Short-Term Biology Effects on Grapefruit by Fertilizing Biosolids from Municipal Sewage Treatment Plant of Xiamen

Municipal sewage biosolids(MSB) contain bacteria, heavy metals(HM) ,other organic and inorganic compounds which lead to ecological, soil, water, and human health risks potentially. MSB can provide a source of nutrients for plant growth and as soil conditioners it can enhance the physical and microbiological properties of soil. In 2006, there were 235 m3 MSB (76% water) each day in Xiamen City, China. To dispose so many biosolids safely, lots of experiments were carried out to determine biology effects on grapefruit fertilized by biosolids from municipal sewage treatment plant of Xiamen for 1 year: the growth of the grapefruit trees and the transfer and accumulation of HM in soil, leaves and fruits of grapefruit trees. Results showed that it was feasible for land application to dispose MSB. But nutriments of total nitrogen (TN) and total phosphorus (TP) must be appended, and concentrations of Ni, Cr and Cd must be controlled before MSB application. Concentration of Ni was a control factor. Zn in MSB could be used as a resource for land mending. MSB compost can not be used for edible leafage plants.