Context: The modern sanitation system, designed to contain, convey, treat, and either dispose of or reuse the used water was built in London around the 1800s due to the emergence of industrialization-driven modern cities.
About Sanitation System
- Definition: A sanitation system includes the capture, storage, transport, treatment and disposal or reuse of human excreta and wastewater.
Types of Sanitation System
Sanitation Systems are usually determined based on the density of the population it is meant to serve.
- On-site sanitation systems (OSS):
- These systems serve as collection and storage structures that passively treat the used water and dispose of the liquid into the surrounding soil.
- The solid residue that collects within the pits is called faecal sludge, or septage
- Generally a feature of rural areas or spacious urban residences, these system includes twin pits, septic tanks and bio digester systems.
Twin Pits:
- Twin pits are separated by at least one meter. The pits, used alternatively, have porous walls that allow the liquid part of used water to soak into the ground while solids collect and degrade at the bottom of the pit
- One pit functions at a time and when it reaches full capacity, it is left unused for atleast 2 years for its contents to naturally dispose off into a dry, pathogen free safe residue which can be reused.
|
Septic Tanks:
- They are watertight tanks through which the waste water flows. The solids settle at the bottom, while scum – mostly oil and grease floats to the top.
- The accumulated faecal sludge and scum in the tank must be removed at regular intervals using trucks equipped with vacuum pumps that suck the faecal sludge out and transport it to treatment facilities called faecal sludge treatment plants (FSTPs).
|
- Off site Sanitation system:The faecal sludge needs to be transported to a centralised plant for its treatment. Generally a feature of densely populated urban areas.
Sewage Treatment plant (STPs):
- It is an underground network of interconnected pipes called sewers that collects and conveys the used water from the community to treatment facilities called sewage treatment plants (STP) by gravity or with the help of pumps.
- Sewers have machine holes for maintenance and to remove blockages.
- They are large, centralized installations designed specifically for large urban areas. They require substantial infrastructure and are usually located near water bodies to discharge treated water.
|
Faecal Sludge Treatment Plants (FSTPs):
- The process of containing, conveying and treating faecal sludge is called faecal sludge management (FSM).
- It uses a series of physical (separates solids from the liquid part) biological (purification (where microorganisms digest solids) and chemical processes (disinfection)
- It can be colocated with municipal solid waste management sites. They can also be decentralised and located closer to the sources of faecal sludge.
|
Need for Sanitation System
- The treated solids can be reused in agriculture or landscaping as organic manure when composted with organic municipal solid waste.
- Pollution: Direct disposal of waste water will lead to pollution of the environment and cause public health issues. Also to protect our increasingly precious water bodies and groundwater aquifers.
- Odour and aesthetics: To maintain a safe standard of living free of disease outbreaks, care has to be given to maintain the air and aesthetics of city surroundings. For example, the Great Stink of England prompted the British Government to invest in sanitation systems.
News Source: The Hindu
Must Read: Progress on Household Drinking Water, Sanitation and Hygiene (WASH) 2000-2022
December 26, 2023
