Hydroponic using waste water

[maximus]

I was recently in Egypt (Sharm el Sheikh, Sinai) where I am trying to develop an aquaponic system.
However I have noticed that most hotels have gardens with nice but uneatible plants.
They are irrigatad with treated waste water, and in fact the plants are quite lush, but the irrigation water stinks horribly.

I thought of converting the waste for profit and veggies producion, because the cost of basil, or other veggies are quite high (in egyptian term or 2$kg), therefore I proposed to use part of the garden as a production units, and the idea was accepted in principle.
The potential problem is water contamination (heavy metals, chemicals and pathogens), but if the water (that is already partially treated with sludge removal) will be filtered with a slow sand filter with top layer of granular active carbon, to remove the first two and some suspended solid and then treated by UV irradiation, I guess it should be ok. I would possibly add an air stripping to remove volatile chemical compound (the bad smell) for futher irrigation and O2 increase.

Anyhow my idea was to set few flood and drain system where some tree as papaya might be growth allowing an aerobic environment and then recirculate in DWC for crops. Finally the remaining water could be used for irrigation of plant in the hotel as currently but few bushes could be replaced with basil, oregano, etc.

I will go to the local University in few days, so if anyone spot a mistake in my idea, please let me know so I can make some change

By the way would you think possible of placing a fish tank somewhere within this system?

Cheers

Maximus

[Ravnis]

You might look up duckweed as part of your filtration system. There are ongoing studies I came across that shows it will filter heavy metals and chemicals and is being considered for large scale wastewater treatment. I do not know the outcome. Our local water system uses an artificial reed wetland that the water flows through prior to going to final treatment. The UV or ozone treatments might prove very useful. The main concern would be to pass on bacterial contamination onto your consumers of your produce. That is the biggest risk of this idea.

I would expect to do some extensive testing to ensure contaminants were truly removed before releasing produce. I am not sure how the Egyptians would react to a bad case of food poisoning.

[maximus]

Thanks, I knew about reed beds but biological filtration by duck weed was unknown to me.
Because the waste water is already partially treated in a basic waste plant and because the data I have on the effluent are not too bad I reckon the added filtration using active carbon, sand filtration duck weed (thanks!) and UV will create multiple barriers that will incresase safety. the flood and drain system will be planted with trees as papaya and after passing in the areated gravel bed the aerobic condition and resident bacteria should kill any bacteria into the water that will then be used in DWC for herbs, lettuce.
My main concern are chemicals, because if any workers would dump thinner in a drain I am not sure of the ability of the system to remove it from the water.

Any Idea is welcomed.

Maximus

[svc]

There is someone near me using chicken poo to feed beds of comfrey then using comfrey tea for his hydroponic nutrient. Something like this maybe useful to put another barrier between the poo and the food.
John

[ande]

http://pdf.usaid.gov/pdf_docs/PNADP168.pdf

[GaryD]

Hi Maximus,

Duckweed has a role to play in bio-remediation but water hyacinth is an even more effective plant filter. It will not only remove substantial nitrogen and phosphates but heavy metals, too.

It has a long history of use in removing contaminants from wastewater. NASA has even trialled its use in its space colony experiments.

I would possibly add an air stripping to remove volatile chemical compound (the bad smell) for futher irrigation and O2 increase.

If you get enough air into the wastewater early enough, you'll avoid the odour problem. As you are probably aware, the bad odours are biogas elements (largely hydrogen sulphide) which is the consequence of leaving the water exposed to anaerobic conditions.

Gary

[maximus]

Thanks for the interesting and useful link and suggestions on heavy metal water hacynt uptake.

cheers