Kind: captions
Language: en
think that is in 2007 he was in
uh my lab for
around four months and for how long did
he was here almost six months yeah
almost six months almost six months
and then he was here last year
so that one is featured last year with
the dean at the time
professional dede and myself
and raj is now is the professor in the
nicole state
university and that's probably you can
read that
he was she was
doing research and and teaching it's a
bit excellent teaching and research as
well
and more 30 years of research experience
in the area of bioremediation and
bioprocessing
and his works a lot on the
bioremediation of hazardous chemicals
including the oil spill and explosive
and biological treatment of fish water
drink fresh water and also
antibiotic resistant genes in the
environment so i thinks and also the bio
ethanol products so uh he uh
prostrates will give a lectures uh
not only today but also the next uh
friday and then
there will be four uh lecture from
uh pro so right things that uh
the introduction of you probably you you
could you may start your your lecture
your class uh right so you can
uh share by yourself okay yeah
okay i think
for inviting me to give a talk and today
i'm going to talk about
bioremediation i'm going to share the
slides
let me get this slide sharing feature
um so the talk is going to be on
starting with the fundamentals of
bioremediation
and then build up to a little bit of
actual
bioremediation methods
and then we're gonna next class i'm
gonna talk about
introducing some case studies and that
some other research i
had done here uh can everybody see my
slides okay
can y'all see the slides uh yes yes
clearly
okay all right so let's talk about
bioremediation
i'm going to introduce so it's going to
be some of you may already know some of
this thing because
of the mixed group of students i start
with very basic and then i'm going to
build up
different methods okay so first of all
uh
so we live in the environment the
environment is basically everything
including organisms and abiotic
conditions soil air water
temperature humidity radiation so
environment
includes everything biotic and abiotic
things okay
so when we talk about biotechnology and
environment
when you combine these two things
together environmental biotechnology is
the
use of organisms to clean up
whatever pollutant we throw out in the
environment so it's a
development use and regulation of
biological system
for remediation of contaminated
environment it's everything land air and
water
and also for environmental friendly
processes so
basically we're trying to use the
microorganism to remedy um
whatever problems we have in the
environment
so it's all started um for the
the events of the environmental movement
started when rachel carson
carlson in 1960s published a book called
silent spring
and she was actually a usda department
agriculture scientist in
u.s and she wrote a book about the
use of ddt and the problem it is causing
in the environment in the 1960s
okay at that time she was met with
skepticism and
but she published the book and that book
became a bestseller
and then she already in the 60s he was
warning about the
misuse of ddt it's going to be a big
problem and then we had a
nuclear accident in new york state in
low canal
that created environmental awareness and
then we had a lot of rivers in the u.s
in the 1970 was burning because of
pollution in the river
they couldn't put out the fire so these
even
build up to um to look at the
environment
and you know you need to make sure that
we clean up the environment and recently
went like oil spills exxon valdez in 89
and 2010 right in my backyard we had
this
bp oil blow up that happened so a lot of
these
environmental problems that we that
triggers
the awareness to public to take care of
the environment and start
you know looking at cleaning the
contaminated contamination we already
did to the environment
so what do they all have in common all
this problem because of industrial
revolution
there is increase in a lot of products
and increase in waste
and population increase in worldwide
and people are moving to urban cities
and the human population so these are
all
building up for a long time and um
as a result um everything out of
balance and we're throwing a lot of
waste and contaminating the
environment and perpetuating this
problem and uh
not my money solution is uh put in place
correct
currently so a little bit of a u.s
history but
indonesia has a same um history too
regarding environmental law
so there are a lot of regulation passed
uh here we have
called resource conservation recovery
act which basically
identify all the hazardous waste and
establish
standard and how to manage these
hazardous waste properly
how to store them how to transport them
and you have to keep
records of everything called chain of
custody and then we have
environmental protection agency initiate
what they call super fund programs
every year they dedicate certain amount
of
budget to clean up a contaminated site
if they couldn't find the
who polluted the site um so the
government will clean it up and then
later on they go to the legal system to
look for who did the pollution and try
to recover the money so instead of
waiting for the people to do the cleanup
the government will do the cleanup
and then later on they will get the
money back
somehow through legal process okay and
nowadays we introduce
the environmental genome project which
is basically looking at the
impacts of environmental chemicals that
we throw in
causing human disease a lot of those
chemicals that
can induce some autoimmune disease and
other diseases that
we're trying to make sure that we
account for everything okay
uh so where the waste comes from waste
come from all forms
solid liquid gas everything we throw
them
for daily use and they end up in the
environment
so how do you classify that is hazardous
and anything that can explode anything
that can catch fire
and release toxic fumes and particles
and cause corrosion
so there's a lot of label uh to make
sure
which chemicals are put in what category
but there are generally called
hazardous chemicals okay so here's a
simple example of what we throw in how
long it will going to persist in the
