Wastewater Treatment Plant Tour
Summary
TLDRThis educational video script takes viewers on a tour of King County's wastewater treatment plants in Renton and Woodinville, Washington. It explains the process of treating wastewater from homes and industries, which includes removing pollutants, organic matter, bacteria, and trash. The script highlights the importance of source control, the reuse of resources like biosolids and recycled water, and the generation of biogas from organic waste. The aim is to educate on sustainable practices that reduce environmental impact and promote clean water for the Puget Sound ecosystem.
Takeaways
- ๐ Wastewater includes water from household drains like showers, sinks, washing machines, and also from industrial sources.
- ๐ฟ Wastewater contains a mix of organic matter, chemicals, bacteria, and sometimes trash.
- ๐ฑ The primary goal of wastewater treatment is to remove pollutants before the water re-enters the environment.
- ๐ The treatment process involves physical, biological, and chemical methods to clean the water.
- ๐ฏ Trash is removed through bar screens, which are crucial for preventing clogs and damage to the treatment system.
- ๐ Primary treatment uses gravity to separate out about 50% of the solid materials from the wastewater.
- ๐ก๏ธ Aeration activates microbes that consume organic matter, helping to purify the water further.
- ๐ช๏ธ Secondary clarifiers allow the microbes and any remaining organics to settle out before the water is disinfected.
- ๐ง Disinfection involves using chemicals like sodium hypochlorite to kill any remaining bacteria.
- โป๏ธ Treated wastewater is either reused or released into the environment, and the byproducts like biosolids and biogas are recycled.
Q & A
What is the primary purpose of a wastewater treatment plant?
-The primary purpose of a wastewater treatment plant is to clean pollutants out of the water before it returns to the water cycle and the environment, such as Puget Sound, ensuring the water is safe and free of harmful substances.
What are the four Ps that should only be flushed down toilets?
-The four Ps that should only be flushed down toilets are 'poop, pee, puke, and toilet paper', as mentioned in the script to avoid causing clogs and damage to the wastewater system.
How does the bar screen room contribute to the wastewater treatment process?
-The bar screen room contributes to the wastewater treatment process by physically removing trash and large debris from the water using bar screens with gaps about a pinky nail width apart, which helps prevent these materials from entering further treatment stages.
What is the role of gravity in the primary step of wastewater treatment?
-In the primary step of wastewater treatment, gravity is used to separate out about 50% of the solids from the water. Heavier materials like sand and organic matter sink to the bottom, while lighter materials like oil rise to the top, allowing for their removal.
What is the purpose of aeration in the wastewater treatment process?
-Aeration in the wastewater treatment process involves pumping hot air into the water to activate special microbes that consume organic matter and pollutants, helping to clean the water further before it moves to the next stage of treatment.
How do secondary clarifiers work in a wastewater treatment plant?
-Secondary clarifiers work by allowing the water to settle after aeration, where the activated bacteria and organics they've consumed sink to the bottom. The clean water on top is then piped to the next stage, while the bacteria and organics are either recycled back into the process or sent to digesters.
What is the function of sodium hypochlorite in the disinfection step of wastewater treatment?
-Sodium hypochlorite is used in the disinfection step to eliminate any remaining bacteria, such as E. coli, that may have escaped previous treatment stages, ensuring the water is safe for release back into the environment.
How does the treated wastewater from the plant eventually reach Puget Sound?
-The treated wastewater is piped 13 miles to a diffuser pipe off the coast of Alki in West Seattle, where it is diffused under the pipe and slowly spreads out, getting mixed and moved by ocean currents.
What are some ways that King County wastewater treatment facilities reuse resources from the treatment process?
-King County wastewater treatment facilities reuse resources by capturing biogas from digesters to use as renewable energy, turning organic material into biosolids for agricultural use, and producing recycled water for irrigation and other non-potable uses.
What is the significance of the 'membrane filter cassette' technology used at Brightwater treatment plant?
-The 'membrane filter cassette' technology is significant as it uses microscopic pores to filter out bacteria and other microscopic particles, allowing only the cleanest water to pass through, which can then be reused for various purposes, such as irrigation.
