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• There are 2 types of waterborne diseases. Biological and chemical waterborne.

  Biological waterborne – caused by water contaminated by feces. It contains harmful pathogens: cholera, typhoid, dysentery, amoebic.

  Chemical waterborne – chemical pollution of water which affects health. Fluorides, nitrates, lead.
• there are many types of water diseases - water-borne, water based, water related and water washed.
• Water-washed Diseases – diseases caused by poor personal hygiene. Also caused by skin and eye contact with contaminated water.

  Can form scabies, typhus, trachoma and flea/tick disease. 
• Water based diseases – caused by parasites found in intermediate organisms living in contaminated water. Causes guinea worms.
• Water related - caused by insect vectors (mosquitos) which breed near contaminated places. This is also due to poor hygiene and lack of sanitation and access to drinking water.

  Can cause dengue, filiarisis, malaria, yellow fever and sleeping sickness.
• Sanitation is the hygienic measure of promoting health and preventing transmission of diseases through human contact as well as proper disposal of waste.
• Latrines – slit trench latrines (microbial fauna inactivates pathogens in feces)
• Pit latrine – needs to be emptied regularly (long drop)
• Ventilated improved pit (VIP) latrines – it is a permanent toilet that does not require emptying. Mortar are used between the brick layers to allow the feces to slowly decompose which keeps the pit from filling up too quickly.
• Municipal water treatments – recontamination occurs due to illegal access to municipal water supplies. The water is pumped through these supplies but is stagnant for a long period of time leading to the chlorine concentrations to drop to ineffective levels.
• Household water treatment and storage (HWTS) – the safe water that is collected outside the house is re-contaminated during the journey from source to point of consumption.

  PoU (point of use) treatment can be used to ensure safe water in the house.

  There are several HWTS methods.
• HWTS used if it can solve a problem, cheap, effective and easy to use
• Filtration can cause 90-99% removal of pathogen. There are many filtration methods-

  Sari filter, ceramic filter, bio sand filter, ceramic pot filter.
• Ceramic filter – uses similar materials needed for brick production.
• Biosand filters – there is an ecosystem that is established in the sand filter.

  The protozoa in schmutzdeck feeds on the pathogens in the water.
• Chlorination – chloride ions can be used as an effective microbicidal agent.

  Within 24-48 hrs of treatment, water should be consumed as the chlorine concentration reduces with time.

  Some pathogens like Vibrio cholera have become resistant.

  Tablet and liquid formulations are used. This is not used that much because the taste of treated water can be problematic.
• Flocculation/chlorination – flocculation can treat turbid water. This binds to the solids at the bottom of the container.

  The clear water is decanted off.
• SODIs are solar disinfections – require fill sunshine and any transparent container (plastic, glass). Replaced every 6 months and is a cheap version of HWTS.