AWWA WQTC62550

The objectives of this study are to establish a technical and economical comparison of conventionalexisting and innovative treatments for Arsenic removal in drinking water. The work shows the interest ofa new technology based on the use of ferrate for enhanced Arsenic removal.Ferrate(VI) ion (molecular formula FeO₄^2-) is a very strong oxidant, which under acidic conditions, has aredox potential greater than that of ozone and of other main oxidants/disinfectants typically used for watertreatment. Also, since the ferric ion generated in all oxidation reactions forms hydroxide oligomers,coagulation occurs eventually. Hence, ferrate(VI) represents a dual-function (oxidant and coagulant)chemical reagent that can be an effective alternative to current approaches for drinking water andwastewater treatment.Within a research and demonstration project partially funded by the European Community 5th FrameworkProgram, a consortium of nine European partners, is currently developing optimized methods for ferrateproduction on a large scale and studying several applications of ferrate in industrial, urban waste ordrinking water treatment. Consequently, improvement of existing treatment processes and evaluation ofnew technologies such as Ferrate are needed to comply with the new regulation. Within this project,laboratory scale tests concerning the use of potassium ferrate for municipal water treatment have beencarried out.Arsenic removal optimization was conducted on bench scale (Jar test, oxidation and filtration tests)performed on natural groundwater polluted by arsenic and manganese. The following treatments werecompared and optimized:use of coagulant FeCl₃ and KMnO₄;use of new chemical (ferrate); and,use of combination of FeCl₃ and ferrate.A classification of the different treatment processes according to their efficiency to remove arsenic,manganese and iron has been obtained. The optimal operating conditions and chemical dosage have beendetermined, for each treatment process.Because of the new regulation on arsenic, drinking water suppliers need to assess specific processes toremove this pollutant. Several efficient treatments are available. Ferrate(VI) having a dual-function(oxidant and coagulant) can be an effective chemical and promising alternative to conventionalapproaches for arsenic and manganese removal in drinking water production. Includes references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

15

File Size:

1 file , 700 KB