Outlines
๐ง Wastewater Treatment Introduction
Charity, an educator for King County Wastewater Treatment, introduces the process of wastewater treatment. She explains that wastewater from household drains and industrial sources is full of pollutants, including organic matter, chemicals, bacteria, and trash. The video tour aims to show how environmental engineers clean pollutants before the water re-enters the water cycle. The primary step in treatment uses gravity to separate about 50% of the solids from the water. The process involves large tanks where the denser materials like sand and organic matter settle at the bottom, while lighter substances like oil rise to the top, allowing for the cleanest water to be removed from the middle layer.
๐ Aeration and Microbes in Treatment
The second paragraph delves into the aeration process, where hot air is pumped into the water to activate microbes that consume organic matter, thus cleaning the water. These microbes form a complex ecosystem, with different types of organisms playing roles similar to those in a natural environment. The process also involves the use of secondary clarifiers, where the microbes and organics they've consumed are separated from the water. The clean water is then piped to the next step, which is disinfection, while the microbes are either recycled back into the process or sent to digesters to be turned into fertilizer.
๐ Final Stages and Releasing Water
This section describes the final stages of wastewater treatment, including disinfection using sodium hypochlorite to eliminate any remaining bacteria. The treated water is then aerated further by flowing over artificial waterfalls to increase oxygen levels, which is crucial for the health of the Puget Sound ecosystem. The paragraph also discusses the remaining pollutants, such as nitrogen, phosphorus, and persistent chemicals, and the importance of source control to minimize their impact. The tour concludes with a look at the treated water being released into the environment, highlighting the effectiveness of the treatment process in removing most pollutants.
๐ฑ Resource Recovery at Brightwater
Kristen Covey introduces Brightwater, a newer wastewater treatment plant with a different secondary treatment system aimed at higher water cleanliness for reuse. The aeration process is similar to South Plant, but instead of secondary settling tanks, Brightwater uses microscopic filters. The filters are membrane filter cassettes with pores so small that only water molecules and smaller particles can pass through, effectively removing bacteria. The clean water is then extracted for reuse, while most of it still goes into the Puget Sound. The paragraph emphasizes the sustainable practices of the treatment plant, focusing on resource recovery and reduced environmental impact.
๐ Recycling Organic Material and Biosolids
The final paragraph focuses on the recycling of organic material from wastewater. The organic material is sent to digesters, where it is broken down by anaerobic bacteria, producing methane gas, which is captured and used as biogas. The resulting biosolids, rich in nutrients, are used for agricultural purposes, supporting plant growth and improving soil health. The paragraph also mentions the production of a compost made from biosolids and sawdust, suitable for home gardens. Additionally, a portion of the treated water is further processed into recycled water for non-potable uses like irrigation, contributing to water conservation and sustainable practices.
โป๏ธ Sustainable Practices and Energy Recovery
The last part of the script emphasizes the sustainable practices employed in wastewater treatment, such as using recycled water for irrigation and industrial purposes, reducing the demand on freshwater resources. It also highlights the recovery of biogas as a renewable energy source, which helps reduce carbon emissions. The script concludes by underscoring the environmental benefits of these practices, including healthier soils, preserved water resources, and the promotion of renewable energy, showcasing the wastewater treatment process as an integral part of a sustainable ecosystem.
Mindmap
Keywords
๐กWastewater
๐กPollutants
๐กTreatment Plant
๐กBar Screens
๐กPrimary Treatment
๐กAeration
๐กSecondary Clarifiers
๐กDisinfection
๐กBiosolids
๐กRecycled Water
๐กSustainability
Highlights
Wastewater treatment is essential for cleaning pollutants before water returns to the water cycle.
Wastewater contains organic matter, chemicals, bacteria, and trash from various sources.
The wastewater treatment process begins with bar screens to remove trash.
Gravity is used in primary treatment to separate out about 50% of the solids from the water.
Aeration activates microbes that consume organic matter and help clean the water.
Microbes form a complex ecosystem within the wastewater treatment tanks.
Secondary clarifiers help separate microbes and organics from the water after aeration.
Disinfection with sodium hypochlorate removes any remaining bacteria.
Treated wastewater is oxygenated as it goes over artificial waterfalls before release.
