Metal phthalocyanines in the presence of visible light are applied in the semi-pilot level for the degradation of organic pollution represented by 4-chlorophenol (4-CP) with potential further scale-up. The effectiveness of the process based on the generation of singlet oxygen active species is compared with commonly used method of photochemical oxidation with hydrogen peroxide in the presence of ultraviolet irradiation. The direct comparison of the reaction systems was conceivable because both oxidation processes were carried out in identical experimental arrangements and under identical reaction conditions. The comparison was performed in terms of 4-CP conversion, TOC removal, apparent quantum yields, kinetic constants, and economy considerations. It must be emphasized there have been no reports on the semi pilot scale utilization of phthalocyanines for decontamination purposes previously. (C) 2014 Elsevier B.V. All rights reserved.