sewage treatment and meteorological environment

1. EXCRETA DISPOSAL
DR MARIYA AMIN QURIESHI
LECTURER
Community Medicine, GMC Srinagar

2. PUBLIC HEALTH IMPORTANCE
HAZARDS-
• SOIL POLLUTION
• WATER POLLUTION
• CONTAMINATION OF FOOD
• PROPAGATION OF FLIES
DISEASES-
1. TYPHOID and PARATYPHOID FEVER
2. DIARRHOEAS
3. DYSENTRIES
4. HOOKWORM DISEASE
5. ASCARIASIS
6. HEPATITIS A AND E
7. PARASITIC INFESTATIONS

3. TRANSMISSION OF DISEASE
FAECES
WATER
FOOD
SOIL
FINGERS
FLIES
HOST

4. SANITATION BARRIER
FAECES
S
A
N
I
T
A
T
I
O
N
B
A
R
R
I
E
R
WATER
FINGERS
FOOD
FLIES
SOIL
PROTECTED HOST

5. Methods of excreta disposal
Unsewered areas
• Service type
• Non-service type
– Bore hole latrine
– Dug well/ pit laterine
– Water seal type
• PRAI type
• RCA type
• Sulabh shauchalya
– Septic tank
– Aqua privy
• Latrines for temporary use
– Sallow trench
– Deep trench
– Pit latrine
– Bore hole latrine
Sewered areas
• Water carriage system and
sewage treatment
– Primary treatment
• Screening
• Removal of grit
• Plain sedimentation
– Secondary treatment
• Trickling filters
• Activated sludge process
– Other methods
• Sea outfall
• River outfall
• Sewage farming
• Oxidation ponds

6. WHAT IS SEWAGE ?

7. WHY SEWAGE PURIFICATION?
• BREEDING OF FLIES AND MOSQUITOES
• SOIL POLLUTION
• WATER POLLUTION
• FOOD CONTAMINATION
The aim of sewage treatment is to convert the
sewage water into an effluent of an acceptable
standard of purity.

8. COMPOSITION
WATER- 99.9%
SOLIDS- 0.1%

9. How do we test the strength of a
sewage?
• BIOCHEMICAL OXYGEN DEMAND-
• ≥300mg/l strong
• 100mg/l weak
• CHEMICAL OXYGEN DEMAND-
• SUSPENDED SOLIDS- 100 TO 500 ppm

10. HOW DOES ORGANIC MATTER
DECOMPOSE??
• AEROBIC PROCESS
• ANAEROBIC PROCESS

11. HOW IS SEWAGE TREATED??
SEWAGE TREATMENT PLANT
PRIMARY TRATMENT
SECONDARY TREATMENT

12. PRIMARY TREATMENT
SEWAGE
GRIT CHAMBER
10-20m (1ft/sec)
30sec- 1min
SCREENING
PRIMARY SEDIMENTATION
TANK
1-2 ft/min
6-8hr
SECONDARY TREATMENT

13. SECONDARY TREATMENT
SLUDGE DIGESTION
PRIMARY
SEDIMENTATION
TRICKLING FILTER
2-30m
ACTIVATED SLUDGE
PROCESS
SECONDARY
SEDIMENTATION TANK
DISPOSAL OF EFFLUENT

15. ACTIVATED SLUDGE PROCESS
Excess
sludge to digestion
Primary
sedimentation
Aeration tank
6-8 hr
Final setting
Return sludge 20-30%
Excess
Compressed air

16. Sludge digester

17. Disposal of effluent
• Dilution-- BOD- 20mg/l
• Land

18. Other methods of sewage disposal
• Sea outfall
• River outfall
• Land treatment
• Oxidation pond
• Oxidation ditches

19. OXIDATION POND
WIND
ALGAE
RAW WASTE
O 2 BACTERIA
CO 2
SETTLEABLE SOLID
O 2

20. METEOROLOGICAL
ENVIRONMENT

21. • ATMOSPHERIC PRESSURE
• AIR TEMPERATURE
• HUMIDITY
• RAINFALL
• DIRECTION AND SPEED OF WIND
• MOVEMENT OF CLOUDS AND CHARACTER OF
WEATHER

22. ATMOSPHERIC PRESSURE
HIGH ALTITUDE-
• ACUTE MOUNTAIN SICKNESS
• HIGH ALTITUDE PULMONARY OEDEMA
LOW ALTITUDE-
• CAISSONS DISEASE

23. ACUTE MOUNTAIN SICKNESS
• Difficulty sleeping
• Dizziness or light-headedness
• Fatigue
• Headache
• Loss of appetite
• Nausea or vomiting
• Rapid pulse (heart rate)
• Shortness of breath with exertion

24. HIGH altitude pulmonary oedema
• Bluish discoloration of the skin (cyanosis)
• Chest tightness or congestion
• Confusion
• Cough
• Coughing up blood
• Decreased consciousness or withdrawal from
social interaction
• Gray or pale complexion
• Inability to walk in a straight line, or to walk at all
• Shortness of breath at rest

25. Prevention
Education of mountain travellers
• Gradual ascent
• Stopping for a day or two of rest for each
2,000 feet (600 meters) above 8,000 feet
(2,400 meters
• Sleeping at a lower altitude when possible
• Oxygen supply sufficient for several days
• Acetazolamide (Diamox)

26. Caisson disease

28. TREATMENT- HYPERBARIC OXYGEN IN
RECOMPRESSION CHAMBER

29. AIR TEMPERATURE
MEASUREMENT
• MERCURY
• ALCOHOL
 DRY BULB
 WET BULB
 MAXIMUM
 MINIMUM
 SIX’s maximum and minimum
 GLOBE THERMOMETER
 WET GLOBE THERMOMETER
 SILVERED
 KATA THERMOMETER

30. HEAT STRESS INDICES
• EQUATORIAL COMFORT INDEX
• HEAT STRESS INDEX
• PREDICTED FOUR HOUR SWEAT RATE

31. EFFECT OF HEAT STRESS
• HEAT SYNCOPE
• HEAT CRAMPS
• HEAT EXHAUSTION- 102 F WEAKNESS,
DIZZINESS FATIGUE
• HEAT HYPERPYREXIA-106 F IMPAIRED HEAT
REGULATORY MECHANISMS.
• HEAT STROKE

32. HEAT STROKE
• FAILURE OF HEAT REGULATING MECHANISM
• 110 F
• DELIRIUM, CONVULSIONS,IMPAIRED
CONSCIOUSNESS,SKIN BECOMES DRY AND HOT
• CFR-40%
• TREATMENT- RAPID COOLING IN ICE WATER BATH
TILL RECTAL TEMP. FALLS BELOW 102 F
• SUPPORTIVE- ELECTROLYTES

33. EFFECT OF COLD STRESS
HYPOTHERMIA
IMMERSION FOOT
FROSTBITE