| 摘要 |
PROBLEM TO BE SOLVED: To prevent the clogging of a filter cloth by removing iron or an iron compound contained in sludge by utilizing magnetism before or during concentrating the sludge. SOLUTION: A flocculant such as polyaluminum chloride or aluminum sulfate is added into raw water 1 in a mixing basin 2, agitated and mixed therein. Then the mixed matter is flocculated in a flocculation basin 4 and precipitated in a precipitation basin 5 to separate the water content. Supernatant liquid is treated in a rapid filter basin 6 and a sterilizing tank 7 and taken out as drinking water 8. Sludge precipitated in the precipitation tank 5 is transferred to an iron-removing tank 13 and agitated therein, and also an oxidizing means like sodium hypochlorite, air gaseous chlorine or others is supplied, and bivalent iron ions are turned into an iron oxide such as Fe2 O3 . Then the iron oxide is adsorbed and removed by a magnetic instrument 14. The sludge from which the iron oxide is removed is settling separated by a sludge concentration tank 9, stored in a sludge storage tank 10, dehydrated by a dehydrator 11 and taken out as dehydrated cakes 12. The clogging of the filter cloth can be prevented by the arrangement. |