environment okay
before it can completely degrade as a
garbage
chest um banana queen for example it's
going to stay in the environment for
half a year
six months before it can be completely
degraded okay
uh wood scrap and sawdust gonna last for
four years
uh wax paper for five years so if you
look at this
list um a plastic curtain can last for
500 years
and glass bottles are more than finally
yeah so this
is some of the simple thing that we use
and we don't even consider
lo you think don't think about it and
don't just throw them
throw out you know um so those things
kind of
accumulate if you look at more than
seven billion people
um gonna you know occupy this earth is
already there
this population growth and so all this
uh contaminants gonna pile up right um
if you look at nature nature has
everything is in balance everything is
recycled
in nature nothing goes waste all right
so
one form is convert another and then
another farm is kind of another and
completely
recycled most of these recycling in
nature is done by microorganisms
bacteria fungi algae and other
microorganisms so
there's nothing piling up right because
everything is completely
recycled in nature there is no waste in
nature okay
this is what we're trying to duplicate
in um you know circular economy the bus
world nowadays right
um so what are those uh different things
that we throw out everything if you
mineralize whatever we
put them uh it's end up in uh mineral
form like carbon nitrogen sulfur
phosphorus
all these minerals are basically um
cycled by
microorganisms and we call that
biogeochemical cyclic
cycle so carbon cycle nitrogen cycle
sulfur cycle phosphorous cycle every
element we have
we have microorganisms that participate
in these biogeos
chemical cycle processes okay so there
is simply going through carbon cycle
carbon cycle is basically between three
events photosynthesis
respiration and decomposition are
degradation
right so it has to be in balance if it
is out of balance
then you're going to have accumulation
of greenhouse gases
and it's going to cause global warming
that's what's happening because we're
putting out more
co2 and methane then nature can recycle
okay and then we have nitrogen cycle
microorganisms um there is plenty of
nitrogen in that
in the atmosphere right almost 80
percent of the gas is
nitrogen gas but none of the organism
can use that
nitrogen the only organism that can fix
the nitrogen is bacteria
and some fungi they do nitrogen fixation
and they take the nitrogen gas and
convert them to ammonia
and then soil bacteria convert them to
nitrate and nitrite and that
plant can take it up and then plant uh
when we eat the plant we get the
nitrate in the form of protein other
stuff and and then when we die and
decompose it's released
in denitrification and decomposition
release of nitrogen gas so if you look
at it
every step of the way that is
microorganism play a key role in
nitrogen cycle
okay um sulfur cycle is the same thing
most of the sulfur is in the form of
elemental sulfur sulfate and hydrogen
sulfide
and these cycles are cycled by aerobic
and anaerobic bacteria
and then the sulfur end up in in higher
organisms in the form of protein
and amino acids and when we die and
decompose it's released back into the
environment so these are completely
in loop and completely cycle
by microorganisms and phosphorus is
another
element phosphorus there is plenty of
phosphorus but all those phosphorus on
earth is
in insoluble form an unusable form
the microorganism make them into soluble
form
so plant can uptake them and then you go
through food chain
and when we die and decompose microbes
break down and make into
a usable form again so this is a
complete loop in every cycle
so the take-home message is there is
no waste in nature microorganisms play a
key role
in cycling everything in the environment
okay
um so let's talk about um
the whole concept of this thing put
together by
uh as a ecologist from england his name
is dr
james lovelock he proposed a concept
called gaia hypothesis so gaia is a
greek word
for a goddess of the earth okay so
he said that all the organism and all
the
surroundings you should consider as one
super organisms
right so they're all in balance so every
organism has its own niche our own role
to play
if one thing go out of back out of
balance everything going to collapse
that's called simply called guy
hypothesis
um so in guy hypothesis it was
maintaining
until we human interfere
and put more stuff into the environment
it's kind of going out of whack
okay so in order to somehow
pull it back we need to clean up the
pollution we put in
you know so that the nature can go back
to its what was been doing before
so also use compounds that are
biodegradable
and produce energy and materials in less
destructive ways so recycle
most of the stuff that we use and also
monitor environmental health
and you have to start from the from the
kindergarten so it can
be incorporated into people when they
grow up
so so you need to be educating
um starting from 10 people okay
so those are some of the things that we
can do to
get back to what nature can um you know
do this
cycling process so let's talk about
bioremediation and how it
finds finds its place nowadays it's
because of
nowadays we have companies that are
specializing in cleaning up a lot of
toxic waste spills
and and then we have super organisms
called superbugs that can do cleanup
um there are however many organism in
nature we still need to be explored
that can do a lot of these uh you know
processes
to degrade chemical that
that we never you know explore yet there
are too many
microorganisms still to be explored
um so if you look at all this
the simple concept of how we clean up
contaminations
all you need to do is look into the
wetlands
okay the wetlands are marshes i mean
some people call them it's the same
thing
and those are ideal places where you see
a lot of
cleaning up a lot of the chemicals that
we throw them end up in wetland
and and they do fantastic job of
cleaning up
the contaminant really well in nature
okay
um so how do all the chemical end up in
the environment waterways made mostly
through runoff and leachate
and they all end up in water bodies you
