Keywords: column study, heavy metals, roof runoff, zero-valent iron barrier, copper, zinc, metal contamination
Development of an on-site Fe0 system for treatment of copper- and zinc-contaminated roof runoff
The objective of the present work was to develop an on-site Fe
0system for treatment of metal-contaminated roof runoff. Breakthrough experiments were performed under laboratory flow-through conditions using runoffs that have varying water quality parameters. Phase analyses and the chemical-equilibrium model were employed for describing the removal mechanisms. The study demonstrated that the breakthroughs of copper and zinc were either accelerated or hindered under different water characteristics. In most cases, the Fe
0treatment columns can hardly cope with efficient removal of contaminants and maintenance of adequate hydraulic conductivity. To enhance performance of the system, various carbonatic materials were tested and combined into the iron system. Following the assessment, the most promising configuration consisted of a column containing spiral shaped Fe
0, followed by an aeration basin and a fixed bed of pumice/dolomite filter was installed on-site for treatment of copper and zinc roof runoff.