Nutrients like nitrogen and phosphorus, and some chemicals, can still pass through the treatment system.
Source control is crucial for reducing persistent chemicals in wastewater.
Brightwater treatment plant uses membrane filters for higher level water cleaning.
Organic material is digested by anaerobic bacteria, producing biogas that's captured and used.
Biosolids, rich in nutrients, are used for agriculture and soil improvement.
Recycled water from additional treatment is used for irrigation and other non-potable purposes.
Recycling wastewater reduces pressure on drinking water sources and benefits the environment.
Transcripts
have you ever wondered where water goes
when it goes down your drains in your
house
it actually goes to a wastewater
treatment plant
hi my name is charity and i'm an
educator for king county wastewater
treatment
today we're going to go on a tour of the
wastewater treatment plant here in
renton
we're going to follow step by step and
learn how environmental engineers
have developed ways to clean all of the
pollutants out of the water before it
returns to the water cycle
and the puget sound let's take a moment
and think about it what is
waste water wastewater is any water that
comes down drains inside of buildings
so that could be showers sinks washing
machines
dishwater dishwashers it could be
things coming from a factory too or
inside schools or
office buildings one thing with
wastewater is that it's full of things
other than water right it's full of
organics
things like poop and pee and toilet
paper
it's full of things like dangerous
chemicals like cleaning products and
personal products like medicine and
makeup
it also has bacteria in it bacteria
naturally occur in our body things like
e coli but could also be because we're
sick
so things like dangerous germs could
also be in wastewater
the last thing that we worry about in
wastewater is trash
trash is a huge issue for our system
you'll see later on in the tour
what happens to all of the trash we have
to take out of the water
i want you to take a minute and picture
in your head what do you think waste
water what do you think raw sewage looks
like
[Music]
i actually have a sample of raw
wastewater right here
we're going to take a look at it so this
is what we call
raw influent that means the water coming
into the facility
[Music]
when i first saw this i was really
surprised because i expected it to be
really sludgy right full of thick brown
chunks
there are chunks in it but most of
what's in wastewater
is water so if you think about it if the
average person
uses about 100 gallons of water every
day right
most of what we're going to be receiving
into the system is water
but all of those pollutants that i
talked about those could be really
dangerous if they got out into the puget
sound which is why
it's so important that we have a system
that removes those things
before we return the water to the water
[Music]
cycle
[Music]
[Music]
here we are in the bar screen room that
is two stories underground the room
contains
seven bar screens water flows through
the bars on the bar screen
the bars are placed about a pinky nail
width apart from each other
and as the water flows between the bars
the trash is caught
things that get caught on the bars
include tampons condoms
and wrappers as well as flushable wipes
[Music]
the trash is then scraped off with the
scraper arm
and then dropped in the channel behind
the screen
once the screens catch the trash it gets
scraped up
and then dropped into the channel behind
the screens
every year king county spends millions
of dollars
dealing with trash clogs in our system
that's why it's important to remember
the four p's
the four peas are the only thing that
should be going down your toilet
poop pee puke and toilet paper
[Music]
let's consider the primary step of the
wastewater treatment process
in this step we actually are using
simple gravity
to clean about 50 of the solids out of
the water
so as you've seen these huge tanks
behind me
are holding our wastewater now free of
trash
they're letting the waste water sit and
the longer the water sits
the more it starts to separate so i have
a model in front of me this isn't real
wastewater
but inside of this bottle i have water
cooking oil and sand you can see really
quickly
that the sand because it's heavier sinks
to the bottom
and the oil rises to the top this cloudy
layer in the middle
is actually the cleanest layer of water
so like i said this is a really
passive low energy way of allowing
gravity to do the work for us
once the water has been sitting in the
tank we
scrape the sand off of the bottom in
this case it's actually
organic so our poop and our food we
scrape it off the bottom using these
long
scraper bars we remove the oil
from the top of the water using uh
recycled water gets sprayed over the top
and pushes the oil over to the scum
scrapers you saw earlier then the scum
scrapers scrape the oil off of the top
so the clean water that's that middle
layer of our water in the tanks
actually gets pulled off from the tank
by the
bars behind me so inside of these long
troughs there are holes that hit about
the middle of the water level
the water gets pulled into these troughs
and then
brought into the next step of the
