Three pipes circular sewer system
How do three pipes instead of one make food waste and wastewater handling smarter – so it’s effortless for Helsingborg residents to keep our environment pristine and preserve water, energy and nutrients from literally going to waste?
The answer is that we separate the three waste streams; food waste, toilet water and grey water from bathing and washing go into three separate pipes at the source, meaning at their point of use in each household. The over 2,000 new homes and offices in our urban renewal neighbourhood Oceanhamnen are first in the world to use the new system at full scale, following its development in Helsingborg, along with sister projects in six cities around Northern Europe.
In Oceanhamnen kitchens, food waste disposals in the sinks collect food waste in one pipe and vacuum toilets collect toilet waste in another pipe. The third pipe collects washing and bathing water and reuses heat in each home as needed, before it follows the other two pipes to a recovery centre nearby. The recovery centre collects nutrients and materials for producing biogas and end-of-waste certified natural fertilizer. It also captures any remaining heat from the grey water stream for heating more homes, before the minimal remaining wastewater from the three streams goes on to our wastewater treatment plant.
This squeezes all possible value out of the food and water we use. It also reduces greenhouse emissions by over 50% compared to the traditional system, cutting energy and water consumption and landfill waste to an absolute minimum.