Wastewater treatment process overview
Summary
TLDRThis video tutorial provides a comprehensive overview of wastewater treatment, explaining the key stages: preliminary, primary, secondary, and tertiary treatments. The process involves mechanical, biological, and chemical methods to purify water. It covers the separation of solid waste (sludge) and the treatment of liquid waste. The video also discusses sludge treatment, which includes digestion, thickening, and dewatering to make sludge usable as a soil conditioner. The biological treatment stage, which uses microorganisms, is highlighted as the most critical step in ensuring water purification.
Takeaways
- 💧 Wastewater treatment involves two main parts: liquid treatment and solid (sludge) treatment.
- 🚰 The liquid treatment is divided into four stages: preliminary, primary, secondary, and tertiary treatments.
- 🛠️ Preliminary and primary treatments are mechanical processes to remove large solid particles from the water.
- 🧹 Bar screens and grit removal systems are used in the preliminary treatment to separate large items like toys or grease from the water.
- 🏗️ In the primary clarifier, smaller particles are allowed to settle and form a sludge layer at the bottom of the tank.
- 🌱 Secondary treatment involves biological processes, utilizing microorganisms to break down nutrients and waste in the water.
- 🌬️ Aeration basins are used in secondary treatment, introducing air to encourage aerobic bacteria to digest organic waste.
- 🦠 The tertiary treatment (chemical treatment) uses chemicals like chlorine or UV disinfection to remove harmful microorganisms.
- ♻️ Sludge from both primary and secondary treatments undergoes digestion, thickening, and dewatering to prepare it for use as a soil conditioner.
- 🔥 Methane gas produced during sludge digestion can be used as a fuel source to power equipment within the wastewater treatment plant.
Q & A
What are the two main components of wastewater treatment?
-The two main components of wastewater treatment are the treatment of the liquid part (water) and the treatment of the solid part (sludge).
How is the liquid part of wastewater treated in general?
-The liquid part of wastewater is treated in four stages: preliminary, primary, secondary, and tertiary (chemical) treatment.
What happens during the preliminary treatment of wastewater?
-Preliminary treatment is a mechanical process where large solid materials, such as debris and toys, are removed using bar screens and grit removal systems.
What is the purpose of primary treatment in wastewater processing?
-Primary treatment focuses on mechanically separating smaller particles from the water, using clarifiers to allow sedimentation of solids to form primary sludge.
How does secondary treatment differ from primary treatment?
-Secondary treatment is biological and uses microorganisms to break down nutrients in the water, with processes such as aeration and anaerobic treatment to further clean the water.
Why is tertiary treatment necessary in wastewater processing?
-Tertiary treatment is required to remove any remaining microorganisms, including potential pathogens, through chemical processes like chlorination, ensuring water is safe for discharge.
What is the role of microorganisms in secondary wastewater treatment?
-Microorganisms, especially aerobic bacteria in aeration basins and anaerobic bacteria in anaerobic chambers, feed on the nutrients in the wastewater, breaking them down and cleaning the water.
What is sludge, and how is it treated in the wastewater process?
-Sludge is the solid waste removed during both primary and secondary treatments. It undergoes digestion, thickening, and dewatering to make it safe and useful, such as being used as a soil conditioner.
How is methane gas used in wastewater treatment?
-Methane gas is produced during the anaerobic digestion of sludge by methanogenic bacteria. The methane can be captured and used as fuel to power generators and pumps in the wastewater treatment plant.
What are some potential environmental concerns with chlorine use in tertiary treatment?
-High concentrations of chlorine can be harmful to aquatic ecosystems if discharged into water bodies, potentially harming flora and fauna. It's important to reduce chlorine levels through additional processes like sulfur dioxide treatment or UV disinfection.
Outlines
🚰 Introduction to Wastewater Treatment Processes
The video begins with an introduction to wastewater treatment, emphasizing the two main components: the treatment of the liquid part (water) and the solid part (sludge). The overview highlights the importance of understanding each stage of wastewater treatment, which includes preliminary, primary, secondary, and tertiary treatments. Wastewater collected from public channels and homes is first pumped to the treatment station for processing.
⚙️ Preliminary and Primary Treatment
The focus shifts to the preliminary treatment, which uses mechanical processes to remove large solid particles from the water. Bar screens and grit removal are used to separate items like toys or other solids. The primary treatment then separates smaller solid particles by allowing them to settle through gravity in a primary clarifier. Both preliminary and primary treatments are mechanical in nature.
