Solar powered, no chemicals and no running costs!

Safe water, everywhere, anytime. This vison is our motivation. We eliminate waterborne diseases and …make the world a better place!

Water disinfection system to provide safe water

Automatic, solar-driven water disinfection system for up to 20.000 liters of pure, disinfected, safe, and healthy water daily.  It is working fully solar-driven, but can also be used on grid or with a backup battery. It is designed for easy maintenance and almost zero running cost, without any having any chemicals to be added. We're using high technology to make life safe, while keeping it simple and providing safe water. We make the water quality visible, as the water quality can be monitored by our App.

GWT is based in Munich. Our solar water disinfection system - we call it INTEWA (intelligent water system) - is automatically delivering safe, disinfected water. We use state of the art technology

  • to create safe and healthy water
  • to make the system easy to operate and maintain
  • to have almost zero operation cost
  • to safe your childrens health

Please learn more about our product & projects on this website.

Automatic water disinfection system of intewa

The water is pumped up from a well, a river or connected to a water-tower. It is then automatically filtered and cleaned by filters and a solar driven process. The quality of the water is constantly monitored online, so safe drinking water is guaranteed!

  1. Pump (up to 70 m)
  2. Microfiltration or Ultrafiltration
  3.  Automatic disinfection (chlorine is produced out of the minerals in the water itself)
  4. Waterstorage
  5. Quality sensor
  6. Automatic Regulation of chlorine production.
  7. Data monitoring and data transfer to PC, Laptop and mobile phone (App)
  8. Solar power or on-grid production
  9. Battery (on demand)
  10. Safety lights

Automatic disinfection

The disinfection cell automatically reacts.

In case of drop down of the water quality the disinfection cell is automatically reacting.

The water quality sensor (5) is automatically regulating the disinfection cell (3) via the internal control unit (6). In case of drop down of the water quality the disinfection cell is automatically reacting.

In case of good water quality the disinfection cell is automatically  producing the disinfectant only at minimum.


  1. Water quality monitoring
    All the system data are shown on the built in touchscreen. In addition the water quality is shown by a light signal (10), that can be installed on top of a water tower or building.
  2. Remote monitoring

    All the system data are also send by the integrated GSM module (7) into the cloud. You can see the data on your Laptop or PC and on your Smartphone (App).

  3. Remote control for several systems
    Many systems can be monitored and controlled by the remote monitoring (7). In case of a malfunction the maintenance people can always be sent immediately and directly to the system, that is sending a problem message. Automatic alarms sent to the smartphones of the maintaining people are also possible.

Water Volume

Up to 24 000 liter clean, fresh water per day

Water production volume

The water production volume is depending on the raw water quality and the raw water accessability.

Is the raw water fresh or comming from a public water pipe,

the volume is up to 24.000 ltr per day.

Is the raw water very dirty and the pump has to pump it over long distance, the volume will be less.


Flexible energy sources

The system can be powered in five ways:

  1. Solar (8)
  2. Solar (8) and battery (9)
  3. Solar (8), battery (9) and grid backup (11)
  4. On grid (11)
  5. On a pick up with a car battery or cigarette lighter (12)


For maintenance we need a lemon and a toothbrush

For maintenance we need a lemon and and a (tooth)-brush, nothing more. The lemon is for cleaning the disinfection cell, about every 4 weeks. The brush is for cleaning the filters.

We provide a metal filter and a polycarbonate filter. The polycarbonate filter can be easily replaced or even washed.

Of course the system should be kept clean, especially the solar cells.

By default we provide washable stainless steel and ceramic filters. In some cases - depending on the raw water quality - we provide special filters, for example to filter out Arsenic, high content of Iron, Fluoride and others.

Requirements & limitations

The system does not make seawater potable

To make sea water potable, we need an enormous amount of energy. The INTEWA system is not suited for that.

The system needs an additional mineralizer to treat rain water (see products)

Rain water does not contain enough minerals. INTEWA needs a minimum of 40mg Cl-/l. It can be added by a mechanical dosing pump (additional part).