liquid, and gas) mixing condition to
hasten the biodegradation of soil-bound and water-soluble contamination
as a water slurry of the contaminated soil, sediment, or sludge and
biomass (usually indigenous bacteria) capable of degrading targeted
contaminants.
Slurry Bioreactors
Fixed Film Bioreactors
  Fixed film bioreactors have become conventional technology for treating
  biodegradable contaminants in air and water. Principal fixed film bioreactor
  applications include treatment of industrial wastewaters, leachates or
  ground water, and air emissions of volatile organic compounds (VOCs).

  In the reactors, biological activity usually converts contaminants to
  innocuous end products such as carbon dioxide, methane, and water.
  Conventional fixed film reactor approaches involve aerobic, aerobic co-
  metabolic (with aliphatic and aromatic organic inducers), and anaerobic
  metabolism. Emerging reactor approaches also include sequential
  anaerobic/aerobic metabolism.
Suspended Growth Bioreactors
 Suspended growth bioreactors are standard technology for treating organic
 contaminants in aqueous and waste sludge systems. The reactors use microbial
 metabolism under aerobic, anaerobic, or sequential anaerobic/aerobic conditions
 to biosorb organic compounds and biodegrade them to innocuous residuals.

 The microbial activity in the systems produces biomass that is removed by
 gravity sedimentation, with a portion of the settled biomass recycled to maintain a
 desired mixed liquor suspended solids concentration in the bioreactor.


 The excess biomass is
 wasted to a sludge
 disposal process.
 Reactor configurations
 includes sequencing
 batch reactors (SBRs),
 completely mixed
 activated sludge
 systems, plug flow
 activated sludge
 systems, and aerobic
 and anaerobic digestors.
Natural Attenuation 1
Natural Attenuation 2
Natural Attenuation 3
Natural Attenuation 4
Natural Attenuation 5
Natural Attenuation 6
Natural Attenuation Summary
Natural Attenuation Summary - Ontario



 Must be proven to not migrate over property boundary.
 Must be monitored
 Can be site specific assessment
 Often used in conjunction or as an addition to other
 remediation procedures

								
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