Siemens to expand new wastewater treatment technology

Siemens has developed technology that allows surplus heat to be recycled in order to make drinkable water from wastewater. Engineers from the company have been looking at how waste heat from industrial processes can be harnessed to treat wastewater to such a degree that it can be drunk.

A demonstration plant has been built in Germany by Siemens, which can use waste heat from different industrial processes for the treatment of wastewater. The low temperature is utilised by the plant to make the water safe for consumption by heating it up.

The prototype plant works by running the wastewater via insulated pipes through a number of heat exchangers. These exchangers use the waste industrial heat to raise the temperature of the wastewater. 

Once it has reached a higher temperature, the water is directed to an evaporator. This converts the wastewater into steam to be channelled by a fan upwards into a condenser. The steam is converted back into water, which is incredibly pure and potable. As well as creating fresh water, the plant produces a highly concentrated wastewater, which can then be treated and disposed of.

Siemens' prototype is able to utilise waste heat ranging between 70 and 120 degrees Celsius, which is generally difficult to use for such a purpose. This means that a greater range of waste industrial heat is able to be used for the treatment of the wastewater, making the process more energy efficient.

In order to fully make use of this low-temperature waste heat a specially constructed heat pump is used. Siemens' engineers have created a pump that uses a special fluid process during the heat cycle. This process can increase low-temperature waste heat up to 140 degrees Celsius, increasing the number of applications it can be used for. 

The prototype is soon to be expanded into a pilot facility that is able to process around 25 cubic metres of wastewater every hour. This will enable the new technology to be utilised by a number of different large-scale industrial processes that create wastewater.