🦠 Biological Treatment in the Secondary Stage
In the secondary treatment, biological processes are used to purify water. Aerobic bacteria in aeration basins break down organic matter. This step also includes an anaerobic chamber where anaerobic microorganisms further treat the water. This biological stage is crucial in reducing nutrient levels, aided by bacteria, before the water moves on to the next phase.
🔬 Chemical and Tertiary Treatment
The tertiary or chemical treatment phase involves removing remaining harmful microorganisms using chemicals like chlorine or UV disinfection. This step is vital for ensuring that no dangerous pathogens remain in the treated water. However, caution is taken to manage chlorine levels, as excess chlorine can harm aquatic life and ecosystems when the water is discharged back into streams.
💡 Handling Chlorine and Final Water Disinfection
Further chemical processes help reduce chlorine concentration, which can otherwise be toxic to humans and aquatic life. Sulfur dioxide or UV disinfection methods are used to neutralize the remaining chlorine, ensuring that the treated water is safe for release. The importance of balancing these chemicals to avoid harmful effects is emphasized.
🌾 Sludge Treatment Overview
This part explains the treatment of solid waste (sludge) separated during the earlier stages. Sludge digestion, thickening, and dewatering are the key steps in converting sludge into a useful byproduct. Methane generated from anaerobic digestion is harnessed as an energy source for running some parts of the wastewater treatment plant. The process results in a thickened sludge that can be used as a soil conditioner.
🌀 Sludge Dewatering and Disposal
The final step in sludge treatment is dewatering, where centrifuges separate excess water from the sludge, leaving a solid cake-like structure. This dewatered sludge is then transported to landfills for disposal, but it can also serve as a nutrient-rich soil conditioner due to its valuable components. This completes the solid waste management process in wastewater treatment.
🔄 Summary of Wastewater and Sludge Treatment Processes
The video concludes with a recap of the entire wastewater treatment process, covering both the liquid and solid parts. Mechanical, biological, and chemical treatments work in conjunction to purify water, while sludge treatment ensures the safe disposal or reuse of solid waste. The secondary (biological) treatment is highlighted as the most critical phase in purifying the water before it is discharged back into natural water bodies.
Mindmap
Keywords
💡Wastewater Treatment
💡Preliminary Treatment
💡Primary Treatment
💡Secondary Treatment
💡Tertiary Treatment
💡Sludge Treatment
💡Aeration Basin
💡Clarifier
💡Chlorination
💡Sludge Digestion
Highlights
Introduction to the basics of wastewater treatment, covering both liquid and sludge treatment.
Wastewater treatment is divided into two parts: liquid treatment and sludge treatment.
Liquid treatment is further divided into four stages: preliminary, primary, secondary, and tertiary treatment.
Preliminary treatment uses mechanical methods to separate large solid particles, like bar screens for removing large debris.
Grit removal in preliminary treatment uses gravitational forces to separate grease and fat from the wastewater.
Primary treatment involves a primary clarifier, which allows smaller particles to settle at the bottom to form sludge.
Secondary treatment, also known as biological treatment, uses microorganisms to break down the remaining organic materials in the wastewater.
Secondary treatment has two parts: aeration basins (for aerobic bacteria) and anaerobic chambers (for anaerobic bacteria).
Secondary clarifier helps sediment the coagulated particles, forming secondary sludge.
Tertiary treatment, also known as chemical treatment, uses chlorination and sometimes UV disinfection to kill any remaining microorganisms.
Chlorine must be removed after tertiary treatment to avoid harming aquatic life when the water is discharged.
Sludge treatment has three stages: digestion, thickening, and dewatering.
Methanogenic bacteria in sludge digestion produce methane gas, which can be used as fuel to power some wastewater treatment processes.
Centrifuges in the dewatering process remove excess water from sludge, turning it into a solid cake that can be used as soil conditioner.
The overall process of wastewater treatment ensures that both the liquid and solid components are treated and made safe for the environment.
