The accumulation of various waste products and their indiscriminate disposal represents a grave hazard to health. Systems of waste disposal are designed to eliminate these hazards.

1. SANITARY WASTE DISPOSAL
Dr. Dalia El-Shafei
Ass.Prof of Occupational Medicine

2. TYPES OF WASTES
Solid
Houses
Paper
Plastics
Glass
Garbage
Industry
Dead animals
Metals
Hospitals
Cotton
Dressings
Liquid
Houses
Sewage
Wastewater
Environment Rain water
Industry
Irrigation wastes
Chemicals

3. Breeding of
insects &
rodents
• Flies, cockroaches, mosquitoes & rats use collection of
human excreta, garbage, agriculture waste and manure
as a breeding place for survival and multiplication.
Spread of
infection
• Breeding of flies & mosquitoes which are vector of diseases.
• Contamination of freshly eaten vegetables by human wastes used as
fertilizers.
• Pollution of sea water by sewage disposal at sea.
• Exposure of scavengers to occupational infection during collection &
handling of refuse & sewage.
Physical &
chemical
hazards
• Nuisance: offensive odor of gases resulting from purification of animals, organic matter &
also it is a bad sight to be seen.
• Injuries by broken glass or empty cans.
• Radiation hazards: Radiation wastes of industry or hospitals when polluting water channels.
• Chemical & metal poisoning on disposal of trade effluents & industrial wastes in water
channels.

5. SOLID WASTE DISPOSAL

7. WASTE STREAM:
Steady flow of varied wastes that we all
produce, from domestic garbage to industrial
agricultural, commercial & construction refuse.

8. 1- OPEN DUMP:
Many people dispose wastes by simply dropping it
to some place.
Open unregulated dumps are still the predominant
method of waste disposal in most developing
countries.
Open dump in rivers, canals, sea & oceans expose
people, animals, and plants to many hazards & make
water not suitable for drinking or use in irrigation.

12. 2- LANDFILLS “CONTROLLED DUMPING”
Solid waste disposal is regulated & controlled.
To decrease smells & to discourage insect & rodent
breading landfill operators are required to compress the
refuse & cover it every day with a layer of earth.
Control pollution, but dirt fill takes nearly 20% of the
space.
Oils, chemical compounds and toxic metals seep to the
underground surrounding areas.
Landfills are chosen to be high away from rivers &
other water sources.
It was inexpensive but with the increase in the cost of
lands, construction and maintenance it became costly.

15. 3- INCINERATION:
It is simply burning of waste. Another name is energy recovery or
waste- to-energy because the energy that is generated is a useful
resource.
2 approaches are used. Refuse-derived fuel where refuse is sorted
to remove unburnable materials & Mass burn where everything is
burned as much as possible.
Residual ash & unburnable materials representing 20% of original
size are taken to landfill for disposal.
Costly & flying ash contains dioxins of lead & cadmium which
are hazardous materials.
To decrease the emissions of these hazards, removal of batteries
containing heavy metals, plastics containing chlorine before
wastes are burned.
Closed incineration is very sanitary & healthy method if done at
small scale as in hospitals and big buildings.

18. 4- RECYCLING:
Reprocessing of discarded materials into useful
products.
Some reuse materials for the same purpose & other
turn old materials into entirely new products.
Saves money, energy, raw materials & land spaces
while also reducing pollution.

21. 5- REUSE:
Shrinking of the waste stream.
Reuse of disposed materials after cleaning them in
the same forms e.g. bottles & food containers.

23. 6- REDUCTION:
Produce less waste.
Better than reusing.
What is a waste to one process may be a resource to
another.
Industry can produce less waste by changing their
manufacturing processes.

25. 7- FERMENTATION:
To manure in rural areas by forming heaps of refuse
covered by layer of earth & left for few days,
decomposition of organic materials occur & they
are changed to useful manure.

26. LIQUID WASTE DISPOSAL

27. Domestic: Excreta &
waste water of kitchen
Municipal: Waste water
of streets (washing, rain)
Industrial trade
effluents

28. URBAN LIQUID WASTE DISPOSAL:
In urban areas liquid waste is disposed of through
water carried system.
After collecting liquid waste from houses, it reaches
the final disposal where it will be disposed of by
either dilution or treatment.

29. 1- LIQUID WASTE DISPOSAL BY DILUTION:
Crude sewage & waste water may be taken as such,
or partially treated & disposes in coastal countries,
or rarely in rivers & streams.
Potential risk to health due to the possibility of back
flow to shore, causing its pollution and causing
hazards to swimmers & fishing. Wind may carry
smell back to city.

30. Sanitary
precautions
Pipes:
- carried to sufficient
distance into the water
stream
-below the surface by
a sufficient distance
Currents: studied to
prevent return of
sewage to the shore
Fishing: prohibited at
that area

34. 2- LIQUID WASTE DISPOSAL BY TREATMENT:
It is the method used in most cities of Egypt.
Separation of suspended matter (sludge) from liquid
part (effluent) & destruction of all micro-organisms
in order to end with a safe material that can be used
for economic values.
Sludge as fertilizers
Effluent for irrigation of farm.

39. Screening
Sedimentation

40. Screening: Removal of large objects through passage of
liquid waste across screens formed of tilted bars.

41. Sedimentation: velocity of the flow of waste liquid will
be reduced & about 2 hours is allowed for it to stay in
the sedimentation tank.
It will thus be separated into 3 layers.

