WP4: Decentralized Wastewater Management


  • Evaluate the potential of energy recovery from wastewater at the household level
  • Quantify energy savings from different water-related technologies at the household level, alone and in combination with other energy-relevant measures.
  • Investigate typical challenges for on-site water technologies in a concrete and highly innovative project on the use of greywater for cooling purposes
  • Test existing and emerging technologies in the NEST Water Hub

Innovation Potential

There are great advantages of recovering heat energy in wastewater at the household or neighborhood level where temperatures are high and the energy is required on-site as compared to recovering the energy at the sewer level. However, small-scale energy recovery has typically not been considered competitive from an economic point of view, due to high maintenance requirements. Emerging maintenance-free and energy-efficient greywater treatment as well as new energy-recovery technologies, which users can easily clean themselves, are promising innovations with a high chances of commercial success. Due to increasing warm summers, the use of wastewater for cooling purposes has an immense potential in a national as well as in an international context.


The research activities within this work package are structured into four modules:

  1. Integrating energy and water modelling
  2. Developing household cooling systems based on treated greywater or treated wastewater
  3. Membrane bioreactor for treating household mixed wastewater to produce water for heat management at the building scale
  4. Testing different existing and new technologies for heat recovery in the Water Hub in NEST

Research Partners


  • Department Process Engineering
  • Department Urban Water Management

Empa, Urban Energy Systems

Hochschule Rapperswil, Institute for Energy Technology

Fachhochschule Nordwestschweiz, Institute for Ecopreneurship