Dechlorination of chlorobenzene and substituted chlorobenzene compounds on fly ash under oxygen deficient and mild conditions was performed. Reactions were carried out at different temperature with different mixed organic solvents. Solutions of sulfur with potassium hydroxide, sodium hydroxide and calcium hydroxide were applied for hydro-de3chlorination. Dechlorination of chlorobenzene, dichlorobenzene,trichlorobenzene and hexa-chlorobenzene was higher in water/isopropanol solvent by using a solution of calcium hydroxide/sulfur which was further increased by addition of sodium hydroxide. Whereas dechlorination % of p-nitrochlorobenzene, p-chloroanisole and 1-chloronaphthalene was higher at temperature <100 oC. Metals in general, and Cu, Fe and Pb in particular, enhanced the catalytic potential of fly ash. But at high temperature (120- 170oC), dechlorination process was adversely affected by these metals. Moreover, the fly ash particles provided the surface to accomplish reduction and substitution reactions. Metals accumulation (source of induction as well) controlled by AVS,TOC, particle size of sediment and its moisture contents in Ariake bay was explored.