Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often supplied through taps, in that case, it is also called tap water. Typically in developed countries, tap water meets drinking water quality standards, even though only a small proportion is actually consumed or used in food preparation. Other typical uses for tap water include washing, toilets, and irrigation. Greywater may also be used for toilets or irrigation. Its use for irrigation however may be associated with risks.
Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for human consumption, but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The history of water purification includes a wide variety of methods. The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.
Tap water is water supplied through a tap, a water dispenser valve. In many countries, tap water usually has the quality of drinking water. Tap water is commonly used for drinking, cooking, washing, and toilet flushing. Indoor tap water is distributed through indoor plumbing, which has existed since antiquity but was available to very few people until the second half of the 19th century when it began to spread in popularity in what are now developed countries. Tap water became common in many regions during the 20th century, and is now lacking mainly among people in poverty, especially in developing countries.
In modern plumbing, a drain-waste-vent is a system that allows air to enter the plumbing system to maintain proper air pressure to enable the removal of sewage and greywater from a dwelling. Drain refers to water produced at fixtures such as sinks, and showers; waste refers to water from toilets. As the water runs down, proper venting is required to allow water to flow freely, and avoid a vacuum from being created. As the water runs down air must be allowed into the waste pipe either through a roof vent (external), or an internal vent.
Main components found on a typical steam locomotive include:
A pit latrine, also known as pit toilet, is a type of toilet that collects human waste in a hole in the ground. Urine and feces enter the pit through a drop hole in the floor, which might be connected to a toilet seat or squatting pan for user comfort. Pit latrines can be built to function without water or they can have a water seal. When properly built and maintained, pit latrines can decrease the spread of disease by reducing the amount of human feces in the environment from open defecation. This decreases the transfer of pathogens between feces and food by flies. These pathogens are major causes of infectious diarrhea and intestinal worm infections. Infectious diarrhea resulted in about 700,000 deaths in children under five years old in 2011 and 250 million lost school days. Pit latrines are a low-cost method of separating feces from people.
A fecal coliform is a facultatively anaerobic, rod-shaped, gram-negative, non-sporulating bacterium. Coliform bacteria generally originate in the intestines of warm-blooded animals. Fecal coliforms are capable of growth in the presence of bile salts or similar surface agents, are oxidase negative, and produce acid and gas from lactose within 48 hours at 44 ± 0.5°C. The term thermotolerant coliform is more correct and is gaining acceptance over "fecal coliform".
An air handler, or air handling unit, is a device used to regulate and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system. An air handler is usually a large metal box containing a blower, furnace or A/C elements, filter racks or chambers, sound attenuators, and dampers. Air handlers usually connect to a ductwork ventilation system that distributes the conditioned air through the building and returns it to the AHU, sometimes exhausting air to the atmosphere and bringing in fresh air. Sometimes AHUs discharge (supply) and admit (return) air directly to and from the space served without ductwork
A water tank is a container for storing water, for many applications, drinking water, irrigation, fire suppression, farming, both for plants and livestock, chemical manufacturing, food preparation as well as many other uses. Water tank parameters include the general design of the tank, and choice of construction materials, linings. Various materials are used for making a water tank: plastics, fiberglass, concrete, stone, steel. Earthen pots, such as matki used in South Asia, can also be used for water storage. Water tanks are an efficient way to help developing countries to store clean water.
The physical process of sedimentation has applications in water treatment, whereby gravity acts to remove suspended solids from water. Solid particles entrained by the turbulence of moving water may be removed naturally by sedimentation in the still water of lakes and oceans. Settling basins are ponds constructed for the purpose of removing entrained solids by sedimentation. Clarifiers are tanks built with mechanical means for continuous removal of solids being deposited by sedimentation; however, clarification does not remove dissolved solids.