wastewater process
leaving behind again the oil and the
poop and the food at the bottom so about
50
of those organic solids
[Music]
the next step of the process is called
aeration in the aeration process we pump
hot air into the water which activates
special microbes that help clean the
water for us
then you'll see we let the water settle
out again and the microbes sink to the
bottom
the hot air that we are pumping into the
tanks behind me
activate bacteria that are naturally
occurring in our digestive system
and occur in the water once the bacteria
are activated they grow in population
to the point where they're saturating
the entire water and they create
a complex ecosystem so the bottom of our
ecosystem the bottom of our trophic
level
are all of the nutrients and the poop
and the food right
the next level is the bacteria that are
clumping together creating something
called a flock
and they're passively absorbing the
nutrients from the water
kind of like herbivores in an ecosystem
we also have more complex creatures
that are actively grabbing food out of
the water
as well as grabbing the bacteria and
feeding off the bacteria
like a predator would in a forest
ecosystem
the really cool thing about this
ecosystem is that it's filled with
literally
thousands of different types of
organisms you can also
take samples of this water and look at
the assemblage of microbes the different
species
and use that to tell how healthy the
water is how healthy the ecosystem is
and how good of a job it's doing in
cleaning the water
vorticella is a type of stocked
flagellate that acts as an herbivore in
our complex ecosystem
they're really interesting protists
because they have long bungee cord like
tails
that hang off of the bacteria flock in
the water
then shoot out to collect food another
type of stocked flagellate in the water
is an epistylus epistyluses are
passive filter feeders like sponges sea
sponges
they live in colonies that look similar
to bouquets of flowers
and they float in the water passively
absorbing the nutrients and the bacteria
[Music]
after a few hours in the aeration tanks
the water gets piped on to the next step
of the process
these are called secondary clarifiers so
at this point
our microbes have been eating the
organics out of the water for us
but now we need to get those microbes
and the organics they've collected in
their bodies
out of the water water from the aeration
tanks enters the clarifier from a
centrally located pipe
pumps pull the water up to the top of
the tank where it goes through a special
device to slow it down
and begin the settling process
the microbes sink to the bottom and are
then piped either back
into the hot tubs or out into our
digesters where they're turned into a
fertilizer
the clean water that's on the top then
gets piped onto the next step
which is disinfection
so behind me is the last step of our
wastewater treatment process here at
south plant
these long channels behind me are called
contact channels
we're introducing a chemical sodium
hypochlorate
to the wastewater that'll remove any
bacteria
that may have escaped into the system
like e coli
after the water has sat in the
disinfecting channels for a while
it goes over what we like to call rent
and falls
these waterfalls aren't just for show
though they're actually for an important
water quality reason
as the water goes over these falls we're
introducing oxygen
back into the water it's really
important that the water
that goes out into the puget sound after
this is
high in oxygen because dissolved oxygen
is incredibly important
for the animals that live in the puget
sound so
like i said this is actually the last
time you'll see the water
on our wastewater tour from here it gets
piped
13 miles to a pipe that goes off of the
coast of alki
in west seattle from there the water is
diffused
under the pipe and slowly spreads out
and then gets picked up and moved around
by the ocean channels
[Music]
when the treated wastewater leaves the
treatment plant
we've removed a majority of those
pollutants that were in the water when
it entered the facility
think back to the beginning of this tour
remember those four categories
we have the trash the organics
the bacteria and the chemicals that are
in the water
so we've completely removed the trash
that's in the water
think back to those bar screens earlier
and that large amount of trash we saw in
the pit
we've also removed all of the bacteria
in the water
both through our aeration and through
our sodium hypochlorite
disinfecting channels there are two
categories though
where some trace amounts are getting
through our system
and it's important that we talk about it
the first thing that we have to think
about
is nitrogen and phosphorus so nutrients
left over from the organics
these are naturally occurring nutrients
in our food
and then in human poop that come into
our system
and many of them are removed from the
water as our bacteria eat them up in
aeration
however some nitrogen and phosphorus
does get through our system
and goes out into the puget sound the
last category that we have to worry
about
is chemicals chemicals are broken down
partially
in our aeration process as bacteria eat
them up and break them into their
different parts
however some chemicals are considered
