(1) Waste incineration to generate electricity uses waste and does not require landfill, saving land resources;
(2) Glass and broken ceramic tiles are not flammable, and old newspapers, PVC plastic and discarded cotton clothes are flammable;
(3) According to the chemical formula of dioxin, C12H4Cl4O2, the mass ratio of carbon, hydrogen, chlorine, and oxygen elements is: 12×12: 1×4：35.5×4：16×2=144：4：142：32=72：2：71：16． Therefore, the mass fraction of hydrogen element is the lowest. Calcium hydroxide can react with sulfur dioxide and hydrogen chloride gas.
So the answer is: (1) Utilizing the energy in garbage or saving land resources; (2) BCE; (3) Hydrogen; Ca(OH)2+2HCl﹦CaCl2+2H2O or Ca(OH )2+SO2﹦CaSO3+H2O.