42. Scum
Effluent
Sludge

43. A- SLUDGE:
- About 60% of suspended solid will be settled
down & form the sludge.
- The removed sludge can be disposed by:
• Lagooning: spreading of sludge over specially
prepared land & is left to dry & then took to be used
as fertilizer.
• Sludge digestion: Anaerobic process in special
tanks, certain gases are liberated “methane” & the
treated sludge is disposed of.
• Sludge pressing: which is compressed into cakes
& used as fertilizer.

44. LAGOONING

45. SLUDGE
DIGESTION

46. SLUDGE
PRESSING

47. B- SCUM:
Light substance like oil, grease &floating matter
will rise to the surface and form the scum.

48. C- EFFLUENT “TANK EFFLUENT”:
- Turbid liquid that is present between the scum &
the sludge.
- It is used for irrigation of farms.
- Plantation of wood trees & not edible plants.

50. RURAL LIQUID WASTE DISPOSAL:
There is no sewage system in all villages so latrines &
cesspits are used.

51. LATRINE
A pit in the ground (better made impermeable to
avoid pollution of shallow underground water) and
is covered by a slab to receive and collect human
excreta.
Contents are emptied periodically & taken to a
suitable place for sanitary disposal.
Latrines must be present inside houses to ensure:
no handling of fresh stool, no contamination of
surface soil, no unpleasant smell, simple, not
expensive & acceptable from the community.

53. CESSPITS
Commonest way to dispose the collected sewage &
waste waters in mosques, schools, big houses.
Sewage is collected by pipes and disposed in cesspit (it
is a large pit 3 to 4 meters deep may be permeable or
impermeable to be evacuated periodically.
In impermeable tanks, under anaerobic conditions,
feces will be decomposed by the action of bacteria.
This breakdown of the complex organic matter will
reduce its volume, kill pathogenic organisms and
convert it into soluble material which is odorless, safe
and stable product that can be reused as manure.

55. ‫اإلسكان‬:50%‫الصحي‬ ‫الصرف‬ ‫خدمة‬ ‫من‬ ‫محرومة‬ ‫مصر‬ ‫قرى‬ ‫من‬

58. HAZARDOUS & TOXIC
WASTE DISPOSAL

59. The most dangerous aspect of the waste stream is
that it can contain highly toxic & hazardous
materials that can be injurious to human health.

60. Hazardous
waste
Dangerous to
health of human
or animals
Fatal in small
dose
Toxic
Carcinogenic
Mutagenic
Teratogenic
Inflammable
Corrosive
Explosive

61. CONTROLLING & MANAGING
HAZARDOUS WASTE:
I- Produce less:
It is the safest & least expensive way to avoid hazardous
waste problems.
Manufacturing processes can be modified to eliminate or
reduce waste production.

62. II- CONVERT TO LESS HAZARDOUS SUBSTANCES
Physical treatment
• Charcoal or resins filters absorb toxins: “Distillation separates hazardous
components from aqueous solution, Precipitation & immobilization in
ceramics, glass, cement so that isolation of the toxins is ensured”.
Incineration
• Quick, Easy, Clean (if correctly done) but not necessary cheap.
• Heated >1000 C for a sufficient time for complete destruction.
• Ash resulting is disposed of by landfill after its size is reduced by 90%.
Chemical processing
• Neutralizing or Oxidation of toxins to become non toxics.
Biological treatment
• Some organisms can digest & detoxify a variety of toxic compounds

63. III- PERMANENT STORAGE
Retrievable storage
• In a secure place
• Periodically inspected for possible leakage.
• Expensive & need continuous guarding
Secure landfills
• It is one of the most popular solutions.
• The land of a pit is covered by an impermeable ground. The wastes are
placed in drums placed in the pit separated by soil or pack-in materials.
• Drain pipes reach to the gravel layer to collect any leakage from stored
materials.
• When the pit is full it is covered by a cover similar to that of the bottom.
• Precautions must be taken to safeguard against pollution of underground
water & accidents during transport of waste materials.

66. RADIOACTIVE WASTE MANAGEMENT:
Radioactive wastes are produced in different forms:
high, low level & also solid, liquid & gaseous with
various half-lives.
Low level must be stored for several decades, while
high level must be stored for thousands of years.
Most low level comes from nuclear power plants,
hospital universities, industries and others.

67. RADIOACTIVE WASTE DISPOSAL:
Bury in deep underground
Favorable method by most countries
Reprocessed to remove very long active isotopes & then fused
with glass or ceramic materials & buried in deep underground.
Dump into deep oceans
May leak & contaminates the oceans or may be moved by
volcanic activity
Change it into harmless or less harmful isotopes
Not done because the costs are very high

69. ELECTRONIC WASTE MANAGEMENT:
Electronic waste or "e-waste" is a term used to describe
old, end-of-life electronic appliances & devices.
Examples of "e-waste" include: computers; fax
machines and copiers; televisions ….etc.
Electronic waste often has hazardous or toxic
components that can impact the environment once the
materials end up in a landfill or if they are improperly
managed and disposed. For example: Arsenic,
Beryllium, Cadmium, Chlorofluorocarbon (CFC),
Chromium, Lead, Mercury and many other toxic
substances.

72. Reduce:
• Choose long-lasting, durable products over disposable ones
Upgrade
• Rather than replace
Repair
• Rather than buy something new.
Re-use
• Give or sell your old technology & appliances to someone who needs it. Or find
an organization that accepts unwanted computer equipment & refurbishes it for
use by schools and charities
Recycle
• Stop solid & hazardous waste going to landfill, save resources which can be
used to manufacture new products, and reduce the use of raw materials
MANAGEMENT METHODS: