Kind: captions
Language: en
okay
so uh okay we
will start uh our
lecture our lecture so that uh uh
thank you to dr eldon eldon raj
so i think i would like to introduce uh
dr eldon
so he is uh now a
senior lecturer in the ihc deaf
institute for water education
uh in the deaf netherlands so
uh he is uh
he works a lot in the uh
wastewater biological uh treatment
uh and also for the waste cash treatment
and also working on the non-point source
pollution prevention resource recovery
from the obese gases and
also he works also on the
uh environmental process control control
and also in the eco industrial park
and dr eldon also currently served as
the managing director
for the review in and from the science
and biotechnology and also in the
journal of
environmental engineering and they are
also the editor for special
issues either in the bio-racist
bioresource technology
and and others i think that doctor eldon
is quite active in the scientific
publication uh so today
uh dr eldon will give a lecture on the
the role of different bioreactor
configuration for the
treatment and recovery of useful
products from waste cases and wastewater
so uh the time is yours
so yes please thank you thank you
professor the genre for your very nice
introduction and also
for inviting me to give this nice
lecture with
a lot of participants and i i'm really
pleased to give this lecture
to all of you so i would like to uh
start my presentation but before i go
into the topic
i would also like to give a little bit
of an introduction to
the institute where i'm working in the
netherlands it's called the
the
ihe delft institute for water education
and we are
located one hour from amsterdam
in a city called delt and that is the
same city where we also have
the technical university of delft that
is located also which is
close by and the institute that we work
it doesn't have a bachelor program
it starts with a master program we have
phd and also
we do uh focus on a lot of capacity
building
projects which also professor tajandra
has been
involved actively involved with our our
research group here
in the same department together with
professor
um damier and also with carlos hector
and many of the other colleagues from
the department so
the institute focuses mainly on water
issues
we focus with water drinking water we
focus on sanitation we also focus on
resource recovery because that is that
has been also the
the prime focus for the last few years
is not just treating water but we also
want to recover some of the
useful products or byproducts for
um from water or wastewater
but then from the mandate of the
institute you maybe
you all know that there is a severe need
for the for drinking water okay there
are countries which have
enormous amount of water but there are
also countries that
don't have sufficient amount of water so
there are water scats region there are
also
countries that that have
and risk from flooding and other type of
natural disasters so the institute was
actually started in 1957
and so far we have obtained more than
24 or 23 000 water professionals from
over 190
uh countries okay so it's a it's an
institute that focuses exclusively on
water issues and the mission of our
institute
the is the institute works in
partnership
to strengthen the capacity in the water
sector to achieve
global sustainable uh development so we
all know about the sustainable
development goals
so our institute also has identified a
few
of these sdgs and we strive to work
together to uh to focus on
on achieving these sdgs so this is done
in three
pillars the first pillar we call the
education and training
education is nothing but the master
degrees that we offer
at the same time the institute is also
has also customized the courses not in
the semester system we have modules okay
modules means each module
runs for three weeks so the three-week
program also becomes a
short course so if you would like to
come and join one of these programs then
you are also welcome
um so we had we have a lot of short post
participants who come from
different countries they come here they
gather specific skills that are required
and then they go back to their home
country okay so it's not that
you have to follow the entire program
you can come and
choose whichever courses that you want
and we also have a new program that is
called
a graduate diploma it's called gpdp
it's a graduate diploma program where
you can also customize and choose
different uh
courses and then you get a graduate
diploma okay so
we we offer a very good flexibility
between the different
tracks you can take a course that is
from engineering aspect
you can also take courses from the
management governance
and different type of courses that can
customize according to your requirements
okay so that is the first pillar that is
called education and training
and with respect to training we also do
a lot of tailor-made training programs
for example if your university wants a
certain expertise
or to develop a new program or to
develop new skills
then our staff members together with
also other experts from this
from the field we would we normally
offer such kind of training
activities so the training can be in
your home country
or you can also select 10 or 15 members
and they can also come here for a
one-month training a 10-day training so
there are different
modes in which we do this training
and the other thing is research and
innovation this is very common
in like also in your university we have
phd students and master students who
also do
uh research and the third one is the
institution and strengthening so this is
this is the prime focus also of our
institute
where we work on different capacity
building projects in the developing
countries okay so most of our partners
are from southeast asia
then from the latin american region the
mina region and also the african
countries okay so this is where we focus
our
institutional strengthening activities
so i'm not going much into the details
so this is what i had mentioned
we go we offer mscs short courses online
courses
and also tailor-made training so if you
have any
desire to put forward a proposal for a
tailor-made training or other things you
are
you're very free to contact
one of our one of the staff from the
