Cistern water is treated to drinking water quality in a multistage treatment process. The first step is to eliminate particles from the cistern water with a filter whose pores are 1 µm in diameter. Then, organic components are oxidized by adding ozone with special focus on eliminating pesticides. The water subsequently flows through an active carbon filter where oxidation products can be adsorbed and degraded biologically. In this step, inorganic components should also be bound from the rainwater by adsorption. In the next phase, the water passes through an ultra filter which catches the finest particles and any microorganisms still remaining in the water. The final step is to irradiate the treated water with UV light to ensure that it is free of germs.
Our plans to reduce the concentration of salt in rainwater have more to do with good organization than with complicated chemical technologies. It is better to reduce the amount of salt by using less to free roads from ice and by closing off the cisterns during adverse weather conditions.
Treated water can then be distributed to the homes on the site from a reservoir. The water flows through a circular set of pipes around the development area and back to the reservoir to stop it from stagnating and becoming re-contaminated. Another UV lamp in the return flow kills any germs which might have grown in the pipes.