Showing papers by "C. Annette Johnson published in 2009"

The development of bone char-based filters for the removal of flouride from drinking water

Abstract: Millions of people rely on drinking water that contains excess fluoride. Only few fluoride removal techniques have been implemented on a wider scale in low and middle income countries. One of these methods, bone char filtration, is highly efficient. However, its lifespan is rather limited. This paper presents first laboratory results and field testing of a new fluoride removal technology, based on a combination of bone char and calcium-phosphate pellets. These chemicals are slowly released to the water for fluoride precipitation. Although this method, commonly referred to as contact precipitation is known, the development of such pellets is new. Fixed-bed laboratory experiments show that this mixture of materials can increase filter uptake capacity by a factor of 3 and more. However, to reduce the phosphate concentration in the treated water, the design of full-scale community filters for field testing has to be slightly modified.