Halazone

Portable water purification devices – better described as point-of-use (POU) water treatment systems and field water disinfection techniques – are self-contained, usually hand-carried units used by recreational enthusiasts, military personnel, survivalists and people without access to water supply services in developing countries for water purification when they need to obtain drinking water from untreated sources (e.g. rivers, lakes, groundwater etc.). These personal devices and methods aim to render water potable (i.e. safe and palatable for drinking purposes - without disease-causing pathogens).

Techniques include heat (including boiling), filtration, activated charcoal absorption, chemical disinfection (e.g. chlorination, iodine, ozonation, etc.), ultraviolet purification (including SODIS), distillation (including solar distillation), and flocculation. Often these are used in combination. Many commercial portable water purification systems or chemical additives are available for hiking, camping, and other travel in remote areas.

Portable water purification methods are also commonly used at household level in developing countries when the source of drinking water is not suitable for drinking (also called "unimproved water source") - an approach called self-supply of water.

Untreated water may contain potentially pathogenic agents, including protozoa, bacteria, viruses, and some larvae of higher-order parasites such as liver flukes and roundworms. Chemical pollutants such as pesticides, heavy metals and synthetic organics may be present. Other components may affect taste, odour and general aesthetic qualities, including turbidity from soil or clay, colour from humic acid or microscopic algae, odours from certain type of bacteria, particularly Actinomycetes which produce geosmin, and saltiness from brackish or sea water.

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Wikipedia