The design of treatment plants is standardised to a great extent and is carried out according to commonly accepted rules by all engineers. Important input data are mainly the number of person equivalents to be treated and the requirements for the quality of the outflow. In Germany for instance, engineers estimate that the daily per capita discharge 150 litres of wastewater comprising 60 g of BOD5. But in reality these figures differ from site to site. Accurate measurements can show a range for water consumption of 60 -250 litre per capita per day. So a properly conducted audit of water flow is absolutely necessary in order to optimise the design of a treatment facility. Otherwise the wise old saying rings true once again: Cheap design means expensive operation costs.

With some additional investments into water appliances, (e.g. water meters, water saving toilets, volume reducing taps, water consumption will further decrease. For example, the installation of water meters in an apartment block in Hamburg reduced the water consumption by 15 %. Learning from the least-cost planning approach in the electricity sector, utilities preferred to invest in new efficient refrigerators for their clients rather than erecting an additional power plant. We would like to implement these principles for our project's pilot plants, whereby an integrated overview of water use and treatment within a facility will lead to cost-effective solutions. Our intention is to achieve a win-win result where all partners will benefit. Consuming less water means lower costs for water supply and water treatment, less throughflow and therefore longer working lives for additional installed water saving appliances. Also, the environment will win through lower use of water resources and less polluted wastewater runoffs.

> Treating wastewater like a resource
> Implementing new sanitation appliances for public use