Sustainable wastewater treatment

1. Sustainable
Wastewater
Treatment

2. introduction
What is
wastewater?
• Originate from
homes, industrial
and factory waste,
commercial or
farming activities,
surface runoff or
storm water
• includes dissolved
contaminants,
suspended solids
and micro-
organisms.
Wastewaters can be
categorized as:
1. Domestic wastewater - used water
discharged from the residential,
commercial and industrial area of a
city and collected though the
sewage system.
2. Industrial wastewater - generated
from industries.
What is sustainable?
• The quality of wastewater not being
harmful to the environment or
depleting natural resources, and
thereby supporting long-term
ecological balance.
Types of wastewater systems:
1. Domestic wastewater system -processes
wastewater from a home, or group of homes.
2. Industrial wastewater system- processes
wastewater from an industrial unit, such as a
factory
What is sustainable
wastewater
treatment?
• Process that coverts
wastewater from its
unusable state into an
effluent that can be
either returned to the
water cycle with
minimal
environmental issues
or reused for another
purpose

3. Wastewater Issues:
1. High concentrations of the contamination
2. Health issues.
3. Salts in wastewater ( nitrates and phosphates )
discharged into natural waters
4. Pollution problems
The scale of wastewater
treatment systems:
1. Individual: serves separate
households, farms or
businesses
2. Cluster: designed so that
treatment of wastes serves
groups of households or
businesses, but not a whole
community
3. Central: usually designed so the
treatment of wastes for an
entire community is managed
at once in one place.
Why is the sustainable wastewater
management very important?
• Water is essential to life.
• To ensure that wastewater treatment procedures are put in
place to avoid problems with contamination, pollution,
spreading disease and poisoning.
• Reduce the level of pollutants in wastewater thus not
harming to human health or to the natural environment

4. process
There are four main
sections that the waste
water will pass through in
order to recycle back to
reusable water:
1. Preliminary Treatment
2. Primary Treatment
3. Secondary Treatment
4. Tertiary Treatment

6. PRELIMINARY TREATMENT:
Preliminary treatment is a screening process that removes a lot of the solid
objects such as sticks, rocks, plastics, garbage, etc. they are collected,
removed from the waste water and disposed in a landfill.
A bar screener is a device with
openings (usually uniform in
size) to remove the floating
materials and suspended
particles.

7. PRIMARY TREATMENT:
After preliminary treatment, wastewater will reach the basin and is allowed to stay for a long period.
Resulting in heavy solids settling down and the much lighter substances such as oil and grease will
float on the surface. Then the chemical coagulant like alum is added here. Now smaller particles
will aggregate and form floc, which settle down easily. This eliminates settled and floating
materials in the primary treatment. Now the secondary treatment can begin. This process removes
about 40-60% of solid waste.
Grit chambers: To remove anything that is
“heavier” than the organic biodegradable
solids in the wastewater such as sand,
gravel & cinder.
Skimming tank: Greasy and oily materials
are removed by using a skimming tank.
Settling tank: Solid waste are allowed to
settle and be removed at the bottom of the
tank.

8. SECONDARY TREATMENT:
Now the wastewater is free from most physical contaminants, but
there are still suspended and biological contaminants. In this
stage biological treatment is used. Aeration tank provides oxygen
which allows the growth of aerobic bacteria. Secondary
treatment removes 85 percent or more of the organic matters in
sewage.
Secondary or biological
treatment is performed in a
tank where air is pumped in. It
contains starved microbes
called activated sludge that
require air to live.
Microorganisms in this aeration
tank use the dissolved and
particulate organic matter as
food, producing more
microorganisms. Therefore,
the waste materials are
converted into microorganisms
which can be collected and
separated from the water in the
secondary clarifier.
In the secondary clarifier, the
collected return activated
sludge are sent back to the
aeration tank and recycled.

9. TERTIARY TREATMENT:
The tertiary treatment specifically removes any component that was not removed in the previous
step. It varies depending on the industry. After this stage usable water is produced. The tertiary
treatment stage has the ability to remove up to 99 percent of the impurities from the wastewater.
This produces effluent water that is close to drinking water quality.
DISINFECTION
The wastewater must be
disinfected, with a
mixture of chlorine and
sodium hypochlorite. The
effluent (treated
wastewater) is later
released into the
environment through the
local waterways.
FILTRATION
Filtration which helps
primarily to remove
residual suspended
matter in wastewater.
Sand filtration is the
usual method that is
used for this purpose.
REMOVAL OF NUTRIENT
CONCENTRATION
Nutrients such Nitrogen and phosphorus
are usually found in high concentrations.
Nitrogen can be removed in the form of
ammonia is first oxidized to form nitrates
and then nitrates to nitrogen gas which is
released to the environment. On the other
hand, phosphorus can be removed
biologically as well by chemical
precipitation with salts of iron, aluminum,
or lime.

