Page 56 - GRIHA Manual Volume IV - Introduction to National Rating System
P. 56
Building planning and construction 47
CRIteRIon 20
wAstewAteR tReAtMent
Introduction
Water scarcity, poor water quality, and water-related disasters are the three main concerns related
to current and future water resources (UNESCO, 2003). Solutions to water scarcity and water quality
issues directly or indirectly lie to some extent in sewage/wastewater management.
Wastewater can be broadly classified as greywater and blackwater. Greywater is wastewater
from baths, showers, hand basins, washing machines and dishwashers, laundries, and kitchen sinks.
However, wastewater from kitchen sinks requires special attention due to high content of oil and
food particles. Blackwater refers to wastewater from toilets.
Depending on the sources, greywater has the following speciic characteristics
Kitchen Kitchen greywater contains food residues, high amounts of oil and fat, including dishwashing detergents. In addition, it
occasionally contains drain cleaners and bleach. Kitchen greywater is high in nutrients and suspended solids. Dishwasher
greywater may be very alkaline (due to builders) and show high suspended solids and salt concentrations.
Bathroom Bathroom greywater is regarded as the least contaminated greywater source within a household. It contains soaps,
shampoos, toothpaste, and other bodycare products.
Bathroom greywater also contains shaving waste, skin, hair, body-fat, lint, traces of urine, and feaces. Greywater
originating from shower and bath may, thus, be contaminated with pathogenic micro-organisms.
Laundry Laundry greywater contains high concentration of chemicals from soap powders (such as sodium, phosphorous,
surfactants, nitrogen) as well as bleaches, suspended solids and possibly oils, paints, solvents, and non- biodegradable
ibres from clothing. Laundry greywater can contain high amounts of pathogens when nappies are washed.
Source Sandec 2006, Greywater management in low and middle-income countries
Greywater constitutes about 70% of the wastewater generated. Thus, there is huge potential to
treat this water and reuse for various applications.
India is a water stressed country with urban centres trying to get water from far-off and
deep sources. One of the prime reasons for our water sources (surface and sub-surface) getting
polluted is due to the indiscriminate disposal of untreated/partially treated sewage. Centralized
sewage treatment systems are very costly and difficult to implement given the large number of
them required for the entire country. In such a situation, treating and reusing/disposing the
wastewater at the very stage of generation is quintessential and is, therefore, promoted through the
GRIHA system.
The treatment of wastewater by conventional systems at the centralized level requires large
amount of land, huge capital, and operation and maintenance costs, and is energy-intensive. In
view of these consequences, the greywater and blackwater can be separated using dual plumbing
systems at the source of generation, which can then be treated separately using appropriate systems
and thereby increase its reuse potential. GRIHA attempts to provide solutions to some extent in the
form of decentralized wastewater treatment.
CRIteRIon 20
wAstewAteR tReAtMent
Introduction
Water scarcity, poor water quality, and water-related disasters are the three main concerns related
to current and future water resources (UNESCO, 2003). Solutions to water scarcity and water quality
issues directly or indirectly lie to some extent in sewage/wastewater management.
Wastewater can be broadly classified as greywater and blackwater. Greywater is wastewater
from baths, showers, hand basins, washing machines and dishwashers, laundries, and kitchen sinks.
However, wastewater from kitchen sinks requires special attention due to high content of oil and
food particles. Blackwater refers to wastewater from toilets.
Depending on the sources, greywater has the following speciic characteristics
Kitchen Kitchen greywater contains food residues, high amounts of oil and fat, including dishwashing detergents. In addition, it
occasionally contains drain cleaners and bleach. Kitchen greywater is high in nutrients and suspended solids. Dishwasher
greywater may be very alkaline (due to builders) and show high suspended solids and salt concentrations.
Bathroom Bathroom greywater is regarded as the least contaminated greywater source within a household. It contains soaps,
shampoos, toothpaste, and other bodycare products.
Bathroom greywater also contains shaving waste, skin, hair, body-fat, lint, traces of urine, and feaces. Greywater
originating from shower and bath may, thus, be contaminated with pathogenic micro-organisms.
Laundry Laundry greywater contains high concentration of chemicals from soap powders (such as sodium, phosphorous,
surfactants, nitrogen) as well as bleaches, suspended solids and possibly oils, paints, solvents, and non- biodegradable
ibres from clothing. Laundry greywater can contain high amounts of pathogens when nappies are washed.
Source Sandec 2006, Greywater management in low and middle-income countries
Greywater constitutes about 70% of the wastewater generated. Thus, there is huge potential to
treat this water and reuse for various applications.
India is a water stressed country with urban centres trying to get water from far-off and
deep sources. One of the prime reasons for our water sources (surface and sub-surface) getting
polluted is due to the indiscriminate disposal of untreated/partially treated sewage. Centralized
sewage treatment systems are very costly and difficult to implement given the large number of
them required for the entire country. In such a situation, treating and reusing/disposing the
wastewater at the very stage of generation is quintessential and is, therefore, promoted through the
GRIHA system.
The treatment of wastewater by conventional systems at the centralized level requires large
amount of land, huge capital, and operation and maintenance costs, and is energy-intensive. In
view of these consequences, the greywater and blackwater can be separated using dual plumbing
systems at the source of generation, which can then be treated separately using appropriate systems
and thereby increase its reuse potential. GRIHA attempts to provide solutions to some extent in the
form of decentralized wastewater treatment.
