Chapter 17: Inactivation of Microbial Pathogens by Photosensitized Processes: Environmental Applications

The photodynamic inactivation of microbial pathogens represents a very flexible technology which has a broad scope and potential for tackling a range of problems connected with the microbiological contamination of waters of different origin and physical or chemical characteristics. In this way it is possible to achieve a thorough control of the population of a variety of harmful bacteria, fungi and parasites by using a single protocol, which can be properly modulated, in fish-farming tanks, natural ponds, industrial wastewater, potable water basins. Moreover, the technique can be useful as a tool for the preservation of biodiversity through the protection of endangered species. The process can be considered as based on a natural chemical agent, the porphyrin, and a natural physical agent (sunlight or a solar simulator). Therefore, the impact of the technology on the environment is likely to be very low, especially since the dosages of the porphyrin are generally small and no significant accumulation in the application sites or their surroundings is expected.