During the process of sewage treatment, some by-products are generated and among them, the sludge stands out, because of the largest volume and mass generated, and for containing heavy metals in its composition. Sludge is generally disposed of through land filling and spreading on reclaimed land. It has resulted in seriously contamination. It is necessary to improve the method of the disposal of sludge. Balanced with the environmental and economic benefit, the disposal of sludge, the economy and the environment can be optimized so as to realize the sludge stabilization, sludge reduction and sludge reutilization.