Kind: captions
Language: en
and then uh we also have students from
uh environmental engineering I think and
we also have uh some audience that we
invited for this occasion and today I
will be the moderator since P Chandra
has another engagement in this morning
so I will I would like to welcome Prof R
to give the
lecture thank you very much Aran um good
morning everyone it's um good to be um
seeing you again one more time I have
I'm this this lecture is going to be as
Dr Arian said this is biological
treatment of
Wastewater um is I it's because of the
mixed group of audience I kind of you
know start with basic information and
then I'm going to talk about some of the
um biological reactor and then what is
currently practiced in the US and then
I'll will finish with case studies so um
some of you might already know what I'm
talking about um so you have to beir
with me because it's a mixed group of
audience okay um let me uh start with my
first slide
um so first of all if you look at the
waste water we generate
worldwide um the only 10% of the waste
water is being treated 90% of the world
does not World waste water does not
receive any treatment at all so uh it
just go straight into the moving um
water body so that's a fact okay only
10% of the waste water worldwide
produced being treated
okay so what is the concept of
wastewater treatment uh basically we
generate the carbon uh organic carbon in
the waste water we want to reduce them
if you if you there is Rich an organic
carbon that goes into the water body
what's happening is the aerobic bacteria
going to consume the carbon and as a
result it's going to decrease the
dissolved oxygen in the water as a
result you're going to see fish kills
lot of fish out of see dying in the
rivers so the concept is it wanted to
reduce this carbon load um into the
waste in the Waste Water by encouraging
the growth of microbes but the one
limiting factor is um the oxygen so you
provide oxygen so so when you do that
micro going to convert this carbon into
carbon dioxide and they're going to
produce more biomass going to produce
more Sal and then water is produced
during the biochemical reaction the the
limiting factor is oxygen so most of the
time you aate the waste water and allow
the microbes to grow on the carbon and
then of course there are waste water
that contains other material like
nitrogen phosphorus and you also have
some acidus chemical so you need to make
sure what type of waste water you have
characterize the waste water and then
you know sometimes you had introduce
special microorganisms to do that so the
general concept is to reduce carbon uh
loading in the waste water before
treatment and when it is treated it
should be within the accept acceptable
limit of the regulatory agencies in in
every
country so since um since it's a mixed
group of audience I'm going to start
with the definition of few terms because
most of these waste Waters you start
with the loading um based on the bod
cood and solid so just is just a
fundamental definitions so bod is
defined as biological or biochemical
oxygen demand it basically defined as
the amount of dissolved oxygen needed by
aerobic bacteria to completely break
down organic materials in a given volume
of water at a certain temperature over
specified period of time usually they
incubate bod 5 days and they call it B5
some sometime B3 3day incubation at 20°
temperature
to analyze how much carbon is in the
water um so bu is basically what they're
measuring is the biologically degradable
organic matter in water so if there is
more carbon in the water during the
incubation time with the sample the more
oxygen will be consumed when that
consumed there is a relationship between
the carbon concentration and oxygen
consumption another term is cod which is
chemical oxgen demand it is the
measurement of chemically oxidizable
carbon in the water organic carbon so
this includes both biodegradable and
nonbiodegradable carbon there are two
kinds of cod we measure total Cod which
is taking sample and chemically digest
the sample and look for how much carbon
in the water and that include the the
contaminant as well as the microorganism
because microbes are basically
containing 50% carbon and then the
soluble Zod refers to only um you filter
the sample so what is dissolved in the
water is what you're measuring so we
have total Cod and soluble Cod which
exclude biomass in the water
sample um the next definition is lot of
solids also um when you talk about waste
water you need know how much solids go
in there so we have total solid
suspended solid dissolved solid so the
regulatory agency make standard based on
how much solid in the water because you
want the discharge discharge water
should be you know as clear as possible
you don't want to have turbid water
going in there when the water is turbid
and and the receiving water body gets
turbid and then that's going to affect
the light going through that's going to
affect photosynthesis so you need to
make sure your solid is less when it is
treated and let it go so total solid is
basically all partic matter that reminds
after evaporation at 105° um as a
residue suspended solid are the
particulate matter that are suspended in
water so that you filter the sample and
and how much um sample is filtered the
solid that's filtered is suspended in
the water right that is called suspended
solid if you know this total solid and
suspended solids the difference is
dissolve solid the dissol solid is
mostly the ions in water sample okay you
already know what is a reor reactor is a
container or vessel in which you make
the biological reactions carried out and
then the arganic loading is basically
the amount of carbon that is loaded into
the reactor when you treat the waste
water um so basic features of waste
water system is you should have primary
secondary and tertiary treatment and
primary is basically physical process
you screen the waste water to remove
remove any um um floating material and
also allow the Wastewater in a
sedimentation tank to remove solids um
so basically remove any physical
material in the waste water secondary
treatment is where the biological
process takes place and this is where
you allow the bacteria to multiply and