persistent
these are things like cleaners and
pharmaceuticals
that aren't broken down in our system
and trace levels are getting out into
the sound
easiest way and the most important way
to control this is through something we
call
source control that means that people
are making choices where they live
and where they shop and manufacturers
are making choices
to not make products or use products
that are going to be getting into the
sound
and are too persistent to get removed
through the wastewater system
this means that you can actually do
something to make our water cleaner
you can choose to use chemicals that are
considered green or
biodegradable and will break down in our
system
rather than going out into the sound and
having a negative impact
thanks for joining me on this tour of
the south king county wastewater
treatment plant
next up go meet my colleague kristen
covey at the brightwater wastewater
treatment plant
[Music]
welcome to brightwater hi everyone my
name is kristen covey
and i work with charity on the education
team for king county wastewater
and you are at our newest treatment
plant
um called bright water and bright water
came online
in 2011 about nine years ago we're
located in woodenville washington
and because we are a newer treatment
plant we have a different
secondary treatment system from south
plant as charity mentioned
the reason why we have a different
secondary treatment system
is so that we can clean the water to a
higher level
in order to reuse it instead of sending
all of it out to the puget sound
so if you can remember at south plant
they had a process called aeration or
the bacteria hot tub
so we have that same process at bright
water as well
and for us it's located behind me one of
those silver pipes
so one thing that's different about
bright water is our tanks are all
covered because we want to control odors
and so
it's really hard to show you what the
tanks look like
but just know that that's where aeration
is happening at bright water
so the bacteria are consuming and eating
everything they're getting really fat
and instead of putting that water into
secondary settling tanks like they do at
south plant
we instead put it into another set of
tanks which are located over here
that contain microscopic filters
so underneath that area um
are the filters and we're going to learn
how they work
next so remember
what we have left in the water at this
point is
a lot of bacteria chemical compounds
and some other microscopic particles
right so
if we have filters in these tanks
they're going to need to be pretty tiny
right
so i'm going to show you the filter
technology that we have here
you might be surprised at what it
actually looks like
are you ready here it is
this is
the technology we have here
and how does this work
so here we are standing on top of the
tanks that contain all of the filters
you can see that behind me they're
covered right now so you can't see
inside the tank but if you were able to
you would see what you see in this
photograph
so this is what we would call a membrane
filter cassette
so this is one of them and we have 160
of these
in all of the different tanks so when i
say
the word membrane what does it remind
you of have you heard of that word
before
so it's pretty cool because a membrane
is what is on the outside of a cell so
it's the outer coating of a cell
and it's selective so it allows certain
things to go in or out
so we have basically mimicked a cell
membrane
in this technology but the limiting
factor
for this technology is size
so in this case the only things that are
going to fit
through this filter have to be small
enough
to pass through teeny tiny pores or
holes
in this filter and i'm not talking about
the holes at the end which means that
there are
actually microscopic
pores in this plastic
that you can't see with your naked eye
so that means that this straw is a
filter
and the filtering part of the straw is
the plastic
so anything that goes through this
plastic
ends up in the center of the straw and
gets extracted
so these pores are so tiny
they're only .04 microns which might
mean something to some of you
but for most of us that means nothing so
what means something to me
is that if i were to line up
2 000 of those pores
side by side so 2 000 in a line
the width of that could fit across a
human hair
so that's tiny which means that only
a water molecule a molecule or anything
smaller could pass through one of those
pores
which means that the bacteria do not go
through this filter and they stay on the
outside
okay but so how does the water actually
get pulled
through the plastic and into the center
of each filter
so if you can remember here's the
cassette right
so it's submerged vertically into these
tanks behind me
and on top of each cassette is a vacuum
pipe pulling upwards
you can see the pipes behind me so each
cassette has one pipe that
pulls upwards it provides a suction so
when that happens
it's going to pull into the center
of each filter just whatever can fit
through those pores so
just the cleanest water will go through
into the center and get extracted out by
that vacuum pipe
so this is a very valuable freshwater
resource that we can
reuse for certain purposes which you're
about to learn about