project office
or you can also contact this email
address okay
okay friends so i'm very happy to give
this small introduction but now i would
go into the topic so before i go into
the topic i would like to
uh to tell what are the learning
objectives of this lecture
okay so you're going to spend the next
uh one hour or one and a half hours with
with me we will have some very nice
discussion okay
it's not that i will be talking all the
time i also want you to share your
experiences with
with everyone so that we will also
co-learn
from each other okay and if you
if you don't understand something or if
i'm very fast
you please tell me to stop okay or you
can also put your questions on the
chat box on the right side
okay i also see that submit question
please go to the link so
there is also a link where you can put
your questions okay that's also
great so the learning objectives
are to realize the practical
applications of different bioreactor
configurations and their role
in resource recovery so you all of you
must have or might have at least a
little background
okay on bioreactors okay we also had a
very nice talk by our friends on
on wednesday where they also explained
about different reactor technologies
different processes and they also showed
some very interesting results from their
research
so in the same way there are there are
different types of battery reactors
either it can be a batch reactor a
continuous reactor
it can be a fed batch it can be
semi-continuous it can be operated in
different modes with the recycle without
recycle
it can be a single stage a two stage it
can be one tire two tire it can be
different stages of bioreactor either it
can be a standalone process it can be a
hybrid process
it can have you know innovative packing
material
so all these bioreactor configurations
that are used
for waste water they can also be
customized and adapted for
waste gas treatment okay so
i'm not going to talk more about
wastewater because
many of you know about the conventional
wastewater treatment processes like the
activated sludge trickling filter
rotating biological conductor membrane
reactors so
in in my presentation i will focus more
on waste gases okay the waste gases are
nothing but
gases that have a lot of contaminants
that are present
in the gas phase so this can be a
volatile
organic compound like for example
benzene
it can be a volatile inorganic compound
like hydrogen sulfide
it can also contain other other
components
that are maybe in trace levels or it can
be also in high concentrations but it
depends
on the process the conditions and
the raw materials the use by the company
okay so the first thing is i would like
to specify
in my presentation a few bioreactor
configurations
that we can use for base gas treatment
and also for resource recovery
and i will also tell you uh how to
optimize bioreactor configurations and
if you have some issues with
troubleshooting
you can also do troubleshooting which i
will also cover
and and then at the end of this lecture
you will be also able to suggest
some options for downstream
recovery of the valuable products okay
so it's not just
treatment alone we also try to convert
the
gaseous form of pollutant into something
that is useful
okay which means for example the
volatile organic compound can be
converted by
certain micro mediated processes
into valuable products it can be a
platform chemical
it can be bio gas okay so it can be
anything that
depends on the process so in our chair
group
the chat group is called pollution
prevention and resource recovery chair
group
we focus on all the three aspects of
waste we focus on
solid waste for example we have we have
a research line
which focuses exclusively on recovering
critical elements precious metals base
metals
from electronic waste then we also have
a researcher who is focusing more on
dry or wet anaerobic technologies and
we have another research group that is
focusing on biochar hydro chart
production
then we also have a group on solid waste
management
and on on the application of
echo technologies for example an algal
photobioreactor or an or an algae
bacteria consortium
for wastewater treatment and i am
focusing more on waste gas treatment
okay so
that is my focus
so this is a very nice schematic that
gives you
and the application of different
environmental concepts and technologies
and modeling tools
for environmental sustainability okay so
when you look at this
simple schematic
it's very clear that it's not just
treatment we also
need a very good monitoring protocol if
we
if we really want to assess the
sustainability of the processes or
sustainability of the ecosystem
for anything we finally need a very good
monitoring tool
once we have a monitoring tool then we
will be able to at least
suggest options to control we can do an
online controller for example
we can measure different parameters in
bioreactors we can also adapt
technologies for water reuse and
and now recently as you all know
everything is connected
with with remote sensing data gis
and you can still have make all these
data that are available
to environmental engineers in different
conditions
okay and there are also a lot of new
technol
new tools uh such as the application of
artificial neural networks or artificial
intelligence
tools for for prediction for
modeling and also for controlling
different state
variables in a bioreactor okay so when
you have
all this thing that is in place it's
quite easy to control
um the bioreactor or bioprocess
so that you can trigger or to
to model the system into the way that
you want it to treat the pollutant okay
it's not just
a pollutant is just absorbed or just
removed no it's also
it is probably absorbed biodegraded or
bio mineralized into some useful
products
or to carbon dioxide and water if it's
an aerobic process
okay so if you look at the whole concept
of environmental
sustainability then of course the
bioreactors or the bioprocessors they
also
have a major role play in
water treatment wastewater treatment and
also for
resource recovery okay friends now
before
i go into the into the first slide
i have a few questions for all of you
okay
you can use the chat what are the
different types of
