Reducing water purification material, method for producing reducing water purification material, method for treating wastewater, and wastewater treatment apparatus

A method for treating wastewater to remove contaminants from wastewater by adding a reducing iron compound to wastewater containing contaminants to precipitate the contaminants, followed by separating the precipitate by a solid-liquid separation to remove the contaminants from the wastewater, the method comprising the steps of:

• adding a reducing iron compound to wastewater;
• leading the wastewater to which the reducing iron compound is added to a reaction tank, and forming a precipitate;
• separating the formed precipitate by a solid-liquid separation to obtain a sludge;
• and
• alkalinizing all or a portion of the separated sludge to form an alkaline sludge, followed by returning to the reaction tank,
• wherein in the precipitation step, the wastewater to which the reducing iron compound is added and the alkaline sludge are mixed and are allowed to react in a non-oxidizing atmosphere under alkaline condition to form a reducing iron compound precipitate as the precipitate, thereby incorporating contaminants in the precipitate to remove the contaminants from the wastewater.