know when it gets into water bodies it's
going to easily get into food chain and
food wherever it gets it comes all the
way to you know human
um food chain we are the super uh
predators on
on the earth so so bio remediation
depends on
um what is contaminated you need to know
what chemicals are there
and what type of chemicals need to be
cleaned up there is you know not one
chemical in the environment there's so
many of them they're complex of
chemicals environment i also need to
know the concentration
and because too much chemical uh
particular compound can be toxic to
microorganisms
and then how long this chemical persists
in the environment so those are some of
the basics you need to know
before you start up um cleaning this
particular
contamination site um
so we we have if you look at simply the
sewage that we let out
we have a lot of stuff we put in there
so most of the um
food that we eat can be easily degraded
these are like carbohydrate protein
lipids that's in our fecal matter that
bacteria can take care of them because
they have seen it before
a thing that the bacteria never saw
before like antibiotics
birth control pills and those kind of
chemicals
um it's going to take a while for
bacteria to develop
enzyme to degrade that kind of chemical
you've never seen before
okay i mean have a lot of perfumes and
throw them medicines unused medicine
fertilizer as to say everything end up
in sewage of water
and then we have industrial chemical and
agriculture chemicals so these are some
of the
contaminants that we use in our everyday
life that
end up in in the environment so some of
the lists just to give you some examples
this is some of the
top 20 chemicals that we throw
starting from benzene you know all the
way to antibiotics to
medicine to even explosive chemicals we
use in our
construction sites to demolish buildings
and so
these are some of the top 20 chemicals
we
use we never even think about it but get
into the environment
okay um let's look at how microorganisms
clean
um these chemicals it's very simple
chemistry
it's a oxidation reduction reaction so
this oxidation reduction
happens aerobically or anaerobically
depending on the site
so aerobic organisms can do oxidation
processes anaerobic can do reduction
process
so it need to have this you know
electron donor an electron acceptor
in a very simple term so when you break
down a compound you release electron the
electron has to
go somewhere you need to have electron
acceptor so in aerobic condition oxygen
is your electron acceptor so here is a
simple
oxidation reduction reaction so this
reaction takes place simultaneously
that's why it's called redox reaction
um just to give you some examples so in
aerobic conditions we have say look at
the benzene
be broken down by simply breaking uh the
ring
opened by a bacterial enzyme called
dioxygenase enzyme they break the
benzene ring and then once you break the
benzene being you have these electrons
released for so
the hydrogen has to go somewhere and
hydrogen ended up in the electron
acceptor oxygen and it's simple
oxidation reduction reaction okay under
anaerobic condition this
the same chemical or toluene in this
case
um under anaerobically the same
mechanism keep
the ring open the electron has to go
somewhere but there is no oxygen
available in the anaerobic condition so
what they look
different oxygen containing salt like
nitrate sulfate
iron oxide manganese all those
um chemicals could be used as electron
acceptor so as a result you have nitro
reducing bacteria
sulfate reducing bacteria iron-reducing
bacteria
can process this electron transfer them
to these acceptors that is available in
the environment under anaerobic
condition
but it is simple oxidation reduction
reaction you need to get the electron
the electrons go somewhere
you need to have electron accepted to
receive them so aerobically oxygen is
the most
commonly used terminal electron acceptor
anaerobically you need a lot of
different
electron accepting conditions depending
on the redox condition
of the environment okay so let's look at
uh some of these
man-made compound these are called
xenobiotic compounds
and these are the compound never existed
in the environment these are produced by
humans for our own use and end up in the
environment so some of them are
a lot of pesticides and herbicides
insecticide fungicides
everything end up in the environment and
we have
some others pesticide bacteria can use
them as carbon source if it is not
heavily substituted with a lot of these
different
inorganic substitution because bacteria
had seen some of the similar form of
chemicals in in nature example phenol
phenol is a naturally accept
present compound so vector has mechanism
to degrade canal
but if you substitute phenol with nitro
group or
amino group or some other methyl groups
and
it's kind of tricky for the
microorganism it has to wait for a
long time to develop the enzyme
mechanism to degrade them so
we have so many chemicals those are
called xenobiotic chemicals end up in
the environment so here's some list
uh halogen substituted organic so
anything chlorine bromine fluorine
iodine that is substituted an organic
compound or halogenated compound
we are nitro substituted compound like
trinitrotoluene which is our dynamite
tnt
a lot of solvent right trichloroethylene
pentachloroethylene
okay and then you have pcbs polychromos
biphenyl
a lot of detergents the detergents
contain some have phosphate
although we are eliminating phosphate
containing detergents
then plastics and everybody uses
plastics and that's all
you know high molecular weight and it's
very hard to
degrade and then of course our petroleum
hydrocarbon which is even though it's a
natural
compound and because of its such
heavy polyaromatic nature and
it is very hard to degrade by
microorganism it takes some time
okay so so if you give favorable
condition
and enough time um the natural organism
uh in the present environment will take
care of these chemicals so that's why we
don't have a large scale
pile up of naturally occurring chemicals
in the environment it's been cycled by
microorganisms because they
evolved enzyme to take care of it but
when you throw the
xenobiotic compound the compound that
are substituted heavily or
