UNIT7:INTROUCTION TO ENVIRONMENTAL SANITATION
Key unit competence
Apply house and environmental sanitation
Introductory activity 7
1) Observe and think about the environmental aspects of image A, B, and
C
2) Does the status of the above images have an impact on people’s health?
Yes or No? Explain your answer.3) What can you do to maintain a good sanitation in this environment?
7.1. Introduction to environmental health
Learning activity 1.8
1) Identify image(s) that reflect on good environmental health and explain
why.
2) Identify image(s) that reflect on poor environmental health and outline thethree possible health risks for people who live in that area.
7.1.1. Concepts definition
Environment
The term environment refers to “the complex of physical, chemical, and biotic
factors (as climate, soil, and living things) that act upon an organism or an ecologicalcommunity and ultimately determine its form and survival.
The term environment captures the notion of factors that are external to the
individual.
Environment also refers to ssurroundings in which an organization operates,
including air, water, land, natural resources, flora, fauna, humans and their
interrelationships.
Environmental aspect
Element of an organisation’s activities, products or services that interacts or can
interact with the environment – the activity
Environmental condition
A state or characteristic of the environment as determined at a certain point in time.
Environmental impact
Change to the environment (adverse or beneficial), wholly or partly resulting from
the organisation’s environmental aspects – potential change or harm.
The environment has a major impact on the risk of chronic diseases such as
cancers, chronic lung disease, and birth defects and on the risk of acute illnesses
such as viral gastroenteritis, respiratory infections, and such vector-borne diseases
as malaria.
Ecological System (Ecosystem)
An ecosystem is a dynamic complex of plant, animal, and microorganism
communities and the nonliving environment interacting as a functional unit. Humans
are an integral part of ecosystems.
Survival of the human population depends upon ecosystems, which aid in supplying
clean air and water as part of the earth’s life support system. Ecosystems are being
degraded with increasing rapidity because of human environmental impacts such
as urbanization and deforestation. Degradation of ecosystems poses environmental
dangers such as loss of the oxygen-producing capacity of plants and loss of
biodiversity.
Environmental Health
Environmental health comprises those aspects of human health, including quality of
life, that are determined by physical, chemical, biological, social and psychosocial
factors in the
environment. It also refers to the theory and practice of assessing, correcting,
controlling, and preventing those factors in the environment that can potentially
affect adversely the health of present and future generations.” (World HealthOrganization)
Environmental pollution
Pollution is the introduction of contaminants into the natural environment that
causes adverse change. Pollution can take the form of chemical substances
or energy, such as noise, heat or light. Pollutants, the components of pollution,
can be either foreign substances/energies or naturally occurring contaminants.
Environmental pollution is one of the most serious problems facing humanity and
other life forms on our planet today.
“Environmental pollution is defined as “the contamination of the physical and
biological components of the earth/atmosphere system to such an extent that
normal environmental processes are adversely affected.” Pollutants can be naturally
occurring substances or energies, but they are considered contaminants when in
excess of natural levels. Any use of natural resources at a rate higher than nature’s
capacity to restore itself can result in pollution of air, water, and land.
Environmental pollution is of different types namely air, water, soil, noise and
light-weight. These cause damage to the living system. How pollution interacts
with public health, environmental medicine and the environment has undergone
dramatic change.
Environmental health Prevention
Prevention lies at the core of environmental public health. It includes not only the
control of hazards but also health promotion through environmental strategies.
Prevention in environmental health extends upstream to the root causes of
environmental change and to the resulting environmental pressures that eventually
have an impact on human health and well-being.
Actions to reduce or control the hazards (or to promote environmental health) can
be taken at all points in this chain of events. In this three-level model:
Primary prevention involves interventions prior to the development of any signs of
ill health. In the case of environmental health, strategies directed toward modifying
driving forces, pressures, and state of the environment are primary prevention
efforts.
Secondary prevention is early detection of a health problem, prior to the onset of
disease, for the purpose of intervening at an early stage to prevent the development
of the disease. In environmental health this is usually a preventive effort targeting
the phase when exposure has begun to occur but prior to the development of any
health impacts.
Tertiary prevention involves early identification and treatment of people with
a disease, to prevent or forestall disability and/or death. An example of tertiary
prevention is the effort to ensure that patients with asthma follow recommended
guidelines for medical treatment and environmental remediation in order to reducethe frequency and severity of asthma attacks.
7.1.2. Essential Services of Environmental Health
1. Monitor environmental and health status to identify and solve community
environmental health problems.
2. Diagnose and investigate health problems and health hazards in the
community.
3. Inform, educate, and empower people about health issues.
4. Mobilize community partnerships and action to identify and solve health
problems.
5. Develop policies and plans that support individual and community
environmental health efforts.
6. Enforce laws and regulations that protect environmental health and ensure
safety.
7. Link people to needed environmental health services and assure the
provision of health care when otherwise unavailable.
8. Assure a competent public health and personal health care workforce.
9. Evaluate effectiveness, accessibility, and quality of personal and population
based environmental health services.
10. Research for new insights and innovative solutions to environmental healthproblems.
Self-assessment 7.1
1) What is the difference between environment and environment health?
2) What are the environment impacts that degrade the Ecosystem?
3) Why is it important to assess and control environmental factors?
4) Explain environmental pollution and outline its types.
5) Enumerate 4 essential services of Environmental Health7.2. Sanitation
Learning activity 7.2
7.2.1. Definition
Sanitation is the hygienic means of promoting health through prevention of human
contact with the hazards of wastes. Hazards can be physical, microbiological,
biological or chemical agents of disease. Wastes that can cause health problems
are human and animal feces, solid wastes, domestic wastewater (sewage, sullage,
greywater), industrial wastes, and agricultural wastes.
Sanitation generally refers to the provision of facilities and services for the safe
disposal of human urine and faeces.
7.2.2. Objectives of Sanitation
a. Protect and promote Health
Keeping disease carrying waste and insects away from the people, toilets and
home, break the spread of disease, prevent spreading of waterborne diseases,and improve the health and quality of life.
b. Protect environment against pollution
Keeping disease carrying waste and insects away from the environment prevent
environment from pollution (air, soil and emission) and prevent contamination ofwater resources (surfaces and ground water)
7.2.3. Types of Sanitation
Basic sanitation: refers to the management of human feces at the household
level.
On-site sanitation: the collection and treatment of waste is done where it is
deposited. Examples are the use of pit latrines, septic tanks, and imhoff tanks.
Off-site sanitation: A sanitation system, in which waste is collected, transported
away from the plot where it was generated and treated.
Food sanitation: refers to the hygienic measures for ensuring food safety.
Environmental sanitation: the control of environmental factors that form links
in disease transmission. Subsets of this category are solid waste management,
water and wastewater treatment, industrial waste treatment and noise and pollution
control.
Ecological sanitation: a concept and an approach of recycling to nature the
nutrients from human and animal wastes. Ecological sanitation is based on
composting or vermicomposting toilets where an extra separation of urine and
feces at the source for sanitization and recycling has been done. It thus eliminates
the creation of backwater and eliminates fecal pathogens from any still presentwastewater (urine).