solid waste generated in your house or
your if you're a student staying in a
dormitory or a hostel
what are the solid ways that you
generate you can use the
chat and you can type okay
what are the solid ways that you
generate if i ask you
a very simple question
you can use the chat function and you
can type yes
okay it can also be your office okay
because i'm also sitting in my office
i also have a plastic already i have
plastic i have
already paper cup
okay very good i see food waste
biodegradable and non-biodegradable yes
so can you be a bit specific to say what
is biodegradable what is
non-biodegradable
okay very good we go a little step
further chemical waste battery bulb
okay but but is the battery and bulb
generated every day that is my question
now to you
to patricia susana do you generate
batteries and bulb every day as a waste
okay patricia you may open your mic
if you if you like yeah okay
okay maybe once a year okay so let us
not consider
that frequency because i'm asking a
frequency that is
very common okay every day let us
consider every
day basis or a weekly basis
okay so the answer is very clear that we
have
plastics we have food items okay so i
think we are not wasting
rice or meat or other foods food as such
probably these are some residues that
are comes from the cooking or
the peel peel of the skin or
vegetable skin or other things okay i
think we will not waste food
isn't it as such a prepared food is not
wasted
okay then we see uh plastic waste okay
friends this is very important
the reason is if you know the
composition
of the waste the quantity of generation
in a waste or a household that is when
you can
you can decide what is the next step of
treatment that you can adapt
okay if you say that okay in my street
it is full of food waste every day okay
if it is food waste every day from every
house
then i would go for a very nice
technology that would convert
a food waste into energy right you can
also do anaerobic digestion
you can produce bio gas you can produce
bioelectricity
you can also convert the food waste into
other
value products you can convert them into
fertilizer so there are different ways
in which we know so if you say that my
street is generating a lot of plastics
then plastics can be separated you can
then go for recycling
plastics or you can produce by pyrolysis
you can do a lot of things
with plastic okay so the composition
is really really important and you need
a very good strategy to to quantify
how much it is generated is it generated
every day
every week or over a period of year
is it generated every year okay so this
is very important for any of the
treatment
processes you need a very good strategy
to identify what are the com
concentration and composition
of the of the waste stream okay so
we just took a small example of solid
waste but this is the same
for waste water it's also the same for
um
waste gas okay so waste gas is also
a form of air pollution okay friends now
let me ask you another very nice
question
okay we are not we have already covered
number two and three
point number four new type okay can you
type
what are the different type of
bioreactor configurations
that you have heard or that you know
okay what type of bioreactors do you
know
or you can write the name of the
bioreactor configurations
okay very good christian submerged
bioreactor solid state by reactor
yes so these are all for fermentation if
i'm right
am i right christian submerged reactors
yeah okay very good and what about
others can you please type
some names that you know
okay very good say photo bioreactors
yes so if it is a photobioreactor we
have algal biomass in it because there
is photo
light yes okay more
please okay i got
i think i got all the answers now from
desi leon
am i right this is leon leone so we have
a continuous tertian reactor bubble
column reactor a lift bioreactor
fluidized bed
packed bed photobioreactor okay we have
all the type of reactor
which i am also going to cover but now i
would like to have a small discussion
with these
nice points okay they see leonie okay
if i'm right with your name which type
of reactor configuration will you choose
for waste water treatment okay i mean
for industrial wastewater treatment
among these reactor configurations
which one will you choose and why
let's assume it's from uh it's from a
textile industry okay it's from a
textile industry like let's say
the textile industry produces a lot of
color containing wastewater
it has dyes it has high cod
so which reactor will you choose from
here
i guess i'll go for the anaerobic
membrane by reactor
provided that it has the efficiency to
actually degrade colors
okay so you mean that all of this
reactor that you have mentioned
will not work for textile is that right
well it may work i guess it's the
um i think it's more of the
bubble column or part but i think i'm
not sure though
okay so the bubble column air lift
fluidized but
they all work in a similar way isn't it
because the biomass is in suspension but
in a packed bed they are attached a
photobioreactor is also a suspended
growth process
a cstr is also suspended growth
am i right i suppose so
okay okay so very good that you also
mentioned about this
anaerobic membrane bioreactor yes it is
also very good
for high strength cod containing
wastewater anaerobic processes are very
good
because they can they can work
at very high organic loading rates
okay we call that as olr at very high
organic loading rates
the anaerobic reactors for example a usb
reactor
a egsb reactor they are all able to work
with very high performance and they are
able to convert
them into biogas okay or of course or
also
many other reactor configuration many
other useful products so now you know
we have seen quite a lot of reactor
configurations but please
friends understand okay you have to now
understand for waste water it's a little
bit different
for waste gas it's it's
the criteria are different okay the
reason is
the waste gas contains a lot of
uh pollutants that could be
hydrophobic in nature okay for example
if you
take a chemical that is called alpha
pinene
okay pinene pinein is not hydrophilic
hydrophilic examples are methanol
ethanol
in the gas phase they are all very hydro
hydrophilic