A spring supply is a provision of piped mains water to a number of consumers direct from a natural spring. Spring supplies are therefore a source of groundwater, which in most instances has fewer micro-organisms and chemical contaminants than a supply from surface water. The point at which the groundwater reaches the surface is prone to contamination, so must be protected using a structure called a spring box. This is often surrounded by a fence to keep animals out, with other common features being a ditch on the uphill side, an overflow pipe and a well fitting lid. Spring supplies can range from single property supplies that are privately owned, to large supplies that are managed by water companies and serve entire communities. As with any water supply, a spring supply may need to be treated in order to bring it up to drinking water standards. The method for doing this will vary according to the contaminant, but can include sand filters, pH balancing units and ultraviolet light.
A rainwater tank is a water tank used to collect and store rain water runoff, typically from rooftops via pipes. Rainwater tanks are devices for collecting and maintaining harvested rain. A rainwater catchment or collection system can yield 2,358 litres (623 US gal) of water from 2.54 cm (1.00 in) of rain on a 92.9 m2 (1,000 sq ft) roof.
Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to motion of the water. Suspended solids can be removed by sedimentation if their size or density is comparatively large, or by filtration. It is used as one indicator of water quality and of the strength of sewage, or wastewater in general. It is an important design parameter for sewage treatment processes.
Access to water supply and sanitation in Ethiopia is amongst the lowest in Sub-Saharan Africa and the entire world. While access has increased substantially with funding from foreign aid, much still remains to be done. Some factors inhibiting the achievement of these goals are the limited capacity of water bureaus in the country's nine regions, two city administrations and water desks in the 770 districts of Ethiopia (woredas); insufficient cost recovery for proper operation and maintenance; and different policies and procedures used by various donors, notwithstanding the Paris Declaration on Aid Effectiveness.
A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The well water is drawn up by a pump, or using containers, such as buckets or large water bags that are raised mechanically or by hand. Water can also be injected back into the aquifer through the well. Wells were first constructed at least eight thousand years ago and historically vary in construction from a simple scoop in the sediment of a dry watercourse to the qanats of Iran, and the stepwells and sakiehs of India. Placing a lining in the well shaft helps create stability, and linings of wood or wickerwork date back at least as far as the Iron Age.
An improved water source is a term used to categorize certain types or levels of water supply for monitoring purposes. It is defined as a type of water source that, by nature of its construction or through active intervention, is likely to be protected from outside contamination, in particular from contamination with fecal matter.
Groundwater pollution occurs when pollutants are released to the ground and make their way into groundwater. This type of water pollution can also occur naturally due to the presence of a minor and unwanted constituent, contaminant, or impurity in the groundwater, in which case it is more likely referred to as contamination rather than pollution. Groundwater pollution can occur from on-site sanitation systems, landfill leachate, effluent from wastewater treatment plants, leaking sewers, petrol filling stations, hydraulic fracturing (fracking) or from over application of fertilizers in agriculture. Pollution can also occur from naturally occurring contaminants, such as arsenic or fluoride. Using polluted groundwater causes hazards to public health through poisoning or the spread of disease.
Hazmat diving is underwater diving in a known hazardous materials environment. The environment may be contaminated by hazardous materials, the diving medium may be inherently a hazardous material, or the environment in which the diving medium is situated may include hazardous materials with a significant risk of exposure to these materials to members of the diving team. Special precautions, equipment and procedures are associated with hazmat diving so that the risk can be reduced to an acceptable level.
Lesotho is a mountainous and fairly 'water-rich country', but suffers from a lack of clean drinking water due to inadequate sanitation. In recent decades, with the construction of dams for the Lesotho Highlands Water Project (LHWP), Lesotho has become the main provider of water to parts of northern South Africa. Despite the economic and infrastructure development occasioned by the LHWP, waterborne diseases are common in the country and the infant mortality rate from them is high. In 2017, a project to improve the rural water supply in the Lesotho Lowlands was funded by the Global Environment Facility and the African Development Bank, and is ongoing.
A water distribution system is a part of water supply network with components that carry potable water from a centralized treatment plant or wells to consumers to satisfy residential, commercial, industrial and fire fighting requirements.
