Clean drinking water through fluoride removal at Lake Baringo, Kenya

Lake Baringo is one of the main water sources for residents in the region of Baringo County in Kenya. It serves a population of almost 9,000 people for washing, bathing and as a drinking water source. Around and on the lake, 11 municipalities are located having 800 inhabitants on average each. Most of the population live from fishing or livestock farming of goats. Due to high temperatures, a daily freshwater demand for drinking and cooking of about 10 liters per person is required which results in a daily demand of about 90 m³ of drinking water in the region.

Besides bacterial contamination and turbidity, the water contains high concentrations of geogenic fluoride (F-). With values between 4 - 15 mg/l, the concentration of fluoride in the water of Lake Baringo exceeds the World Health Organization (WHO) recommended limit for drinking water of 1.5 mg/l by far. Due to high temperatures and droughts in the region, people are forced to drink a lot to keep their water balance. This leads to the intake of high amounts of fluoride and the occurrence of skeletal and dental fluorosis.

Fluoride ions can be removed from water by using hydroxyl apatite as filter material. In comparison to other techniques like reverse osmosis (RO) the process is much easier, cheaper and can also be realized in remote areas. The synthetically produced filter material is used as an alternative to previously used bone char. It is produced under hygienic conditions and has a significantly higher fluoride adsorption capacity than bone char. Since then, the use of the filter material with the corresponding technology has proven itself in numerous municipal filter systems.

Since 2013, hydroxyl apatite filter material has been produced in Nakuru, Kenya. In 2020 a new plant to produce synthetic hydroxyl apatite (HAPaqua) as filter material for fluoride removal was installed by Harbauer GmbH, in cooperation with the company Dr. Ecker GmbH. At the beginning of 2021 the subsidiary Harbauer Limited - Kenya in Nakuru was founded to advance the production of HAPaqua.

Fluoride reduction by means of HAPaqua has several advantages over the use of bone char, e.g., faster adsorption and higher adsorption capacity which leads to smaller filters and footprint, as well as regeneration and reuse capability. For the regeneration of the filter material, the construction of two regeneration stations is planned. Furthermore, the filtration system can be fully solar powered. To ensure hygiene drinking water, the treatment systems will be equipped with UV disinfection units.

The aim of the project is to provide the population around Lake Baringo with clean drinking water with a fluoride concentration of < 1.0 mg/l.  Due to the high demand of drinking water in this region the WHO recommendation of < 1.5 mg/l fluoride is not sufficient to protect the residents against fluorosis.

It is planned to install new filter systems with HAPaqua filter material in the 11 communities around Lake Baringo in order to provide the population with hygiene drinking water with reduced fluoride concentrations. The maintenance of the plants and the regeneration of the filter material is to be maintained and ensured in the long term through donations from non-governmental organizations, other collaboration partners and the water sales. The local sale of the purified water at affordable prices not only ensures the supply of clean drinking water, but also creates jobs, and strengthens local economic structures.