provide oxygen so they they reduce the
carbon in the water so that's this is
where the biological process take place
secondary and tertiary is mostly
chemical process to kind of remove the
pathogen in the water so mostly
chlorination ozonation precipitation
absorption takes place in tertiary
treatment so when you when you when you
design um the waste water system you
need to take into a lot of things into
consideration you should know waste
water characteristics and how much
volume of waste water is generated in a
site so you need to you know design BAS
Bas on the volume generated so you need
to know how much loading rate goes into
the system how much flow rate going into
the system okay so the the basic concept
of Designing waste water is based on
this um the HRT and SRT hydraulic
retention time is basically the the time
the waste water SP spends inside the
reactor okay solid retention time or
sludge retention time is the amount of
time the bacteria the
biomass is to spend in the reactor so
when you design a reactor need to have
high Sr you want to keep your bacteria
in the system as long as possible
because these are the bacteria that is
removing the carbon you don't want to
lose this waste but along with a treated
water so you need to try to retain the
biological solids as much as possible
but at the same time you need to treat
your waste water as fast as possible
because time is money he wanted to treat
them as fast as possible to meet the
regulatory standard so you want to keep
your HRT short your SRT long so when you
design a system that's that's what most
of the engineers you know calculate and
do this process and then you do process
analysis you need to basically analyze
what is going in which is called
influent to the reactor and the cod in
solids and you know and bod and then
after you know certain amount of HR s
what is coming out and you analyze that
and then you do the performance of the
reactor so what how much Cod is removed
how much solid is removed in a system
and then you need to do MCH balance so
you how much is removed how much is
still inside the reactor you calculate
and then come up with the carbon mass
balance you know biomass mass balance
you can calculate
that so having said that basic
parameters if you look at all the
commercial reactor they are based on
four principal type of reactor there's
only four principal type um but all the
commercial reactor follow any one of
these four principle type the first one
is batch reactor which is um it's a
batch system there is no influent there
is no effluent so you fill the waste
water in a tank and allow the reaction
to occur and when the Cod bod level goes
down to the regulat standard you pump it
out and wait for the next batch to come
okay the liquid of course is there's a
mixing so to get better
mass and the next reactor is called plug
flow FL flow is also sometimes referred
as tubular flow reactor here the
particle that enter the tank are
discharge the same sequence in which
they enter so there is a diffuser put in
the influent point so they go through
the same level it it comes into the
system it goes out so basically there is
no mixing so you save some money for not
putting mixing device the particle
retain the identity and remain in the
tank at a equal uh time of theoretical
value that you set in when you design
the reactor and then uh cstr is called
continuous tank reactor this is where
complete mixing takes place and the
particles are completely dispersed so
you have better Mass transfer between
bacteria and the biome and the and the
carbon in the system the uh and and and
it is completely mixed and there is an
influent there is an effluent so it's a
continuous system the waste water coming
in the waste water going out so this is
where you lose your bacteria when um so
you want to keep this SRT long you want
to try to keep the sludge inside as long
as possible and then the arbitrary flow
is um is a kind of a partial mixing in
between a PLU flow and a complete mixing
so you put a baffle in inside the system
so instead of putting a mixing device
the baffle will create a partial mixing
in the reactor so any commercial reactor
Falls within these four principle type
of reactor biological reactor so let's
look at some other the pictures so batch
reactor is simply a batch system which
have a mixing device and initially you
load them and then mix them and allow
the whatever HD set it out for the BC to
go down once it's reached it and then
you charge the waste water and wait for
another batch to come in cstr is almost
like a batch but it it's mixing but it
has a influent and effluent waste water
coming in waste water going out in the
system okay it's a continuous process
and pl flow is like a linear flow and
it's um um it's it's also called tubular
flow reactor the B water that comes in
it's a diffuser the each one goes in the
same
and Direction it entered so you don't
see a mixing it just goes so it's it's
just throughout the reactor the waste
water is distributed so you don't need
mixing right um so if you look at
another way of thinking about this
resident time inside the reactor is
actually it's it's a basically the the
volume and flow rate is set then that
will calculate the resent time okay the
time SP the reactor is equal to all so
there is no mixing it just comes and
goes in during that process the
microorganism interact and remove the
carbon in the waste water and that's
another design to look for look like the
PLU flow reactors so you have a
continuous process waste goes in in a
tubular form and then comes out during
this HRT you set in bacteria will work
on the base water to remove the car and
this is the we call the um you know they
put a baffle in there so you have a
partial mixing and we call arbitrary
flow so here you don't have to have a
mixing device so the waste water coming
and hitting this baffle and it creates a
partial mixing without you know using
energy to mix it and we call it
arbitrary flow reactor so um now I'm
going to show you some of those reactors
so all of them follow this one of these
principle type of
reactor
yes
here uh so when you um design a reactor
you need to know what process you're um
applying for there are a lot of waste
