Before you want to use rainwater in industrial buildings, you want to make sure that the rainwater is clean. GEP has developed rainwater filters for this purpose based on Trident & trade; filter technology. This technology ensures that dirt particles are separated from the rainwater before the clean rainwater is stored in the tank. The pre-tank filters for rainwater are designed to be installed in front of a rainwater tank or rainwater citern, so underground or above ground, in front of the rainwater tank. With a Trident & trade; rainwater filter you are assured of pure and clean rainwater before use.