Household defluoridation unit design and development

Abstract

The 1984 World Health Organization (WHO) guidelines suggest the permissible fluoride concentration in drinking water to be 1.0 mg/l in warm climate and 1.2 mg/l in cooler areas.  Excessive fluoride intake causes an irreversible health problem widely known as fluorosis. There are three stages of fluorisis: Dental, skeletal and crippling fluorosis and all of them are known to prevail in Ethiopia. In the sample areas in this project the fluoride concentration lies between 3.4 and 24.3 mg/l.

The objective of this paper is to present the result of a research aimed at designing and developing a household defluoridiation unit that is simple, inexpensive and that uses locally manufactured Aluminium Sulfate that will reduce the fluoride concentration to the recommended range.

The defluoridation unit developed by the researchers is simple, just a bucket with a tap. The bucket can be produced from plastic, clay or metal. A sample defluoridiation unit has been developed in the Chemical Engineering laboratory with a plastic bucket and it has been checked to be effective. For the sample produced in the laboratory the cost is around 25 Birr, just the cost of the bucket and the tap. The cost of locally produced Aluminium Sulfate and lime is 2.5 Birr/Kg and 1 Birr/Kg respectively, hence the total cost of chemicals for treating a 20 liter bucket of water is less than 10 cents