but most of it still does go into the
puget sound
so let's go check out the waterfall that
we have here at brightwater
to see the water leaving the plant and
going into the puget sound
[Music]
hi everyone i'm sienna and i'm an
educator with kin county wastewater
treatment division
i'm going to be talking to you all about
how we recycle resources
from our wastewater treating
wastewater requires lots of energy to
pump
all the millions of gallons of
wastewater around our system every day
so at king county wastewater treatment
division we think a lot about
how to be sustainable and reduce our
energy consumption
and reuse the valuable resources that
are already in wastewater
thinking back to the organic material
such as the poop and food that was
removed from
primary and secondary treatment you may
have wondered where
does that go and what happens to it
so these big tanks behind me are called
digesters
and all the organic material is sent
into these tanks
so that material spends two weeks or so
in these tanks getting broken down by
naturally occurring
anaerobic bacteria
and these tanks are heated to 98 degrees
so it actually is the same temperature
as our bodies
and that process of breaking down the
organic material is similar to what
happens in our stomachs
as the anaerobic bacteria breaks down
the organic material
and consumes it they give off a few
different gases including methane gas
now methane gas is actually a
greenhouse gas and so it contributes to
climate change
so instead of letting that gas just
escape into the atmosphere
we actually capture it here and we call
it biogas
so you can see those black pipes behind
me
are actually where that methane gas is
getting removed from
the digesters it's then going to get
scrubbed and cleaned
and used to heat the boilers
here at the treatment plants as well as
it's going to be sold as natural gas to
help heat and fuel
energy in people's homes follow me to
see what happens with all the organic
material from the digesters
[Music]
all the organic material comes to this
room where it's spun through
a centrifuge which removes the water
from it
and next we're left with
this biosolid it's full of nutrients and
organic matter
what do you think we use it for
so king county's brand of biosolids is
called loop
and in fact you may have seen one of
these trucks traveling on the i-90
corridor
east where it's bringing these this
material
to farms and forests in eastern
washington to help grow trees
for timber as well as canola
wheat apples and hops
in addition to providing nutrients to
plants
loop helps build healthy soil that
retains
more moisture which is especially great
in eastern washington where it's drier
and hotter
so businesses that use loop go through a
permitting process
because there are a small amount of
pathogens
left in the material that just helps
make sure that
the product is used safely and doesn't
cause any problems
something that you may not know is that
every year king county produces
a hundred and twenty thousand tons of
loop
that's enough loop to fill a football
stadium 70 feet high
thanks for your contribution so we turn
a small portion
of loot biosolids into a compost
that's sawdust mixed with
loop and it can be used at home gardens
as well as here at our demonstration
garden to grow
fruits plants and flowers
so what about all that cleaned effluent
or treated water that goes out to puget
sound
couldn't we reuse some of that
[Music]
the answer is yes we actually send a
small portion of that water
through an additional treatment process
which is a sand filter
and it ends up as something called
recycled water
and it looks like this
[Music]
to the human eye you actually can't
really tell that it's any different from
drinking water
but it's not drinking water it has to
travel in its own set of pipes
which are always purple in color
recycled water is great for irrigation
of farms and sports fields
it's also used for street cleaning it
can even be used for flushing toilets in
certain facilities
as well as industrial water a fun fact
is that the seattle sounders practice on
starfire sports and their fields are
also watered with recycled water
recycled water is also great because it
still has nutrients in it so
it can actually add a fertilizing boost
to the plants that it's irrigating
and in terms of the pipes it has to
travel in
recycled water can't travel in the same
pipes as drinking water so if
a business wants to use it they need to
help
build out purple pipes to their facility
or they can come to one of our
truck refill stations and pick up
recycled water and take it to their
facility
using recycled water is really helpful
for our
planet because it puts less pressure on
the streams and aquifers that we get our
drinking water from which means
there's more water left for drinking and
for salmon and other wildlife to use so
now you've learned about
how we reuse organic material
some of the water as well as the biogas
energy
from our wastewater treatment process
this is an effort to help reduce our
carbon emissions and environmental
footprint
by building healthy soils keeping more
water in rivers and reservoirs
and creating renewable energy sources
thanks for joining us
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