We search for the best conditions for the growth of algae in a pond with (diluted) human urine.
The purpose of our search is to remove urine from slum areas and to treat it with the help of algae. Algae in the form of green material, what can be used for husbandry or for improving soil, can be harvested. This process should potentially be self-sustaining in urban slums where entrepeneurs get income from providing sanitation.
We consider a batch process as better to control and easier to realize than a continuous process. For good algal growth, we assume that the pure urine should be diluted with water in a certain ratio. When the urine in a pond is succesful treated the algae are harvested and new urine is lead into the pond.

Our Experiment
We are setting up a small pond for experimentation in which the aeration of the fluid as well as the temperature can be controlled. The pond that we are setting up treats 27 liters of urine and depending on the dilution ratio(maximum 1 urine on 10 water) the content of the pond has a maximum of 270 liter. With a content of 270 liter and a depth of 10 cm the diameter of the pond is 1,954 meter (We calculated 300 liter to have some space)

Information we lack:

  1. For effective algae growth, should urine be diluted with water and in what ratio?
  2. To promote the growth of algae, should air be pumped into the fluid?
  3. Concidering the many thousand existing kinds of algea, what kind- or mix of algea suits best our experiment 1? (Is the algae "Phormidium bohneri" a good option?)
  4. How much light is needed for growing algae in our situation (how to quantify?).
  5. How about the stability of urine?
    1. Does contact of the urine with feces influence the algal pond proces? (related to the chemical processes taking place in urine when contacted with faecal bacteria)
    2. Does contact of the urine with air influence the algal pond proces? (related to the chemical processes taking place in urine when contacted with air)
  6. Should processing of urine in a new batch start with adding a part of the algae grown in a prior batch?
  7. Is it possible to leave the clean water, when the process is finished and the algae are recovered, in the pond and lead new urine directly into the pond?
  8. Is it correct that for each kilogram of urine, an equal weight of algae can be produced?
  9. Can our kind of algea easily be overgrown with a toxic or less productive kind? If so, how to prevent this?
  10. Is our batch system vulnerable for poisonous/toxic matter, either from an an-organic or organic cause?
  11. What would be the best low-cost algae harvest way for us to use?
  12. What time will the complete batch-proces take (Temperature 25-30 degrees, a lot of light, aeration and plenty of nutrients)?
  13. Collection of urine can possibly be done in containers that are properly locked, thus minimizing contact with oxygen from air. Also contamination with facials can be minimal, but not 100% excluded. Should this be promoted?
  14. How can the harvested algae be prepared as (a component of) animal food
  15. How can the harvested algae be prepared as fertilizer or for soil improvement?

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