7.2.4. Poor sanitation
Poor sanitation is linked to transmission of diseases such as cholera, diarrhea,
dysentery, hepatitis A, typhoid, polio and stunting. Poor sanitation reduces human
wellbeing, social and economic development. Poor sanitation also is a major cause
of neglected tropical diseases such as intestinal worms, schistosomiasis and
trachoma. Poor sanitation contributes to malnutrition.
a. The main causes of poor sanitation and solutions
The biggest cause of poor sanitation globally is simply lack of education. Even the
simple act of washing hands regularly can have a huge impact on the overall health
of a community. There are many causes of poor sanitation, let’s explore a few ofthese.
Open defecation
This is an area we focus on as Ecoflo-WASH has the capacity to help communities
with composting toilets that will alleviate many of the issues surrounding open
defecation. Put simply, open defecation fouls surrounding environments and is a
major cause for the spread of preventable diseases.
Unsafe drinking water
Unsafe, untreated and contaminated drinking water is estimated to cause more
than 500,000 diarrhoeal deaths each year. Many of these could be prevented
with simple sanitary practices and clean drinking water. Diseases like diarrhoea,
cholera, dysentery, typhoid and polio are rife in areas where clean drinking water
isn’t available.
High density living
In areas where informal or temporary / semi-permanent settlements crop up, the
high-density nature of these areas along with less access to sanitation programs
and products means there’s a high likelihood of sewage and waste not being dealt
with properly.
Lack of education
This is a relatively easy issue to combat as education starts typically in the form of
school programs teaching children the importance of healthy habits when it comesto sanitation, waste control, clean drinking water and washing their hands.
7.2.5. Benefit of improving sanitation
Benefits of improved sanitation extend well beyond reducing the risk of diarrhea.
These include: reducing the spread of intestinal worms, schistosomiasis and
trachoma, which are neglected tropical diseases that cause suffering for millions;
reducing the severity and impact of malnutrition; promoting dignity and boosting
safety, particularly among women and girls; promoting school attendance: girls’
school attendance is particularly boosted by the provision of separate sanitary
facilities; and potential recovery of water, renewable energy and nutrients fromfaecal waste.
Self-assessment 7.2
1) Define sanitation
2) Explain the objectives of sanitation?
3) Explain 2 factors that may contribute to poor sanitation4) What are the benefits of improving Sanitation?
7.3. Environmental Sanitation
Learning activity 7.3
In the previous lessons we learnt about environment and sanitation, Please
think more on that lesson and respond to the following questions:
1) What do you think is environmental sanitation?
2) What do you think as characteristics of good environment sanitation?3) What can you do to maintain a good environmental sanitation?
7.3.1. Definition of environmental sanitation
Environmental sanitation is a set of interventions that reduce peoples’ exposure to
disease by providing a clean environment in which to live, with measures to break
the cycle of disease. This usually includes hygienic management of human and
animal excreta, solid waste, wastewater, and storm water; the control of disease
vectors; and the provision of washing facilities for personal and domestic hygiene.
Environmental Sanitation involves both behaviors and facilities that work togetherto form a hygienic environment
7.3.2. Importance of environmental Sanitation
There are so many reasons why sanitation and hygiene are crucial.
a. Protecting from illnesses and diseases
The lack of sanitation in water and nutrition kills many people. Eating contaminated
food has been shown to be one of the leading causes of worm infections. Individuals
who live in neglected houses suffer from asthma conditions, experience more fall
and slip injuries, and can get microbial infections from germs growing up in their
bathrooms and kitchens. Maintaining a good environmental sanitation enhance the
prevention of illness and diseases.
b. Maintaining mental health
Maintaining good sanitation and hygiene also plays an essential role in nourishing
mental health. Researchers have long linked mental stress and anxiety to messy
environments and lack of organization. Mental health also comes hand-in-hand
with physical health, and each of them will always impact the other in turn. A healthy
body will nurture a healthy mind, and the opposite holds true as well.
c. Improving self-image and self confidence
By ensuring the house, nutrition, and lifestyle are sanitary and by guiding population
through proper personal hygiene care, are empowering them to be the best
versions of themselves. As a result, their self-image improves and they gain more
self-confidence.
d. Improving population social status
Good environmental sanitation improve social status of the population, because the
people are clean, no skin rashes or other pathology their sociability will increase.
e. Increasing population focus and productivity
Providing the optimum environment for them, both physically and mentally, will help
them grow. They’ll grow as balanced individuals who strive to achieve the best
versions of themselves, and they’ll have an adequate environment that helps in
achieving that. They’ll be able to focus more on their work or studies without any
distractions or limitations. As a result, their productivity will increase, allowing them
to achieve more growth and nourishment.
f. Providing a better quality of life
By maintaining proper sanitation and ensuring good hygiene, create the perfect
environment for the community. Making the most out of living conditions, and, in
doing so, it provides a better quality of life. The quality of life provided can be
measured by the lack of illnesses and diseases, the lack of psychological issues,and the growth they experience while living under your roof.
7.3.3. Characteristics of environmental sanitation
7.3.4. Strategies to improve environmental sanitation
The improved sanitation shall be promoted through a combination of measures:
Awareness campaigns related to visible and non-visible health impacts of poor
sanitation and aiming at behavior change;
Marketing the sanitation offer, targeting on people’s expectations and preferences
such as comfort, status, health benefits, value or safety;
Education and training in schools and universities; Urban and rural population about
the maintenance of environmental sanitation
Provision of limited material incentives or subsidies to accelerate the improvement,
construction or replacement of sanitary facilities; using the provision of water supply
services as an incentive and opportunity to improve sanitation facilities.Self-assessment 7.3
1) In which way good environmental sanitation can improve population
social status: Choose the correct answer
a. If the people are clean, no skin rashes or other pathology their sociability
will rise
b. If the people are clean, with skin rashes or other pathology their sociability
will rise
c. If the people are clean, no skin rashes or other pathology their sociability
will decrease
d. If the people are dirty, no skin rashes or other pathology their sociability
will rise
2) Define Environmental sanitation
3) Outline two strategies that my enhance environmental sanitation
improvement
4) Explain how environmental sanitation increase population focus andproductivity
7.4. Human excreta management
Learning activity 7.4
Observe the above image A and B respond to the following questions:
1) What are the sanitation problems do you observe?
2) What do you think as consequences of the sanitation problems observed
for human health?
3) What advices can you give to that people in order to resolve the observed
problems
7.4.1. Introduction
Human excreta are the wastes products of the human digestive system, menses
and human metabolism including urines and feces.
Human excreta should be disposed safely in order to avoid contamination of the
environment, food or hands. Safe disposal of excreta is crucial to ensure a health
environment and for protecting personal health; is one of the principal ways ofbreaking the fecal -oral disease transmission cycle.
Bacterial, viral and parasitic zoonotic pathogens that transmit via the fecal-oral
route have a major impact on global health. A well-established sanitation system is
a key barrier to disease transmission.7.4.2. Sanitation system
A sanitation system is a combination of different functional units and technologies
for safe collection, transport, treatment or disposal of human waste in order toprotect people and environment.
