HEALTH AND SAFETY OF RAINWATER HARVESTING by : ENGR. REX L. LABADIA Department of Health Center for Health Development Davao Region

WATER CYCLE

In harvesting rainwater for drinking, care should be taken to avoid materials or coatings for roofing, drains and pipes that can dissolve to give high concentrations in water. Elevated levels of zinc and lead in harvested rainwater have been reported.

Drinking rainwater is not advised where potable water supplies exist, particularly in urban areas where rainwater can contain higher contaminant levels.

If harvested rainwater is used for drinking, it must be regularly examined for physical, chemical and bacteriological quality. 1. Physical and chemical examination– at least once a year 2. Bacteriological examination – at least once in 3 months

In areas where there are no sources of potable water supply, rainwater contaminated with undesirable microorganisms may be rendered safe for drinking by applying appropriate disinfection procedures.

What is SODIS Stands for Solar Water Disinfection 1. 2. SODIS is a household water treatment method to provide safe drinking water SODIS utilizes the synergy of the UV-A radiation and temperature gain to inactivate the micro-organism in the water

SODIS is ... SODIS can be applied anywhere where sunshine is available SODIS can be done by all members of the family SODIS is simple, easy methodology to have safe drinking water for the family SODIS utilizes solar energy to improve water quality by killing the bacteria in the water

S un S hine PET P lastic Bottles O pen s pace w hat is n eeded to do SODIS

Yayasan Dian Desa Can be divided into three different kinds : Ultra Violet Radiation ( it cannot be seen but can destroy living cell – e.g. our skin will be destroyed when we stayed too long in the sun Sun light Infra red radiation (it cannot be seen but we can feel the heat - micro organism is sensitive to heat) S olar R adiation

synergy Yayasan Dian Desa Water in the container gain temperature from the infra red radiation and also the Ultra violet radiation penetrates into the water in the container --- they synergize to kill the bacteria in the water That is why in SODIS the container has to be transparent so that the UV radiation can penetrate through the bottles into the water How does SODIS work

1 3 2 Fill with the raw water for treatment Expose to sunshine in clear area, make sure that the place will not be shaded How to do SODIS ??? Prepare 1.5 liters PET plastic bottles, and wash them using soft materials in order not to scratch the bottles

SODIS L imitations Cannot be applied with large containers 1 2 Cannot be applied if the water is turbid Can only inactivate microorganism , not change others such as chemical substances, smell, or salinity 3

BRINGING CLOSER ACCESS TO SAFE DRINKING WATER IN EVERY HOME

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