TREATMENT OF WASTE WATER FROM THERMAL ELECTRIC POWER PLANT

• Main Authors: WATANABE TSUKASA, TSURUMARU AKIYOSHI, MUTO KENICHI, TSUBOYA HISAO, OGOSE TSUTOMU
• Format: Patent
• Language: English
• Published: 11.11.1997
• Edition: 6
• Subjects: CHEMISTRY; METALLURGY; TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE

PROBLEM TO BE SOLVED: To effectively remove the harmful matter, especially selenium, contained in the waste water from a thermal electric power plant by bringing the waste water with the pH specified into contact with iron, conducting flocculation and solid-liq. separation and then biologically denitrifying the waste water. SOLUTION: The waste water from a thermal electric power plant contg. such oxidative matter as iodic acid and selenic acid is introduced into a pH regulating tank 1, controlled to <=pH5 with hydrochloric acid and then sent to a fine iron grain-packed column 3 by a pump 2 to elute the iron as ferrous ion and to reduce the oxidative matter and selenium compd. in the water. Sodium hydroxide is injected into the water flowing out from the column 3 in a reaction tank 4 to flocculate the iron ion as iron hydroxide, the water contg. the iron floc is sent to a settling tank 5, and solid is separated from liq. The supernatant water in the settling tank 5 is aerobically nitrated in a nitration tank 6, anaerobically denitrified in a denitrification tank 7 and further subjected to solid-liq. separation in a settling tank 8 to obtain treated water.