Study on purification of black-odors river water by floating-bed-grown Lythrum salicaria with root regulation

The potential of Lythrum salicaria with root regulation to improve black-odors water quality in Wenzhou city was evaluated using a constructed ecological floating bed system. The roots of plants were regulated by three varieties of regulating materials which had same dimension but different pore sizes. The results showed that root regulation by materials with pores on the surface could enhance the growth of plants and create a favorable rhizosphere providing a large root surface-area for biofilm development. The material of smallest pore size had the best regulating effect. The floating beds planted with Lythrum salicaria at a static state all had a promising removal potential. Compared with plants without root regulation, the regulated plants achieved higher biomass yield, removal efficiencies and uptake of N and P. The results indicated that root regulation could promote the growth of plants and elevated the nutrient removal.