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Characteristics of Electrolysis, Ozonation, and their Combination Process on Treatment of Municipal Wastewater
Author(s) -
Kishimoto Naoyuki,
Morita Yukako,
Tsuno Hiroshi,
Yasuda Yuuji
Publication year - 2007
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143007x184023
Subject(s) - electrolysis , aeration , chemical oxygen demand , ozone , chemistry , wastewater , anode , chlorine , nitrogen , biochemical oxygen demand , chloride , inorganic chemistry , oxygen , pulp and paper industry , waste management , environmental chemistry , environmental engineering , environmental science , electrode , organic chemistry , electrolyte , engineering
The characteristics of municipal wastewater treatment by electrolysis, ozonation, and combination processes of electrolysis and aeration using three gaseous species (nitrogen [N 2 ], oxygen [O 2 ], and ozone [O 3 ]) were discussed in this research using ruthenium oxide (RuO 2 )‐coated titanium anodes and stainless‐steel (SUS304) cathodes. Electrolysis and electrolysis with nitrogen aeration were characterized by a rapid decrease in 5‐day biochemical oxygen demand (BOD 5 ) and total nitrogen and a slow decrease in chemical oxygen demand (COD). In contrast, ozonation, electrolysis with oxygen aeration, and electrolysis with ozone aeration were characterized by transformation of persistent organic matter to biodegradable matter and preservation of total nitrogen. The best energy efficiency in removing BOD 5 and total nitrogen was demonstrated by electrolysis, as a result of direct anodic oxidation and indirect oxidation with free chlorine produced from the chloride ion (Cl − ) at the anodes. However, electrolysis with ozone aeration was found to be superior to the other processes, in terms of its energy efficiency in removing COD and its ability to remove COD completely, as a result of hydroxyl radical (˙OH) production via cathodic reduction of ozone.