Although the actual execution of plumbing and sanitary works is done after completion of the RCC work and masonry work , it is necessary to include this in the master planning in the beginning of any project.
This article gives inputs on the overall scope of plumbing and sanitary works and gives insights as to how to execute this in a way that maintenance does not become a nightmare.
What’s the basic difference ?
Plumbing talks about all pipelines, valves storage & distribution system related to fresh , usable water whereas sanitary refers to everything related to waste water.
The scope of plumbing starts from source of water, storage , distribution up to the tap at your home.
The moment this water comes out from the tap and is used or ( abused ),it comes under the scope of sanitary.
Plumbing would start from the river or lake or open well or bored well to Jack well to pipe line to storage to filtration plant to water distribution system to underground storage tank to pumps to overhead storage tank to loft tanks to individual taps or cocks in the apartments.
Sanitary Scope detailed out:
Sanitary would start from wash basin to waste coupling to drain pipe to gully trap to chamber to septic tank to soak pit or municipal drainage system.
Black water & grey water:
All waste coming out from the latrines which is also known as human excreta or night soil is called as black water.
Every other waste from the house is termed as grey water or also known as ablution water.
Nature of Black water:
This is organic matter containing biological waste from the body and is therefore has high BOD content.
( BOD: Biological oxygen demand.
Higher is the organic or putrefying matter higher shall be the BOD value)
Nature of Grey water:
All effluent from wash basin , bath rooms , kitchen sinks , utensils wash ,washing machine is termed as grey water and it is basically inorganic in nature with lot of chemicals from various soaps , detergents, shampoos , body wash etc.
Single line collection system :
Black water and grey water are collected in a single pipe line and is taken directly to the septic tank.
There is only one line to be provided and hence economical as compared to double lines.
In case of any blockage in the single pipe line , the entire sewage system shall render useless and shall call for emergency maintenance.
Double line collection system :
Black water and grey water are collected in different pipe lines. Black water is taken directly to the septic tank whereas grey water is discharged into the municipality drainage.
Septic tank has to be adequately designed to cater the combined load of black & grey water and hence it has to be much bigger in size .
Only disadvantage is that since one line is only catering to black water , there shall be lesser flow and hence probability of chock in the pipe shall be higher.
What is a septic tank ?
It is a method by which the unstable black water which is highly putrefying is converted into inorganic and stable output through a process of decomposition.
Structure of septic tank :
Visualize a long box with 2 partitions creating 3 equal compartments .First partition has opening at the bottom while the second partition is open at the top.
Process in a septic tank :
The black water enters in the first compartment while the treated water leaves the last compartment.
The central chamber is where the anaerobic bacteria decompose the organic matter into a stable mass.
The output of septic tank are : sludge , liquid and foul gases.
Short circuit of septic tank :
If the untreated waste gets discharged through outlet.
This can happen if the opening in the first partition is kept at the top ( instead of at the base ).
Choke in the septic tank :
The sludge deposits at the base of the septic tank. If it is not cleaned at a specific interval , this prevents the passage of waste water from first to second compartment. The entry chamber is thus flooded and does not allow entry of additional waste water.This is a very troublesome situation since the toilets on the ground floor gets flooded with back water .
Only solution is to immediately clean the sludge .This is done with a sludge pump which is mounted on a tanker.The sludge is sucked by the pump and gets filled up in the tanker.
The effluent from the septic tank is discharged into the soak pit from where it gets slowly absorbed into the soil beneath through percolation.
Soak pit needs to be provided only when there is no municipality drainage in that locality .
Construction of a soak pit:
Brick bats are filled up in a deep circular pit and the septic tank effluent is discharged at the centre through a percolated pipe. Top of the soak pit is usually covered with coarse sand only.
Manhole or chamber:
A chamber is smaller in size . If it is large enough that a person can down inside for
maintenance , it is known as the manhole.
A chamber is normally cubical in shape whereas a manhole is cylindrical or conical in geometry.