Safe sanitation is essential for health; for preventing infection, improving and
maintaining mental and social well-being. The lack of safe sanitation systems leads
to infection and disease, including: Diarrhea, a major public health concern and a
leading cause of disease and death among children under five years in low- and
middle-income countries, neglected tropical diseases such as soil-transmitted
helminth infections, schistosomiasis and trachoma that cause a significant
burden globally and Vector-borne diseases such as West Nile Virus or lymphaticfilariasis through poor sanitation facilitating the proliferation of Culex mosquitos.
7.4.3. Components of a sanitation system
Figure 7.4 2 Components of sanitation system
A sanitation system has five components: User interface, Collection and storage,
Conveyance, Treatment, Use and /or Disposal
a. User interface
The user interface is the way in which the sanitation system is accessed. The user
interface strongly influences the technological choices of subsequent processes.
The following should be considered while siting the on-site systems:
• An on-site sanitation system must not be located over a surface water body
and should be at 30 m from the edge of the flood plain of a surface water
body.
• Onsite systems should be sited away from trees to prevent obstruction of
their features such as ventilation pipes.
• On-site system should be constructed with enough space for easy access
and movement during desludging.
• Soil conditions such as rocky outcrops, unstable ground and depressions
with shallow water table should be avoided as much as possible.
They are two types of toilets depending on operational modes:
Dry toilets: A dry toilet refers to a toilet that operates without flushing water. The
design for dry toilets requires careful judgment and considerations for the following
features:
• The slab or pedestal (user can sit on) base should be well sized to the pit so
that it is both safe for the user and prevents storm water from infiltrating thepit (which may cause it to overflow).
• For smooth emptying, the slab should provide a hole for desludging with
cover,
• Slab should be at least 150 mm above the ground level with a hole covered
with a lid when not in use.
• The hole should be closed with a lid to prevent unwanted intrusion from
insects or rodents entering the containment technology. The lid also controls
odours and flies from the toilets.
• The pit should be lined with stones or burnt clay bricks to prevent the collapse
of the earth.
• The superstructure should be designed and constructed so that it prevents
intrusion of rainwater, storm water, animals, rodents or insects. It should also
provide maximum level of privacy. Features of the superstructure include:
– Roof should be waterproof to ensure user comfort (protection against the rain
and sun)
– Ventilation should be provided between the walls and roof for aeration,
– Door with a locker.
• Accessible handwashing facilities with soap and water should be available
nearby in a location that encourages use.
Operation maintenance of dry toilets
The following practices should be respected in operation and maintenance for dry
toilets:
• Operation and maintenance of the interface (toilet) should be practiced to
avoid risk of illness to public health.
• Cleanliness: The toilet and all surfaces of the room (e.g. bathroom, washroom,
rest room, cubicle, etc.) should be kept clean and free of excreta.
• Cleaning arrangements: Locally-available cleaning materials should be
safely stored and used, and all people carrying out cleaning should observe
safe working practices.
• Where dry toilets are used as public ones, the following should be specifically
catered for operation and maintenance:
– Safety (adequate lighting, no slippery grounds or surface, firm construction
and cleaning agents), privacy (doors with lockers) and accessibility should be
ensured,
– Public toilets should be placed again with a visible sign for visitors’ convenience,
– Each public toilet should have at least one toilet for the people with disability.
They should have bigger doors for wheel chair access, and railing for support
near the latrines.
– Each public toilet should also be well designed to meet the needs of the
children and pregnant women.
Water-based toilet: flush toilets; toilets that uses water.
The design of water-based toilets should consider the following minimum
requirements to ensure safely managed sanitation across the service chain.
• The water seal at the bottom of the pour flush toilet or plan should have a
slope of at least 25o.
• Water seal should be made out of plastic or ceramic to prevent clogs and to
make cleaning easer (concrete may clog super easily if it is rough or textured),
• The s shape of the water seal determines how much water is needed for
flushing and optimal depth of the water seal head should be approximately 2
cm to minimize the water required to flush the excreta,
• The trap should be approximately 7 cm in diameter
• For public toilets, the design should mention clear sign boards for visitors and
at least one door for disabled (with big door with wheel chair access) and
railing for support near accessible,
• Appropriateness: Pour flush toilet is appropriate for those who sit or squat
(pedestal or slab) as well as for those who cleanse with water. It is also
appropriate when there is a constant supply of water
Operation and maintenance
• Pour flush toilets rarely require repair. However, it should be cleaned regularly
to maintain hygiene and prevent the build-up of stains.
• To reduce water requirements for flushing and to prevent clogging, it is
recommended that dry cleansing materials and products used for menstrual
hygiene be collected separately and not flushed down the toilets.
• For pour flush toilets used as public toilets, priority should be given to efficientflush toilets5 which can reduce each full flush, from 11 to 3 litres per flush.
b. Collection and storage
The products generated at the user interface need to be collected and stored safely.
In the case of extended storage, some treatment may be provided, though it is
generally minimal and dependent on storage time.
Where groundwater is used as a drinking-water source, a risk assessment should
ensure that there is sufficient vertical and horizontal distance between the base
of a permeable container, soak pit or leach field and the local water table and/or
drinking-water source (allowing at least 15 m horizontal distance and 1.5 m vertical
distance between permeable containers and drinking-water sources is suggested
as a rule of thumb).
When any tank or pit is fitted with an outlet, this should discharge to a soak pit,
leach field or piped sewer. It should not discharge to an open drain, water body or
open ground. Where products from storage or treatment in an on-site containment
technology are handled for end use or disposal, risk assessments should ensureworkers and/or downstream consumers adopt safe operating procedures.
Table 7.4 1 Examples of Collection and storage technologies
c. Conveyance of wastes products
Consist of empting and transport of products from one functional group to another.
Full latrines must be either emptied or moved to a new location. Latrines should
be emptied in a safe and hygienic manner by well trained, equipped and protected
workers (e.g., gloves, masks, hats, full overalls and enclosed waterproof footwear)
who transport the sludge to a treatment, use or disposal site.
For septic tanks, a common rule is that they should be emptied when the solids’component of the waste fills between one-half and two-thirds of the. Based on the
most common sizes, septic tanks should be cleaned, at the least, every five to
seven years.
The choice of the technology for emptying and transportation depends on different
factors including types and quantity of products to be transported, distance to cover,
accessibility, topography, soil and ground characteristics, financial resources and
availability of the service provider
They are two types of emptying and transportation of Feacal sludge:
• Human powered emptying technologies:
Human powered emptying technologies have been innovatively developed in
recent years. These technologies are appropriate for areas that are not served or
not accessible by vacuum trucks, or where vacuum truck emptying is too costly.
They are well suited to dense, urban and informal settlements. The most common
types of human powered emptying equipment including Sludge Gulper, Diaphragm
pump, Nibbler and semi-manual pit emptying technology.
• Fully motorized emptying and transportation technologies
Fully motorized emptying and transport technologies refer to a vehicle equipped
with a motorized pump and a storage tank for emptying and transporting faecal.
The pump is connected to a hose, which is lowered down into the tank or pit, and
the sludge is sucked up into the holding tank of the vehicle. These technologies are
powered by the electricity, fuel or pneumatic systems. Provide an essential service
to unsewered areas. They are more used in urban areas with good road and to
containments that are easily accessible. They can also be used to empty schools,
public places and public institutions.
d. Treatment of Fecal sludge
Treatment helps to protect the environment and public health from fecal pathogens
and other contaminants. The treatment facility should be designed and operated
according to the specific end use/disposal objective and operated using a risk
assessment and management approach to identify, manage and monitor risk
throughout the system.
