Sanitation
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
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.
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
In developed countries treatment of municipal wastewater is now widespread, 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
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, 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.  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
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.  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.  Composting value will ultimately be limited by the market demand for compost product.

# Sanitation in the food industry
Sanititation within the food industry means to the adequate treatment of food-contact surfaces by a 
process that is effective in destroying vegetative cells of microorganisms of public health significance, and in substantially reducing numbers of other undesirable microorganisms, but without 
adversely affecting the product or its safety for the consumer (FDA, Code of Federal Regulations, 21CFR110, USA).
Additionally, in the food and Biopharmaceutical industries, the term sanitary equipment means equipment that is fully cleanable using Clean-in-place (CIP), and Sterilization in place (SIP) procedures: that is fully drainable from cleaning solutions and other liquids. The design should have a minimum amount of deadleg or areas where the turbulence during cleaning is not enough to remove product deposits. In general, to improve cleanability, this equipment is made from Stainless Steel 316L, (an alloy containing small amounts of molybdenum). The surface is usually electropolished to an effective surface roughness of less than 0.5 micrometre, to reduce the possibility of bacterial adhesion to the surface.

# History
The earliest evidence of urban sanitation was seen in Harappa, Mohenjo-daro and the recently discovered Rakhigarhi of Indus Valley civilisation. This urban plan included the world's first urban sanitation systems. Within the city, individual homes or groups of homes obtained water from wells. From a room that appears to have been set aside for bathing, waste water was directed to covered drains, which lined the major streets. Houses opened only to inner courtyards and smaller lanes.
Although the Romans had some elements of sanitation systems, especially related to wastewater collection and transport away from populated areas, there is little record of sanitation in Europe until the High Middle Ages.  Unsanitary conditions were widespread throughout Europe and Asia throughout the Middle Ages, but there were no cataclysmic results until the 1300s when overpopulation of some regions created overcrowding and magnified the impacts of lack of sanitation.  Between 1348 and 1351 the plague killed 25 million Europeans or almost one third of the entire population.
Very high infant and child mortality prevailed in Europe throughout medieval times, due not only to deficiencies in sanitation but to insufficient food for the population that had expanded faster than agriculture.  Thus sanitation and food supply are looked upon as the balances of rapidly population in the period 1300 to 1600 in most of Europe, especially for the towns.