1- PV-Power systems
2- Storage tank for drinking water
3- Deionised water storage tank
4- Solar steam generator
5- Buffer tank for UF treatment
6- Ultrafiltration (UF) tank
7- Capacitive deionisation (CDI) modules

Solar Water Container

The water treatment container is designed to produce hygienically clean and cooled drinking water as well as demineralised water for steam production and for different applications in the selected SophiA hospitals. It is equipped with an ultrafiltration (UF) membrane technology and a membrane capacitive deionisation (MCDI) system. The storage and buffer tanks in the container are equipped with an ultraviolet (UV) system for disinfection purpose. A cooler is placed at the outlet to provide cooled drinking water to the consumer.

The UF technology includes the latest Cube® filters manufactured by the SophiA partner Martin Systems GmbH. They use polyethersulfone (PES) based membranes that can successfully remove organic and inorganic impurities while retaining the mineral content of inlet water. The UF membranes produce excellent and consistent water quality, regardless of turbidity variations of the influent water quality. Moreover, the water after filtration is free from any biological contamination. An UF system with Cube® membrane module from Martin Systems is currently being tested in the laboratories from University of Applied Sciences Karlsruhe (Hochschule Karlsruhe – HKA).

The UF treated water in the buffer tank is passed through the MCDI unit, which is based on a novel desalination technology. Deionised water with electrical conductivity below 20 µS/cm can be produced. It can be safely used for sterile and pharmaceutical applications in the hospitals. Moreover, the deionised water will be used to generate steam using the PVSteamCube produced by SophiA partner Simply Solar GbR. Ultrapure water can be further obtained from the produced deionised water by passing it through end filters like polishing cartridge or ion exchangers. By applying the MCDI system to the UF treated water, drinking water with optimised mineral content is obtained. The resulted water quality meets the guidelines for drinking water quality stipulated by the World Health Organisation (WHO). The drinking water and deionised water production is tested in a prototype system at HKA laboratories. The lab-tests are conducted using model water based on the water samples collected from all 4 demonstration sites of SophiA containers. The quality and impurities present in the water samples were analysed both in the labs of HKA in Germany and at the Institute for Solar Technology of the Eastern Switzerland University of Applied Sciences (OST-SPF).

The water treatment process in the container operates autonomously. All water tanks in the container are provisioned with level sensors to prevent any overflow. The water treatment container is completely powered by photovoltaics and lithium-ion batteries with an overall monitoring and smart energy management system.