Generally, faecal sludge treatment plants treat faecal sludge in three steps: (i) solid/
liquid separation, (ii) dewatering and (iii) stabilization of further treatment.
From the technical performance, investment needed for installation, operation
and maintenance (O&M) perspective for different systems, the following treatment
systems for faecal sludge are most appropriate in Rwanda:
• Imhoff tanks: Can treat high organic loads and are resistant to organic shock
loads. Space requirements are low and Imhoff tanks can be used in warm
and cold climates. As the tank is very high, it can be built underground if thegroundwater table is low and the location is not flood-prone.
• Settling/thickening tank: It is a low-cost technology for treating faecal
sludge, low operating costs can be built and repaired with locally available
materials and no energy is required.
• Unplanted drying beds: Have low operating costs, can be built and repaired
with locally available materials, no energy is required and good dewatering
efficiency.
• Anaerobic digestion (for biogas production): It is a net energy-producing
process which produces renewable energy in the form of biogas. The liquid
digestate is a better fertilizer in many ways than normal chemical fertilizers.
The digestate produces fewer odours when it is spread on farmland, and is
less likely cause pollution of local rivers and streams and spreading untreated
manure.
• Solar drying beds: Solar greenhouse is the use of renewable energy
sources, reduces the cost of drying. The dried sewage sludge is characterized
by a smaller volume and a ceramic structure, which facilitates storage and
transport.
• LaDePa (Latrine Dehydration and Pasteurization): Converts raw FS
from pit latrine, public toilets and households’ septic tanks into enriched and
pelletized compost, low-cost technology with limited energy requirement.
• Co-composting: Enriches soil, helping retain moisture and suppress plant
diseases and pests, reduces the need for chemical fertilizers, encourages the
production of beneficial bacteria and fungi that break down organic matter to
create humus, a rich nutrient-filled material
e. Disposal / Reuse
Excreta should be disposed or used in ways that are the least harmful to people
and environment. Workers handling effluent or faecal sludge (FS) should be trained
on the risks and on standard operating procedures and use personal protective
equipment. A multi-barrier approach (i.e., the use of more than one control measure
as a barrier against any pathogen hazard) should be used.
There are different options for FS use, particularly as a soil conditioner (land
application in raw form or as compost or co-compost), building material (cement
mixture), biofuel (gas, char briquettes) and in the production of protein (e.g., animal
feed and via the black soldier fly). Inappropriate disposal in soils and leach field are
discouraged.
In Rwanda, faecal sludge is mostly used as a soil conditioner for agriculture
purposes especially in rural areas to schools and prison farms. However, the end
products should be well treated to avoid illness that may occur once in contact with
them. The dewatered solid content seen with no viable reusable option is disposedin either dumpsite or sanitary landfill.
Self-assessment 7.4
1) Family of X live in rural area where it is difficult to access water, which kind
of toilet will you advise them to use and why? Enumerate the features to
consider while designing that toilet.
2) Enumerate and explain three components of a sanitation system?
3) What are benefits of safe excreta disposal?
4) Talk about a urine diverting toilet?
5) Differentiate Cistern Flush toilet from a flush pour toilet6) Define a septic tank and give its class in a sanitation system component
7.5. Animal Excreta management
Learning activity 1.8
Observe carefully the above image and respond to the following questions
1) Think about the practices observed on image A
2) What may be the consequences of practices on image A?
3) What do you think will be good practices can you advise to the people on
image A.
4) Think about image B, what is your observation?
7.5.1. Definition
Animal excreta consist of animal feces and urines; also called manure. Animal
manure contains significant number of micro-organisms such as bacteria, virus and
parasites, responsible of many diseases in humans.
7.5.2. Importance of Animal excreta management
Animal excreta may cause pollution of air and water. If animal excreta are well
managed; it can be beneficial to the population.
Management of animal excreta has a great importance on environment, health and
economy:
• Environment: Reduce detrimental environmental effects; prevent the
environment impacts on air, soil, wildlife and the marine, reduces greenhouse
gas emission from waste, reduces liter and odor and prevent the risks of
flood.
• Economy: Increases business opportunities, provides savings to
business, especially in resources extraction and use, by waste prevention
actions recovery and/or recycling activities, achieves economic saving
by improvements in human health and the environment leading to higher
productivity, lower medical costs, better environmental quality and the
maintenance of ecosystem services. Capturing methane as biogas provides
cooking fuel and lighting that can replace firewood and charcoal.
• Agriculture: used as fertilizer, promote sustainable agriculture and increase
crop production.
• Public Health: Protects human health and safety in community and at waste
management facilities, minimize the risks associated with the wastes, and
improves occupational health. Prevent transmission of zoonotic diseases that
be transmitted through manure.
7.5.3. Animal excreta management practices
Safe and effective animal excreta management practices are key to prevention of
disease transmission from animal excreta to human.
Animal excreta management is done into four steps: Collection, storage, treatmentand reuse or application.
a. Excreta collection or manure collection
Manure collection is very dependent on livestock housing.
Zero –grazing system that consist of confinement of animals in housing with open
sheds with roofing, sloping, concrete floor , slurry pit and manger. Frequent dung
removal is recommended and if possible separate urine collection and drainage
to limit Nitrogen loss. Remove manure as frequent as possible, locally available
materials such tridents, hoe and basket may be used to handle manure.
Deep litter system: these are system where layers of bedding material are
repeatedly spread on older layers as the get soiled. Deep litter poultry ensure a
collect moisture balance in the litter. Prevent any water spills from drinker and addlitter when necessary.
c. Treatment of animal excreta
They are three most common ways of treating manure:
• Drying: urines and feces captured using bedding materials
• Composting: is the natural process of decomposition of organic matter by
micro -organism under aerobic condition.
• Anaerobic digestion: anaerobic digestion is biological process that produces
biogas.
d. Manure application
Consist of safe use of manure in agriculture as fertilizer.
Manure application rates vary according to the type of animal, Collection and
storage method available soil nutrient content and the crop cultivated.General rule; apply two handfuls of solid manure (cattle, goat, sheep etc) or one
handful of poultry manure per hole/plant.
7.5.4. Animal manure, potential pathogens and illnesses Caused
in humans
Animal excreta can cause many illnesses if handled inappropriately.
The table below summarizes potential pathogens and illness caused in humans
7.5.5. Different ways to block transmission of pathogen fromanimal excreta
• Treat your water to make it safe to drink
• Wash your hands
• Prepare food well (e.g., washing vegetables with safe water)
• Cover food and water to prevent contact from animals and flies
• Fence or tether animals
• Fence gardens to prevent animals from accessing them
• Wear protective footwear to prevent soil-transmitted helminth infections
• Remove excreta from the living environment and treat/dispose in a safelocation
Self-assessment 7.5
1) What is the collect sequence of animal excreta management:
a. Collection, storage, treatment and application
b. Collection, treatment, reuse and storage,
c. Storage, Collection, treatment and application
d. Treatment, reuse, Collection, and storage,2) Match the following items:
7.6. Solid waste management overview
Self-assessment 7.6
In your community you have various waste resulted from home activities,
community population activities, industries, and medical waste.
