I’m trying to make a grey water filter with readily available materials at home or elsewhere. It is a scaled version of one I found in some documents. I know that because of the dimensions of the box the water won’t be filtered perfectly, but when I test it with clean water, the water is far dirtier than clean. I wanted to know if the type of materials I’m using is what is affecting me and if so then what kind of materials are suitable for constructing it.

We bought some of the materials in a construction store (gravel of different sizes and sand) and collected the stones from the field. As the materials were very dirty, we clean them with clean water until the water no longer came out dirty. We also bought soil for plants in a local store (I don’t know if this is the type of soil that you should use). We start testing with clean water but the water came dirtier than before, so we remove the soil and it improved. But with soapy water the filter did not filter enough (I don't know if it is because the lack of soil layer). We also thought to make another filter to pass the water through a double filter to improve water quality but I don´t know if that will work.

Hi Fer,

Please tell us more about your project's goals.

Your box seems really small, so it would only treat tiny amounts of water. Also, since this is a slow sand filter, you need a lot more sand. The stones and gravel in the bottom are just for keeping the sand from coming out with the filtered water, so you should minimize them and maximize the sand.

If you add a marsh grass, or some other aquatic plant, it will help to oxygenate the water and promote a community of beneficial bacteria, plus help keep the sand permeable.

Why do you want the box to be portable?
Why not just build artificial wetlands in the ground?
What greywater do you want to process and how clean do you want it to get?
Why put soil, since nutrients come in the greywater?

Best wishes,
Chris Canaday

Hi Fer,

thanks for that interesting question! Generally, if you are adding soil you are likely to end up having a "dirty" outflow until the entire soil has been washed out.

Hence, you should go for something more coarse (like the gravel and sand) or even better: for some volcanic stones (where available) since they provide good aeration and space for microbia that facilitate the treatment process (due to the bubbles, the surface is huge). Sometime you can get them at horticulturalists or a construction store.

This is a quite good publication regarding constructed wetlands www.susana.org/lang-en/library?view=ccbk...mp;type=2&id=930 and I recommend you read thoroughly section 5.2. (vertical flow beds) since you can easily construct those ones using a barrel and some pipes. So, you could also consider this a prefab filter.

Hope that helps!
Best,
Enno

Thank you for your comments. I will tell you more about what my project’s goals are.

My first intention doing it so small was because I was trying to explain to a group of colleagues how the process was and how it was supposed to worked, at the end it didn’t work like I wished but I could give them some general idea. It was like trying to explain it with a scale model. Since I start I knew that it won’t filter correctly the water but what I didn’t knew was about the soil. Few years ago, while I was at university, I participate in a project on an indigenous community where we built some grey water filters with this characteristics but bigger and also with some aquatic plants. They really worked with soil but I can’t remember exactly how they were built and I can’t get in touch with the architect that helped us with the project. (It is in Spanish but it has some pictures that can help to understand www.acuaviva.org/filtro.html)

The other reason why I want it to be portable and not build artificial wetlands is because I was thinking, for example, to go camping. If you go camping for 1 or 2 days it won’t be so much trouble but if you go for more than 2 days and with a group of 5 persons, they will all need to take a shower, clean dishes and sometimes even clothes, and where all this water will go? Having a portable filter you could take it with you and try to adapt it to your needs, for example cleaning the dishes, you could put another empty plastic container on the top of the filter and wash the dishes there and all the grey water will go first throw the filter and then to de ground but without soap.

How clean I want the water to get? It might depend, you will always want it to be the most clean it could possibly be, but as it is a filter for temporal use I would be happy if the water came out without soap.

Other thing I was trying to test with this filter model is to design a bathroom sink with a filter included connected to other filters in the house so you reduce the size of an artificial wetland in the ground for the houses or building that don’t have enough place to build it.

Thank you again for your comments and information, I will try to do it again with more sand and some aquatic plants and I will try to get a bigger container.

Best wishes,
Fernanda Rizzardini

Hi Fermanda,

Would you be interested to collaborated with me regarding my water cleaning & recycling system. I have an presentation here on this forum. The concept will copy the natures way of cleaning water.

For any comments/questions or for exploring strategic partnerships, please contact me directly.

With very best regards from Sweden.
Börje Brandt
Regulus teknikutveckling
Storgatan 6J
SE-93431 Kåge
Sweden
Phone: +46 910 53485 or +46 70 3607580
Mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Skype: boerje.brandt