water out there right from not only in
municipal waste water but different
Factory producing different chemicals uh
food industry leather industry and all
kinds of Industry you need to look at
what kind of waste you are dealing with
and again you need to know the volume of
um waste generated um you need to do the
analysis of waste water and then look at
is there any um toxic chemical in there
that can inhibit microorganism if that
is a case you need to design a
pre-treatment and then of course in
Indonesia may not be applicable but
other other places there is a
temperature issue if it is like cold um
countries and um cold Zone you have
during winter month it's going to have
performance problem if the temperature
is too cold and then climate and then we
have to also do the reaction kinetics
you know what's going in what's coming
out what rate it is being removed make
the calculation and do the performance
analysis of the reactor H you also need
to know bacteria there is some nutrients
that is missing you may have to provide
nutrient to make the bacteria happy and
then of course you need to calculate how
much energy you're going to use to to
operate the reactor and then the
relability and complexity of the system
so you want to keep this as simple as
possible you don't want to make your
reactor too complex okay and make sure
it is compatible with if there is
existing system there try to make it
compatible don't create something
totally new
okay um so when you when you get that
set up the reactor then then you follow
this um characterization you need to
select particular reactor and of course
you need to treatability study if you if
you're asked to design a system um you
need to do in small scale in a lab make
sure everything is working and then you
do a do a little scale up and do a pilot
plan testing and then you do commercial
reactor uh design so this is the way um
Everybody operates and then you need to
make sure you um leave options for
modification because um once you said it
sometimes the factory modify system they
don't produce as much V water sometime
they produce more than you designed for
so you need to make room for a
modification if necessary when you
design a
system so some of the commercial reactor
let's look at some common one this is
the upow anerobic sludge blanket reactor
um so here what we're trying to do you
as I said you want to keep your biomass
inside as long as possible so what they
create here they create the bacteria in
the the Sledge pad in the form of a
granule so the granules have um High
settling velocity so they settle at the
bottom of the reactor so when you pump
in this waste water into the system uh
so you don't lose this bacteria in the
granule form you keep it so and then
theu goes out this is a continuous
system of course this is an anerobic so
you collect the Maan the bacteria
converted uh organic carbon to methan so
you can use his bio gas as energy so
this is one of the most commonly used
reactor um in in industrial settings um
so the here you have large volume uh
inside the reactor and you you're not
putting any filter you're not putting
any uh you know film that's going to
have a your volume problem so you're
actually keeping the bacteria in the
form of granules in this ledge pad
that's one of the common commercially
operated reactor okay uh so another
design of USB to just to show you what's
happening inide so sometimes the
granules move up and down and it also
create a partial mixing so without
putting any mixing device you can have
the gas gas it is produced also mix the
gas bubbles and the bed also moving up
and down going to create mixing for you
so you don't have have any mixing device
okay another type is fluid dice bed
reactor in flu dice bed reactor you have
1/3 or one F of the reactor you put fine
sand and so when you pump the waste
water um uh the the sand moves up uh in
the in the fluidized motion and it
creates mixing for you without any
mixing inside the reactor you don't have
to put a mixing device and of course
this in between the sand particles
bacteria grow and form biofilm so when
waste water go through the system Bia is
able to convert this carbon into carbon
dioxide and you know completely remove
Cod and bod so this is another type of
commercial reactor called fluidized bed
reactor and this is just to show you the
fluidization process so when the bed
moves up uh you can see the sand
particles mixing create its own
fluidized motion so you have this mixing
occurs at the same time when bacteria
remove the
carbon this is a lamp setup of a
fluidize bed just to show how lab
reactor look like um so you can have
this sand particle in there and then you
have influ fuen going through and then
you can um look at the fluidization of
the reactor so sometimes you have
clogging problem but most of the time it
works another type is fixed film so you
have this big reactor where you have big
film mostly plastic sheets you allow
bacteria to grow on this film as a as a
bofilm so then you pump operate this
waste reactor either UPF flow or down
flow depending on how you're operating
um so the when the waste water goes
through the system it's going to pass
through these bofilm and come in contact
with the bacteria and so um it's all um
bacteria grown and attach so you don't
lose the biomass when the base water
goes out of the reactor so you retain
your Sledge inside so you have no
problem of washing out of bacteria so
that's another type of commercial
reactor but this is all this reactor
allow PLU flow uh principle type the
motion of the particles inside go
similar to PL flow
reactor and then we have um early bioed
he can
put waste water going through biological
materials and we call it biobed and then
again the same principle bacteria is
growing on this um um bofilm and the
waste water is pumped through the same
concept so you retain the biomass inside
the reactor longer period of
time and then we have bio filter there
is lot of um uh filter material we can
use like Ceramics rocks plastic material
um and then inside this uh biof filter
we have again bofilm you can see
bacteria attached to the bofilm and then
the concept is again the same you try to
retain this biomass these are the good
