Phytoremediation On Heavy Metal Contaminants In Sewage River Sediment

With the widely use of heavy metal and its compounds in flourishing development of industries of metallurgy, chemical engineering, electroplating and printing and dyeing, the remediation and treatment to heavy metal contamination has become a world-wide environmental problem because of the ever increasing heavy metal contaminants into urban river and even its potential danger to human beings. In order to remediate heavy metal in urban sewage river sediment, planting experiment and adding hydrogen peroxide treating research were conducted to study phytoremediation of lead, cadmium, copper, zinc, manganese and nickel in sediment by Lolium multiflorum and maize.Results showed after planting Lolium multiflorum the total concentration of heavy metal and different forms of heavy metal could be changed. In addition, the effect of rhizosphere, microorganism and urease activity in sediment could also help to uptake and translocation to heavy metal from sediment to plants. More important was the amounts and kinds of heavy metal or different forms heavy metal after adding hydrogen peroxide treating were largely changed. Heavy metals in sediment were activated efficiently and the ability of accumulation and translocation to heavy metals increased from sediment to plants.Through the research of uptake and accumulation of heavy metal in different parts of plant, results showed the root, stem and leaf had different phytoremediation mechanism to heavy metal. Even though extending planting time could make the amount of heavy metal in plant increased, efficiency of remediation decreased dramatically. The kinds and amounts of organics in sediment changed greatly. More rhizosphere exudates and microorganisms also helped to increase accumulation of heavy metal in plants. The activity of polyphenol oxidize had been increased after planting and adding hydrogen peroxide treating. The research firstly advised the activity of polyphenol oxidize could be considered as an important proof to judge the phytoremediation effect in sewage river sediment.Based on the mechanics of phytoremediation on heavy metal contaminants in sewage river sediment, the four dynamical processes of accumulation were described as a class of nonlinear dynamical systems. Then, the stability analysis of the nonlinear dynamical process of uptake and accumulation was achieved based on Lyapunov stability theory, and the result was formulated as the feasibility of linear matrix inequality (LMI) which could be solved numerically with available software. Numerical simulation and experimental data show the reasonableness of the dynamical model and the effectiveness of the proposed methods which will provide technical support for phytoremediation on heavy metal contaminants in sewage river sediment.