Environmental health about waste management and public health interventions

1. Chapter Three
Community waste management
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2. Community waste management
Definition of terms & concepts
Public health importance
Classification of waste
General waste management
Solid wastes
Liquid wastes
Healthcare wastes and its management
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3. Introduction
Waste is introduced into the environment due to
the day-to-day activities of humans
Improper management of wastes results in many
ecological phenomena such as water and air
pollution
 For instance, liquid from dumps and poorly engineered
land fills has contaminated surface waters
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4.  Waste (also known as rubbish,
trash, refuse, garbage, junk,
litter, and ort) = normally
discarded as unwanted or useless
materials
 In biology==any of the many
unwanted substances or toxins that
are expelled from living organisms,
metabolic waste; such as urea and
sweat
Introduction…
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 Any material which is not
needed by the owner,
producer or processor
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5. Definition of Terms…
Solid waste: is defined as any waste that is solid in form and is
discarded by people as unwanted
Refuse: It is a general name given to all wastes except liquid
waste
It includes all putrescible (decompose rapidly by bacteria)
and non putrescible (non decomposable) wastes
Bio-degradable waste: those that can be broken down
(decomposed) into their constituent elements by bacteria and
other microorganisms
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6. Definition of Terms…
Garbage: Putrescible wastes resulting from the growing,
handling, processing, cooking and consumption of food E.g.
Vegetables, fruits, bones, bread, injera etc.
Rubbish: all non-putrescible wastes except ash
There are two categories of rubbish:
A. Combustible -organic in nature and includes items such as
paper, cardboard, wood yard clippings, bedding, plastics etc.
B. Non-combustible- are inorganic materials, which include
metals, glass, ceramics, and other minerals
Ashes: an incombustible material that remains after a fuel or
solid waste has been burnt
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7. Definition of Terms
Sewage: is a liquid state of waste matter including excreta,
kitchen and sullage
It’s a combination of grey water and black water
Excreta: is a human waste, mainly composed of faeces and
urine
Sullage: also known as grey water, is water that has been
used for washing in bathrooms and kitchens; it does not
include human waste
Runoff: is simply rainwater that collects on the ground and
runs off into channels, ditches and rivers
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8. Definition of Terms
Sewer: Pipe or conduit which is normally closed for carrying
sewage
Effluent: Liquid waste that flows out
Influent: Liquid waste that flows in
Sewerage (sewerage system): The organized network of
drainage system used to remove or dispose sewage
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9. Household Human Wastes and
Wastewaters
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10. Definition of Terms…
Hazardous wastes are defined as wastes that have one or more
of the following properties
Corrosive: substances that cause damage on contact, e.g.
acids
 Ignitable: materials that can catch fire easily like benzene
Toxic: materials that can be poisonous to humans when
inhaled or ingested, or come in contact with skin or mucous
membranes
Reactive: substances that can yield a harmful chemical if
they react with other substances
Infectious: substances that are capable of causing or
communicating infection
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11. Definition of Terms
Infectious wastes:
 are wastes that contain/carry pathogenic organisms in part or
in whole
– such as wastes from hospitals and biological laboratories
soiled with blood or bodily fluids
Special wastes:
 These are wastes that may be hazardous
 Includes for example: chemicals, petroleum and paint
products and residues from pollution control devises etc.
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12. Public health Importance
Cause of morbidity
Cause of mortality
Cause of disability
Cause of discomfort
 Measured by: magnitude;
severity
– OPD visits
– Diarrhea episodes
– Admission rates
 2.5 billion people (35% of the
world's population 2010) lack so
called improved sanitation
 It is estimated that food wasted
by the US & Europe could feed the
world three times over
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13. Public health Importance…
1. Increase disease transmission or otherwise threaten
public health: breeding place for vectors of diseases,
people can contact dirty
2. Contaminate ground and surface water: MSW
streams can bleed toxic materials and pathogenic
organisms into the leachate of dumps and landfills
3. Create greenhouse gas emissions and other air
pollutants: undergo anaerobic degradation and
become significant sources of methane and other
greenhouse gases
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14. Classification of Wastes
According to physical state:
• Solid wastes: wastes in solid forms, domestic, commercial and
industrial wastes
– Examples: plastics, styrofoam containers, bottles, cans,
papers, scrap iron, and other trash
• Liquid Wastes: wastes in liquid form
– Examples: domestic washings, chemicals, oils, waste water
from ponds, manufacturing industries and other sources
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15. Classification by Sources…
According to Sources:
Residential: generated from living house holds (domestic), generally
contain non-hazardous solid wastes; kitchen waste, and ash
Agricultural: solid wastes due to agricultural activities: food residues,
animal dung, crop residues, etc.