Transcripts
[Music]
Welcome Friends uh in this video
tutorial I'm going to talk about uh the
basics of
uh wastewater treatment and uh we'll be
seeing uh the different stages of
wastewater treatment and how the
wastewater treatment is being done now
uh I first tell you about the wastewater
treatment and in any kind of wastewater
treatment there is two different way of
handling it uh one is uh the Water
wastewater treatment which is only about
the watery part or the liquid part and
the second part is the treatment of the
solid part that are dispense dispensed
in the water which is called the sludge
treatment so we have to talk about both
of the treatments now in this picture in
this video tutorial I'm going to talk
about the basic overview of the
treatment system but uh in any kind of
Wastewater system uh you must know the
overview otherwise you cannot correlate
each of the steps because each of the
steps are because there are a lot of
different steps
and those STS are done finally to get
rid of all the all the contaminants that
are present in the water now in this
case what we are looking at uh the water
is collected from the public Channel
network in uh from through these pipes
and the small pipes in the bigger pipe
then then those pipe contains all this
waste Waters from from house supplies or
something from Wastewater storm water
basin also and it will come into the
palm station now the palm station will
pump it towards the first round of
treatment which is called the
preliminary treatment now first
treatment is the preliminary second
treatment is a primary then the
secondary then finally the chemical
treatment or the tertiary treatment has
been conducted so if we divide it in uh
we can divide into four parts the liquid
treatment is divided into four parts
preliminary primary secondary and
tertiary so this is a preliminary
treatment uh then then the primary
treatment so this is a primary then
secondary and then tertiary the this
four type of treatments are there now in
the preliminary treatment this only the
mechanical treatment is being done and
any in many wastewater treatment plans
this primary and preliminary treatment
are fused together and they call it the
primary treatment now in this primary
treat treatment basically the physical
apparatus are used to mechanically
separate uh particles from the water
because the water which we collect
contains solid as well as liquid parts
now uh the liquid parts they are also
having the nutrient sources because this
waste water contains the human waste
that means we are having uh those
protein products we are having those
carbohydrate or sugar products and all
these things uh in in it and also the
fatty fatty acid products now in the
solid we are we can have many
different things that means some
sometimes toys are flashed down or
sometime dollar bills are flashed down
so these things can also be collected
and that those things can be uh
separated from the Water by using this
preliminary Tre treatment now in the
preliminary treatment we uses bar
screens to screen all those huge
elements from the water so they screen
out all these things by mechanical bar
screeners now the second treatment is a
grit removal treatment now in this grit
removal treatment what they are doing
they are utilizing uh the gravitational
force and for example like fat uh or fat
materials like gree materials so they
are not water soluble they will uh be
floating on on the water if we give the
time for settling them down now what we
utilize in this case we utilize any fat
solution and we can see all those grease
which uh which uh we have collected and
which can pass us through the bar skins
can be uh coagulated in this tape and we
can have this grease balls formation
which will float and we take those
grease balls scrap off with the help of
the scum removal now we we take up all
these things with the help of scum
removal and you take and uh left them
aside and it will remove all those
Grease materials and right after that we
end up with the water and with with in
in the water we are having small
particles of other nutrient sources but
not the bigger particles because all the
bigger particles are being removed in
this bar screens and the GRE removal
system of preliminary treatment now in
this uh now right after that uh this
this enters into uh the primary
treatment in the primary treatment
basically primary treatment is
consisting of one large SC which is
called uh the primary clarifier in this
primary clarifier what we are having we
are having one Central ring and with the
help of central Ling we have two
different parts we we are having one
strand here at the top and we are having
another strand at the bottom now both of
the strands are functioning in different
ways now this this top strand which is
just moving on the surface of the water
is is collecting all those small
particulate matter which is floating on
which are floating on the water water
and uh they drag them into one side and
keep them away from the water and the
second uh uh second uh what you can say
uh the layer or second uh system which
is placed here which is also rotating
and this second uh layer or second uh
strand what we can see is uh actually
slightly uh rotating in a very very low
uh velocity and as a result of this
rotation it actually helps all the small
sediment all the small particles to
sediment in the in in the layer or the
lower region or lower tank or reserver
tank for this primary clarifier which is
called the primary sludge now I I'm
telling you this this sludge whenever
you heard this name of sludge the sludge
means the solid waste part of a
wastewater treatment in any cases there
are this waste water is consisting of
two parts as I've told you before there
the liquid part then the solid part the
solid part would be very very huge
solids which can easily be separated
using preliminary treatment like bar
screens and grit removal but in the
secondary treatment we in the primary
treatment we must remove all those small
parts we give the time for them to to be
sedimented utilizing the gravitational
force and they start to sediment onto
the bottom and as they're sedimented we
drag them away and take them in the slud
treatment process now we have we will
discuss this SL treatment later now
right after that all the P all the water
which is uh being clarified using
primary clarifier is been taken onto the
second round which is called the
secondary treatment of waste water and
this type of treatment is called the
biological treatment because in this
treatment we utilize uh the
microorganisms to purify the water or to
clarify the water now in this kind of
section there will be two different
sections one is the irration Basin and
another is will be the uh anerobic
chamber now these two things can also
happen now in airation Basin what we
what we have done we take the water from
the primary clarifier we put it onto
this Iration Basin and in this Basin we
actually vigorously air this Basin all
the time throughout the time and we
Propel a fan here and we we keep on
adding air bubbles onto it and it will
help some of the bacterias which we add
onto this water to grow and multiply
very rapidly and those bacteria will
love to eat uh those nutrients which are
being stored on onto this waste water
because this waste water is consisting
of human waste so bacteria can feed onto
it so we need to select the type of
bacteria that we are using in this
Iration Basin because those bacteria
must be aerobic type because there is a
lot of air in this case and we also
design another chamber which is not uh
seen which is not put in this picture
but that is called the anerobic chamber
inside the anerobic chamber we also put
some microorganisms but those
microorganisms are anoxic or anerobic
microorganisms which can also uptake the
nutrients but an aerobically so that's
why you give them their own room for
doing this so we set uh this water there
we put the microorganisms and the
microorganisms do the work for us for
this part and in the Iran Basin almost 5
to 6 hour we need to spend this water so
this this is a long time at this
particular point now right after uh
release from this aration Basin we have
another clarifier which is called a
secondary clarifier because this
clarifier is little bit much more bigger
and this is placed in the secondary
treatment that's why it's called a
secondary clarifier in the secondary
clarifier we we use uh we put this water
from the Iran tank or an arobic
treatment plant and then in this this
clarifier what happens as a result of
bacterial enzymatic action all those
small nutrients start to coagulate with
each other and they are going to
sediment uh they are going to form a
layer at the bottom of this secondary
clarifier as the sludge and this is
called the secondary sludge and we can
also drag this sludge for our treatment
with the help of sludge treatment
process now after that the water uh will
come from the secondary clarifier
towards the third layer of water
treatment which is called the tertiary
treatment or the chemical treatment
because in this part of the treatment we
are treating this waste water with
chemicals to get rid of uh the bacterias
or microorganisms which are left behind
because remember we utilize
microorganisms to degrade our food or
nutrient materials that's fine they do
the job for us but now it's time for
removing those microorganisms because if
they live on the water they can be
dangerous for us because those
microorganisms can be pathogenic can be
devastating for us so we need to kill
them too so we utilize all those
chemical process to kill those
microorganisms in this tertiary
treatment so we utilize all those
chlorination sometimes chlorination can
be a form of gaseous chlorine or can be
a form of liquid chlorine or sometimes
in form of tablet chlorine uh then right
after this chlorination we we we need to
uh uh control the number of or
concentration of chlorine in the water
remember sometimes when the higher
amount of chlorine come into the water
we can we can can taste it really in the
water so this is a flog of this
wastewater treatment or sometimes this
chlorine can make a damage uh to us
because chlorine is halide and any
helide is dangerous for a human body or
any is dangerous for any animal so this
chlorine which we put it is in higher
concentration or sometimes this
chlorinated water if we direct uh
directly discharge this water onto the
streams then it can damage uh our fresh
water Flora for example those fishes and
all those phytoplankton Z planton
whatever place there they can be uh
harmed by by this chlorine that's why we
need to remove the chlorine due to some
extent or we need to uh we need to take
uh the concentration of the chlorine
down to some extent we can do this by
utilizing UV disinfection or sometimes
we can just do this with the help of
another chemical treatment by utilizing
so SO2 sulfur dioxide is a very
important key player in this case so we
add sulfur dioxide right after the
addition of uh the treatment by sulfur
dioxide or UV disinfection our water is
totally pure and it is ready to be
discharged in the Stream again so that
is how the liquid part of the waste
water is travel from preliminary
treatment which is the mechanical
treatment so this is the mechanical
treatment and then we go to the primary
treatment which is also a mechanical
treatment so preliminary and primary are
the mechanical treatment then you go to
the secondary treatment which is a
biological treatment through which
finally we end up with the chemical
treatment which is the tertiary
treatment and finally we release the
water onto the stream where we have
taken all this water from okay so that's
how it's work now let us talk about the
slge treatment process now uh what is
the SL treatment M as we have told
before in the primary clarifier and in
the secondary clarifier we have we have
sedimented out fewer uh not few many
amount of all those solid materials
which are being stored in this waste
water for so long now these nutrients
are dangerous those are toxic but if we
if we utilize them properly if we
process them properly then they might
end up with some very very interesting
and very very uh economic product which
we can utilize in the soil as a soil
conditioner so that is a very important
