|
Arcata Wastewater Treatment Plant and Wildlife Sanctuary is an innovative sewer management system employed by the city of Arcata, California.〔(City of Arcata - Arcata Marsh & Wildlife Sanctuary )〕 A series of oxidation ponds, treatment wetlands and enhancement marshes are used to filter sewage waste. The marshes also serve as a wildlife refuge, and are on the Pacific Flyway. The Arcata Marsh is a popular destination for birders. The marsh has been awarded the Innovations in Government award from the Ford Foundation/Harvard University Kennedy School of Government. Numerous holding pools in the marsh, called "lakes," are named after donors and citizens who helped start the marsh project, including Humboldt State University professors George Allen and Robert A. Gearheart who were instrumental in the creation of the Arcata Marsh. In 1969 Allen also started an aquaculture project at the marsh to raise salmonids in mixtures of sea water and partially treated wastewater. Despite being effectively a sewer, the series of open-air lakes do not smell, and are a popular destination for birdwatching,〔(Arcata Wastewater Treatment Plant & Arcata Marsh and Wildlife Sanctuary - Birds )〕 cycling and jogging. ==Sewage treatment== The sewage treatment process takes place in stages:〔(【引用サイトリンク】title=The Arcata Wastewater Plant Process Overview )〕 #Primary Treatment (completed in 1949): Sewage is held in sedimentation tanks where the sludge is removed and processed for use as fertilizer. #Secondary Treatment (completed in 1957): Primary effluent is pumped into oxidation ponds (here bacteria break down the waste). #Disinfection (completed in 1966): Secondary effluent is chlorinated to kill pathogens and dechlorinated to avoid damage to natural environments. #Tertiary Treatment (competed in 1986): Disinfected secondary effluent is put into artificial marshes where it is cleansed by reeds, cattails, and bacteria. #Disinfection: Tertiary effluent is chlorinated to kill pathogens from bird droppings and dechlorinated to avoid damage to natural environments.〔Oppelt, E. Timothy ''Manual: Constructed Wetlands Treatment of Municipal Wastewaters'' (2000) United States Environmental Protection Agency pp.18,61&139〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Arcata Wastewater Treatment Plant and Wildlife Sanctuary」の詳細全文を読む スポンサード リンク
|