Commercial: wastes generated from business establishments: food
establishments, shops
Industrial wastes: from various types of industrial processes
 The nature of the waste depends on the type of industry, kind of
raw material
Institutional solid waste: generating from public and government
institutions: offices, religious institutes, schools, universities, etc.;
generally not hazardous
Healthcare facilities: Wastes from HCFs & consists of both non-
hazardous and hazardous waste
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16. Waste management
Waste management refers to the many methods and processes
of dealing with waste at every stage from generation and
collection through to final disposal
To prevent contact with humans or their immediate
environment
Human waste management: is the proper collection and
disposing of excreta and sewage so as not to endanger the
health of individuals and the environment
 Therefore, the main purpose of waste management is to isolate
waste from humans and the environment, and consequently,
safeguard individual, family and community health
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17. waste management…
Objectives of waste management:
A. Prevent and control of communicable diseases
Avoid direct contact with man
Make inaccessible to vectors (flies, mosquitoes, roaches)
Prevent food contamination
B. Control of environmental pollution
C. Prevent and control public nuisance (odor, fly breeding,
etc.)
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18. Functional Elements Of Solid Waste Management
The activities involved with the management of solid wastes
from the point of generation to final disposal have been
grouped into six functional elements:
I. Waste generation
II. On-site handling, storage, and processing
III. Collection
IV. Transfer and transport
V. Processing and Recovery
VI. Disposal
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19. Functional
element
Description
Waste generation
Those activities in which materials are identified as no longer being
of value and are either thrown away or gathered together for disposal
On- site handling,
Storage, and
processing
Those activities associated with the handling, storage, and
processing of solid wastes at or near the point of generation
Collection
Those activities associated with the gathering of solid wastes and the
hauling of wastes after collection to the location where the
collection vehicle is emptied
Transfer and
transport
Those activates associated with (1) the transfer of wastes from the
smaller collection vehicle to the larger transport equipment and (2)
the subsequent transport of the wastes to final destination
Processing and
recovery
Those techniques equipment and facilities used both to improve the
efficiency of the other functional elements and to recover usable
materials (conversion products or energy from solid wastes)
Disposal
Those activities associated with ultimate disposal of solid wastes
including those wastes collected and transported directly to a
landfill site, semisolid wastes (sludge) from wastewater treatment
plants incinerator residue compost, or other substances from the
wires solid waste processing plants that are of no further use 19
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20. Waste Disposal Options
A. Sanitary Landfill:- A structured disposal place operational
segments, refuse damping, spreading, compacting, and
covering with soil
B. Controlled open dumping: a modified form of sanitary
landfill: there is refuse spreading, leveling, and compacting
with dozer and compacting machine, except soil covering is
lacking
C. Open damping: uncontrolled and deregulated
D. Land farming: (composting) if the solid waste has larger
proportion of biodegradable
E. Incineration: commercial and domestic types
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21. Integrated Solid Waste Management
 Waste management hierarchy indicates an order of
preference for action to reduce and manage waste
 The aim of the waste hierarchy is to extract the
maximum practical benefits from products and to
generate the minimum amount of waste
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22. Waste hierarchy
“By recycling almost 8 million tons of metals (which includes aluminum,
steel, and mixed metals), we eliminated greenhouse gas (GHG) emissions
totaling more than 26 MMTCO2E
This is equivalent to removing more than 5 million cars from the road for
one year.”
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 Reduction: keeping the production of waste to a minimum
 Reuse: Using something more than once
 Recovery: Includes several separate processes that enable
material or energy resources to be recovered from the waste
 These include recycling, composting and energy from waste
 Disposal: which includes landfill, tipping and incineration
(burning) without energy recovery
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23. Types of excreta disposal and WWT systems
A. Non water carriage:
traditional pit latrine, VIP
latrines, pour-flush latrine,
cesspools, aqua privy,
trench latrines, bucket
latrine, compost latrine,
bore hole latrine.
B. Water carriage system: a
system that is connected to
municipal sewerage system
and local small scale system
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24. 1. Drop-and-Store Systems
 Pit latrines/pit privy
 VIP latrines
 Compost latrines
 Aqua Privy
 Bucket latrine
 Trench latrine
 Overhung latrine
 Borehole latrine
2. Drop-Flush-and-Discharge
Systems
 Water carriage
 Pour-flush latrine
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1. Individual containment
and Treatment Systems
 Cesspools
 Septic tanks
 Soak pits
 Seepage pits
2. Community Treatment
Systems
 Primary treatment of
Sewage
 Secondary treatment of
sewage
Types of excreta disposal…
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25. Types of excreta disposal…
A. Non water carriage: - General consideration:
Proper sitting: in relation to housing unit, kitchen, ground
and source of water, direction of wind, insulation, available
site;
Size of the underground structure: depends on users
number and minimum service 4 years;
Construction material: availability of wood, cement, nails,
stones, gravel, sand, etc.,
Technology feasibility and sustainability: simplicity,
acceptability, affordability, community concern for
participation in planning, construction, financing,
maintenance, and use;
Final disposal options: Burial? Seepage? Sewerage?