concept so we take up all those slud
from the primary clarifier as well as
from the secondary clarifier and we take
and we we go through the sludge
treatment process now in any slud
treatment process there are three
different parts one is the sludge
digestion then is uh the sludge uh
thickening and then is the sludge
dewatering so these three part parts are
really important during any sled
treatment process so what we have seen
in this case we utilize we take the
sludge we digest the sludge now what do
we mean by the sludge digestion it means
that we we are having a huge pipes and
pumps are there we utilize heat we
utilize few amount of bacteria which are
present on the sludge to digest the
sludge anaerobically and as a result of
this anerobic digestion of the sludge
they produces methane gases now in this
particular process we can utilize fewer
amount of microorganisms which are
methanogens now we know that action of
methanogens that they can utilize carbon
sources and generate methane gas now the
methanogens can act on this sludge they
can produce methane gas and as a result
of they produce this methane gas as you
can see in this case this methane gas uh
is a very good fuel as we know so we can
utilize the energy which is stored in
this methane gas to run few generators
and few pumps in the same wastewater
treatment plant so it's a circulation of
energy in the wastewater treatment plant
so it is a pretty good for us to utilize
this kind of uh sludge digestion and the
energy which is derived from the sludge
digestion right after this sludge
digestion we we
utilizes the sludge thickener to thick
uh to make the sludge thicken so how can
thick make make sludge thicken so we we
utilizes sludge thickers and in the
sludge thickeners usually there are
different types of sludge thickers like
uh gravitational force gradient
dependent and all these different types
so there are SL ther common type of
Slash ther that are used are called DS
or okay it is called dissolved air flow
type of Slash thicker now this type of
Slash thickner what they are doing they
are actually uh inside a huge chamber
they uh push the air onto the sludge in
very high pressure and then just release
the pressure so that this sludge will
float onto the top and the watery part
remains on the bottom now as a result of
this uh this process we can have really
solid and thick sludge now right after
this made up this sludge thickening we
we have to dry the slud why because in
this particular step or after the
particular step what we end up with we
end up with a pretty thick sludge which
is having almost most of the sludge
components but uh it is uh still
containing very uh moderate amount of
water so we need to dewater it before
utilizing it for the soil conditioning
purpose otherwise those watery part are
pretty uh pretty problem pretty problem
creating for handling and all these
things so we need to make them dry so uh
this drying will help us in different
ways of transport and or or Market uh
marketing or placing them so for that
purpose we need to dry them a little bit
so we we them we dry them we dewater
them utilizing the chambers denoting
here these Chambers are called
centrifuges and we know in scientific
Labs we have used centrifuges and those
centrifuges are small there those are
micro centrifuges but these centrifuges
which are used in this case of slud
dewatering uh these are really really
huge and mega centrifuges and in this
centrifuge the mechanism is remaining
the same so it is sedimented at the
bottom and the water uh is uh placed at
the top and the sludge is sedimented at
the bottom so it's a layer of sludge at
the bottom we just take out this sludge
from this
place and the sludge becomes a solid
cake like structure we we take this
ludge we put it on the van we we take it
onto the Landfield and we dump it there
and this ludge is containing very very
important nutrients and ingredients
which will help to nourish the soil for
a long time so that's why uh this L
treatment is done in this way so this is
the overall wastewater treatment process
so remember wastewater treatment process
is conducted in two different ways one
is the watery part dealing second one is
the solid part dealing in the watery
part dealing we are having four
different sections one is called the
preliminary then primary then secondary
and the tertiary treatment in the
primary and uh preliminary treatment are
mechanical treatments utilizing the
mechanical process to separate out
solids and in the secondary treatment we
utilizes biological system like
microorganisms to treat the water and in
the tertiary treatment we utilizes
chemical uh things to actually take out
all those necessary uh bad things from
the water okay and
and also in the chemical treatment
sometimes utilizes aluminium chloride
and all these type of salts to actually
settle down some of the solid particles
or some of the phosphorus particles who
still uh there in this water but but
most of the nitrogenous compound and
phosphorus particles are gone right
after the secondary treatment so if we
if you uh if somebody tells you which is
the most important part uh of this
system you must say this is the
biological part of the secondary
treatment part which is the most
important because in this part almost
everything is treated except for fewer
uh fewer consideration like odor
sometimes few amount of phosphorus
dissolved phosphorus and sometimes uh
and those bacterias which are added
right except for this the water is
almost ready to be discharged onto the
onto the water stream right so that's
why it's important now in the second
part we are having the slash treatment
process in the slash treatment process
we go through three different steps one
is the slash digestion we in this case
we utilize the energy from the SL dig to
run out a few pumps and generators in
our wastewater treatment plant that's a
very important part and then we are
having thickener and also we are having
those dewatering part so these are the
steps of w waterer treatment plant and I
hope it will help you to understand what
it is thank you
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