Electrochemical treatment of urine by using Ti/IrO2/TiO2 electrode

Faced with water shortage problems, recycling human urine for flush water may be one of the ideas to help solve such problems. Diluted urine with water was electrochemically treated, and its reuse was tested for possible recycling. A cell was designed where an anode prepared by thermally coating TiO2 layer over a Ti/IrO2 plate was stacked with a stainless steel 316 cathode. Titanium oxide coating over IrO2 was more efficient for electrochemical oxidation than the conventional IrO2 electrode, generating 28% more free chlorine and 55% more hydroxyl radicals in this study. Electrochemical treatment with a loaded voltage of 4.0 V was applied to the urine solution to which 40 mM NaCl was externally added. A variety of water quality factors of COD, color, turbidity, ammonia, and total nitrogen were measured throughout the experiments, and 72%, 96%, 100%, 85%, and 71% of respective removal rate was obtained after 6 h of treatment. Electrochemically treated recycle water was mixed with urine, simulating its use for the possible toilet flush. The recycle experiments were successful showing the water qualities after electrochemical treatment was good enough for flush purpose in a closed system.