Users type: house hold, community, camps, etc.
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26. Types of excreta disposal…
B. Water Carriage system (Waterborne sewerage system)
Definition:
Sewerage system is a system in which excreta is deposited
into sanitary appliances and immediately carried away by
water through a network of underground structure (sewer
lines) to a final disposal site
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27. Ethiopian Situation
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28. Objectives of Wastewater Treatment
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Water
Hands
Vector
Soil
Excreta:
Focus of Infection
Food and
milk;
Vegetables
New
Host
Debility
Death
Excreta:
Focus of
Infection
Water
Hands
Foods/Vector
Soil
Protected Host
 Remove or destroy pathogenic organisms and parasites
 Communicable diseases:
 High Infant Mortality Rate (IMR)
 Remove or reduce toxic and organic materials in wastewater
 Reduce or remove nutrients to lower pollution of surface or groundwater
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29. Unit operations and processes in sewage treatment
֎The contaminants in wastewater are removed by physical,
chemical, and biological means
i. Physical Unit Operations
 By the application of physical forces
 Screening, mixing, flocculation, sedimentation,
floatation, filtration, and gas transfer
ii. Chemical Unit Processes
 Treatment methods in which the removal or conversion of
contaminants is brought about by the addition of
chemicals or by other chemical reactions
iii. Biological Unit Processes
 Treatment methods in which the removal of contaminants
is brought about by biological activity
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30. Steps of Conventional wastewater treatment
1. Preliminary treatment
2. Primary treatment
3. Secondary treatment
4. Tertiary treatment
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31. Healthcare waste & its management
What is Healthcare waste?
 Total waste stream from HCW generators (major
and scattered sources)
 75-90% if general waste (similar to domestic waste)
 10-25% in hazardous (infectious, toxic etc.)
– Diagnosis
– Treatment
– Prevention of diseases
– Alleviation of disablement
– Associated research
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32. Sources of HCW
Major sources
– Hospitals
– Clinics
– Laboratories
– Research centers
– Animal Research
– Blood banks
– Autopsy centers
Minor sources
– Physician’s office
– Dental clinics
– Home health-care
– Nursing homes
– Acupuncturists
– Psychiatric clinics
– Cosmetic piercing and
tattooing
– Funeral services
– Paramedic services
– Institutions for disabled
persons
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33. Waste category Description and examples
Infectious wastes Waste suspected to contain pathogens eg lab. Culture, waste from
isolation wards, tissues (swabs), materials or equipments that have
been in contact with infected patients, excreta
Pathological wastes Human tissue or fluids eg. Body part, blood and other body fluids,
fetuses
Sharps Eg. Needles, infusion sets, scalpels, knife, blades, broken glass
Pharmaceutical wastes Expired or no longer needed medicine or drugs and containers (bottle
and boxes)
Genotoxic wastes Wastes consists substances with genotoxic properties eg. Waste
containing cytostatic drug and genotoxic chemicals
Chemical wastes Waste containing chemical substances eg. Lab reagents, film
developer, disinfectant that are outdated, solvents
Waste with high content
of heavy metals
Batteries, broken thermometers, blood pressure gauges etc.
Pressurized containers Gas cylinders, gas cartridges, aerosol cans etc.
Radioactive waste Wastes containing radioactive substances eg. Unused liquids from
radiotherapy or lab. Research, contaminated glassware, packages,
absorbent papers, urine and feces from patients treated or tested with
unsealed radionuclides etc.
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34. 34
What hazards are there in the healthcare facilities?
Chemical, physical and biological
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35. Hazard and risk
The problem is…
1. Potential health effects because of exposure to
infectious & toxic wastes:
 AIDS
 Hepatitis B and C
– Studies revealed that:-
» 33% of HBV direct or indirect
» 42% of HCV exposure to infectious wastes
 Gastro enteric infections
 Respiratory infections
 Blood stream infections
 Skin infections
 Effects of radioactive substances_cancer
 Intoxication
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36. Hazard and risk
2. The “recycling” practices that have been reported,
particularly, the reuse of syringes is certainly the most serious
problem in a number of countries
– The WHO estimates that over 23 million infections of
hepatitis B, C and HIV occur yearly due to unsafe
injection practices (reuse of syringes and needles in the
absence of sterilization)
– Re-saleing of needles recovered from the waste
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37. Hazard and risk
3. There is also a public health risk linked to the sale of
recovered drugs in the informal sector when the elimination
of expired drugs isn’t properly controlled/monitored
4. In addition to health risks from direct contact, HCW can
impact human health by:
– Contaminating water bodies,
– Polluting the air
• Open burning
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38. Hazard and risk
 During incineration, if no proper filtering is done, air can
also be polluted causing illnesses to the nearby
populations
– Emission of toxic gases like:
• Dioxins dangerous to human health
• Furans and the environment
5. Fire Hazard and injuries
6. Public nuisance ( offensive smells, unsightly debris)
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39. Hazard and risk
 Who are at risk?