compounds which means they are easily
soluble in water
when they are easily soluble in water
you can use reactor configuration such
as a bubble column
air lift fluidized bed or a
photobioreactor or other
things okay but but in the if it is a
hydrophobic compound
it's always advisable to go
for a packed bed system okay
the um yeah it's a
it's a packed bit system but at the same
time when you
also want to do a technology selection
for reactor configurations for
base gas treatment the first thing you
have to know
is the concentration of the
individual compounds the composition of
the
pollutant then the
the generation rate okay how many meter
cube of
gas is generated per hour then you also
need to know whether these are all
hydrophobic these are all
hydrophilic and when you know at least a
rough estimate of how much
amount of waste gas is going to be
generated per day
and then you can decide what size of the
reactor do you want
and at with what packing material or
what reactor configuration
okay so before you go for any technology
selection matrix
you need to really understand what are
the criteria for selecting bioreactors
what is the composition and then you go
for
a proper uh selection of the technology
so the first
case study that i'm going to talk is
hydrogen sulfide removal under anoxic
conditions okay this was done by one of
my phd student
and we did we did some research that
was mainly focusing on
the removal of hydrogen sulfide which is
a gas phase pollutant
from biogas okay so as you all know
biogas is not completely methane all the
time
it only contains 40 to 75 or maybe 60
of methane while you have other
impurities
such as hydrogen sulfide you can also
have cyloxin
you can have co2 and all the other
things okay the problem
when you have biogas with hydrogen
sulfide
is that hydrogen sulfide as you know
it's a corrosive
gas it will immediately start to
to to
to corrode your pipeline that you will
use for
transferring the biogas okay so
and on the other hand it will also
uh reduce the calorific value of the
fuel that you are going to produce
so you need to focus on technologies
that have that can be removed
uh that can remove the hydrogen sulfide
so in this case what we tried to do was
we used a sulfide
we use the sulphide oxidation process
under autotrophic denitrification
conditions
and we used a specific
bacterial strain that can grow under
anoxy conditions that is called the
nr so b it will it will use
nitrate okay nitrate as electron
acceptor
and all the sulfur these inorganic
reduced sulfur compounds
as an electron donor and convert sulfur
into elemental sulfur or sulfate
okay and this microorganism is called
the nitrate reducing sulfur oxidizing
bacteria
this is what we try to do
so in this case we chose a bioreactor
configuration that is called the
bio-trickling filter
you might have heard the word
bio-tickling filter and it is the same
okay it's the same bio-trickling filter
except that we have all these
we have the system that is completely
closed okay because we are dealing with
the gas phase pollutant
we cannot keep anything open so we have
to close them
and now you may ask me
the next question where did you
how did you generate the waste gas
okay you might ask me now how did you
generate the waste gas
so let me tell you honestly the answer
the answer is
we did not generate hydro biogas as such
but at in the laboratory we simulated
hydrogen sulfide production
okay so if you want to produce hydrogen
sulfide in the lab
you have to mix sodium sulfide okay na2s
and h2so4 in a certain combination in a
homogenizing tank and you have to bubble
nitrogen okay we bubbled nitrogen
because our
our bio tickling filter was not aerobic
okay it was an anoxic
biofilter so we don't have oxygen in it
we bubbled nitrogen
once hydrogen sulphide was produced and
it was bubbled with nitrogen
get carried away and it goes
to the biofilter so this is the bio
filter
and within the bio filter you can see
this little tubes
okay these cubes are nothing but
packing material we used polyurethane
foam as a packing material because
it has high surface area it is highly
porous
it can have all the biomass that can
grow inside
okay so we pack this bioreactor very
nicely but not
don't press it we just loosely pack the
reason is
as you all know after some time the
biomass starts to grow
and it will then occupy all the pores
okay
and so we don't normally pack it
very tight we just loosely pack it and
as this is a bio trickling filter and
the microorganism
needs nitrate okay nitrate is not in the
gas phase nitrate is in the liquid phase
so we said we prepared a synthetic
medium with nitrate containing waste
water
because nitrate is also a pollutant and
we pumped it in a downflow
mode okay so the nitrate was fed in a
downflow mode
hydrogen sulfide was fed in an up flow
mode so once you have the
the flow and the downflow it's very easy
to have
very good gas to liquid contact
okay and this type of operation is
called the counter current operation
and this is really nice for bio tripling
filters especially when you have pom
bones
when you have pollutants that are also
readily
soluble in water so this was the
configuration that we
that we did but i'm just going to show
only i'm not going to show you many
slides about results i will just
uh show one slide okay with the results
or two slides
and as you all know in wastewater we
talk about
carbon to nitrogen ratio we talk about
cod to sulfate ratio we talk about
different ratios
in wastewater treatment okay but in the
same way
for gas treatment we have in this case
okay in this case
means because we have nitrogen here
we have sulfur here therefore we had
what is called a nitrogen to sulfur
ratio okay okay friends so
these are some ratios that we that we
can
easily manipulate now manipulate means
we change
the conditions or the concentration here
we change the concentration here
then we will be able to achieve
different patterns of different
ratios but
but i would also like to say that the
calculations for
the calculations that you use for a
waste gas is is
more or less same okay but we use a
different factor that is called inlet
loading rate
in wastewater we use organic loading
rate okay
here we use inlet loading rate that is
