ENHANCED ELECTRO-OXIDATION FOR TKN REMOVAL FROM HIGHLY POLLUTED INDUSTRIAL WASTEWATER

摘要

Many industrial effluents contain concentrated Total Kjeldahl Nitrogen (TKN), which may might be also accompanied with ammonia, sulfur, iron, total solids, etc. Conventional wastewater treatment plants are unable to remove TKN, to a level acceptable for the ecosystem, thus, such wastewater has to be treated at the source; however, adequate methods have not been demonstrated yet. The industrial wastewater of concern, which contained 14 g TKN/L and 11 g NH4/L had a low probability to be biologically treated, therefore, an enhanced electro-oxidation method was proposed in this study. The industrial effluent was subjected to a series of tests, where finally the electro-Fenton oxidation demonstrated the best results; however, the method was designed to be effective without an addition of external iron; iron pollutant contained in wastewater was used instead. DC electrical field permitted to keep iron at an adequate state for the Fenton reactions. The results from batch reactors of 2.2L showed an excellent removal of TKN and ammonia - 98.7% and 99.5%, respectively. In order to decrease the detention time to 24h, an Electro-Fenton Sequential Batch Reactor (EF-SBR) was invented and designed. Considering a low degradability of TKN in the form of amides, the developed Enhanced Electro-Fenton Oxidation method based on wastewater components, is an effective approach in preventing the discharge of organic nitrogen to the sewage system and therefore protecting the environment. Moreover, the proposed design is sustainable since limits supplying additional chemicals and optimizes energy use. The technology is ready for a full-scale application.