high molecular weight like plastic um
bacteria it's recently it's been we have
done
that in terms of evolutionary um
time scale it's been only recent the
bacteria has been exposed to this
chemical
so they are slowly developing uh enzyme
to degrade so i don't know how many of
you followed now there is
plastic eating microbes people already
isolated from
a meal worm a worm inside the worm there
is bacteria that can now
degrade plastics okay so if the compound
persists for a
long period of time in the environment
the term is called recalcitrant
compounds so recalcitrant compound are
very hard to degrade by microorganism
okay
so because of as i said before unusual
substitution
like chlorine and other halogenic
compound and high molecular weight
because of the size and then condensed
aromatic structure
a ring so this all these properties
to a chemical make the compound hard to
degrade
we call that recalcitrant compound and
this result
recursion compound um also pursues the
environment for
other reasons the other reasons are as i
said before the microorganism doesn't
produce enough enzyme
to degrade because it didn't develop
that enzyme okay
and the compound is sometimes not
bioavailable because these compounds are
not water soluble some of them are
if it is not water soluble it's not
going to be
available for degradation some of them
are absorbed
in you know clay matrix so it's not
bioavailable so there's a
bioavailability problem
and sometimes we throw excess of this
chemical in one particular spot
that lead to toxicity so it's going to
kill up kill all the good bacteria in
your system
so and so that's some of the reasons so
as a result these compounds could bio
magnify in food chain that means the
compound will accumulate
at every trophic level of food chain
and then the super predator the organism
that sitting on the top of food chain
like humans
we we're going to be accumulating this
chemical in our body in our system
okay for example when ddt was used in
the 60s and 70s in u.s
every person on average in u.s had
blood ddt level of 2 ppm
okay it accumulated in everybody in
in us when they use this chemical
heavily right
so that's called biomagnification even
though you're applying the ddt in the
environment to control mosquitoes
it goes through the food chain and you
accumulate in
in in your body so the same thing ddt
almost wiped out the u.s
symbol of bald eagle so it is just a um
picture of how this uh biomagnification
occurs in every trophic level even
though
the ddd concentration is um you know
point zero zero zero zero three ppm
or in parts per billion then it goes up
in the
food chain it accumulates and and if you
look at the bald eagle
which is sitting at the top of the food
chain the ddt
in in the in the eagle was 20
25 ppm and uh it
almost the whole species almost wiped
out okay so
and then it they banned the ddd and then
and slowly the population come back
again okay
so how do you define biodegradation
it's a biologically catalyzed reduction
in complexity of chemicals so that means
a
microorganism play a role
and modify the chemical structure and
kept in doing during catalysis
reaction it reduced the complexity of
the molecule okay
there's another term called
biotransformation and biotransformation
is not complete mineralization it's just
a slight modification of the structure
of the compound
that is called biotransformation so
nitro group become amino group
in organic compound so that's like a
nitrophenol become aminophenol so that's
going to be a bad transformation nothing
happened except
in order to become nh2 okay that is
biotransformation
uh mineralization is what you want if
you want to clean up
you want to completely convert all the
organic moiety into inorganic
entities so everything is converted in
organic form carbon end up in carbon
dioxide
any substitution end up in in released
and become
ionic form and then precipitate out okay
so that's what you want in real complete
cleanup we call
mineralization so
um if you look at the the testing
process of biodegradation before you get
into bioremediation you need to know a
little bit about how we
um we test the chemical so uh the fact
shortly after the widespread use of this
pesticide uh it was recognized that a
lot of these compounds
have um different periods of persistent
in soil and water
okay but slowly they found out there are
organisms out there
that can take care of this okay well one
time they said that tce cannot be
degraded but now tce can be easily
degraded trichloroethylene okay
so the xeno4 molecules is what the
substituent i said the chlorine
halogens and nitro group amino group
methyl group
that added to the organic molecule they
are called xenophobe molecule these are
foreign
molecule added to an organic compound
okay these are the molecules that make
the compound more
more tough to degrade okay so bacteria
has hasn't
seen this structure before um
if you look at the
structure of different compound the
aliphatic compound
and the non-branch molecules are more
really degradable than highly
branched uh alkane in in oil still
okay and if you look at the polyaromatic
hydrocarbon the three ring compounds are
more easily degraded than
um more than three income and the more
ring you have polyaromatic
it's a highly condensed um aromatic
structure so it is
hard to degrade so the more ring it
it's very hard to degrade it's going to
hang around for a long time okay
um so then we also have environmental
effect
uh it varies from place to place so in
one place you have the right organism
in another place you don't see the same
organism that take care of it okay as i
said before
trichloroethylene if you look at it one
out of 43
sample size you find organism that can
completely degrade tce
now another example 240 which is the
pesticide used in rice fields
and it easily can mineralize
an eutrophic lake uh which is the lake
with a lot of nutrients
not in oligotrophic like the lake with
less nutrients so
the place to place microorganism varies
and some places you have a lot of good
ones that can easily take care of the
chemical and some place it
you don't have that many good bacteria
that you want to clean up okay
if you look at some of the compound like
methyl parasite
