| Sanitation is the
hygienic means of preventing human contact from the hazards
of wastes to promote health. Hazards can be either physical,
microbiological, biological or chemical agents of disease.
Wastes that can cause health problems are human and animal
feces, solid wastes, domestic wastewater (sewage, urine,
sullage, greywater), industrial wastes, and agricultural
wastes. Hygienic means of prevention can be by using
engineering solutions (e.g. sewerage and wastewater
treatment), simple technologies (e.g.latrines, septic
tanks), or even by personal hygiene practices (e.g. simple
handwashing with soap). The term "sanitation" can
be applied to a specific aspect, concept, location, or
strategy, such as:
Basic sanitation - refers to the management of
human feces at the household level. This terminology is the
indicator used to describe the target of the Millennium
Development Goal on sanitation.
On-site sanitation - the collection and teatment
of waste is done where it is deposited. Examples are the use
of pit latrines, septic tanks, and imhoff tanks.
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.
Sanitation and wastewater
Wastewater collection
For more details on this topic, see Wastewater.
The standard sanitation technology in urban areas is the
collection of wastewater in sewers, its treatment in
wastewater treatment plants for reuse or disposal in rivers,
lakes or the sea. Sewers are either combined with storm
drains or separated from them as sanitary sewers. Combined
sewers are usually found in the central, older parts or
urban areas. Heavy rainfall and inadequate maintenance can
lead to combined sewer overflows or sanitary sewer
overflows, i.e. more or less diluted raw sewage being
discharged into the environment. Industries often discharge
wastewater into municipal sewers, which can complicate
wastewater treatment unless industries pre-treat their
discharges.[1]
The high investment cost of conventional wastewater
collection systems are difficult to afford for many
developing countries. Some countries have therefore promoted
alternative wastewater collection systems such as
condominial sewerage, which uses smaller diameter pipes at
lower depth with different network layouts from conventional
sewerage.
Wastewater treatment
For more details on this topic, see Sewage treatment.
Sewage treatment plant, Australia.In developed countries
treatment of municipal wastewater is now widespread,[2] but
not yet universal (for an overview of technologies see
wastewater treatment). In developing countries most
wastewater is still discharge untreated into the
environment. For example, in Latin America only about 15% of
collected sewerage is being treated (see water and
sanitation in Latin America)
Reuse of wastewater
The reuse of untreated wastewater in irrigated agriculture
is common in developing countries. The reuse of treated
wastewater in landscaping (esp. on golf courses), irrigated
agriculture and for industrial use is becoming increasingly
widespread.
In many peri-urban and rural areas households are not
connected to sewers. They discharge their wastewater into
septic tanks or other types of on-site sanitation.
Ecological sanitation
For more details on this topic, see Ecological sanitation.
Ecological sanitation is sometimes presented as a radical
alternative to conventional sanitation systems. Ecological
sanitation is based on the separation of urine and feces at
the source for sanitization and recycling. It thus
eliminates fecal pathogens from the wastewater flow. If
ecological sanitation is practiced municipal wastewater
consists of greywater, which can be recycled for gardening.
However, in most cases greywater continues to be discharged
to sewers.
Sanitation and public health
The importance of waste isolation lies in an effort to
prevent water and sanitation related diseases, which
afflicts both developed countries as well as developing
countries to differing degrees. It is estimated that up to 5
million people die each year from preventable water-borne
disease[3], as a result of inadequate sanitation and hygiene
practices.
Global access to improved sanitation
The Joint Monitoring Program for water and sanitation of WHO
and UNICEF has defined improved sanitation as
connection to a public sewer
connection to a septic system
pour-flush latrine
simple pit latrine
ventilated improved pit latrine
According to that definition, 59% of the world population
had access to improved sanitation in 2004. [1] Only slightly
more than half of them or 31% of the world population lived
in houses connected to a sewer. Overall, 2.6 billion people
lacked access to improved sanitation and thus had to resort
to open defecation or other unsanitary forms of defecation,
such as public latrines or open pit latrines. This outcome
presents substantial public health risks as the waste could
contaminate drinking water and cause life threatening forms
of diarrhea to infants.
In developed countries, where less than 20% of the world
population lives, 99% of the population has access to
improved sanitation and 81% were connected to sewers.
Solid waste disposal
Hiriya Landfill, Israel.Disposal of solid waste is most
commonly conducted in landfills, but incineration,
recycling, composting and conversion to biofuels are also
avenues. In the case of landfills, advanced countries
typically have rigid protocols for daily cover with topsoil,
where underdeveloped countries customarily rely upon less
stringent proocols[4]. The importance of daily cover lies in
the reduction of vector contact and spreading of pathogens.
Daily cover also minimises odour emissions and reduces
windblown litter. Likewise, developed countries typically
have requirements for perimeter sealing of the landfill with
clay-type soils to minimize migration of leachate that could
contaminate groundwater (and hence jeopardize some drinking
water supplies).
For incineration options, the release of air pollutants,
including certain toxic components is an attendant adverse
outcome. Recycling and biofuel conversion are the
sustainable options that generally have superior life cycle
costs, particularly when total ecological consequences are
considered[5]. Composting value will ultimately be limited
by the market demand for compost product.
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