Assalamoalikum & welcome back to "Orange Shots"
Another very interesting question -
What happens to the Human Waste on a Ship ..
While flushing a toilet requires a simple push of a button,
where does it actually go ..
The vacuum Toilet System sucks everything from a
toilet bowl but where it takes all of it and what
happens to it ..
Are we allowed to discharge it to sea
or are there some regulations that we have to adhere to
Just like regulations about Garbage?
If Yes then is there any special System installed
on Ships to handle it?
The thing is that not only is there a special system
to handle Human Waste
but the things are actually more complicated
when it comes to handling the Water or effluent
discharge from the Ships
And believe it or not, there are special chemicals
we are allowed to use for cleaning our toilet bowls,
the purpose is to not interfere with chemical
reaction and dosing that will happen to this in engine Room
What chemical reaction you may ask ..
Well, let's tell you all of this in Good Detail.
The Waste water on Ships is actually divided into
2 Categories
One is called Grey water
and the other is called Soil or sewage
Take our mess rooms as an example,
Mess man has to wash dishes here
and Chief Cook needs to make food,
all of this involves washing various items using detergents.
Then everyones takes shower
and use their wash basins for various purposes,
some soaps and shampoos are used in this case ..
The crew needs to wash clothes
and to do that we have laundry spaces on ship
where they can do so ..
obviously the detergents and
cloth softeners are used here.
These all processes involve water mixed with various
detergents, washing powders and Soaps ..
This kind of water is called Grey Water.
at open sea ,
It's usually permitted to discharge grey water directly to sea
with no special treatment,
usually the grey water lines from all spaces lead directly
to Engine Room from where this water
directly go to sea.
Now, some of the ports allow discharge of grey water
and some don't ..
if the vessel calls a port that doesn't allow the discharge
of grey water from ships,
we gather all of this water in either Grey water holding tank
- if provided -
or Sewage holding tanks and then discharge
the same at sea when the ship proceeds on a voyage.
Now comes the Soil,
this water is basically mixed with Human waste
and is the flushed water from everyone's Toilet on ship.
Direct discharge of this water overboard is strictly
prohibited as this water Contains COD and BOD
That is CHEMICAL OXYGEN DEMAND
and BIOCHEMICAL OXYGEN DEMAND.
This kind of waste water contains both of them
and if such water is discharged untreated,
this can can cause oxygen deficiency in receiving
environment and can be very dangerous for fish
and other aquatic species living there.
You must be wondering what is actually COD and BOD,
[the more clear version of it]
BOD stands for BIOCHEMICAL OR BIOLOGICAL OXYGEN DEMAND,
the Human wastes contains Bacteria
and more the bacteria is present,
the more oxygen they consume while decomposing Human waste,
the High demand of this Oxygen can cause Oxygen in
receiving environment to fall critically low and
hence become Dangerous for Fish and other aquatic organisms.
Hence High BOD is not good.
Now let's talk about COD or CHEMICAL OXYGEN DEMAND,
a Chemical reaction that consumes Oxygen,
an cause (AGAIN) deficiency of Oxygen,
such as in HUMAN Waste,
and more strong such chemical reaction is,
more oxygen it will absorb,
and more will be the COD,
again if such waste water is released in the sea,
it can cause the Oxygen in the receiving environment to
fall below critical limit and is Hence dangerous
for Fish and other aquatic Organisms.
So, you guys see,
simply speaking we have to treat such waste water before
discharging it at sea, that's where this thing comes in,
it's called Sewage Treatment Plant,
we treat sewage here to decrease the COD and BOD levels
before discharging it to sea.
For doing that we keep dosing this tank with NaOCl
or Sodium Hypochlorite
his helps in decomposition inside the tank
and hence decrease the levels of COD and BOD below
125 mg/litre and 25 mg/litre respectively --
That by the way are the limits that we Cannot exceed.
Sensors in our system keep analysing the COD AND BOD levels
the dosing of NaOCl keeps happening automatically
and we keep discharging this Treated sewage in Open seas.
At the same time we also need to monitor the chlorine
values in the discharged Water and that shouldn't exceed
a value of 0.5 mg/litre, because again
Excess of everything is Bad.
And Just for the record there are various types of this Plant,
This is just One of them,
they can have a different working principle or
dosing chemical But the end result and
main aim stays same - To REDUCE COD AND BOD.
To keep them below the allowed limits
Again when the vessel goes to a port where Treated
sewage discharge is also Not allowed,
we again reroute our treated sewage to Sewage Holding Tank
and Keep storing it there until we depart
from the port and treated sewage can be safely discharged
at open sea.
Another important thing is, that when the vessel is in dry dock,
that's when she is lifted out of water for 5 yearly repairs,
the DryDock connects their Own sewage pipes to the ship
and in that case we discharge all of the sewage
to Shore and then they handle it according to the local laws.
So you guys see that how such a small job as flushing your toilet
becomes so much interesting and
so much complicated on ships ...
well I am very certain that you must have enjoyed todays video
and must have Got something to learn about our life
- YET AGAIN ..
If you did, then consider liking this video,
sharing it with your friends and Consider subscribing
to this channel.
Take very good care of yourself,
keep me in your prayers and
With Tonnes of love for my Orange Shots family
and to be Orange Shots family ..
This is Zahid Nisar,
You are watching "Orange Shots"
& Until the next Video .. Allah Hafiz..