Inners in a minute

INNERS gives you energy!

Improving the energy balance of the urban water cycle. That is the purpose of INNERS, which stands for INNovative Energy Recovery Strategies in the urban water cycle. Eleven organisations think in a new way about the urban water cycle. Not only as a system that transports water, but also as a potential source of energy. Valuable energy which is lost in the current situation.

The urban water cycle: a source of energy

The urban water cycle is designed to transport water. Recent studies show that the water cycle includes a lot of energy, for example as heat. In the current situation this energy is not used and is lost. Moreover, it takes a lot of energy to transport and purify wastewater from houses and industry.


INNERS aims to contribute to an energy-neutral or even an energy producing urban water cycle.

Our activities

Four main activities in INNERS are:

  1. Data collection and modeling studies to understand the working of the urban water cycle in terms of energy.
  2. Demonstration projects.
  3. To inspire technical specialists and policy makers by showing the short and long term benefits of a sustainable urban water cycle.
  4. To remove barriers for the implementation of innovative techniques.


INNERS is a collaboration of partners from the Netherlands, United Kingdom, France, Germany, Belgium and Luxembourg. The Water board Groot Salland is the lead partner. See the map for the participating organizations.


Two examples of INNERS projects are highlighted here.

Sustainable swimming pool by using heat from wastewater

In this project the Water board Groot Salland and the municipality of Raalte want to use thermal energy from wastewater effluent to heat the nearby swimming pool Tijenraan. The questions to be answered in this project are:

  • What is the most efficient way to use the thermal energy from effluent to heat a public building?
  • How can we overcome the organizational, financial and legal barriers we encounter?

Development and testing of an Energy Online Service (EOS) tool

In INNERS, four partners will develop a multicriteria expert system for the real-time energy optimization of wastewater treatment plants. The system is called the Energy Online Service Tool (EOS). It will result in a continuous provision of energy consumption data of a wastewater treatment plant (WWTP).

To test whether the tool can improve the energy balance of a WWTP, investigations will be carried out on two
wastewater treatment plants.


… Students

Do you want to find out what innovative water management looks like in preactice? Please check our website for the latest news and possible internships.

… Technical specialists

Interested in the work of the INNERS partners? Please go to

… Policy makers

Do you want to get insight in the benefits of a sustainable urban water cycle? Check