nothing but gram
cubic meter of air per hour elimination
capacity
is nothing but the amount of pollutant
remote
per meter cube okay per meter cube of
bed volume
per hour so the inlet loading rate is
also
gram per cubic meter per hour
elimination capacity is also
gram cubic meter per hour so this gram
in this case we don't have benzene or
tooling we have sulfur
so it is the gram of sulfur that is
removed
meter cube of bed volume per hour
and removal efficiency as you all know
that's the same
so we have different criterias
and what we did with different n by s
ratios we found that the removal
efficiency
okay the remote efficiency of of um
of hydrogen sulphide it was not very
high okay it was not up to
100 percent or 99 or 90 only
varying between uh
60 to 70 uh in the in the
in the best case but of course there are
also bioreactor configurations that can
go
to very higher loadings and that can
also remove much better than this
reactor configuration
but you have to understand that this is
not an aerobic process
and the idea was to remove biogas in the
presence of
nitrate okay so it's two pollutants that
are removing
removed at the same time but in the case
of nitrate we
found that the removal efficiency was
close to 80
or 60 to 80 percent and
what you also see from this reactor
configuration
is it's very difficult for us you know
in a
in gas phase systems to maintain a
steady state
you may ask me now why your data points
are going up and down
right this is a very obvious question
and this question also comes from
the reviewers you know of the paper
the reason for that is as you know we
are we did not have a canister canister
means a
tank a ready-made tank that we buy from
the company
which has hydrogen sulfide that is
pressurized
at high pressure but we made this in our
lab so the problem is
once you dose this na2s and h2so4
it depends on the operation rate okay it
depends on the temperature it depends on
the liquid level here
it depends on many other factors so that
is why if you look
our induct load you know these black
lines
the black lines are not in a straight
line okay they are going up and down
for the most part of the work but but at
least
this study was able to do much better
but in some studies i will show you in
the
further slides it was not that really
easy to control the gas phase
concentration so what we did in this
bioreactor
because it's a it's a nitrate nitrate
reducing sulfur oxidizing bacteria we
also took one
of the one strain of uh
bacteria from a hot spring in thailand
because as you know the hot spring has
rich sulfur isn't it
so we took one of these paracorkers
strain
and we also did what is called bio
augmentation
so bio augmentation means you you have
the micro you have your
already present microorganism that is
doing the job but now we
seed it with a new microorganism
that with the hope that it will really
perform well
okay but i'm not going into the results
of those that those studies but what i
want to tell you is
a biotic link filter can be applied for
waste water and waste gas treatment okay
but
the good thing about these bioreactor
configuration is
you can customize it in different forms
now if you look at this slide here we
have a fluidized bed
okay like our friend who mentioned
previously
fluidized bed bubble column okay so this
is also a very similar
we have a bubble column reactor or a
fluidized bed reactor where we have
a packing material that floats and
agitates we have uh the biomass that's
growing
on the top of that or around the packing
material
and that is the first step okay and then
the treated gas
goes to the next step probably
you can also then use a bio filter you
can use a bio trickling filter you can
use
multi stages of this bioreactor
configurations
in order to in order to remove different
compounds okay
the advantage of having such bioreactor
configuration in stages is
if you want to have only a bacteria here
you can have them if you want to have
only fungal colonies here you can have
them if you want to maintain low ph
you can have okay so so this is one
advantage of gas phase bioreactors that
you
you can you can design customize and
operate
reactor configurations depending on the
land space
okay you may ask me now is it very
expensive
of course it is expensive because you
also when you
go for any bioreactor design you should
also consider
several costs isn't it you have to
consider the land cost
you have to consider the cost for
excavating for piping for network
you need you need to do a complete study
it's it's just like building a house
okay it's not that you build the reactor
you come and fit there you need to
have the space ready you need people to
work you need
tubing you need electricity you need
blower you need so many
things so in fact these configurations
are quite
nice and very appealing and it will be
nice that
if you if you can also initiate this
type of research okay which means it's
not just
one system one performance and one
pollutant
the good thing would be to integrate
different phases of pollutant liquid
gas and also integrate different type of
bioreactor with different functions
and different microbial ecology okay so
these are called
as advanced biofilm bioreactors
okay friends before i go to case number
two
i would like to ask do you have
any questions because i don't want to i
don't want to keep talking
all the time is there any question in
the case study number one
uh eric it might be is there any
oh yeah there's still no any questions
there
in the slide though i think but probably
i will check this this this slider
in the slider it might be in the center
slider
yeah but no question in the slide
okay if there are no questions it means
two things it means either they
understood
everything or they don't care
yeah no no i'm joking yeah yeah
yeah thanks but one question uh added
because you uh your uh
dissolve uh the the the sulfur may
convert it to
a sulfate and then make the
scp condition right in the in the media
so that that will be one
of how to deal because the media will be
become acidic inside so that might
may inhibit the biological processes
yes no no you are right
you are you are absolutely right but i'm
unable to find my stream now
