Electrolysis

Decentralised urine treatment requires treatment facilities that are small, robust, easy to handle and therefore should be fully automated. Electrolytic urine treatment combines most of these aspects.

Electrolysis

Electrolysis uses electric current to converse or remove pollutants from a solution. The basic principle is to apply a current between two metal plates or bars (electrodes), which leads to the oxidation and reduction of certain pollutants. The use of current as the only process input allows easy process control and a high degree of automation. As no bacteria or chemicals have to be used, electrolysis is robust and easy to handle.

First experiments

First experiments show that it is possible to remove ammonia from stored urine by oxidising it on graphite electrodes. Compared to biological systems (e.g. trickling filters), electrolysis can achieve about 50 times higher removal rates. Further research will focus on the production of more nitrate as an alternative to biological nitrification and the construction of a reliable and well controllable reactor for nitrogen and organics removal.

Further readings

• Electrochemical ammonia removal: former collaborative project Eawag - EPFL
• Kapalka et al. (2010) [pdf] Electrochemical behavior of ammonia at Ni/Ni(OH)₂ electrode. Electochemistry Communications 12 (2010) 18-21.
  
• Anglada, A., Urtiaga, A., Ortiz, I. (2009) Contributions of electrochemical oxidation to wastewater treatment: Fundamentals and review of applications. Journal of Chemical Technology and Biotechnology, Vol 84(12), 1747-1755.
• Bunce, N.J., Bejan, D. (2011) Mechanisms of electrochemical oxidation of ammonia. Electrochemical Acta, Vol 56(24), 8085-8093.