Based on observed waste in your community, respond to the following questions:
1) What types of solid wastes do you observe in your community?2) What do you do to manage them?
7.6.1. Introduction
Waste in general is defined as materials, which have lost their value to their first
owners. In other words, the term waste is used to describe materials that are
perceived to be of negative value.
“Solid Waste” is defined as a solid material possessing a negative economic
value, which suggests that it is cheaper to discard than to use.
Solid waste is another type of human wastes, which refers to the solid or semi-solid
forms of wastes that are discarded as useless or unwanted. It includes food wastes,
rubbish, ashes and residues, etc.
Solid wastes generated from human activities include those from residential,
commercial, street sweepings, institutional and industrial categories. Solid waste
can create significant health problems and a very unpleasant living environment if
not disposed of safely and appropriately. If not correctly disposed of, waste may
provide breeding sites for insect-vectors, pests, snakes and vermin (rats) that
increase the likelihood of disease transmission. It may also pollute water sources
and the environment. All generated solid waste must be managed to minimize
environmental impact and to protect human health.
7.6.2. Classification of solid waste
Solid waste can be classified into two categories by its characteristics. These are:
Organic solid waste and Inorganic Solid waste
Organic solid waste: Wastes that are generally biodegradable and decompose in
the process of which emits offensive and irritating smell when left unattended.
Putrescible wastes e.g., Garbage
Inorganic solid waste: Solid matter that does not decompose at any rat. This
category of waste matter may be combustible depending on the type of the nature
of the material they constitute. Non-putrescible wastes e.g., Rubbish7.6.3. Solid Waste Management
The most environmentally preferred strategy consists of reduction of waste
production. Through source reduction, the volume of solid waste that must be
deposited in landfills is limited, e.g: Improved packaging designs that reduce the
number of materials that must be discarded (e.g., the use of smaller packages for
products); design products, such as refillable bottles, that can be reused.
Solid waste management consists of four steps: storage, collection, transportation,
and disposal.
a. Storage
Storage is a system for keeping materials after they have been discarded and prior
to collection and final disposal. Where on-site disposal systems are implemented,
such as where people discard items directly into family pits, storage may not be
necessary. In emergency situations, especially in the early stages, it is likely that
the affected population will discard domestic waste in poorly defined heaps close to
dwelling areas. If this is the case, improved disposal or storage facilities should be
provided fairly quickly and these should be located where people are able to use
them easily. Improved storage facilities include:
• Small containers: household containers, plastic bins, etc
• Large containers: communal bins, oil drums, etc.
• Shallow pits: is larger-diameter sewer that carry both solid and liquid wastes.
• Communal depots: walled or fenced-in areas
In determining the size, quantity and distribution of storage facilities the number
of users, type of waste and maximum walking distance must be considered. The
frequency of emptying must also be determined, and it should be ensured that allfacilities are reasonably safe from theft or vandalism.
b. Collection
Collection simply refers to how waste is collected for transportation to the final
disposal site. Any collection system should be carefully planned to ensure that
storage facilities do not become overloaded. Collection intervals and volumes of
collected waste must be estimated carefully. Waste collection services are provided
by private operators or companies based on door-to-door collection. Waste is
collected using specific trucks which are dominated by used roll-on-trucks owned
by private operators.
c. Transportation
This is the stage when solid waste is transported to the final disposal site. There
are various modes of transport which may be adopted and the chosen method
depends upon local availability and the volume of waste to be transported. Types of
transportation can be divided into three categories:
• Human-powered: open hand-cart, hand-cart with bins, wheelbarrow, tricycle
• Animal-powered: donkey-drawn cart
• Motorized: tractor and trailer, standard truck, tipper-truck
d. Disposal
The final stage of solid waste management is safe disposal where associated risks
are minimized. There are four main methods for the disposal of solid waste: Land
application (burial or landfilling), compositing, Burning or incineration and recycling.
i. Land application: burial or landfilling
A landfill is an engineered pit, in which layers of solid waste are filled, compacted
and covered for final disposal. It is lined at the bottom to prevent groundwater
pollution.
Advantages
Effective disposal method if managed well
Sanitary disposal method if managed effectively
Energy production and fast degradation if designed as a bioreactor landfill
Disadvantages
Fills up quickly if waste is not reduced and reusable waste is not collected separately
and recycled
A reasonably large area is required
Risk of groundwater contamination if not sealed correctly or the liner system isdamaged
High costs for high-tech landfills
If not managed well, there is a risk of the landfill degenerating into an open dump
Once the landfill site is shut down Operation, Maintenance (O&M) and monitoring
must continue for the following 50 to 100 years.
ii. Composting
Defined as “the aerobic biological decomposition of organic materials (e.g., leaves,
grass, and food scraps) to produce a stable humus-like product. A natural process
that breaks down organic material (material that once came from a living thing) to
create a valuable soil amendment.
Items that can be composted include: vegetable scraps, fruit scraps, nuts,
nutshells, eggshells, coffee grounds, tea leaves, yard trimmings, grass clippings,leaves, twigs, woodchips and straw
Figure 7.6 1 Organic waste compositing at the landfill
Benefits of composting
• Supports healthy soil structure and plant growth
• Creates valuable resource for agriculture, including a home garden
• Reduces the amount of waste to be collected and transported
• Eliminates the need for chemical fertilizers by serving as a homemade organic
fertilizer
• Soil holds water better
• Reduces methane emissions from landfills
• Costs very little to get started and nothing to operate, can be done at home
How to Use the Compost
• Place it around the plant that requires extra attention
• Cover the compost layer with soil
• Add extra compost on top by scooping out a small proportion of the soil from
around the plant
• Create a shallow dip to make watering easy and for runoff to not occur
Wait a few weeks so that the plants have time to grow. Hopefully, when they’re
grown, you will be able to see the effect compost has on your plants.
iii. Burning or incineration
Incineration is defined as the controlled burning of solid, liquid, or gaseous wastes.
In other words; incineration is a treatment technology involving the destruction ofwaste by controlled burning at high temperatures.
Burning wastes at home is dangerous to public health and environment; chemicals
released into the air cause serious air pollution and are related to illnesses such as
cancer. Smoke from burning is hazardous to human health, especially lungs. Also
bothers eyes, nose, and throat. Plastics are especially dangerous than wood, paper
and some construction debris.
Benefits of Waste Incineration
Proper and responsible waste incineration provides various benefits:
Some progressive countries use modern waste treatment and incineration facilities
to convert heat used in the burning of trash to electric power.
The incinerator bottom ash can be used as an aggregate in creating lightweight
blocks, pavement concrete, bulk fill, and more. Environment conscious entities are
using novel technologies to create bricks, tiles, shingles, and other construction
materials from ash.
Incineration can decrease the solid mass of the original waste, which is already
compacted by garbage trucks, to a further 80 to 85%. It can also reduce the volume
of trash up to 95%.
The reduction of solid waste by incineration drastically reduces the amount of trash
that ends up in a landfill.
