This document discusses sludge processing and disposal. It defines sludge as organic matter that settles in sedimentation tanks during wastewater treatment. Left untreated, sludge decomposition causes foul odors and pollution. The document outlines various sludge treatment processes including thickening to reduce moisture, anaerobic and aerobic digestion to reduce volume and pathogens, and dewatering through methods like drying beds and centrifugation. The main objectives of sludge treatment are digesting organic matter, destroying pathogens, and achieving safe and odor-free disposal, such as through incineration, application to agricultural land, or ocean disposal.

1. Romanus Peter
BEHP1109 1442

2. Sludge
- organic matter which settles down
in primary and secondary
sedimentation tanks.
Decomposition of organic matter
- foul gas,
pollution, health hazards.

3. 
Domestic sewage

Industrial sewage

Water treatment plants

4. 
Humus sludge

Activated sludge

Digested sludge

5. 
PHYSICAL
includes moisture, density, color, texture,
fluidity and plasticity etc.

CHEMICAL
includes organic matter, volatile solids,
Nitrogen, phosphate, fats etc.

6. Main objectives Digestion of organic matter by Common
methods.
 Destruction of pathogenic organisms.
 Safe and aesthetically acceptable disposal of
sludge.
 By product of methane is used as fuel & and
helps in controlling temperature and also
generates power.

7. •
1.
2.
3.
4.
Thickening or concentration
Reduction of moisture content of raw sludge.
Helps in reducing capacity of digestion tank and
provides control of digestion condition.
It can produce sludge of less than 10% solid
content.
Units of thickening are gravity thickener,
floatation thickener, elutriation thickener.

8. •
1.
2.
3.
4.
5.
Digestion or Stabilization
Results in reduction of organic content.
Improved drain ability.
Greatly reduces odor of the pollutant matter
Overall reduction in the volume of the sludge
finally to be deposed.
Units of digestion are– anaerobic & aerobic

9. 
•
•
Anaerobic digestion—
converts sludge into liquid & gases and also
reduces odor, volume, putrescence & produces
gases.
Bacteria like saprophytic organisms are present
that react on complex organic matter and
decomposed.

10. Temperature of anaerobic digestion
 Mesophilic digestion
 Thermophilic digestion

11. 
Dewatering

produces sludge of greater than 10% solid content and
is used after digestion process.
 sludge drying beds.
 Centrifugation
 mechanical methods by
vacuum filtration.

13. 
Drying beds are generally used for dewatering
of well digested sludges. Attempts to air dry
raw sludge usually result in odor problems.

Sludge drying beds consist of perforated or
open joint drainage pipe laid within a gravel
base.

14. 




Partial disposal
Incineration—sludge burnt in incinerator.
Ultimate disposal
disposal by crops land
disposal by oceans

15. MISCONCEPTIONS
unimportant additional operation, increase in total cost
of waste water treatment.
IMPORTANCE
represents SS and BOD loads, impact of biological
processes, stabilized sludge considers hygienic and
aesthetic requirements, aerobic digestion contains
lower BOD value than anaerobic digestion.

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