RESUMO
In spite of numerous studies on Fe[VI] capacity in treating wastewater, no equations are presented yet for the design of a Fe[VI] treatment facility. In most studies, Fe[VI] has been mentioned as the most effective substance for wastewater treatment; however, none is currently available about the operation costs in treatment facilities. This paper aims to introduce the necessary equations for the design and development of facilities that use Fe[VI] through the electrolysis methods and conduct the necessary calculations regarding its navigation costs. As the first step, a pilot plant test was conducted to find the basic information for municipal wastewater treatment by Fe[VI]. Then, all the costs pertaining to electricity, acid and sodium hydroxide used in the treatment process were calculated to evaluate the total navigation costs. Our results indicates that treatment of every cubic meter of municipal wastewater would bear the following costs: US $1.17 for Fe[VI] production, US$ 2.52 for reducing the pH below 2 and US$ 146 for the production of 14 M sodium hydroxide solution. The overall costs for such facility would be equal to US$ 149.7. As it is demonstrated, the generation of 14 M sodium hydroxide solution is the most expensive element in the treatment process. It appears that the aforementioned cost is very high for the municipal treatment facilities; however, it might be appropriate for wastewaters that are resistant to biological methods. Nevertheless, more research is still needed to address this issue