yeah so in this uh can you see my screen
now yes
yes yes yeah so in this slide um
we we have assist we have ph control
basically yeah yeah we have a ph
controller here
this uh in this tank because if you look
at this tank you are right okay we
produce
uh because the sulfur is the sulfide
is converted into a sulfate and a part
of them
you can see here we remove them okay we
don't keep them because it gets
accumulated
and then you will have a lot of other
issues then you're right
so we do this adjustment also here in
the
in this feed tank and also we do ph
adjustment here
but the part of them is usually taken
out and
of course it becomes a sulfate rich
wastewater and there are of course
technologies
here you can you can use other
technologies where you can also
precipitate
with metals to get metal sulfide
precipitates
or you can also go for sulfur reduction
srbs
yeah but yeah in that case in this study
we did not uh
do that post treatment yes
okay then i think i i can edition in the
slido
there is a question regarding uh
how can we collect and measure inlet and
outlet of the
uh h2 s2s gas
how do we collect the
the question is about how can we collect
and measure
inlet and outlet of the gas hydrogen
sulfide case
yes professor can you now see the slide
yes if if you look here this is the
hydrogen sulfide
lit the inlet we have here
a small sample collection port
it's nothing but a small port the hole
and we can pass
a hand held okay it's a handheld
hydrogen sulphide or biogas analyzer
that is what
that is what we used and this biogas
analyzer can go up to a concentration of
ppm of hydrogen sulfide so we only
we only we only plug
a tube and we collect the sample in the
in the device and it immediately shows
the reading
so there is there was one inlet port
here for inlet concentration
and the treated gas here we have another
port for outlet
gas concentration but at the same time
we also have ports here you can see here
one this
on the right side one two three four
these are called gas sampling ports
they are in the reactor with holes we
can remove them
and we can insert this tube and we can
we can measure the concentration of h2s
in different levels of the bio-tickling
filter the reason for that is
then we will be able to know how much if
it is 100 here maybe it is
it is 80 here it is 60 here it is
already
0 here we know what we call as
the concentration stratification okay
it's
stratified between the height
of the filter material so in this way we
know which
part of the biotrickling filter removes
a lot of pollutant which portion removes
less
so in order to do that stratification
profile it's very important that we
also measure this
the question is do you find any
any uh problem during the operation and
then how to
to troubleshoot or to overcome the
problem
yes professor yeah it's a very
interesting practical question
okay and as you can see here we operated
only for 100 and
140 days but that is the result i showed
here but in fact the
reactor was operated for around 300
days so the first problem what we had
was ph control that was very clearly
highlighted by professor about sulfate
okay when we have excess amount of
sulfate accumulation
but then you know these are lab scale
reactors and we wanted to operate it in
uh anoxic conditions which means that we
were not expecting
sulfur crystals okay sulphur means these
sulfur
yellow color crystals but we also had
some local
crystallization here that is probably
because there might be
some oxygen inclusion into the reactor
so there was partly oxidation also but
in any case it was
if this was not a completely oxidized or
an
aerobic reactor but the main problem
what we had
okay which i have not mentioned to you
was the
the pressure drop increase because as
you know
this is a this is a polyurethane foam
polyurethane foam
is nothing but like a cushion you know
like a sponge
it's a sponge and when you continuously
pass water and when you continuously
have micro
micro organisms growing the weight
increases
when the weight increases it gets
compressed
it was not for example when we operated
it started here
but then if after a few days
it was almost compressed and packed when
you have this packing
okay when you have this kind of issues
the water that you pass from the top it
will not flow okay it will
it will start forming a pool you know
like like a small
swimming pool in the top that is not
what we wanted
but in fact yes that that happened twice
that is mainly because of excess biomass
growth then
[Music]
com compression of the material
and also the pressure drop increase so
now i would like to answer the next
question how did you
get rid of that the easy and simplest
way
okay it's a most trouble-free
way in the laboratory is first you try
to backwash
backwash means you stop all this
it's called a maintenance step it will
require at least one day of thing
operation just plus water okay
water from the bottom to the top the
presence of nitrogen
reason why we want nitrogen is we don't
want
aerobic conditions so in the presence of
nitrogen you only
backwash from the from the bottom to the
top
okay that is one way of doing it even if
you think the pressure drop did not
decrease then you can remove the lid
okay you have to yeah you have to remove
you remove a part of the packing
material out then you add new packing
materials
and you mix it so that is one of the
safest
way as well okay because sometimes also
in the industrial cases
packing materials such as fall rings or
other
plastic or ceramic is mostly plastic
rings
they could rupture you know rupture or
they could break
so in those cases also they periodically
replace during the maintenance step
so the other question is i put it from
the slider
what is the concentration of the
hydrogen sulfide
in the inlet yes yeah it's a very nice
interesting question because here if you
see
i mentioned to you it is point five to
two percent
point five to two percent means if you
if you convert it into parts per million
okay ppm
it is you have to multiply by ten
thousand
which means it is five thousand twenty
thousand twenty thousand ppm
is not allowed in our laboratory to work
because of safety we are not even
allowed
to work more than if i am right
greater than 500 also yeah we are not