bacteria they already remove the carbon
so you don't want to lose this bacteria
along with the effluent so you're
keeping this bacteria in this um um
biofilter trapping them inside the
reactor as long as
possible um cstr so cstr is sometimes
really good but it is energy intensive
you had have this mixing device you're
spending some money to operate the
reactor and then the problem with cstr
you're going to lose your biomass along
with the fluent so so they modify the
cstr they put settling tank and to
retain the sludge that goes out allow
the Sledge to settle and then you
recycle the Sledge back into the reactor
so you get this good bacteria back into
the system so um the basic concept is
the same you want to keep your bacteria
inside the system as long as possible
you don't want to lose it along with
your and then you can have hybrid you
can combine you know couple of reactor
together and create your own reactor
depending on what type of Base water
you're treating here is your um sludge
blanket as well as um filter put in
there you have this bacteria created in
a granule form and then you also put uh
filter on top so you combine two system
together and we operate filter another
common one is the baffle reactor baffle
reactor also um follows same principle
of PLU flow so you put down baffle and
up baffle and the waste water follows
certain path so waste water comes in and
then goes down and up and down up
through this baffle and then comes out
of the fluent so you're keeping most of
the biomass inside these Chambers so
you're not losing the biomass out as
fast as the water goes out so there's
another type of reactor called anerobic
baffle reactor and then the methan is
collected and used for energy energy
purpose um just to show you a la setting
of USB um treating um you know the food
industry waste
water um
you can create your filter any type of
design you want you can have a
horizontal flow or vertical flow or UPF
flow or downflow depending on what type
of waste you're dealing with
okay another type of reactor is called
RBC which is rotating biological contact
reactor it's basically big biod disc and
this biod discs move slowly there's a
motor in there and you bacteria grow on
this biod disk and bofilm and every time
they go down and touch the water and
come come in contact with the carbon and
remove and they go back up and and get
oxygenated get oxygen and um and you
need to have a good viable bofilm in the
system biofilm there's a different
degree of biofilm you have anerobic
biofilm aerobic biofilm in the same dis
so you have a lot of complex Dynamic
going on in the RBC so this another
popular um reactor out there um in the
industry just to show you actual picture
of a bio filter rotating contact RBC
biological contact reactor so you can
see the motor here the whole disc
rotates and there's a bofilm growing on
this um biod
disc just to show you the how this pels
are there the disc arrangements are
there you can see it's whole pack and
then there's the shaft and there's a
motor and each one is attached to that
and then the whole drum rotate so very
slowly and then we have the household um
um type if you live in a rural community
in the US you have the septic tank and
the septic tank could be could be
treated in anerobic filter you can um
you know the same type of filter that
you put different rock or ceramic or
beat filters and I'm trying to go
through the waste water go through this
filter and before you let it out um in
the in the moving body because we have
some strict regulations so in in us what
they do the septic tank collects into
the community they don't have a big
waste water it's a rural community and
they'll have the anerobic filter set up
for say 100 household the Wastewater go
in there and then after they treated it
you
know people monitor the cod in solids
and they let it out
okay and that's another design to show
you the how anerobic filter look like um
basically the filters are there to trap
the biomass and waste water coming in
and the gas is collected and sometimes
you need to do nutrient addition like
carbon nitrogen ratio follow but most of
the time they work well and just to show
you what packing media is inside the
filter so nowadays there's a lot of
plastic media but when I started in grad
school it was basically big rock and
then they replace with ceramic now we
have this plastic media inside in the
filter um just to show you how these
different designs are located you can
have different layers of this biof
filter and you can um you know put a
rotating arm and then move this waste
water distributed from the top following
the gravity instead of pumping it
okay just to show you um actual working
um trickling filter system so you have
the the filter in here and big rotating
arm move and distribute the waste water
so you have waste water going through
the system the way it enter and then
it's go through the filter the filter
has a bofilm and it's going to remove
the carbon nitrogen in the waste
water um just to show you sometimes you
lose biomass you can put um clarifier
and allow the waste to settle and
sometimes you can recycle it and then
you can collect the Sledge and sledge
goes separately and just to show you
this arm that rotate and trickles the
waste water down this filter in the
tricking
filter um commonly most of the municiple
waste water the only thing they do is
they air it in a big uh Pond or big tank
and that's called activated sludge H
because the only thing that is lacking
is oxygen so the bacteria is there
carbon is there enough nitrogen in the
waste water you don't have to do
anything except to oxygenate and keep it
in certain hyic retention time and then
most of the time you get 80 to 85% Cod
removal in this system
okay um and then again you can
uh how to remove the solids from this um
ation tank you put a clarifier and allow
the solid to settle down and then the
sludge goes to the anerobic digestor to
treat further and sometimes you have to
recycle the sludge if you Lo if you're
losing most of the um bacteria in your
system sometime you recycle the sludge
back into the activated Sledge
process H you can calculate how much W
water going in how much is um you know
collected and how much is retained in