can be easily degraded in sediment
samples compared to
water columns because sediment has more
bacteria than water column
and and also microbial physiology and
optimum conditions you need to know
for complete degradation of a chemical
okay
so every bacterial strain has a range of
tolerance
you need to know what is the ph what is
the temperature range
so if you don't provide optimum
conditions
um you're not have not have a optimum
biological catalyst to degrade your
chemical it's like a chemical reaction
so you need to make this
bacteria happy they provide all the
right conditions so you need to provide
anything that is limiting okay for the
nitrogen limiting phosphorus limiting
you need to provide them for bacteria to
speed up the chemical process
and so in the environment you don't have
one single compound
because there's multiple contaminants
you don't
only only have mono compound um
only one compound dominating an
environment so
you always find a lot of different
chemicals so as a result
bacteria is looking at multiple
substrate right
so so you need to have organisms that
you know go through this um different
um what they prioritize they go for easy
carbon first
and then they go through a tougher
compound left later and all the uc
carbon is completely consumed it goes to
the less easy one
and then and so on so there's multiple
substrate available
so um so i need to make sure that
which one is at high concentration and
which one you want to degrade
and then you need to provide additional
resource for the microorganisms
and and after you provide all of the
things most of the bioremediation people
forget about this
predation so bacteria has predators so
you provide everything for a cleanup and
then you forget about
protozoa forget about some um
bacteriophage which is viruses in the
environment that's going to kill your
good ones
so you need to understand predation a
microbial predation in
your cleanup environmental side
so these are some of the uh
conditions you need to know before you
jump into
cleaning up a contaminated site okay so
there's some basics okay
and so we not only concentrate on
aerobic because most of the cleanup is
aerobic
condition because oxygen electronics
after your reaction rate is faster
but there are a lot of anaerobic
bacteria that can do the same thing if
the
chemical is in anaerobic site you don't
have to create an aerobic pocket
to clean up an anaerobic site that is
contaminated
you try to grow anaerobic bacteria to
take care of it okay
so a lot of compounds can be degraded
anaerobically like nitrophenol
nitrogen carbon tetrachloride pcb tce
they can be degraded anaerobically as
well
um so what is lacking as i said before
and the right organisms right you need
to have a right organism to
do this chemical degradation if don't if
you don't have the right organism
you you grow them in your lab and
in a large quantity depending on how
much the bigger site you have
and then you go inaculate this organism
right that's called inoculation of
bacteria
so you to enhance or speed up your
degradation process that you want to
clean up
so when do you do that and so you cannot
um you know do it right away without
doing any research you need to know that
if the rate of degradation is slower in
the contaminated side
then the the leaching of the chemical
that's going to spread the chemical
into farther places then you need to
intervene you need to do
add this good bacteria grow in the lab
and add to the site
if there is no specific biodegrading
bacteria is absent then he had to do
that
if the addition of certain bacteria is
essential for syntrophic degradation
because
if it is a two-step process a three-step
process
in nature you only have uh one or
two-step uh process bacteria available
there is a
additional bacteria needed to you know
completely mineralize then you have to
find that bacteria and you add
into the mixture of cleanup process
okay and lastly the chemical
concentration very high
wiped out all the good ones uh all the
good bacteria in the contaminated site
then
you obviously have to grow bacteria in
the lab and and
put it in the environment where we want
to clean up that's called by
augmentation
inoculation okay and so those are some
of the inoculation
um factors that you need to be prudent
you need to do some research find out
first to use the indigenous bacteria
inside
if it does not work then only you do
bioaugment
and also there is no genetically
modified
organism you cannot put them out in the
environment so in the u.s it is banned
you can use a genetically modified
organism only in control conditions
it should be in a reactor in a tank
after cleanup
you kill the organisms okay so you
cannot use them
out in the environment so you need to
prepare the inoculum
develop the enrichment culture grow them
in big tanks
and into select the population that
works for you and optimize the condition
and get the high c uh high cell yield
okay
um again some more about inoculation
inoculum prep
um so you need to do some previous
research you don't have to reinvent the
wheel
do some literature search uh if your
contaminated site has say parathyan you
already know pseudomonas tootsie rice
the right bacteria for you you can buy
this from
culture collection and grow them if you
have a pcb
contaminated site the rhodococcus
chlorophenolics arthrobacter flavi
bacterium are the good ones
uh if you have a linden chlordane kind
of chemicals
white rod fungus will do the job a lot
of crude oil contamination
east candida gilar mandia can do the job
so if you do some literature search you
know which bacteria which fungus
can clean up the site you grow these
organisms and then you go
add to the sides to speed up cleanup
process
and then we have three kind of mode of
action most of the time
you need growing cells to do your
cleanup because when bacteria actively
divide
that's where the faster the reaction
that's where the cleanup takes place you
need to have growing cells but sometimes
the resting cells do it
sometimes you can use cell free extract
like enzymes
so you can grow the bacteria and develop
and get the enzymes out of the cell
and then use this enzyme in different
form okay
and so that's different mode of action
out there