allowed so
what we did was most of the time in our
lab
we operated it at less than
500 ppm week in some cases we went up to
2 000 ppm we but that was only for a
short
duration of time yeah
i think the next question from slido i
think you have
you have answered this one yeah the bio
did the filter need maintenance right
and then so there will be some saturated
uh condition so each day uh elemental
sulfur
also will attach to the biomass it's
correct yes yes
yes yes yeah yeah there there was but in
in
reality we are not we were not expecting
that you know yeah
yeah okay i think that
all that's the all the uh the question
from the slider
okay you may move on yeah i'm going to
now
um stop and now i'm going to
restart with my small
tutorial okay
professor and friends can you see my
slide now
it's not a slide it's a excel file yes
yeah yeah excel file yeah yes yes
correct
okay okay friends um now i'm going to
tell you
because you know i have shown you many
values it's very important for all of
you to know
how do these numbers come from where do
they come what do they mean
you know it's not that you only see a
graph
and you know what is the performance no
you need to know
how does it come where does it come from
and
how to interpret any data okay you have
data but what is the
science behind that okay so i took a
very simple example
of a pulp and paper mill located in
indonesia produces
several voc voc means volatile organic
carbon okay or possible organic compound
among which alpha pinene okay i took
alpha pinene
it's c10h16 okay that is the
formula of alpha pinene so
the first thing is you already know that
it is alpha pinene alpha pinein
you need to now go back and check what
is what are its characteristics
is it easily biodegradable is it uh
toxic to the microorganism is it
hydrophobic
is it hydrophilic okay then the
researchers
had decided the feasibility of using a
biofilter
okay so it's a biofilter now
the previous example was a bio trickling
filter so in a bio filter
there is no liquid phase that comes from
the top
okay friends there we used a synthetic
packing material a synthetic packing
material was
sponge here it's a biofilter
it is packed with natural packing
material
such as compost so compost is nothing
but as you all know
we also in our garden we have compost
so it's the same compost but of course
not as a powder
okay at least with some size you can see
the you can see the
compost to a certain diameter and then
you can
add it and ceramic beads ceramic beads
were added because you know
compost if you put compost in a packed
bed
after some time it will also get
clogged you know so in order to give
a good structured packing we
also added ceramic beads the biofilter
was operated at different gas flow rates
so this is where we talk about residence
time
okay friends you might have now thought
oh eldon did not tell
anything about hydraulic retention time
or
solid retention time which you already
hear a lot in
wastewater okay but here we don't use
the word hydraulic retention time
we use the word that is called empty bed
residence time
empty bed residence time means so if you
have this as the bed
if the bed is empty okay the bed is
empty
that is the volume of the biofilter
okay so in this case the
the empty bed residence time is
calculated by
volume okay the volume is point zero
five meter cube
so this is not a very big reactor okay
and the flow rate is given here
at different cube so volume by flow rate
will give you
empty bed residence time okay friends
this is not this is a very easy
calculation
you take volume you divide it by the
flow rate you get the
empty bed residence time in terms of
seconds it is 36 seconds
so in a wastewater treatment plant you
operate them
at at different hrts
as you all know maybe 24 hours 2 days
hrt 10 days
i don't know okay you can operate at
different
hrts but in this case here it's a high
rate system
we operated at very low empty bed
residence time
and you can see here they even operated
it
at 2.4 seconds okay
it's the time that you close your eyes
and you
open your eyes again the gas passes from
the inlet to the outlet okay so these
are
extremely high rate systems where the
gas
particles they don't spend no longer
than
maximum of two minutes okay
so now i have also mentioned here that
the researchers
have done the research for 450 days 450
days means they are not going to take
sample every day day and night okay you
don't have to do that because it's a
long term study
you can take at different time intervals
so this is the time you can see here
days
and up to around 450 they have done all
these
samples okay so like what our friend has
asked before
the concentration was monitored at the
inlet and the outlet in gas phase
compounds okay for gas phase pollutants
there are two ways in in where you can
represent the concentration
uh one is at as m v
per million in volume and or
in gram per cubic meter okay friends we
don't use the unit milligram per liter
here
it is gram of pollutant per meter cube
of
air okay that is the meaning so
c i is their inlet this is the outlet
this is the flow rate this is the empty
bed residence time
so once you know the inlet concentration
you can find
what is the inlet load isn't it it's
very similar to
the organic loading rate for wastewater
treatment
and then once you know the outlet
concentration then
inlet minus the outlet okay inlet minus
the outlet
divided by the volume and multiplied by
the
by the flow rate will give you the
elimination capacity
elimination capacity is nothing but the
amount of newton that is removed
per meter cube of bed volume per hour
and the removal efficiency i think all
of you know how to
estimate okay so this is how we did the
simple calculations
and they did this experiment at
different phases cases means
for any bioreactor as you know if you
have a bioreactor
you add the microorganism you add the
pollutant it will not remove
everything from the first day okay it
needs some time
what we also call as an adaptation time
or a startup time
or an acclimatizing phase so during this
phase
the microorganism will slowly get
utilized
or will start using the pollutants
as its carbon and energy source so in
this case it was
alpha pinen papinin was given as a