the form of sledge it can come up with
your own hit s in your system it's just
simple calculation of the volume of the
reactor how much much time it spends you
can calculate how much Sledge is
produced how much sled is being recycled
okay so what is doing the JW mostly um
it's a heterogeneous population organism
it's not only bacteria we have fungi we
have yeast we have bi algae we have
protozoa there's a lot of organisms
growing in this base water you don't you
don't worry about um keeping this as
pure culture because you want to have as
many bacteria or microorganisms in the
system because your purpose is to remove
carbon and nitrogen so as long as they
remove it um that's fine but the one
organism that do bulk of the removal in
in the sewage is um kugia Raga which is
organism we prefer they remove bulk of
the car carbon in the system and
sometimes when there is a shock in the
system because the waste water is coming
from different household some sometimes
you put toxic material in the system
you're going to kill bunch of these
organism so in that case there is a
succession of microbes takes place so
you're going to wipe out the good ones
because they are sensitive to this toxic
chemical then you're going to have a
filamentous bacterial growth and we call
that bulking okay the bacteria that is
responsible is called spirital as not
nens it's a filamental bacteria it
started to flow
and um instead of settling in the waste
the whole waste going to float in your
waste water so we have some problem to
address how to control this um bacterial
system in the flock um just to show you
another um picture of different
filamentous bacteria in the system and
you have all kinds of organism you have
yeast you have protoo rotifers and lot
of different organisms growing in this
biological system and then you can get
as sophisticated as you want here you
can this cogenic plan there using pure
oxygen to you know pump into the waste
water they spending money um so but um
some some sometime this the waste water
process get more sophisticated yeah so
pure oxygen is pumped in this one and
then just to show you you know another
big system showing the settling tank a
big
clarifier so what other design
parameters you need to know you need to
know the volumetric loading how much bod
or Cod that going into the system and
then the food to microorganism ratio how
much what is a biomass what is a carbon
in the system um so we we need to
calculate that because you don't want to
starve the microb putting less carbon or
you have more microb and you know the
other way around so you need to make
this in balance and then when you're
recirculating you can add the
recirculation ratio so you need to
consider these into account when you
design a
bioreactor and so far we talked about
carbon removal but nitrogen is another
problem so when you have nitrogen in the
waste water um um if it is not removed
then you're going to have UT tropication
when it is let out so here is the
beautiful NY in Norway um the Norway is
supposed to be a pristine country but he
can they have frequent utr fication
because of nitrogen in the in the ocean
dischar and you can see in the Stream in
Norway the alal growth um that's at you
know Mountain elevation at 1200 meters
in in you know elevation was high but
even there the fresh water has lot of
alal growth because of nitrogen in the
discharge in the waste water you can see
the AL growth growing in this um
pristine supposed to be a pristine
environment and the Other Extreme if you
don't treat the waste water in poor
countries like Nepal um you're going to
have less dissolved oxygen High bod in
the waste water so you hardly have any
treatment going on waste water going
right into the river and this this is
where you're going to have problem you
can see big foam coming up basically
there is no oxygen 1 milligram per liter
Heat here and then High bod in the waste
water you're going to see fish kill and
other um actually call anerobic septic
system taking place so in order to
remove nitrogen you follow nitrogen
cycle nitrogen cycle is you know the
ammonia is converted to nitrate and
nitrate by these two organism encourage
the growth of nitron as nitro actor they
oxidize am ammonia into nitrite and
Nitro nitr Nitro Amon Nitro do this job
and then uh you turn the system into
anerobic mode and denitrification will
take over and convert the nitrate back
to the nitrogen gas into the atmosphere
and just to show you can do this in one
reactor in a sequence sequential
operation we call the sequencing batch
reactor operate first aerobically and
then anerobic and remove the nitrate and
ammonia in the system
another issue is passate uh passate is
also another major element that that
trigger alal Bloom if you don't take
care of the passway again it's the same
I'm going back to Norway because Norway
is supposed to be very clean country and
they have this problem of the lake with
alal Bloom and you can see here um the
water taken out of the lake showing big
a bloom because of high posor in this so
you can also remove phosphorage by
designing uh phosphate anerobic and also
convert them back to aerobic so operate
the reactor in sequential fashion and
you can um remove the pass pass is
absorbed by the bacteria in in the
inside the cell and you can modify the
process uh depending on how much
nitrogen phosphorus and carbon of course
most of the reactor are designed to
remove carbon but you also have to look
into these two nitrogen phosphorus so if
you don't remove them you're going to
have
utopic where you're letting your waste
water okay so let's look at uh the
general process of the sewage treatment
uh so you need to remove as I said all
the solids and carbon and nutrient like
nitrogen phosphorus and then you need to
of course eliminate pathogen so you want
to you know the final fuan is going
through um disinfection process either
chlorine chlorinated or you can use U
light or ozone and recently we have this
problem of emerging contaminant which is
pharmaceutical product antibiotics nanop
particles um all these are going to um
the waste water system is not designed
to take care of these and these are now
called emerging now people are trying to
address how to remove this um