– Doctors and nurses
– Patients
– Hospital support staff
– Waste collection and disposal staff
– General public
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40. HCW Management
A. Minimization
B. Segregation
C. Handling, Storage and collection
D. Transportation
E. Treatment
F. Disposal
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41. Key steps in HCW mgt
A. Minimization
This is the first and best way to reduce healthcare
waste quantities, cost and environmental impacts
 Source reduction: measures such as purchasing
supplies that are less wasteful or generate less
hazardous waste
 Recyclable products: use of materials that may be
recycled, either on-site or off-site
 Good management and control practices: apply
particularly to the purchase and use of chemicals
and pharmaceuticals
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42. Key steps in HCW mgt
B. Segregation
Separating waste by type at the place where it is
generated
Waste should be separated by the person generating
the waste immediately according to its type
Color coding for waste segregation
Black color code__Non- infectious waste
Yellow color code__Infectious wastes
Contaminated gauze, cotton, dressings, lab.
cultures, IV fluid lines, blood bags, gloves,
anatomical and pharmaceutical wastes
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43. Key steps in HCW mgt
 Safety boxes/puncture–resistance/leak-resistance
containers __Sharp wastes
 Needles, scalpels, knives, blades, lancets, broken glasses
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44. Key steps in HCW mgt
C. Handling, collection and storage
Waste Handling: place waste containers close to
where the waste is generated
Waste Collection: removing waste bags or containers from
the service point and taking to storage or disposal area
Waste Storage: placing waste in a secure place until it can be
disposed off
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45. Key steps in HCW mgt
Ideal storage area should be:
 Designed, secure, kept clean, dry and pest free
 Healthcare waste should be stored no longer
than 2-3 days
 Organic waste should be disposed of daily
 Segregation must be maintained throughout until
final disposal
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46. Key steps in HCW mgt
D. Transportation
 Use plastic or galvanized metal containers with
tight-fitting covers
 Replacing manual handling and transportation
system by mechanical (trolley or carts)
 Wash all waste containers with a disinfectant
cleaning solution (0.5% Chlorine solution plus
soap) and rinse with water regularly
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47. Key steps in HCW mgt
E. Treatment
- Methods used to render the waste to non-hazardous
Treatment Methods
 Incineration
 Chemical disinfection
 Autoclaving (is an efficient wet thermal disinfection
process)
 Microwave Irradiation (microwaves of a frequency of
about 2450 MHz and a wavelength of 12.24 cm)
 Encapsulation
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48. Key steps in HCW mgt
Encapsulation
 Disposal of healthcare waste in municipal landfills is less
advisable if it is not pretreated
 One option for pretreatment is encapsulation
Encapsulation Process:
 Three-quarters a container/s filled with sharps and
chemical or pharmaceutical residues
 The containers or boxes are then filled up with a
medium such as plastic foam, cement mortar, or
clay material
 After the medium has dried, the containers are
sealed and disposed of in landfill sites
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49. Key steps in HCW mgt
Incineration
Incineration of waste has been widely practiced but
 Inadequate incineration or
 The incineration of unsuitable materials results in the
release of pollutants into the air
Incinerated materials containing
 Chlorine and heavy metals/materials with high metal
content (in particular lead, mercury and cadmium)
can generate dioxins and furans and toxic metals and
spread in the environment
 Which are human carcinogens and have been
associated with a range of adverse health effects
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50. Key steps in HCW mgt
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Efficiency_80–90%
Destruct 99% of mos and
Reduce the volume and weight
of waste
 However, many chemical and
pharmaceutical residues will
persist if temperatures do not
exceed 200°C
 In addition, the process will cause
massive emission of black smoke,
fly ash, and potentially toxic gases
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51. Key steps in HCW mgt
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 Only modern incinerators operating at 850 -1100 °C and
fitted with special gas-cleaning equipment are able to
comply with the international emission standards for
dioxins and furans
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52. Key steps in HCW mgt
Things must not be incinerated:
 PVC plastics ( includes blood bags, & IV lines)
 Syringe bodies are NOT PVC plastic
 Mercury thermometers
 Batteries
 X-ray or photographic materials
 Aerosol cans or gas containers
 Glass vials
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53. Key steps in HCW mgt
F. Disposal
 Is a process of eliminating healthcare wastes without
posing any risk to health facility workers and the general
public
Final disposal methods:
 Burial inside premises/ Municipal Landfill
 Burn covering with soil
 Discharge into sewer
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