10. case study
1
rio de
janeiro

11. 1. The 2nd most
populated area in
Brazil
2. Host of the 2016
Summer Olympics
and the 2016
Summer Paralympics
3. Due to the events,
they have to reduce
the raw sewage
spilling into the
Guanabara Bay
which is located in
Southeast Brazil in
the state of Rio de
Janeiro.
1. Level of water
cleanliness is at a
critical point
2. Wastewater are left
untreated and bypass
into the sea.
3. The raw sewage and
garbage can be seen
floating in the water
4. The growth of
bacteria has
increased.
1) Building a new water waste
treatment plant based on a Dutch
technology known as the Nereda
technology
2) Nereda is technique for water
purification, based on a
technological solution which uses
aerobic granular mass.
3) Process treats wastewater by
using aerobic biological action to
purify it before returning clean
water to the environment.
4) The plan included 200km of new
sewage networks, 11 pumping
stations and connections for 25
thousand households.
Problems faced in
Rio:
About Rio de
Janeiro:
Solution to the problem:

12. Biomass in Nereda develops
as fast settling aerobic
granular sludge.
These granules have
excellent settling properties
and therefore Nereda does
not require a separate time-
consuming decant phase
like conventional SBR's.
Further, all the biological
treatment processes take
place simultaneously in the
granules, requiring only one
tank.
1. Named: Deodoro
WwTp- the largest
Nereda plant built so far
anywhere in the world
and the first of its kind in
South America, with a
further five planned in
Brazil.
2. Treat eventually the
wastewater of 480,000
people, the equivalent to
86,400m3 per day.
3. With 10 times the
capacity of the original
plant, the flow of
domestic sewage into
the local rivers and bay
has been massively
reduced.
How does Nereda
works ?
The outcome:

13. • Demand for water is unlimited-important in
our daily routine
• It is predicted that 1 litre of untreated
wastewater can pollute 8 litres of
freshwater
• Therefore ,efficient wastewater
management is important to help remove
harmful waste, microorganism and
chemicals in a water supply
• Fish and wildlife will be protected by the
uncontaminated streams or lake .
• Unwanted event such as storm water can
be prevented
advantages
• During the wastewater
treatment process, the
sludge is collected,
treated by anaerobic
bacteria
• These anaerobic
microorganism carries
out anaerobic process
in the absence of
oxygen
• Methane gas - to
generate electricity
• Reduce the
dependence on non-
renewable energy such
as fossil fuels
• Untreated water that
contain bacteria
,viruses and chemicals
would cause harmful
effect to people that
consume it
• Diseases -dysentery,
typhoid , and cholera.
• Thus ,wastewater
treatment plant is able
to remove 97% of
contaminants in water
• These contaminants
will be filtered to ensure
no bacteria or
pathogens are present.
Energy
Production Preserve & protect natural
environment
Prevention of
diseases

14. • Wastewater treatment system is expensive
• Government will have high expenditure for
installation of wastewater treatment
 Up-front planning of wastewater treatment
plant infrastructure which includes planning
concepts, designs, and regulatory
requirements for your project
 High labour cost when recruiting
professionals who are well-versed in this
field. They are knowledgeable on method
and procedures to operate the machineries
 Regulatory cost in terms of waste disposal.
Prior to discharging any waste, you’ll need
to ensure your facility have approval to
release waste, otherwise you will be fined
disadvantages
• Chemical substances are
important to treat the
wastewater
• If proper measures are not
taken during the disinfection in
chemical unit processes, there
can be too much chlorine in the
water
• If waste product not discharged
or handled effectively, it can
cause environmental impacts
to wildlife in sea
• Thus, government should
involve in research and
development on minimizing
harmful waste product
• Many countries have
poor wastewater
treatment system that
cannot purified the
water sufficiently
• So there might be
presence of
pathogens and
bacteria in water
• Therefore, an
outbreak of water-
borne disease such
as typhoid and
cholera
• In that case , each
household usually
overcome this
problem by installing
a water filter at home
to have cleaner water
Health concern
High Capital cost
Various chemical
substances &
waste product
from process

15. • This applies throughout a treatment plant, both for
maintenance activities and routine operations, and
also unscheduled maintenance tasks.
• At the other end of the scale, an anaerobic digester
can build up sediment in it over time, reactor space
will then be slowly diminished and impact the
performance
• The task of taking the digester offline and removing
the sediment is unpleasant, time-consuming and
costly one.
• Electricity cost is expected to increase over the
years as the number of plot ratio and density of
developments within regional wastewater treatment
plant keeps increasing more than is allowable in
urban areas to connect to the existing sewer line.
possible problems
Incur High Cost

16. • Wastewater treatment systems is one of the
source of greenhouse gas emissions.
• Greenhouse gas emissions contribute to global
warming and climate change.
• Emission of CO2 due to degradation of organic
matters
• Emission of N2O during the process of
nitrification and denitrification
• Emissions of CH4 and N2O from anaerobic
digestion during sludge treatment
• Indirect emissions from sludge treatment
• Usage of electrical power and chemicals during
the operation and maintenance of the treatment
plant and disposal of sludge.
• Production and transportation of construction
materials
Greenhouse GasHuman Health Risk
• Wastewater that are not treated well in the
wastewater treatment system can spread
disease and contaminate drinking water
sources through bacteria viruses and
disease-causing pathogens.
• Pollutants that can be found in wastewater
are chemical contaminants such as
chlorine compounds and toxic metals such
as mercury, lead and cadmium.
• Bacteria, viruses, and parasites (including
worms and protozoans) are hazardous to
humans.
- Pollute beaches
- Contaminate shellfish populations
- Causes restrictions on human recreation
- Drinking water consumption and
shellfish consumption are restricted as
well

17. Using Anaerobic
Biological Treatment to
replace Aerobic Biological
Treatment
• Increase the potential of reduce
the energy demand at a
treatment works
• Uses less energy than aerobic
treatment
• Biogas produced can be used for
Ammonia in wastewater act as a renewable
energy sources
• converted to electricity in an alkaline fuel cell, or decomposed
to provide hydrogen for a non-alkaline fuel cell
• potential at wastewater treatment plants to use the ammonia
as a fuel source to produce electrical energy
future improvements
Using Landfill gas energy
technologies to capture
renewable energy
• process of landfill gas recovery
and use is similar to that of
recovering methane from
anaerobic digesters
• could be applied to water and
wastewater treatment facilities
situated near landfills

18. Thank you