Comparativperformance of potassium ferrate(VI) in drinking water and sewage treatment

The use of potassium ferrate(VI) as an alternative water treatment chemical for both drinking water and sewage treatment has been studied and is reported in this paper. The performance of potassium ferrate(VI) was evaluated in comparison with sodium hypochlorite (NaOCl) and NaOCl plus ferric sulphate (FS) and aluminium sulphate (AS). The effects of the dosages of ferrate(VI), NaOCl and FS/AS and sample pH values on the treatment performance were investigated. The study demonstrates that in drinking water treatment, ferrate(VI) can remove 10-20% more UV254 abs. and DOC than FS for the same dose compared in natural pH range (6 and 8). The THIVIFP was reduced to less than 100 mu g l(-1) by ferrate(VI) at a low dose. In addition to this, ferrate(VI) can achieve disinfection targets (> 6 Log inactivation of E. coli.) at a very low dose (6 mg l(-1) as Fe) and over wide working pH in comparison with chlorination (10 mg l(-1) as Cl-2) plus coagulation (FS, 4 mg l(-1) as Fe). In sewage treatment, ferrate(VI) can reduce 30% more COD, and kill 3 Log more bacteria compared to AS and FS at a similar or even smaller dose.