INDICATOR 6.3.

1 : PROPORTION OF BY: MISHIKA MALIK

ROLL NO.:21/946

SAFELY TREATED DOMESTIC COURSE: BA PSYCHOLOGY

HONOURS
WASTEWATER FLOWS
RATIONALE
Wastewater data are crucial to promote strategies for sustainable and safe wastewater use
or reuse to the benefit of the world’s population health and the global environment, but also to
respond to growing water demands, increasing water pollution loads, and climate change
impacts on water resources. Sustainable Development Goal 6 (SDG 6) is about ensuring the
availability and sustainability of water and sanitation for all by 2030. SDG Target 6.3 sets
out to improve ambient water quality, which is essential to protecting both ecosystem and
human health, by eliminating, minimizing and significantly reducing different streams of
pollution into water bodies. The purpose of monitoring progress using SDG indicator 6.3.1 is to
provide necessary and timely information to decision makers and stakeholders to make
informed decisions to accelerate progress towards reducing water pollution, minimizing release
of hazardous chemicals and increasing wastewater treatment and reuse. The target wording
covers wastewater recycling and safe reuse with implication on water use efficiency, although
it is not fully addressed by the global indicator and methodology. SDG indicator 6.3.1 tracks
the proportion of wastewater flows from households, services and industrial economic activities
that are safely treated at the source or through centralized wastewater treatment plants
before being discharged into the environment, out of the total volume of wastewater
generated.
INDUSTRIAL WATER TREATMENT

Two of the main processes of industrial water treatment are boiler water treatment and cooling
water treatment. A large amount of proper water treatment can lead to the reaction of solids
and bacteria within pipe work and boiler housing. Steam boilers can suffer from scale
or corrosion when left untreated. Scale deposits can lead to weak and dangerous machinery,
while additional fuel is required to heat the same level of water because of the rise in thermal
resistance. Poor quality dirty water can become a breeding ground for bacteria such
as Legionella causing a risk to public health.
Corrosion in low pressure boilers can be caused by dissolved oxygen, acidity and excessive
alkalinity. Water treatment therefore should remove the dissolved oxygen and maintain the
boiler water with the appropriate pH and alkalinity levels. Without effective water treatment,
a cooling water system can suffer from scale formation, corrosion and fouling and may
become a breeding ground for harmful bacteria. This reduces efficiency, shortens plant life
and makes operations unreliable and unsafe.
Boiler water treatment : Boiler water treatment is a type of industrial water
treatment focused on removal or chemical modification of substances potentially damaging to
the boiler. Varying types of treatment are used at different locations to avoid scale, corrosion,
or foaming. External treatment of raw water supplies intended for use within a boiler is
focused on removal of impurities before they reach the boiler. Internal treatment within the
boiler is focused on limiting the tendency of water to dissolve the boiler, and maintaining
impurities in forms least likely to cause trouble before they can be removed from the boiler in
boiler blowdown.
Cooling water treatment: Water cooling is a method of heat removal from components of
machinery and industrial equipment. Water may be a more efficient heat transfer fluid
where air cooling is ineffective. In most occupied climates water offers the thermal
conductivity advantages of a liquid with unusually high specific heat capacity and the option
that of evaporative cooling. Low cost often allows rejection as waste after a single use, but
recycling coolant loops may be pressurized to eliminate evaporative loss and offer greater
portability and improved cleanliness. Unpressurized recycling coolant loops using evaporative
cooling require a blowdown waste stream to remove impurities concentrated by evaporation.
Disadvantages of water cooling systems include accelerated corrosion and maintenance
requirements to prevent heat transfer reductions from biofouling or scale formation. Chemical
additives to reduce these disadvantages may introduce toxicity to wastewater. Water cooling
is commonly used for cooling automobile internal combustion engines and large industrial
facilities such as nuclear and steam electric power plants, hydroelectric generators, petroleum
refineries and chemical plants.
DOMESTIC WATER
Domestic wastewater is generated in households or office buildings from streams
without fecal contamination, i.e., all streams except for the wastewater from toilets.
Sources of greywater include sinks, showers, baths, washing machines or dishwashers.
As greywater contains fewer pathogens than domestic wastewater, it is generally
safer to handle and easier to treat and reuse onsite for toilet flushing, landscape or
crop irrigation, and other non-potable uses. Greywater may still have some pathogen
content from laundering soiled clothing or cleaning the anal area in the shower or
bath.
The application of greywater reuse in urban water systems provides substantial
benefits for both the water supply subsystem, by reducing the demand for fresh clean
water, and the wastewater subsystems by reducing the amount of conveyed and
treated wastewater.] Treated greywater has many uses, such as toilet flushing or
irrigation.
TREATMENT OF DOMESTIC WATER
Most water is easier to treat and recycle than sewage because of lower levels of contaminants. If collected
using a separate plumbing system from black water, domestic greywater can be recycled directly within the
home, garden or company and used either immediately or processed and stored. If stored, it must be used
within a very short time or it will begin to putrefy due to the organic solids in the water. Recycled greywater of
this kind is never safe to drink, but a number of treatment steps can be used to provide water for washing or
flushing toilets.
The treatment processes that can be used are in principle the same as those used for sewage treatment, except
that they are usually installed on a smaller scale (decentralized level), often at household or building level:
Biological systems such as constructed wetlands or living walls and more natural 'backyard' small scale systems,
such as small ponds or biodiverse landscapes that naturally purify greywater.[7]
Bioreactors or more compact systems such as membrane bioreactors which are a variation of the activated
sludge process and is also used to treat sewage.
Mechanical systems (sand filtration, lava filter systems and systems based on UV radiation)
In constructed wetlands, the plants use contaminants of greywater, such as food particles, as nutrients in their
growth. Salt and soap residues can be toxic to microbial and plant life alike, but can be absorbed and
degraded through constructed wetlands and aquatic plants such as sedges, rushes, and grasses.
WASTEWATER TREATED SAFELY IN PREVIOUS
YEARS
GRAPH OF WASTEWATER AND ITS TREATMENT IN
RECENT AND FUTURE YEARS