• several layer of different material
  • water runs through the layers only with gravity
  • layers: sand, activated carbon, gravel, wood chips

The source of the sketch: Ökologisches Bauen | Hrsg. Umweltbundesamt | P. und M. Krusche, D. Althaus und I. Gabriel


[water recycling with sand, active carbon and gravel]

With the concept of P. Franchino no plants are used. The grey water is cleaned over a bucket equipped with a strainer and connected with a second bucket until it’s clear again.

Both buckets are filled up to the overflow with alternating layers of sand – activated carbon – wood chips – gravel and have several holes in the ground, over which the water is pressed into the gravel as a result of its own weight.

This system can be used to replace the revision chamber. The filters can be connected to a heat recovery system and the water can introduced into a sewage plant system.

The prototype demonstrates how the principles of the concept are transformed in an installation I build. The main idea is the access to the knowledge and an interesting frame in combination with the concept.

In the installation the layers for the filter are constructed as a gutter with a gradient on the roof of the installation to generate a small fall without energy. Inside the gutter lays several nylon nets. Each is filled with one filter material in the same way like in the concept.

On the roof a bucket with a tap for the greywater stands at the beginning of the gutter. When the tap is open the grey water runs through the layers in the gutter to the end and flows in the bucket on the ground. There I can take a sample to test the effinciency. If this concept brings good results I’ll build a prototype for an installation in a tiny house.

The aim is to test whether a water recycling system can be built with the components of sand, activated carbon and gravel that cleans adequate the used water.

In the frame I set a lot of plants so that the garden is a part of the gardens around my tiny house.


The installation visualise the principles according to Franchino and to enable an access to knowledge for the visitors. So I constructed an installation with an open, accessible and attractive design with an inclined roof surface.

On the roof the area is accommodated for experiments and the remaining installation surface is formed attractively with plants. By the roof inclination the gravity is usable as a kinetic energy for the water flow through the filters. The filter materials can be laid one after the other and in different combination and size in the rain gutter into which the grey water flows from above down. On the upper roof a vessel is placed which allows to run grey water through a regulable tap. In a lower vessel water can be collected and tested.

This design enable an experimental experience of the effect principles of different filter materials. Several events take place in May in which exciting scenarios are played through. Everything moreover soon.



Measurements start at the “Lange Nacht der Wissenschaften 2018” | HTW | June 2018. Find more information on the page measurements.