materials and because when they design
these system these are like in us this
some of the systems are you know 50
years old and they didn't um you know
Envision that they're going to have this
kind of problem they want to just simply
remove carbon nitrogen pass forus now we
have to deal with this new um emerging
contaminant so again U going through
this process so sewage you go through
the physical biological and chemical
process um physically siment ation
flotation um screening biologically is
where most of the bacteria come into
play you want to remove um your carbon
and most of the time and then chemical
process is to disinfect your waste water
uh screening could be simple screen
where the waste water is all the
floating material can be um you
know caught in this screen and then you
size reduction you compress them and and
take it to landfill and then you
experimentation remove the solids that
settleable solids and the membrane
filtration comes later on in tertiary
treatment
process and in the chemical process you
can do
precipitation um adding lime iron and
aluminum salt to form Strite or you can
do absorption and disinfection so there
are lot of option for doing tertiary
treatment in chemical um using chemical
unit press
process um absorption you can use ion
exchange and then then disinfection
using chlorination U light ozone lot of
things so you need to make sure you have
um the regulatory standard of how much
eoli is our indicator organism that that
you're
removing so you have the chlorination
dechlorination now in us if you live in
Marine system you can do um inject this
into the down well below the salt line
in the coastal system so that's another
way
of you know removing these
pathogens so this is how the whole SE
treatment look like yeah primary
secondary tertiary so of course all
those uh physical chemic biological
chemical process and then the solids
collected here primary solid secondary
solids come to this anerobic digestor so
this is where you operate anerobic and
remove um the carbon nitrogen in the
sludge and and here you C convert them
into methane in the anerobic process and
you get some energy out of the system
after all this done then you have the
Sledge drying system then Sledge is
dried and and taken out as
biosol just to show you UV light is also
used for um tertiary treatment These Are
banks are UV
light so this this how unit operation
look like a primary secondary and
tertiary uh when you when you design a
system in Sage treatment plant and this
is actual plant to show you uh all these
units are in place you have um various
operation of primary second these are
all trickling filter uh with a with a
filter that going through with the
rotating
arms and they can make more
sophisticated here you can have uh
design of a treatment system to remove
even the scum
that is floating in the system and then
you can have the anerobic digestor and
the dryer and the dry sludge going in
and then during this process you get
methan so this this you can make it as
sophisticated as you want as made as
simple as you want when you design a
system and then um now in in in state
like California they have water problem
so what they do they treat the waste
water
and the waste water that treated go
straight into the drinking water plant
for treatment and then the water goes to
the drinking water this total recycle of
water all right so what they do they
after they go through primary secondary
tertiary disinfection stage it goes
through the membrane filtration unit
which is you know tery treatment and
they use various size membrane from
micro filtration to ultra filtration
nanofiltration then reverse osmosis and
then the water comes out supposed to be
has clean the waste water is completely
cleaned up you can see what is being
removed and each filtration micro
filtration all the suspended and
collidal materials are removed and ultra
filtration you see the bacteria and
virus and proteins are removed and then
nanofiltration you see less molecular
weight organic molecules are removed and
the reverse ASAS will take care of all
the ions and then you get the pure water
comes out and this of course go back
into drinking water treatment plan and
it goes through another you know
treatment process before it goes to
public so this is being used in uh
places like California where they have
Water
Crisis and what is actually happening in
membrane filtration is this operating
under different pressure systems yeah
this is how the micro filtration work
ultra filtration work and and you can
see the the
the pressure in the bar
here H just to show the what what is
happening how much is removed in
different stages you can see bulk of the
solids and carbons are removed in
secondary treatment process where
biological activity okay so a lot of
carbon nitrogen phosphorus and solids
are removed in secondary um treatment
process and then of course your eoli
should be reduced with a disinfection
so let's move on to how the Sledge is
treated because how the Sledge collected
goes to anerobic digestor is basically
another big reactor and but you operate
an anerobic so B so you have a complex
Organics that converted into simple
soluble Organics and then you have
acidogenesis that convert the long chain
organic to short organic chain compound
like acetic acid and then the last step
termal oxidation stuff where the
methanogenic bacteria take these acids
convert them to methan and carbon
dioxide so in generally have 55 to 65%
methane in anerobic digestion
okay this is just to show you this
biochemical pathway what's happening
inside a digestor carbohydrate protein
fats are converted to simple monomer and
then you have acetogenesis you have
volatile fatty acids produced into
acidic ACI hydrogen CO2 and then have
this methanogenic bacteria take this
acidic aogen CO2 convert to methan
CO2 and just to show you another way
pictorially this is your anerobic
digestor what is going in what gas is
produced and what is in the liquid that
comes out most of the time the
concentration here is very very low
compared to what is going in because
enic digest is a well matur technology
is being used everywhere nowadays
okay uh it could be a csdr completely
mixed um system but anerobic big big
