As per standard public health guidelines, how much bleaching powder is generally required to disinfect 1000 liters of clear water under normal conditions?

According to various public health studies (such as those by the WHO), which of the following is a major environmental factor linked to recurrent diarrhea and stunted growth in children?

What is the minimum recommended safe distance that should be maintained between a septic tank and a source of drinking water (like a well)?