waste water residue, sludge treatment and its methods and adcantages

1. Design of facilities for the treatment and
disposal of sludge
Presented to: Miss Hafiza Aroosa
Presented by: M. Asrar , M. Rizwan Jamil

2. Contents:
• Introduction
• Methods of
disposal
I. Thermal drying
II. Incineration
III. Wet air oxidation
IV.Land fill disposal
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3. Introduction
Sewage sludge treatment describes
the processes used to manage
and dispose of
sewage sludge produced during
sewage treatment.
Sludge is mostly water with lesser
amounts of solid material removed
from liquid sewage.
Reducing sludge volume may
increase the concentration of some of
these toxic chemicals in the sludge. 3

4. I. Thermal Drying
Thermal drying involves the application of heat to
evaporate water to reduce moisture content of the
biosolids (sludge).
High level of drying is achievable with production of
dried sludge of up to 90 % dry solids content.
Some heat drying systems are able to produce dense
and dried sludge pellets which are easy to handle
and to dispose of.
The advantages of heat drying include reduced
transportation cost, further pathogen reduction, and
improved storage capacity. 4

5. 5
Drying types:
1) Thermal dryer

6. 6
2) Drying by solar Radiation

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8. 8
Cycle of Disposal of sludge after usage:

9. ii. Incineration
To incinerate a combination of dried (90 to 95% Dissolved Solids )
and dewatered sludge (20 to 25% Dissolved Solids ).
Incineration process:
Step 1: The dried and dewatered sludge is premixed
Step 2: Premixed sludge is sent for drying
Step 3: After drying, it is incinerated. The heat from the
incineration process is recycled for the drying process.
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10. 10
1. Mono incineration 2. Co- incineration
Calorific value of sludge high enough
 no biogas use before, no
stabilisation
Water content not minimised (no full
drying)
Fluidised bed incinerator, incineration
at 800 – 950°C in fluidised sand bed
Expensive
In coal power station
In solid waste incinerators
In cement production, ash is
bounded to cement
• Incineration is Use for energy content, but not
of nutrients

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Incinerator diagram:

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In waste water treatment, the primary use of alum (or alternatively ferric
salts) is as coagulant or as phosphate precipitant, via formation of
insoluble aluminum phosphate.
Thus, in the generation of the sludge investigated in the present study,
alum was dosed into the post clarifier effluent to precipitate phosphate,
which also precipitates any residual organics through coagulation. Alum
and phosphates may therefore be separated from the liquid aqueous
stream by WAO providing a significant economic benefit to this process.
iii. Wet air Oxidation

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The organic component of the sludge is significant in terms
of proportion and overall quantity and, amongst other
criteria, is necessary to be removed from the aqueous
stream.
Analysis of chemical oxygen demand (COD) provides a
suitable measure of the organic content. A primary benefit of
this technique is a significant reduction in COD of the liquid
output.
Cont….

14. Conclusion of WAO:
The destruction of sludge by WAO is well established and is
reconfirmed in a continuous embodiment here, successfully
reducing the COD of the liquid effluent and demonstrating
separation of nutrients and other chemicals from the liquid
phase.
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15. PFD OF Wet air oxidation:
.
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16. iv. Land fill disposal
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Although landfill are probably the most commonly used and the oldest
methods of hazardous waste disposal, until recently landfill disposal has
received relatively little study.
General Types of Landfills
1. Open Dump
2. Sanitary Landfill
3. Secure Landfill

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1) Open Dump
As the name implies, an open dump is
a disposal site where wastes are piled
on the surface of the ground. There are
generally no provisions for controlling
vectors, littering due to wind action, or
runoff to surface or ground waters.
The Resources Conservation and
Recovery Act of 1976 specifically
prohibits open dumping, and most
states also have existing regulations
against open dumps. As enforcement
becomes more complete, open dumps
should be phased out of existence.

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2) Sanitary Landfill
• Sanitary landfills are sites where waste is isolated from the environment until it is
safe. It is considered when it has completely degraded biologically, chemically
and physically. In high-income countries, the level of isolation achieved may be
high.
• It has advantage over open dump fill system.

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Figure of sanitary landfill:

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3) Secure Landfill
• There is no widely accepted definition of a secure
landfill.
• A secure landfill is a carefully engineered area
that is used to deposit waste products. Typically, a
secure landfill is a hole in the ground, but may
also be built above ground. If the depression is in
the ground, it must provide a 3 meter (10 foot)
separation between the bottom of the landfill and
the underlying bedrock or groundwater table.

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Figure:

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23. Comparison of sludge disposal
techniques:
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Advantages from the disposal
techniques of sludge:
• The general opinion in China is that it is very important
to recycle the nutrients in the sludge.
• An advantage when sludge is composted or treated with
thermal drying is that the end product looks more “clean
and treated” and this increases the public acceptance
for sludge as a fertilizer.
• Use as a power generation of generated gases by these
processes.

25. THANK
YOU!
M. Rizwan
Jamil
Phone
Email
rizwanrss357@gmail.com
03016089774