BABYLON WALL . WATER PROTOTYPE
/PROJECT BY MAEB 2018-19
/DEVELOPED AT MAEB-IAAC VALLDAURA LABS
/COURSE METABOLIC SYSTEMS: WATER
/FACULTY JOCHEN SCHEERER
/LINK BLOGPOST
Water is a basic need.
Nevertheless, it is expensive and not easy-to-be treated.
By studying the cycle of water in the cities, and focusing on the wastewater treatment,
we have developed a protoype which is both useful and didactic.
3 BASIC STEPS FOR NBS WASTEWATER TREATMENT
Wastewater treatment is composed by three main stages:
1ary TREATMENT/ mainly separating the solids from the water
2ary TREATMENT/ the organic matter is removed from the grey water
3ary TREATMENT/ nutrients such as nitrogen and phosphorus are removed
BABYLON SYSTEM PROTOTYPE
In the prototype we go through the first and secondary treatment, so that we get a water good enough for the purpose we intend: irrigation.
The tertiary treatment would also be feasable, it would require a higher cost though.
The prototype is installed in the north façade of the basement floor of Valldaura Labs, where most of the piping system is located.
We attach the units to the existing brick wall, and then to the grey water (shower and lavatories) system.
Since the first tank is located indoors, we add a float system controlling the input of water to avoid flooding.
BABYLON SYSTEM TREATMENT
THE PROTOTYPE
The Babylon system we developed connects to the existing grey water system.
First, the grey water fills a container where the first treatment is installed.
Then, a pump brings the water to the top of the first two (out of six) wall-panels.
There, the secondary treatment takes place.
The water, while passing through the panels (basic unit= 3 panels), is filtered by the bacteria in the soil and the soil in itself.
The filtering process takes aproximately four hours.
The treated water then drips into the gutter which brings the water through another filter that takes out the soil, leafs, etc and directs it to the water tank.
The water in the tank is ready to use for irrigation.
The whole system can treat 60 liters of grey water with 3 square meters "soil wall" per day.
SOIL MIXTURE
We tried mixing different types of soil from the site (and nearby) in order to achieve a mixture good enough to act as a filter.
The "pros" of it is that it makes sense to use the (literally)local resources (free and nearby), the "cons" are that the testing would take longer since we wouldn't know the composition of the soil we would be mixing, but it would also be a more didactic/interesting process.
The process consisted on mixing different types in different proportions, the goal was that 80-90% of the water would pass through the soil mixture.
The first test was with organic soil only, but too much water remained in the soil, which means that the filtering process (the water being cleaned while passing through the soil) would take too long.
In the second test, we added some sand to the organic soil. In that case, we noticed the water was driping too slowly, as if the soil was blocking its way through. We then assumed that the sand might contained clay (too small particles)
The third test consisted on mixing the organic soil with sand and stone. The result was the same though.
We then realized the organic soil might contained compost, making the soil too sticky after being filtered several times.
Afterwards, we tried with a different organic soil which looked more "fibrous".
The result is exactly what we wanted to achieve, but the soil is purchased from somewhere else, which is not ideal.
That's why we decided to dig in order to get soil from the ground, and mixed it with pine leafs (acting as fibers).
The mixture of 50% friable soil and 50% fibers is also ideal for our purpose.
In order to keep going on experimenting, one of the wall units will be done with that mixter, and in the other one we will use 50% friable soil and 50% rocks.