carbon source
so it has taken around 28 or 38 days
to remove the pollutant with 100 removal
okay okay friends now you know you have
to be very careful
when you say 100 removal my suggestion
to you
is please don't believe those numbers
okay
the reason why is the reason i'm telling
you don't believe these absolute numbers
because in any gas phase research okay
gas phase pollutant
if i inject inject the sample now
okay and you collect the sample and you
inject you and me will
get different values i can promise and i
can assure you
both of us will not get the same same
value
it's because of i don't know why it's
mainly
because of a little bit of human error
then little bit of sampling time
sampling volume the the level that is
present
so it's always difficult to get a
concordant value but at least we will be
able to get
very similar values okay or we should be
able to get similar values
the second thing is the sensitivity of
the equipment
for example this voc alpha pinen
is measured using a gas chromatography
okay if someone tells you that
100 was removed you should immediately
ask
what was the minimum detection detection
limit of your equipment you know it's
very important because
if they say that 100 was removed but
they still have
emission which your which the gas
chromatography did not measure
then we are into trouble you know so
it's very important that you also
know what is the minimum detect
detection limit
of your equipment so most of the time gc
they are very really very sensitive and
specifically
gas chromatography fitted with uh
with capillary columns okay there
because now
the whole analytical things have
improved a lot you can have a gc with
the ms
so there are many new sophisticated
technologies for
analytical instruments where you can
measure even now the microgram
levels okay so please be also when there
is a report that you read
check what is the analytical things that
they have done is very important to
understand
okay friends so this system of 450 days
was operated with
seven or seven phases of operation
and now i am going to show you
how the results look like okay so
normally this is how we plot
we plot the inlet let concentration
then the outlet concentration
okay i think all of you can see this
clearly
so you normally plot the inlet the
outlet and you can also plot
on the secondary y-axis you can plot
also the removal efficiency
okay if you want to see that so by
looking at this kind of
graphs it's very clear that
the outlet concentration depends on the
inlet concentrations
okay it was not 100 removed at all
it depends on the values but it is only
at this point
you can see that a lot of pollutant
was almost removed so now let us go to
the
removal efficiency re you can see that
the removal efficiency
on day one was only five percent
then it slowly increased it became
hundred percent
so that is when the acclimatizing phase
the startup phase is over
but then from different phases the
concentration changed up and down
okay and the system never
reached a steady state if i look at this
graph you know even if a reviewer
as a if you are if you submit this to a
journal
the reviewer will first ask the question
where is a steady state
if it's a chemical engineer they become
more angry you know
because for them a steady state is a
near steady state it's not a
pseudo steady state or a transient
steady state or a transient state
but this profile it looks very clearly
as a study or a reactor which has not
stabilized at all
okay so all these pseudo steady state
there is no steady state it's more
transient fluctuating conditions there's
only one point
where we reached we can say we got
hundred percent removal
okay friends so now this is not the
exact way to
draw then if you want to know much
better you plot the inlet loading rate
the elimination capacity as a function
of the inlet loading rate
okay so now you can see
that the points are completely scattered
best way to interpret this figure
is the elimination capacity okay the
elimination capacity
increases the increase in the inlet
loading rate
but only up to a certain maximum okay
but then it starts to deviate or it
tends to stabilize or decrease
it never went to the top but again you
can see one strange point here
okay this this might be a might be an
error or it could be an
outlier that's all okay it's not a real
measurement
but if you look at general profile here
you can see that the
elimination capacity it increases up to
a certain value
then it's almost stable or it really
went down
so now uh what do we get from this
plot okay from this plot if you do
elimination capacity versus inlet
loading rate
graph you will be able to know what is
the
threshold of operating this biofilter
okay friends by looking at this figure
okay
at what loading rate would you operate
the biofilter in order
to be safe can you please look at this
profile
and type your answer what loading rate
would you operate the bio filter but
here
you can see that they operate up to 6000
okay
but if you are an engineer you want to
take a decision
what safe loading rate will you
operate can you type i'm looking for
your
answers okay
okay maybe you can type in the in the
chat yes box
yes please type in the chat box what
uh loading rate will you apply okay
kuntareni
uh 1500
okay i'm taking your answer okay let's
see what others tell
1500 is almost here
okay friends what about others
at what loading rate will you operate
this time people
just see the check bro
any address
okay so let us ask okay i see a lot of
answer now
1 200 900
okay okay uh yes dee can you please
tell to everyone why 1200
[Music]
choose 1200.
ah okay very good
so at 1200 there is a chance that
you might get because
no okay it is not elimination capacity
100 okay it this the removal efficiency
is 100
yeah yeah it's not elimination capacity
elimination capacity has the unit
of gram cubic meter robot okay so the
removal efficiency
is i would not not also use the word
100 it is always safe to say that it is
greater than 90 percent removal
okay friends so yes the answer is right
from yesti and also i agree with the
answer of
kundalini you know because this is a
system which is quite complicated
it has performed but maybe 1 500 if you
operate with 1500