NOVA 4
Process Engineering of source separated urine -the
stabilization and precipitation of source separated urine
NOVA 4 is a part of the integrated research project NOVAQUATIS. Within NOVA 4, the
processing of source separated urine and the possible production of a fertilizer
product is studied. Different procedures to stabilize urine, to reclaim the
nutrients (N, P, and K), and to eliminate micro pollutants are being developed
and studied. A wide variety of elimination technologies for nutrient solutions
already exist. However, the adaptation of these technologies for handling urine
still needs efforts. Methods to recover nutrients from urine and the elimination
of micro pollutants are the main focus of this research project. Possible
technologies are biological processes (e.g. biofilm reactors), chemical
processes (e.g. precipitation in fluidized bed or continuous stirred reactors),
and physical processes (e.g. membrane techniques).
Within the Environmental
Engineering department, the stabilization and precipitation of source separated
urine is studied in the context of a PhD thesis at EAWAG and several smaller
sub-projects in cooperation with other research institutions (University of
Applied Sciences, Basel; University of Waterloo, Canada). The project
investigates several complementary issues:
1. The favourable chemical conditions for precipitation of
phosphate minerals in urine source separating systems could be used for the
recovery of phosphorus.
2. Additionally, recovered phosphorus can be used as
fertilizer or as raw material for the phosphate industry. Basically, there are
two possible phosphorus-containing products that can be formed from urine:
struvite and calcium phosphate. Studies are needed to determine whether both
products can be formed in practice or whether one of them is favourable.
3. Finally, the conditions are studied, which favour the
phosphate minerals in a way that the minerals stay in suspension, rather than
forming hard scales which clog the urine-conducting system prematurely (see NOVA
2). Being able to solve the problematic encrustation is a prerequisite for the
development and successful application of technical solutions for local
phosphorus elimination in urine source separating systems.
The other part of NOVA 4, the study of membrane techniques for the
treatment of urine, is a part of the Urban Water Management Department.
Link to homepage Novaquatis