Incineration can also be used to treat hazardous waste (such as materials
contaminated with hazardous chemicals) or medical waste (such as hospital waste
contaminated with blood or other potentially infectious materials). The high heat of
incineration can destroy these hazards. Hazardous and medical wastes can only
go to special incinerators that are permitted to treat these types of wastes.Safety precautions of burning and burying solid waste
• Combustible waste should always be separated from non-combustible waste
before being loaded into the burn chamber.
• The incinerator should have had sufficient air pollution controls, meets specific
air emission standards
• If burning and incineration is used, the equipment chosen should be designed
and sized to accommodate the waste produced, minimize fire hazard and
result in the complete combustion of the waste.
• Burn waste as far away as possible from people and items that can catch fire,
such as your house
• Burn it in a pit or a barrel to prevent fire spreading
• Bury ashes in a pit or landfill; they may have dangerous substances in them
• Locate the site at least 500 meters away and downhill from drinking water
sources.
• Ensure that there is at least 2 meters between the bottom of the disposal pit
and the highest annual groundwater level. The more distance between the
bottom of the pit and the groundwater, the lower the risk of contamination.
• Do not dispose waste in an area susceptible to flooding.
• Locate the site in clay-like soil if possible. The smaller the soil grain size, the
lower the risk of soil and groundwater contamination. Do not dispose waste
in sandy areas.
• Cover waste with 0.1 meters of soil or ash regularly (e.g., daily or weekly) to
reduce smells and pests, and prevent waste from blowing away.
• Construct a fence to keep animals and children out of the disposal site.
iv. Recycling
Recycling is defined as the process of “collecting and reprocessing a resource
so it can be used again,” e.g: collecting aluminum cans, melting them down, and
using the aluminum to make new cans or other aluminum products.” Recycling is
taking a product, breaking it down from its current form and making something new
from the same material
Items that can be recycled are: Papers, metal, plastics and glass.
Benefits of recycling
• Reduces emissions of greenhouse gases
• Prevents pollution generated by the use of new materials,
• Decreases the number of materials shipped to landfills, thereby reducing theneed for new landfills,
• Recycling companies often pay for materials, income can be generated
• Preserves natural resources, opens up new manufacturing employment
opportunities and Saves energy
Self-assessment 7.3
1) Wastes that are generally biodegradable and decompose in the process
of which emits offensive and irritating smell when left unattended. These
wastes are known as:
a. Inorganic wastes
b. Organic wastes
c. Metal Wastes
d. Paper Wastes
2) One of the following items is the benefit of waste composting
a. Supports healthy soil structure and plant growth
b. Eliminates the need for chemical fertilizers by serving as a homemade
inorganic fertilizer
c. Increase methane emissions from landfills
d. Discourage household because composting consume much time3) Match each concept with its definition
4) define the following terms
a. waste
b. solid waste5) outline 5 safety precautions of burning and burying solid waste
7.7. Hazards waste management
Learning activity 7.7
Observe the above images and respond to the following questions
1) What do you consider as difference or similarities between images in row
A?
2) Illustrate the difference between images in row A and B
3) What to do you think as risks to the environment or Human health can beresulted from Images in row A if are not well handled?
7.7.1. Definition
Hazardous waste: is a contaminant that is a dangerous good and is no longer
wanted or is unusable for its original intended purpose and is intended for storage,recycling, treatment or disposal
Hazardous waste is waste that is dangerous or potentially harmful to our health
or the environment. Hazardous wastes can be liquids, solids, gases, sludge’s,
discarded commercial products (e.g., cleaning fluids or pesticides), or the by
products of manufacturing processes.
7.7.2. Categories of hazardous waste
a. Radio-active substance
Radioactive waste is the type of hazardous waste that contains radioactive
material. Radioactive waste is a by-product of various nuclear technology
processes, industries based on nuclear medicine, nuclear research, nuclear power,
manufacturing, construction, coal and rare-earth mining and nuclear weapons
reprocessing. Any substances capable of emitting ionizing radiation are said to
be radioactive and are hazardous because prolonged exposure often results in
damage to living organisms.
b. Chemicals
The hazardous chemical wastes can be categorized into five group’s namely
synthetic organics, inorganic metals, salts, acids and bases, and flammables and
explosives. Some of the chemicals are hazardous because they threaten human
lives.
c. Bio-medical wastes
The main sources of hazardous biological wastes are from hospitals and biological
research facilities. The biological waste has the capability of infecting other living
organisms and has the ability to produce toxins. Biomedical waste mainly includes
malignant tissues discarded during surgical procedures and contaminated materials,
such as hypodermic needles, bandages and outdated drugs.
d. Flammable wastes
The hazardous waste category also includes flammable wastes. This grouping is
necessary because of risk involved in storage, collection and disposal of flammable
wastes. The flammable wastes may be of solid, liquid or gaseous form. Examples
of flammable waste include organic solvents, oils, plasticizers and organic sludge’s.
e. Explosives
Explosive hazardous wastes are mainly ordnance (artillery) materials. Explosives
also involve high potential for hazard in case of storage, collection and disposal.
These types of wastes may exist in solid, liquid or gaseous form.
7.7.3. Risks of hazardous waste
Hazardous waste presents a danger to the environment, or to people in the nearby
vicinity if it is not handled correctly. Inhalation, ingestion, or dermal exposure to
hazardous materials can cause significant harm to humans, animals and plantswhilst the environment can and has been damaged by improper disposal. Hazardous
waste presents a serious danger if:
It’s released into the air, water, or land and can contaminate the surrounding
environment
A large amount is released at one time, or if small amounts are released frequently
at the same location
It comes into contact with humans via skin contact, ingestion, or breathing in
hazardous materials
Improper storage or disposal leading to spills and leaks which can lead to fires
Hazardous wastes can cause dermatitis to the skin, some cause asthma on long
exposure, and others cause the eyes to smart and run and also tightening of the
chest
7.7.4. Principles of hazardous waste management
a. Requirement for Environmental Impact
No person shall engage in any activity likely to generate any hazardous waste
without a valid Environmental Impact Assessment Certificate issued by a competent
Authority.
b. Collection of hazardous waste
Any generator of hazardous waste shall ensure that all hazardous waste generated
are collected in appropriate manner.
c. Segregation of hazardous waste
The segregation for hazardous waste must meet the following requirements:
• All hazardous waste must be segregated to prevent incompatible mixtures;
• The segregation can be done by hazard class
d. Packing material for hazardous waste
The packing materials of hazardous waste shall be: inert and not react with the
hazardous waste the materials which can be used include: Steel; Aluminium;
Natural Wood; Plywood; Reconstituted wood.
e. Types of containers for hazardous waste packing
The hazardous waste containers shall be in the following types: Bags; Boxes;
Drums; Jerrycans; Combination packaging; Composite packaging.
f. Characteristics of containers
The containers when used for packaging of hazardous wastes shall meet the
following requirements:
Container shall be of mild steel with suitable corrosion-resistant coating and roll-on
roll-off cover or plastic drums, cardboard cartons for a variety of wastes. However,
all such containers should hold up mechanical handling; the containers for liquid
hazardous waste should be completely closed, in fact sealed. Container should
be easy to handle during transportation and also emptying. Manual handling of
containers should be minimized to the extent possible.
g. Packaging of hazardous waste
The containers of hazardous waste must be able to withstand normal handling
and retain integrity for at least six months. In general, packaging for hazardous
waste must meet the following requirements: All packaging material shall be of
such strength, construction and type that they would not break or become defective
during transportation; Packaging material should be such that there will be no
significant chemical or galvanic action among any of the material in the package.
h. Labeling of hazardous waste
All hazardous waste containers must be clearly labeled showing all its contents.