to clean so let's talk about
biodegradation testing so you need to
know when you look at the
cleanup site and what are the
the various size of organisms that
already exist
how they are distributed what are the
metabolic activity
and the enzyme and nutritional
requirement for these organisms
and and then the bacteria with all this
condition they developed
evolutionary process to take care of
this chemical
they either use them as carbon source we
call that growth
linked enzymatic reaction or growth link
biodegradation
and they can simply detoxify
and modify like biotransformation and
then they leave the chemical in
on the side and the chemical will not
undergo any more
further degradation ah co-metabolic
condition is called non-growth
linked biodegradation in this case you
need to add
some simple carbon source substrate and
so the bacteria can grow
on the simple substrate and then
metabolize the chemical you want to
degrade so those are three different
um evolutionary process microorganism
develop
to that we can take advantage of
depending on
ideally you want growth linked
biodegradation bacteria could
use the carbon as a chemical that you
clean up as your carbon source so they
can eat
and and eliminate from the environment
okay
and as i said before there are
thermodynamic conditions that exist in
nature so you need to look at
a contaminated site what is the redox
potential of the site
you don't want to go create an aerobic
condition in an anaerobic site that's
not
viable so there is aerobic respiration
and there is go down the ladder on
different
nitro reduction all the way to
methanogenic condition depending on your
redox potentially
negative 200 to 300 you get sulphur
reducing condition methanogenic
condition so just to
show you this redux potential starting
from oxygen as electron acceptor
all the way to hydrogen is electron
acceptor um
i mean i relate to co2 as electron
acceptor the methanogenic bacteria can
take care of
um at highly redox conditions so we can
exploit
every level of redox different group of
microorganisms
so if you know what is redox in your
contaminated site
okay so step one
you develop your enrichment study very
fundamental go get the sample
and look for the organisms at the site
and grow them in enrichment condition
and just to a simple experiment whether
the chemical is going away
what other metabolite is producing then
you go next step to isolate
pure culture and study metabolic pathway
if there are multiple arguments from
doing the job which are
doing water reactions so that's the
first thing you do
in biodegradation and testing okay
uh with that information now you're
going to jump into actual
cleanup so so what is bioremediation
so bioremediation as i said is the use
of biological
treatment system to reduce or to destroy
the concentration of hazardous waste in
a contaminated site that is a broad
definition of bioremediation and
so what you're doing in bioremediation
is to
either reduce the concentration or
completely eliminate the hazardous
chemical in from a contaminated site so
bioremediation is basically
intentional use of what i just talked
about biodegradation process
so we are intentionally using the
biodegradation process
to eliminate the pollutants that we have
put them in the contaminated side
okay and so we are exploiting
microbial physiology so we are using
microorganism
and exploiting their physiology to
eliminate so it basically
knows basic micro chemistry engineering
so it's like a multi-disciplinary
science
uh uh doing an actual cleanup okay
so the simple theory of bioremediation
is called bioremediation triangle
theory which is you have if you want to
clean up any particular
contaminated side there are three points
and those three points are contaminants
the chemical itself
and the right microorganism that can
degrade it
and then the optimum condition like
nutrients what what kind of nutrient the
bacteria need
if you provide all this um to the site
um you did the job the bacteria are
going to do clean up the
chemical so the problem is there's an
engineering challenge to bring all these
three
things together in a difficult
environmental
site condition some of those sites are
100 feet down in groundwater
some of these sites are in between
buildings uh some of the sites are in
the
middle of the city right so that's where
the engineering
come into play how do you provide these
three things for this microorganism to
bring your bioremediation triangle so
the next slide
shows the picture so you have the
pollutants you have the microorganisms
you have the optimum conditions for the
environment
so you provide them all and the bacteria
will take care of the
condition these are the three corners of
bioremediation triangle
so you bring it everything together on a
very very difficult environment
environmental site condition that's
where the engineers come in play
how to you know provide these things to
a difficult
conditions so let's look at how are you
going to implement
this bioremediation um if you do the
cleanup
outside we call that
in-situ bioremediation but if you remove
the contaminated
contaminant and put them in a container
or do it in a separate place
it is called exeter depending on where
you are doing the cleanup
it's inciting is right on site where the
contaminant is
exeter is um you just remove the
contaminant put in a reactor or
something uh take it on other side or
clean up
when you disturb the site you call it
exit to bioremediation so based on
where you do the cleanup okay so here's
an example
so you if you do it right on the place
um we call the institute if you dig up
and put in a reactor or take it another
side it's
called exit 2 so some of the examples
are the slurry phase
solid phase composting and land farming
are institute
i'm going to talk about it and then when
you
put in a reactor it becomes a slurry
phase reactor then that's called exo2
bioremediation
so how do you implement bioemulation
depending on
how aggressive you are bioremediation is
classified as
intrinsic bioremediation or it's also
called past
so you just leave to the inner capacity
of microbes at the contaminated site
and they are going to do the job all
you're going to do is simply monitor
the chemical concentration how it's
