Abstract: According to one embodiment, an apparatus for measuring hydroxyl radicals that measures hydroxyl radicals produced by irradiating a liquid to be treated flowing through a channel in which an ultraviolet lamp is arranged with ultraviolet rays, the apparatus includes a diverting unit, a reagent adding unit, and a measuring unit. The diverting unit has a diverting channel that diverts the liquid to be treated before being irradiated with the ultraviolet rays from the channel and part of which is arranged at a position enabling the liquid to be treated within the channel to be irradiated with the ultraviolet rays. The reagent adding unit adds a hydroxyl radical measuring reagent to the diverted liquid to be treated. The measuring unit irradiates the diverted liquid to be treated with the ultraviolet rays and measures the amount of hydroxyl radicals produced based on a change in the hydroxyl radical measuring reagent between before and after the irradiation with the ultraviolet rays.

Abstract: An activated carbon adder adds activated carbon to raw water before flocculating sedimentation, to adsorb suspended matter contained in raw water, a liquid cyclone is adapted to separate activated carbon with suspended matter adsorbed thereon, from raw water containing activated carbon, an inflow line is connected with the liquid cyclone so as to cause raw water containing activated carbon before flocculating sedimentation to flow into the liquid cyclone and swirl therein, an activated carbon discharge line discharges activated carbon spun down out of raw water containing activated carbon in the liquid cyclone, from the liquid cyclone, and a pretreated water discharge line discharges raw water having got rid of activated carbon as pretreated water from the liquid cyclone, allowing for a reduced amount of chemicals to be used, with production of a reduced amount of sludge.

Abstract: A former (11) works, when supplied with wastewater containing heavy metals and hydrogen sulfide, to react heavy metals contained in wastewater with hydrogen sulfide to form sulfide salts, an acquirer (12) works, when supplied with sulfide salts and acid, to acquire hydrogen sulfide and heavy metal ions produced by reactions between sulfide salts and acid, a hydrogen sulfide supply line (13) supplies hydrogen sulfide acquired by the acquirer to the former, and a collection line (20) collects heavy metal ions.

Abstract: An activated carbon adder adds activated carbon to raw water before flocculating sedimentation, to adsorb suspended matter contained in raw water, a liquid cyclone is adapted to separate activated carbon with suspended matter adsorbed thereon, from raw water containing activated carbon, an inflow line is connected with the liquid cyclone so as to cause raw water containing activated carbon before flocculating sedimentation to flow into the liquid cyclone and swirl therein, an activated carbon discharge line discharges activated carbon spun down out of raw water containing activated carbon in the liquid cyclone, from the liquid cyclone, and a pretreated water discharge line discharges raw water having got rid of activated carbon as pretreated water from the liquid cyclone, allowing for a reduced amount of chemicals to be used, with production of a reduced amount of sludge.

Abstract: A former (11) works, when supplied with wastewater containing heavy metals and hydrogen sulfide, to react heavy metals contained in wastewater with hydrogen sulfide to form sulfide salts, an acquirer (12) works, when supplied with sulfide salts and acid, to acquire hydrogen sulfide and heavy metal ions produced by reactions between sulfide salts and acid, a hydrogen sulfide supply line (13) supplies hydrogen sulfide acquired by the acquirer to the former, and a collection line (20) collects heavy metal ions.