The labels must be waterproof and firmly stuck to the containers so that they cannot
be removed. Containers storing hazardous waste shall be labeled with the words
“HAZARDOUS WASTE” in official language or Warning or caution statements
which may include any of the following as appropriate: the words “WARNING” or
“CAUTION”. The information on the label must include the waste type, origin (name,
address, telephone number of generator), hazardous property (flammable), and the
symbol for the hazardous property (The red square with flame symbol).
i. Transportation for hazardous waste
The following are requirements pertaining to the transportation of hazardous wastes:
• The transportation vehicles and containers shall be suitably designed to
handle the hazardous wastes and must be closed at all times;
• Vehicles shall be painted preferably in blue color to facilitate easy identification;
• Vehicle should be fitted with mechanical handling equipment for safe handling
and transportation of wastes;
• The words “HAZARDOUS WASTE” shall be displayed on all sides of the
vehicle in one of the officials’ languages;
• Transporter shall carry documents of manifest for the wastes during
transportation;
• The trucks shall be dedicated for transportation of hazardous wastes and
they shall not be used for any other purpose;
• Each vehicle shall carry first-aid kit, spill control equipment and fire
extinguisher;
• Driver(s) shall be properly trained for handling the emergency situations and
safety aspects involved in the transportation of hazardous wastes;
• The design of the trucks shall be such that there is no spillage duringtransportation.
j. Storage facilities for hazardous waste
The following are requirements pertaining to the storage of hazardous waste
facilities:
• The storage area should have a proper containment system. The containment
system should have a collection area to collect and remove any leak, spill or
precipitation;
• No open storage is permissible and the designated hazardous waste storage
area shall have proper enclosures, including safety requirements;
• Proper stacking of drums with wooden frames shall be practiced; d. In case of
spills/leaks, cotton shall be used for cleaning instead of water;
• Signboards showing precautionary measures to be taken in case of normal
and emergency situations shall be displayed at appropriate locations;
• Manual operations within storage area are to be avoided to the extent possible.
In case of personnel use, proper precautions need to be taken, particularly
during loading/unloading of liquid hazardous waste in drums.
k. Treatment of Hazardous Waste
Any person who generates hazardous waste shall treat or cause to be treated
such hazardous waste using the classes of incinerators manner. Any products
treated shall be disposed of or treated in accordance with the conditions set by the
Regulatory Authority in consultation with the concerned stakeholders.
Do not dispose hazardous waste in latrines, drainage channels, water sources or
on the ground.
Dispose hazardous waste in a separate landfill site from general household waste
l. Exportation permit
No person shall export hazardous wastes without a valid permit issued by a nationalcompetent Authority.
Self-assessment 7.7
1) Define hazardous waste
2) Talk about hazardous Bio-medical wastes
3) Give the typical information should appear on label of hazardous waste?
4) Explain 2 requirements pertaining to the storage of hazardous waste
facilities5) Discuss the hazardous waste treatment
7.8. Domestic waste water management
Learning activity 7.8
Observe carefully the above image and respond to the following questions
1) Think about the names the waste water A and B?
2) Do you think that there is a difference between the waste water A and
waste water B. If yes what is the difference between them.3) What do you think as the importance of managing waste A and waste B
7.8.1. Definition
Domestic waste water is the wastewater that is produced due to human activities in
households. They are three types of domestic water:
• Black water: A mixture of urine, faeces and flush water along with anal
cleansing water (if water is used for cleansing) and/or dry cleansing materials.
Black water contains pathogens of faeces and the nutrients of urine that are
diluted in flush water.
• Grey water: Water generated from domestic activities; such as laundry,
dish washing, bathing, cleaning and in the kitchen except water from toilets.
Usually has low levels of pathogens, especially compared to black water.
Any pathogens are usually from cross-contamination with excreta. Fecal
pathogens can end up in grey water through hand washing after defecation,
washing children after defection, and washing children’s diapers. Grey water
may also have other contaminants like oil, grease, soap, detergent or other
household chemicals.
• Overflow water: Waste water that has spilled from wells or water points.
Normally it has very low levels of pathogens. However, overflow water can
quickly become contaminated with pathogens from human and animal feces
when it is not well managed and causes standing water.
Domestic wastes water have a negative impact on the environment and public
health if is not well managed. The table below summarizes the domestic wastewater components and its environmental effect
Table 7.8 1 Domestic waste water pollution
7.8.2. Importance of domestic waste water management
Domestic waste water management aims to remove the wastewater pollutants in
other to protect the environment and protect public health.
• Environment: Prevent pollution of surface or ground water sources such as
ocean, lakes, rivers and streams. It prevents euthrophication and pollution
of sensitive aquatic systems (surface water, groundwater, drinking water
reservoirs) as well as terrestrial systems (irrigated soil). It preserves aquatic
life from toxics and biological decomposition of pollutants that may kills fishes
and other aquatic livings.
• Public health: management of domestic waste water aim to protect public
health by eliminating waterborne diseases. It creates an effective physical
barrier between contaminated wastewater and user, as well as avoid odor
emissions and stagnant water leading to breeding sites for mosquitoes.
• Infrastructure: It prevents erosion of shelter and facilities such roads, bridges
etc.
• Agriculture: well, treated domestic water may be used in agriculture to
irrigate crops.
• Economic: Treatment of domestic water aim to prevent the use of excessive
water as treated water may be recycled and reused thus by reducing the costof water.
7.8.3. Management of Domestic waste water
Management of domestic waste water may be done in two ways: on site management
and off-site management
Off-site safely managed sanitation: A sanitation system, in which domestic waste
water is collected, transported away from the plot where it was generated and treated.
Following this, remaining products are either disposed or re-used. Currently, there
are few safe treatment options for off-site faecal sludge management in Rwanda.
On-site safely managed sanitation: A sanitation system or technology in which
faecal sludge is contained, collected, stored, emptied and treated on the institutionalor household plot where it was generated.
a. Management of black water
Methods and processes to manage fecal sludge (The settled contents of pit latrines
and septic tanks) and sewage (Untreated wastewater which contains feces and
urine) were discussed previously in five components of a sanitation system; through
collection, transport and treatment of faecal sludge from pit latrines, septic tanks or
other on-site sanitation systems.
b. Management of grey water
The amount of grey water produced depends on how much water a person uses in
a day. A household with no water shortages and a piped supply typically produces
about 90–120 liters/person/day. But this can be much less, especially in water
scarce areas where people must fetch their water and use only 20–30 litres/person/
day.
The most main step in management of grey water is to control the source by
reducing the amount of grey water contamination in the first place.
i. Collection and containment
Grey water may be managed by on site system by collecting and containing water
using soak pits, grease trap and septic tanks.
ii. Treatment of grey water
The grey water may be treated using different methods:
Physical treatment: In this stage, physical methods are used for cleaning the
wastewater. Processes like screening, sedimentation and skimming are used to
remove the solids. No chemicals are involved in this process.
