The catalytic hydrotreatment at low temperature of water contaminated by chlorobenzene and o-chlorobiphenyl has been studied experimentally using a Pd/C catalyst. Reaction runs have been carried out in a stirred reactor at constant temperature (T = 30 degreesC) and pressure (P congruent to 1 bar). Liquid phase concentration of chlororganic reactant and hydrogenated products, chloride ions concentration and pH have been measured during reaction time. Experimental results have been modelled assuming gas-liquid and liquid-solid equilibrium and the kinetic constants of the HDCl surface reactions have been evaluated.