Where Does Your Sewage Go? | I Didn’t Know That

[Music]

[Music] waste from london’s toilets sinks and

waste from london’s toilets sinks and

waste from london’s toilets sinks and gutters is carried away by a network of

gutters is carried away by a network of

gutters is carried away by a network of interconnecting ever larger pipes

interconnecting ever larger pipes

interconnecting ever larger pipes designed and built by sewage superstar

designed and built by sewage superstar

designed and built by sewage superstar and pioneer Joseph Basel jet

and pioneer Joseph Basel jet

and pioneer Joseph Basel jet it all ends up here a sewage treatment

it all ends up here a sewage treatment

it all ends up here a sewage treatment works

works

works this is Becton sewage treatment works in

this is Becton sewage treatment works in

this is Becton sewage treatment works in the east of London and it’s Europe’s

the east of London and it’s Europe’s

the east of London and it’s Europe’s biggest it was originally part of Joseph

biggest it was originally part of Joseph

biggest it was originally part of Joseph Bazalgette scheme but I tell you what

Bazalgette scheme but I tell you what

Bazalgette scheme but I tell you what sewage treatment has really moved on

sewage treatment has really moved on

sewage treatment has really moved on since his day in the 19th century sewage

since his day in the 19th century sewage

since his day in the 19th century sewage was simply stored here in tanks then

was simply stored here in tanks then

was simply stored here in tanks then pumped out to the river at high tide so

pumped out to the river at high tide so

pumped out to the river at high tide so you’ll be pleased to know today’s

you’ll be pleased to know today’s

you’ll be pleased to know today’s process is a lot more refined and takes

process is a lot more refined and takes

process is a lot more refined and takes just four hours for raw sewage to be

just four hours for raw sewage to be

just four hours for raw sewage to be clean enough to return to the river

clean enough to return to the river

clean enough to return to the river every day this treatment works handles

every day this treatment works handles

every day this treatment works handles the sewage from 3.4 million Londoners

the sewage from 3.4 million Londoners

the sewage from 3.4 million Londoners and that’s an astonishing volume it

and that’s an astonishing volume it

and that’s an astonishing volume it equates to 34 Olympic swimming pools

equates to 34 Olympic swimming pools

equates to 34 Olympic swimming pools every hour so how does it treat the

every hour so how does it treat the

every hour so how does it treat the byproducts of our late-night sessions

byproducts of our late-night sessions

byproducts of our late-night sessions and trips to the local curry house the

and trips to the local curry house the

and trips to the local curry house the first process happens here at the inlet

first process happens here at the inlet

first process happens here at the inlet works using these screens large loves

works using these screens large loves

works using these screens large loves like bricks wood rags a rake belt once

like bricks wood rags a rake belt once

like bricks wood rags a rake belt once collected these large objects will all

collected these large objects will all

collected these large objects will all be washed and sent to a landfill sites

be washed and sent to a landfill sites

be washed and sent to a landfill sites nearby they’ve even had half a car here

nearby they’ve even had half a car here

nearby they’ve even had half a car here meanwhile the remaining sewage passes on

meanwhile the remaining sewage passes on

meanwhile the remaining sewage passes on to the next part of the process into

to the next part of the process into

to the next part of the process into these primary settlement tanks now very

these primary settlement tanks now very

these primary settlement tanks now very basically it enters at that end and

basically it enters at that end and

basically it enters at that end and flows relatively slowly this way over

flows relatively slowly this way over

flows relatively slowly this way over the top of each tank is a moving bridge

the top of each tank is a moving bridge

the top of each tank is a moving bridge which has two blades to remove a solid

which has two blades to remove a solid

which has two blades to remove a solid organic material from the sewage the top

organic material from the sewage the top

organic material from the sewage the top blade skims scum from the surface while

blade skims scum from the surface while

blade skims scum from the surface while a second submerged blade dredges the

a second submerged blade dredges the

a second submerged blade dredges the heavier settled sludge from the bottom

heavier settled sludge from the bottom

heavier settled sludge from the bottom of the tank all this solid sludge is

of the tank all this solid sludge is

of the tank all this solid sludge is then sent for further processing

then sent for further processing

then sent for further processing the remaining sewage then flows down

the remaining sewage then flows down

the remaining sewage then flows down this way towards the secondary

this way towards the secondary

this way towards the secondary biological treatment process and here it

biological treatment process and here it

biological treatment process and here it is in these tanks the sewage is mixed in

is in these tanks the sewage is mixed in

is in these tanks the sewage is mixed in with billions upon billions of bacteria

with billions upon billions of bacteria

with billions upon billions of bacteria so all the dissolved materials that

so all the dissolved materials that

so all the dissolved materials that still remain can be by degraded and

still remain can be by degraded and

still remain can be by degraded and pumping air from below at very high

pumping air from below at very high

pumping air from below at very high pressures causes the sewage to be

pressures causes the sewage to be

pressures causes the sewage to be saturated with dissolved oxygen and this

saturated with dissolved oxygen and this

saturated with dissolved oxygen and this accelerates the biological breakdown

accelerates the biological breakdown

accelerates the biological breakdown brilliance finally the treated effluent

brilliance finally the treated effluent

brilliance finally the treated effluent is tested to ensure it’s clean enough to

is tested to ensure it’s clean enough to

is tested to ensure it’s clean enough to go back into the Thames meanwhile

go back into the Thames meanwhile

go back into the Thames meanwhile remember all of the solids which was

remember all of the solids which was

remember all of the solids which was skimmed off earlier they’re taken to a

skimmed off earlier they’re taken to a

skimmed off earlier they’re taken to a processing plant these sludges are

processing plant these sludges are

processing plant these sludges are brought to this filter press where it’s

brought to this filter press where it’s

brought to this filter press where it’s be watered

be watered

be watered [Music]

[Music]

[Music] and the resulting sludge cake is

and the resulting sludge cake is

and the resulting sludge cake is incinerated and that provides 75% of

incinerated and that provides 75% of

incinerated and that provides 75% of this entire works power needs