One of the main techniques of physical wastewater treatment includes sedimentation,
which is a process of suspending the insoluble/heavy particles from the wastewater.
Once the insoluble material settles down at the bottom, you can separate the pure
water.
Another effective physical water treatment technique includes aeration. This process
consists of circulating air through the water to provide oxygen to it. Filtration, the
third method, is used for filtering out all the contaminants. You can use special
kind of filters to pass the wastewater and separate the contaminants and insoluble
particles present in it. The sand filter is the most commonly used filter. The grease
found on the surface of some wastewater can also be removed easily through this
method.
Biological water treatment:
This uses various biological processes to break down the organic matter present in
wastewater, such as soap, human waste, oils and food. Microorganisms metabolize
organic matter in the wastewater in biological treatment. It can be divided into three
categories:
• Aerobic processes: Bacteria decomposes the organic matter and converts
it into carbon dioxide that can be used by plants. Oxygen is used in this
process.
• Anaerobic processes: Here, fermentation is used for fermenting the waste at
a specific temperature. Oxygen is not used in anaerobic process.
• Composting: A type of aerobic process where wastewater is treated by mixing
it with sawdust or other carbon sources.
Chemical waste water treatment
Secondary treatment removes most of the solids present in wastewater, however,
some dissolved nutrients such as nitrogen and phosphorous may remain
As the name suggests, this treatment involves the use of chemicals in water.
Chlorine, an oxidizing chemical, is commonly used to kill bacteria which decompose
water by adding contaminants to it. Another oxidizing agent used for purifying
the wastewater is ozone. Neutralization is a technique where an acid or base is
added to bring the water to its natural pH of 7. Chemicals prevent the bacteria from
reproducing in water, thus making the water pure.
c. Reuse and disposal of grey water
Reuse grey water to irrigate household gardens and agricultural crops
Reuse grey water as toilet flush water.
Dispose of grey water into the ground using a soak pit or infiltration trench
Discharge grey water into a surface water body (e.g., pond, stream, river, lake)
7.8.4. Overflow water management
Over flow water should be channeled away so that it does not cause standing water.
Overflow water that does not drain away from water points could backflow into the
water source and possibly contaminate the drinking water. Or the overflow water
can cause the soil to erode away and damage the water point structure. Overflow
water may be used as irrigation water for agriculture. It may be infiltrated into the
ground using soak pits and infiltration trenches. Over flow water may be released
directly to surface waters (e.g., lakes, rivers or ponds). Overflow water does not
normally require treatment before it can be used, infiltrated or disposed.
Self-assessment 7.8
1) What is blackwater and where does it come from?
2) What is greywater and where does it come from?
3) What is overflow water and where does it come from?
4) What are options to manage greywater?
5) What are options to manage overflow water?
7.9. Environmental sanitations inspections
Learning activity 7.9
In the previous lessons, you leant about sanitation and environmental sanitation,
human and animal excreta management, solid waste water management and
domestic waste water management. Based on these covered lessons:
1) What do you think as environmental inspection?
2) What can you think as benefits and purpose of an environmental sanitationinspection?
7.9.1. Environmental sanitations inspections overview
An environmental sanitation inspection is onsite inspection of environmental
sanitation practices and technologies, to identify potential source and transmission
of diseases related to unsafe water, poor sanitation and poor hygiene. Community
representatives, government officers such as environmental health inspectors,
or field officers from national and international organizations, may use sanitary
inspections.
Environmental sanitation inspection focuses on Domestic wastewater, excreta
management, and public facilities. Solid waste and vector control.
7.9.2. The benefits and purpose of an environmental sanitation
inspection.
Environmental sanitations inspection helps to:
• Provide a simple and fast means of assessing and identifying hazards
associated with unsanitary practices
• Observation and inspection of community and household practice• Identify potential and actual risks
• Useful in assessing small community upgrading options
• Identify WASH practices: excreta management, hygiene, domestic wastewater
• Management, animal excreta management, vector control and solid waste
management.
• Identify potential sources of microbiological (fecal) contamination
7.9.3. Environmental sanitations inspections data collection
methods
During Data, collection different method of data collection may be used such as
Observation and Interview.
Observation can be used for observing the presence or absence of things and
their condition. It may also indicate some behavioral practices. For example, you
can directly observe solid waste in drainage ditches, or the lack of a latrine facility,
or animal excreta management practices.
Interview may be necessary to collect information about practices and behavior,
as they are hard to observe directly. For example, defecation practices, hygiene
practices, and the presence or absence of vectors.
7.9.4. Environmental sanitation inspection forms
Environmental sanitation inspection uses standardized environmental sanitation
inspection forms to ensure consistent assessments. Inspectors use appropriate
forms for the situation being assessed. Questions on the form are designed in asimple way by open-ended question by Yes or No to reduce subjectivity
a. Environmental sanitation Inspection Form: Animal Excreta management
b. Environmental Sanitation Inspection Form: Domestic waste water
Management
C.Environmental Sanitation Inspection Form: Human Excreta Management
d. Environmental sanitation inspection forms: Public facilities
Self-assessment 7.9
1) Why do we use environmental sanitation inspection forms?
2) During inspection, you find that the goats and cows lives in the same
house with the family member. What will be you recommendation to the
family and why?
3) Is it dangerous for pregnant women to live with cats in the household?
Yes or No , explain you answer.
4) What data gathering methods could you use to learn about excreta
management practices in a community?
5) What is environmental inspection?End unit assessment 7
1) A dynamic complex of plant, animal, and microorganism communities
and the nonliving environment interacting as a functional unit is:
a. Environment
b. Ecosystem
c. Environmental health
d. Environmental sanitation
2) The contamination of the physical and biological components of the
earth/atmosphere system to such an extent that normal environmental
processes are adversely affected is:
a. Environmental pollution
b. Environmental health Prevention
c. Primary prevention
d. Tertiary prevention
3) The biggest cause of poor sanitation globally is:
a. Lack of education
b. Lack of hand washing
c. Lack of pure water supply
d. Lack of food industry
4) The below items are benefits of improved sanitation except;
a. Reducing the spread of intestinal worms
b. Reducing the severity and impact of malnutrition
c. Promoting dignity and boosting safety
d. Curing the intestinal worms
5) Sanitation system is:
a. Essential for health; for boosting virus vaccination, improving and
maintaining mental and social well-being
b. A combination of different functional units and technologies for safe
collection, transport, treatment or disposal of human waste.
c. Water seal made out of plastic or ceramic to prevent clogs and to make
cleaning easer
d. Well designed to meet the needs of the children and pregnant women.
6) The name of Water generated from domestic activities; such as laundry,
dish washing, bathing, cleaning and in the kitchen except water from
toilets is:
a. Overflow water
b. Black water
c. Grey water
d. No correct answer
7) Explain the importance of disposing safely the human excreta
8) Give difference between dry toilet and wet toilet
9) Explain the way of treating the Manure
10) Explain the ways of using compost
11) Outline 5 safety precautions of burning or burying solid waste
12) Give 3 benefits of recycling solid waste
13) Explain 5 Precautions of transporting hazardous waste
14) Discuss the importance of domestic wastewater management to public
health
15) Enumerate 2 methods used in data collection during environmental
sanitations inspections.