Treatment of water from commercial rainwater harvesting systems generally requires disinfection and filtration for many
applications of the captured water. The catchment surfaces where the rainwater is collected can be contaminated by
birds or materials used on the catchment surface, for example roofing materials. Different roofing materials create
different levels of contamination in water that should be treated by the rainwater harvesting system.
Spartan Environmental Technologies builds integrated systems for rainwater treatment including ozone, UV and ozone/UV systems with and without filtration. Spartan can offer a single source of supply for the treatment system utilizing the technologies below.
UV is a good choice for simple disinfection applications where protection of the storage tank from the formation of biofilms is not an issue. The UV system is usually positioned in the from the storage tank going to the application where the rainwater will be used, e.g. toilet flushing or landscape irrigation. The UV will inactivated most micro organisms present in the water. It will not remove any micro organisms int eh tank, biofilms on the tank surfaces or remove any dissolved organic compounds in water. Organic compounds in the water or micro organisms living int eh tank can result in color or odor problems with the water. In some applications this might not be a problem, but may be in an a pplication such as toilet flushing.
Ozone systems can be positioned to treat the rainwater in the tank by recycling the water through an ozone injection system or by continuously bubbling the ozone in to the storage tank. Ozone is a broad spectrum biocide that treats all of the water int eh tank as well as preventing the formation of biofilms on the tank surfaces. In addition, ozone can remove color and odors from water that allow the water to be used in a wider array of applications.
Ozone and UV can be used together. Ozone would treat the bulk of the water in the tanks while the UV can be used to treat the water sent to the application, e.g. landscape irrigation. This approach offers a couple of benefits: first, it provide redundancy should either system fail insuring that pathogens never reach the end use of the water. Second, for applications where residual ozone might not be desirable int eh water, UV will remove most if not all of the ozone residual prior to the application.