tank depending on how much volume you're
using it could be a USB if it is a uplo
sledge blanket reactor or you can do
csdr in a big covered Lagoon with a big
plastic cover in a pond system in a
lagon system so in all the system the
same operation principle you conver the
sludge reducing the sludge volume and
you produce methane out of the
system and um you can make it sometimes
um recirculate the sludge if you're
losing it in the fu you can put
a recirculating system get the Sledge
back in into the
bioreactor so when you are when you're
done with it then you need to take the
solids out and the solids from the
digesters are removed and dewatered and
dried and then they disposed make sure
there is not much heavy metals in them
and and they can be combined with a soil
amendment and you know C is a commercial
fertilizer are sometimes used as a fuel
so that's a whole operation of sewage
treatment
where waste water is completely created
and solids are removed and then the
solids are dried out okay so now um this
is very conventional process now what
people are moving into is um if you have
enough land or if you have land that you
wanted to restore um they call it sewage
farm so the sewage goes through of
course the basic activated Sledge
process remove much of the C BL and then
instead of going through rest of the
step you go through um the sewage Farm
you release into a contain area and
allow the plants to grow on it okay so
here is one in Detroit Michigan and
people are doing this um with the mild
operation of sewage and then most of
them is released into the contained form
okay so just to show you a picture of
what they can grow and they grow all
kinds of native plants and um this
removes um most of the um residual
carbon nitrogen it comes out the plant
takes up and then the waste water after
going through this Farm it goes into the
treas treatment and release into the
moving river
system and then this one in Berlin you
can see various schematics of where
there are different discharge sewage
coming in the form and then we have
Sledge drying areas and then we have um
these um dewatering trenches that come
out and then these are different
treatment cell basically different
plants are grow growing so this is very
popular nowadays if you have enough land
you don't have to put more sophisticated
sewage treatment plant and make it a
sewage farm so these are different
plants that usually grow um in in
Western countries in this sewage Farm it
goes through trenches and released and
it's highly engineered operation but it
is with
nature and you can see this catchment
treatment beted treatment slope
treatment basically you collect the um
in the trenches and then you have PL
grow in the Terrace and then you
percolate the water down and collect in
the trench and release and depending on
you know different system you have drain
pipes you can have a slope treatment
following the gravity um instead of
pumping so all kinds of things you can
do um another thing catching on in US is
the Wetland so
um this is I'm involved in locally we
call assimilation metland so when you
when you discharge the treated waste
water your regulatory standard is really
little loose because the Wetland is your
final policing step so your Cod bod in
your waste water could be high and
solids could be high but the Wetland
will take care of your final process and
in this way uh what what they are doing
in here is what happened is because the
cities are growing more housing coming
up so the natural wetlands are um built
around with a lot of new houses so they
lost the natural stream of water into
the Wetland so they are dying out
because there's no water so they're
restoring this Wetland by pumping this
partially treated waste water into the
Wetland and lot of this Wetland being um
and improved and we have couple in in
where I live I got involved um so here
is um I had a list of the Tio is one of
them where I live but I don't know why
it didn't show up um so this is we call
that um you know using Wetland treatment
system we call it assimilation Wetland
because this a wetland already there
they're dying up but we are restoring
them that's why it's called assimilation
wetlands system okay now there's also um
constructed Wetland is becoming very
very popular in European countries and
you basically construct this wetland in
different cell and the waste water comes
in even doesn't even go through seage
treatment it goes straight into this
constructed Wetland this is where most
of the treatment takes place and it goes
through you know of course is engineered
highly and a lot of plants grow in there
and it just down and the waste is
collected after it goes through and you
can see the difference in V that comes
in here solids and comes in there and
what is coming out and you know in the
fluent coming out of the system you can
construct them in
vertical construct l or horizontal
construct l so different designs out
there so this is another way of doing it
so here's the another system to show
Surface flow constructed wetland
and this is just a picture and this this
is the actual wetland in in Spain
Valencia and before the waste water led
into the ocean so they don't actually
have a suage treatment plan in this
particular town all the waste water
going through this vetland but um highly
engineered process
okay uh so you collect the waste water
and basically remove the pre-treatment
uh use the pre-treatment to remove the
in know solid
and then goes through septic tank and
then goes through secondary treatment is
our Wetland instead of activated Sledge
instead of um trickling filter you have
this Wetland as your treatment
system so here's actual picture of a um
constructed wetland in in Spain okay
this is working really good and you can
see the treated water coming here before
it is being
discharged so what's happening here is
the most of the carbon is degraded both
aerobically and an aerobically depending
on the depth of the Wetland um organic
matter is also removed by a lot of
different reaction takes place in the
Wetland because there is a lot of
different group of bacteria there in the
last class I talked about the Redux
potential of the the waste so you have
