Sewage treatment with iron: mainly used in electroplating, leather, paper, dyeing and finishing, chemical, ceramics and other industries wastewater treatment, content of 75% -90% 30 to 200 mesh adjustable.When it is immersed in water, the potential of an anode of iron, carbon potential becomes a cathode, electrolyte water, then form a complete circuit, become ten million tiny battery and a micro flow cell, corrosion reaction become iron-carbon filter device.