The Study Of Treating Wastewater Containing Heavy Metal Ions By The DDTC And Composite Flocculants

In this paper ,we introduce the development history and trend of the flocculation method which to treatment heavy metal waste water . The usual methods to deal with heavy metal wastewater are precipitation of hydroxide, precipitation of sulfide, oxidation-reduction, iron-exchange process and ferrimagnetisms etc, which can be used alone or together according to the water quality or quantity.This paper introduces the usual composition of flocculants and the structure, character, chelation-flocculation mechanism of flocculants and its practical application in water treatment, representing the reason to choose DDTC and PAC & PAM and their synergistic effect in water treatment, declaring factors of impacting heavy metal iron removal efficiency and settlement time. The method chelation flocculation by DDTC and PAC & PAM can not only get a high removal efficiency but also can short settlement time .The experiments of this paper are mainly in describing the performance of DDTC and PAC &PAM in treating water containing Ni²⁺ 01 Pb²⁺or Zn²⁺. The experiments include: factors of impacting Ni²⁺ or Pb²⁺or Zn²⁺ removal efficiency and settlement time are quantity of DDTC dosage , concentration of Ni²⁺ or Pb²⁺or Zn²⁺,dosage of PAC &PAM, the ratio PAC to PAM, treatment temperature, pH etc. On the base of experiments above, having gotten the best process of removal wastewater containing Ni²⁺or Pb²⁺ or Zn²⁺ with DDTC and PAC &PAM, and discussing the mechanism of action preliminarily. In treated water, the concentration of Ni²⁺or Pb²⁺ or Zn²⁺ is below the effluent level described by GB9878-1996 . The treatment method is simple, feasible, and convenience with high use value.