sulfur reducing bacteria nitrate
reducing bacteria and aerobic bacteria
and the surface so this is how the
Constructor line look like and just to
show you some data what activity is
going on in this process so it's a
little bit engineered process but you're
trying to put nature um do the bulk of
the activ removal of this
carbon so just to show another profile
of vertical Constructor
Wetland um then just showing you the
what is being removed and the bod
nitrogen and solid removal in this
Wetland system
and this is a horizontal flow at land so
you can see a little bit longer the
system is okay and if you look at it it
has influent and it has this this
filtration permeable line has imperme
liner so there is nothing seeping into
the groundw and then it percolates down
and your plants going to take care of
nutrient uptake and then the the fluent
comes out and treated with in collected
in a pond before it is being discharged
and then if this vetan also produce
sledge so how do you take care of the
sludge a sludge is treated in again a
vetland okay so here is one in Denmark
and they pump the real sludge into this
vetland and this direction and the
plants will take care of the nutrient
and uptake this nutrient and it
percolates down the Sledge and then it
collect in a drainage pipe and then it's
being the water that can come out can be
pumped out the Sledge is retain in this
Wetland right just just to show you
actual Wetland here is the Wetland for
the sled treatment in
Denmark um the the was coming in in a
storage tank and put in different cell
they they they go through in cycle go
through first cell second cell third
cell and come back to first cell so you
don't want to pump the Sledge all in one
big area and alternatively they pump in
different cells
and this is how it looks like when the
sludge comes into the Wetland all right
and then after running you know few few
Cycles so you can see the sludge is you
know kind of in dry and then nutrient
uptake the plant started to grow and
this and the this is actual um um
micropollutant removing Wetland system
talked about antibiotic and personal
care product so here is a engineering
system they built in Spain and this is
the actual site you can see this Wetland
right there um in the in the St and they
this is how the design look like they
have the mhop tank vertical flow
Constructor Wetland horizontal flow and
free water surface Wetland and these are
the design of how much wetland in that
area and the picture I showed you and
this is specific speically designed to
remove those emerging contaminant I just
talked about all right there antibiotic
personal care product
nanomaterials and this works really well
they've been operating for a few years
now more than three years and it takes
care of all those pollutant that normal
sewage plant cannot take and there is a
list of chemical that this constructed
Wetland can remove um a lot of
antibiotic included the antimicrobial
compound trian then common over the
counter pharmaceutical compound those
can be removed but in the conventional
plant it's not so this is where the
Western countries are geared towards now
sewage plant now they combining with
Wetlands treatment to take care of the
domestic and then we of course we have a
lot of rural population and they
everybody has to have septic tank or
individual sewage plant and this is
highly regulated people come and inspect
your home so you need to make sure
you're you're doing it really good and
you had to put chlorine tablet every
week so make sure your pathogens not
getting out so so this is for for um
system that is in rural area so you have
your rural area that your waste
collected and then if you have of course
a farm or you have enough area you can
have this absorption field after you go
through conventional septic tank system
and you can spread it out in your field
and um the waste can you know dry out
and can be taken treated water can go in
later so all the system again um
basically concept is microbes and oxygen
the limiting if it is aerobic conditions
so um so you kind of you know encourage
the growth of bacteria in the system and
um other microbes as well so you can
create um a large Lagoon holding tank
and um provide oxygen and sunlight and
bacteria will take care of your excess
carbon okay so if when you do this in a
Big Lagoon there's a lot of activity
going on they have this aerobic organism
here facult bacteria here then anerobic
Zone at the bottom and then you don't
have to pump oxygen most of the oxygen
come from your natural system of wind
and the surface and then you allow the
algae to grow the algae during
photosynthesis going to produce oxygen
as a natural system and then the
anerobic process uh will take care of
what is being settled down so this is
kind of combining natural carbon cycle
in a Big Lagoon system so this is kind
of some cities are testing this out in
in US instead of building really highly
engineered process that kind of simplify
this in one big
Lagoon um so you need to make sure you
design again depending on how much waste
water coming through you need to design
the Lagoon accordingly and also the
carbon loading nitrogen loading so a lot
of some design go concept go in there
when you design your Pawn
system so this I just got went through
some basic concept and um um little bit
of commercial reactor and then I talk
about what is being popular nowadays
this Constructor Wetland ass simulation
Wetland and sewage forms are getting
popular now so now I'm going to
specifically talk about one case study
which I was involved um I'm going to
talk about how we removed and design a
system that is highly uh High it contain
High concentration of
nitrogen carbon is not a problem in this
case nitrogen is a problem um so so here
is a shrimp aquaculture system where
they feed shrimp 40% of protein in the
diet so the shrimp in aquaculture system
that
highly highly concentrated protein in
the diet so most of those di diet they
feed um sometimes is not being eaten by
the shrimp so the protein goes into the
water and then converts into ammonia
right so the ammonia is what we trying
to remove then nitrogen in the waste
water so I was personally involved I'm
going to you
know show you how um we designed th