Comparative study of sodium sulfide method and ferrous method for removing chelated copper from printed circuit board wastewater

Comprehensive wastewater, which is effluent from the printed circuit board (PCB) manufacturing process, contains chelated-copper compounds. For chelated-copper removal, two well-developed methods exist: the sodium sulfide method and the ferrous method. However, the research currently discusses these methods individually, and no economic and technical comparisons between the two have been done. In this paper, we developed a comparative study of the sodium sulfide and ferrous methods from operating optimization and economic-technical perspectives, especially for the output of sludge. The results showed that the cost of the sodium sulfide method (2.25 yuan·t^-1) was lower than it was for the ferrous method (2.68 yuan·t^-1). Nevertheless, the capital expenditure and control risk of the sodium sulfide method were higher than they were for the ferrous method.