going away you don't do anything else
everything is in place all that
bioemulation triangle i showed you
you have the right organism in place
right nutrients are available
polytron is also right in place by it's
available to the microorganism
so everything is in place you don't do
anything to the side
you just simply monitor the
concentration of chemicals away that is
called
intrinsic bioremediation or passive by
remediation
okay alternatively you can engineer the
bioemulation process
and that you modify the site you're
going to do
something to the site to speed up the
process
and that is called engineered
bioremediation that's what
all uh all the professionals do to do a
real cleanup
uh we basically enhance this
biodegradation process so you just
somehow give all those nutrients to the
bacteria in some form of
another and make the chemical
bioavailable
add the right organism to the site so
you're just manipulating the site that
is engineered by
remediation so how do you select uh
what method to use to clean up a site
so the the decision was selecting bio
emission method
depends on the contaminant
characteristics
what is the toxicity of the chemical
what is the molecular weight of the
chemical
how soluble it is is it a volatile
compound or semi-volatile compound
where the compound is you know
completely susceptible to microbial
degradation so you need to know all
these features before you select the
method
it also depends on the site itself the
geology
hydrology soil type climate
and then he had the other aspect legal
you know economic and political pressure
right all as a scientist we don't think
about that
so if you get into the real world of
cleanup you need to think about that
how much pressure is put on you to do
the cleanup and
what is the cost and all that
you need to put in everything in you
know pen and paper
and come up with what method gonna work
for our particular site
okay so intrinsic violation depends on
the native microorganism
availability of nutrient and and the
availability of the chemical to the
organism all right and in order for
intensity to be effective
you need to have the contaminant
destruction must be faster than the rate
of contaminant migration so you
you don't want it to have a slow
degradation you want to have
somewhat uh you know enhanced
degradation
naturally occurring because you don't
want the chemical
to spread if it is a ground water
contaminant
and the plume going to go farther and
farther if the degradation
of chemical is going to be slower
naturally so
a lot of things depend on how you choose
whether you want intrinsic or
engineered by remediation so engineer
bioremediation is
always the choice people go for this
because it's
first it's faster right um
and then you can clean up completely and
uh
and and but there is cost involved you
know it's a lot of
money involved when you dig up a
contaminated side and put all these
sensors and bioreactors it's going to
cost you a lot of money
and then also there are a lot of
people prefer engineered by remediation
over
intrinsic biology and because of
liability issue in the us because
it's a legal system people going to see
you for millions and billions of dollars
and so
the sooner you get rid of the chemical
better you are even though you're going
to spend a lot of money okay
so how do you assess the strategy see
first you
check whether um the contaminated site
has any undesirable
characteristics such as whether the
chemical has
problem not available to the bacteria
bind to the clay or bind to
humic material in the site so you need
to do a complete environmental
characteristic
where the site is located and toxicity
of the chemical
if such thing if such thing exists you
need to do pre-treatment
so make sure you reduce all those um
problem for the microbe so you do
pre-treatment and then you need to make
sure there is a degradation is happening
in the place with if it is an anaerobic
condition so without oxygen is taking
place
and then you need to make sure there's
all the
contaminants are available to if it is
an aerobic
place it's a substrate is available for
aerobic conditions
and you also check whether the
contaminant is a growth substrate
that's what ideal for you the
contaminant going to be used by battery
as
carbon source so they grow on them all
right
if it is not a growth substrate you need
to look for
what additional substrate you have to
add
to enhance the population that is called
coast substrate
it's called co metabolism okay so all
this condition you need to assess first
that's called site characterization
once you did that then you review the
work plan so you look at
existing data then collect sample and do
a
characterization of material and do a
small treatability study in your lab you
need to do a
first you do a treatability study and
then assess the condition
is it going to work for you if it is not
going to work you need to tell them hey
buyer remediation is not the way but
remember it's not going to work
right go for physical or chemical method
to clean up so
when you do this small um treatability
study you can know
um and then you can tell the people that
this method is not going to work if it
works then you have to choose a method
what method is you're going to recommend
and then it
execute a cleanup so that's kind of a
work plan for
how to clean up a contaminated sign okay
um so let's go through some of the
bioremediation methods so first
we already talked about bioaugmentation
which is basically inoculation of
bacteria
you find the right bacteria and add grow
the bacteria in um
in a lab or in a in a big settings and
then go ahead
when you when these bacteria are needed
and that's called bioaugmentation
okay you can use bio filter for air
contaminant
so you see a if like a volatile compound
you need to
eliminate so you use biofilter which is
basically
like a reactor and they put the volatile
compound into the reactor
the bacteric only use them as carbon so
okay
and then biostimulation which is most
commonly used method because
in the contaminated side at least one or
two nutrient is lacking most of the time
it's oxygen
if it is aerobic bacteria and
our nitrogen and phosphorus those are
limiting factors
so you need to have a certain carbon
