RECYCLING SYSTEM FOR RECYCLING NITRATE NITROGEN AND/OR NITRITE NITROGEN IN CONTAMINATED SOIL

PROBLEM TO BE SOLVED: To provide a low-cost and easily maintainable recycling system for recycling nitrate nitrogen and/or nitrite nitrogen. SOLUTION: The recycling system is constituted of a plurality of electrolyte tanks buried in contaminated soil existing in an underground water zone containing nitrate and/or nitrite nitrogen in a form of nitrate (nitrite) ions which electrolyte tanks are formed of a water-permeable wall through which the underground water can penetrate allowing nitrate (nitrite) ions contained in the underground water to move therethrough, a plurality of electrodes each submerged in the plurality of electrolyte tanks alternately forming an anode or a cathode one after another, a direct current power source that causes a direct current to flow through the plurality of electrodes to form an electric field in the contaminated soil and applies a voltage to the electrodes sufficient to attract nitrate (nitrite) ions to the anodes, an electrolyte circulation device that recovers the electrolyte when the concentration of nitrate (nitrite) ions in the electrolyte present in the electrolyte tanks wherein the anodes are submerged reaches a predetermined level and simultaneously replenishes the electrolyte afresh to the electrolyte tanks in an amount equal to the amount of the recovered electrolyte, and a fertilizer application device that can make use of the electrolyte of the predetermined nitrate (nitrite) ion concentration recovered by the electrolyte circulation device as the fertilizer. COPYRIGHT: (C)2009,JPO&INPIT