Environmental Health Programs Flashcards
CHARACTERISTICS OF WATER
Impurities in suspension
Physical: Turbidity
CHARACTERISTICS OF WATER
Imparted by substances present in solution
Physical: Color
CHARACTERISTICS OF WATER
This is only expressed qualitatively
Physical: Taste and odor
CHARACTERISTICS OF WATER
What are the chemical characteristics of water?
pH
Hardness
Total solid content (mineral impurities)
CHARACTERISTICS OF WATER
What causes hardness of water
Calcium and magnesium
CHARACTERISTICS OF WATER
Determines the kind of microscopic life that are responsible for odor and taste of water
Biological
CHARACTERISTICS OF WATER
An index of pollution degree of water source
Biological impurities
CHARACTERISTICS OF WATER
Most important single test to find out if water is potentially dangerous (“indicator organisms”)
Bacteriological testing
CHARACTERISTICS OF WATER
What are the bodies of water that are principal sources of radium and radon?
Deep wells
Ground water
Mineral springs
Parts/components of initial water examination
These are done before operation of newly constructed system or sources for public use
Physical
Chemical
Biological
Radiological
When are periodic bacteriological water examinations done?
As often as possible but interval not more than 6 months
When are periodic general systemic chemical water examinations done?
Every 12 months
When are periodic radioactive contamination water examinations done?
Every year
Drinking water supply protective measures
• The following are not allowed within 25 meters of drinking water supply
*Washing clothes and bathing
*Source of pollution
*Radioactive materials
• Any physical connection between distribution system from public water supply to any other water supply
• Installatiin of booster pump on areas with low water pressures
HOUSEHOLD METHODS OF WATER TREATMENT:
Heating water for 10-20 mins (>2 mins at 100C will kill most disease causing germs like cholera)
Boiling
HOUSEHOLD METHODS OF WATER TREATMENT:
Allow impurities to settle for 30 min-1 hr then pour top part in new clean container
Sedimentation
HOUSEHOLD METHODS OF WATER TREATMENT:
Use of aluminum sulfate (tawas) crystals to form precipitates of impurities and then allowing them to settle at bottom of container
Flocculation and sedimentation
HOUSEHOLD METHODS OF WATER TREATMENT:
Transfer of water from 1 container to another OR stirring water to create turbulence
Aeration
HOUSEHOLD METHODS OF WATER TREATMENT:
Use of cloth and sand filters
Filtration
HOUSEHOLD METHODS OF WATER TREATMENT:
What are the 2 types of chemical disinfection of water
Chlorination - most common, powerful germicide, combined with suspended organic matter
Tincture of iodine - 2 drips/1L of water
What are the 4 major categories od water-related diseases?
- Water borne disease
- Water-washed diseases
- Water-based diseases
- Water-related insect-diseases
WATER RELATED DISEASES:
Transmitted by contaminated drinking water (water is already contaminated)
Water borne disease
(Microbic or non-microbic)
WATER RELATED DISEASES:
Transmitted from person to person due to inadequate water supply for personal hygiene and or domestic cleaning (e.g., scabies, lice, typhus, trachoma conjunctivitis, hookworm)
Water-washed diseases
WATER RELATED DISEASES:
Caused by agents spread by contact with or ingestion of water (e.g. Schistosomiasis, leptospirosis)
Water-based diseases
WATER RELATED DISEASES:
Transmitted by insects harboring in water (e.g., dengue, filariasis, malaria, onchocerciasis, Japanese encephalitis)
Water related insect-vector diseases
TREATMENT OF PUBLIC WATER SUPPLY:
Most important single treatment
Chlorination
TREATMENT OF PUBLIC WATER SUPPLY:
What are the Components of Complete Standard Water Treatment?
- Coagulation
- Sedimentation
- Rapid sand filtration
- Chlorination
TREATMENT OF PUBLIC WATER SUPPLY: Components of Complete Standard Water Treatment
Use of chemical such as alum to form flocs
Coagulation
TREATMENT OF PUBLIC WATER SUPPLY: Components of Complete Standard Water Treatment
Allowing flocs to settle
Sedimentation
TREATMENT OF PUBLIC WATER SUPPLY: Components of Complete Standard Water Treatment
Settled water is filtered through sand and rained to filtered water reservoir
Rapid sand filtration
TREATMENT OF PUBLIC WATER SUPPLY: Components of Complete Standard Water Treatment
Done using an appropriate water reservoir
Chlorination
Degree of water treatment for bacterial coliform <50
Chlorination alone
Degree of water treatment for bacterial coliform 50-5,000
Standard complete treatment (coagulation, sedimentation, rapid sand filtration, chlorination)
Degree of water treatment for bacterial coliform 5,000-50,000
Double treatment
Degree of water treatment for bacterial coliform >50,000
Look for another source
Main culprit of Great Smog of London (Dec 5-9, 1952)
Sulfur dioxide
(Industrial pollution and high-pressure weather conditions)
Particle sizes from air pollution and their fate in the respiratory tract
> 10 um - filtered by the nose and pharynx, cleared by nasal secretion
2 um - <10 um - deposited in tracheobronchial tree
1-2 um - deposited in alveolar sacs
How to create sanitary landfill?
Alternate layer refuse and earth fill (soil cover of 2-3 feet)
COMMUNITY REFUSE DISPOSAL METHODS
Use of air pumps and frequent turning
Aerobic composting
COMMUNITY REFUSE DISPOSAL METHODS
Burying organic material
Anaerobic composting
COMMUNITY REFUSE DISPOSAL METHODS
Applying pressure to garbage to remove oils, grease, and fats
Reduction and salvage
