Feasibility of Electrolysis in Nutrient Recovery
Gorbatova, Alexandra (2018)
Gorbatova, Alexandra
Tampereen ammattikorkeakoulu
2018
All rights reserved
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-201802232727
https://urn.fi/URN:NBN:fi:amk-201802232727
Tiivistelmä
The need for developing nutrient management systems, in particular, nutrient recycling and reuse, arises from rapid increase in population, which in turn causes nutrient imbalance. Nitrogen and phosphorus, leaching to the environment through fertilization and sewage release, can cause adverse environmental effects, such as eutrophication of water bodies, causing biodiversity loss in the ecosystem. Instead, water treatment technology can be developed for effective nutrient removal and recovery.
Previously, it was tested that phosphorus can be efficiently precipitated in a form of struvite. Tests were carried out on the possibility of nitrogen capturing from the reject water from struvite precipitation process, which did not lead to effective nitrogen capturing. At best, 18% of the total nitrogen was captured in the testing. If capturing nitrogen is not efficient, concentrating nitrogen in the solution with a possibility of volume reduction could be explored, which is the aim of this thesis.
Electrochemistry has earlier been applied for treatment and nutrient recovery from urine. Feasibility of electrolysis in nitrogen recovery from struvite precipitation reject water is yet to be researched. The main findings after conducting the electrolysis and analyzing the electrolyte in comparison to the initial solution include the potential for volume reduction and nitrogen capturing. Volume reduction rate of the system was 60ml/hour, which is 20% of the total volume. Nitrogen levels decreased with the duration of electrolysis, but not significantly. Possible losses can be caused by nitrogen escaping in a gaseous form, such as chloramine and nitrogen gas.
Application of electrolysis in nutrient recovery could be feasible with a few structural modifications to the experimental set-up and testing. Additional nitrogen and foam analyses should be carried out to obtain more reliable results and numerous duplicates of fresh electrolyte samples would provide a better understanding of the chemical process behind the electrolysis of struvite precipitation reject water.
Previously, it was tested that phosphorus can be efficiently precipitated in a form of struvite. Tests were carried out on the possibility of nitrogen capturing from the reject water from struvite precipitation process, which did not lead to effective nitrogen capturing. At best, 18% of the total nitrogen was captured in the testing. If capturing nitrogen is not efficient, concentrating nitrogen in the solution with a possibility of volume reduction could be explored, which is the aim of this thesis.
Electrochemistry has earlier been applied for treatment and nutrient recovery from urine. Feasibility of electrolysis in nitrogen recovery from struvite precipitation reject water is yet to be researched. The main findings after conducting the electrolysis and analyzing the electrolyte in comparison to the initial solution include the potential for volume reduction and nitrogen capturing. Volume reduction rate of the system was 60ml/hour, which is 20% of the total volume. Nitrogen levels decreased with the duration of electrolysis, but not significantly. Possible losses can be caused by nitrogen escaping in a gaseous form, such as chloramine and nitrogen gas.
Application of electrolysis in nutrient recovery could be feasible with a few structural modifications to the experimental set-up and testing. Additional nitrogen and foam analyses should be carried out to obtain more reliable results and numerous duplicates of fresh electrolyte samples would provide a better understanding of the chemical process behind the electrolysis of struvite precipitation reject water.