nitrogen ratio for bacteria to do three
now carbon phosphorus ratio
if you if one of those thing is limiting
and
then the bacteria are going to grow so
you need to find which is limiting and
you add the nutrient that is called
biostimulation you are adding
and nutrient that is lacking and
stimulate the growth
okay then we have soil slurry reactor
where you just like a bioreactor you dig
up the soil that need to be cleaned up
put them in a reactor make it a slurry
form so you have an easy mass transfer
mixing up and then enhance the
degradation process in your reactor
once it's treated then you're gonna you
know dump the soil back into the ground
the treated soil
the water is recycled for a next batch
of
soil that you need to clean up okay then
you have bio venting biominting as i
said most of the time
oxygen may be limiting in um you know
below surface
so you just kind of draw oxygen through
the soil
to stimulate microbial growth and
activity so everything else is available
all it's lacking is oxygen to the
environment so
in that case you just do the bio-venting
process okay
and then this solid face cleanup is
composting
composting is like exactly like your
backyard composting so you just add some
bulking agent like agriculture material
um like you know sawdust
or agriculture waste residue like
straw um so everything you put in the
contaminated side
there's a bulking agent and i i create
this thermophilic
condition vector going to grow and heat
up and then go through the thermophilic
mesophyllic phase
and it's going to clean up the chemical
in the side that's called composting
right then we have land farming another
method
which is basically is exactly like
agriculture operation what you're doing
is you're
plumbing the land so you're aerating it
and then
applying fertilizer like whichever is uh
lacking
nitrogen or phosphorus so it can be done
in situ or extra two mostly in situ two
but extra two you can
if the chemical is going to be leaching
they put a plastic
dig up and put a plastic liner to hold
the leaching material
and put the soil back and do land
falling operation so that's another
method
commonly available for cleanup then if
for groundwater contamination the
commonly used one the u.s is pump and
treat most of the gas stations here are
really really old
and those gas stations have this
underground storage tank that leaked
gasoline into the into the ground water
and those groundwater need to be treated
and the fast way to do that is pump and
treat so you pump the
water from below ground to the
above ground tank and put the right
organisms in place
and so when they clean up the chemical
and then
treated water go back into the
groundwater that's called pump and tree
then we have biofluffing which is
basically
making holes in the air in the soil you
call augering the soil to increase the
porosity
and then biopile another method and
basically you're engineering your pile
of excavated
and contaminated soil and you optimize
the right condition you provide
whatever is necessary for microorganisms
like nutrient water air
so that is called biopin and bioleaching
is mainly for
heavy metals if you are looking for
microorganism to transform
element that is in soluble form to
insoluble form
and then so when you do that you can
easily precipitate it out
and then you can extract the material
out so mainly for heavy metals and
radionuclide cleanup you can do that and
then you can use plant
that's called phytoremediation um
parallel mediation you're not completely
eliminating the chemical you're just
simply mobilizing the
chemical from uh contaminated side into
the plant biomass
and you still have to get it out of the
plant all right the chemical will move
into the plant
biomass uh it could be tree it could be
plant
and then once you have enough um
accumulated cut the plant and then you
have to incinerate it to completely get
it out of the chemical
so it's very good for you know
heavy metal contamination people use
phyto remediation
okay then aqua sparging is basically um
injection of air into
the um contaminated aquifer
to simulate aerobic condition and it may
also assimilate wallet
when you do that when you aerate the
underground
water table you're also volatilizing it
so not only biodegrading it
some of the chemicals going to
volatilize and come out in the
in the atmosphere then the sunbury
landfill is put under by remediation all
the solid waste we uh
we throw out in our cities they go to a
landfill they now call it sanitary
landfill because it's a highly
engineered process
uh so everything is completely contained
including the leachate and the
microorganism do a very slow decomposing
process because the waste is compressed
so much
and it's a process is anaerobic okay
and then there's another process called
treatment train system
you combine one or two method you
combine a physical method
with the biological method or a chemical
method with the biological method
within the biological method you combine
aerobic followed by anaerobic
and followed by aerobic so that is
called you're connecting
different method to clean up a chemical
contaminants
that's called treatment train system
okay
so these are some of the processes
already out there
and so you can do anaerobic like i said
before
using different electron acceptor and
then if a chemical is um
hard to make it soluble you can add
surfactant addition of surfactant is the
bioremediation process
okay for example the chemical called
bean apple
non dense non-aqueous face liquid
ellen apple lightning aqua space this is
the chemical either they float
or they sink depending on the density of
the chemical like
tce trichloroethylene is a dna
it is denser than water it's going to
sink to the bottom of the
water table and it's going to stay there
as a separate layer okay miscible layer
and it's going to slowly release because
the solubility is
less in water so every every time the
chemical is degraded another
concentration going to come out so it's
going to be a permanent source of
pollution okay so in that case you need
to add surfactant to make this chemical
more soluble okay then nowadays they
call it gene by augmentation this is
basically
manipulating and bacterial genes adding
specific gen