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Initially the production of drinking water from seawater was done by evaporation. This is a high-temperature distillation process: seawater is boiled until it forms vapor. On cooling of the vapor pure water is won. The residual product is warm water with a high concentration of salt. Discharges of this warm water in the sea proved to be harmful to marine life.

Reversed osmosis
Thanks to the advent of ‘reversed osmosis’ technique, the production of water on Bonaire has become far more sustainable. Reversed osmosis entails that the seawater is pressed through a membrane under high pressure. The membrane filters out all the residues from the water. Next, the water passes through a second membrane. As a result it becomes extremely pure, with a minimum amount of residual salts (5-10 mg/l).

With reversed osmosis no warm water is discharged into the sea. In addition the installation requires less space and its energy consumption is lower.

The reversed osmosis technique used by WEB for water production provides extremely pure water. This water is not yet drinking water. It needs a post treatment to comply with the legal requirements for drinking water. For example it should contain minerals, including a certain amount of calcium.

Post treatment
Via lime filters calcium carbonate is dissolved in the water. Because of this the water becomes slightly ‘harder’. For dishwasher users: the water has a total hardness of around 50 mg/l or 2.8 German Hardness degrees. With this, the water is still relatively soft; it will give little calcification.

Furthermore, CO2 is added. This acts as a catalyst for the dissolution of calcium carbonate.

On Bonaire no fluoride is added to drinking water. Fluoridation is not a legal requirement anymore in Dutch legislation since 1973.

A safe drinking water supply is important for the inhabitants and visitors of Bonaire. WEB has its own laboratory that checks the quality of the drinking water continuously.

WEB takes samples twice a week at the storage tanks at Hato and the distribution tanks at Seru Largu, Sabadeco and Subi Rincon. Spread across the island WEB has installed 34 sampling points in the water supply system. These points are sampled twice weekly on several parameters.

The WEB laboratory tests the water’s chemical composition, color, turbidity, bacteria and taste. In case of abnormalities are found in the quality, WEB takes measures and rinses a duct on the spot if necessary.

WEB regularly has consultations with the Human Environment and Transport Inspectorate (IL&T). This is a division of the Ministry of Infrastructure and Water Management. IL&T is responsible for the supervision on safe and correct drinking water management

Legionella
Legionella has WEB’s special attention in the care for safe drinking water.
Information about legionella, our approach and prevention can be downloaded here (pdf).

WEB inaugurated the new drinkwater facility on October 31st, 2021. WEB is currently in in charge of the production of 7.200 m3 per day of drinking water.

Since 2015 WEB already has its own production of 1.600 m3 per day. Thanks to a solid position WEB is able to realize the complete drinking water production independently.

In collaboration with Royal HaskoningDHV , WEB since the beginning of 2019 works on development, design and realization of a new Drink Water Treatment Plant (DWTP). In a public tender in 2020 has been chosen for an installation of IDE Technologies from Israël.

As the supplier of water, WEB is responsible for the distribution of high quality drinking water on Bonaire. WEB works closely with the Dutch water company Vitens Evides International (VEI) that shares its knowledge and expertise to optimize Bonaire’s drinking water provisions.