Photo-disinfection processes for bacterial inactivation and underlying principles for water constituents’ impact: A review

Photodynamic Inactivation of Opportunistic Premise Plumbing Pathogens and Their Biofilms

“…Further disadvantages are the high costs of lamps/sources of UV radiation and their installation, and the long-term effect on biofilms in water distribution systems is still not known [55]. There have been many attempts, some also known as SODIS (=solar disinfection), to use sunlight as a renewable energy source to disinfect water, but the appropriate reactors for such applications are currently also expensive [56].…”

“…It is also worth mentioning that recently reviewed light promoted advanced oxidation processes (AOPs) that take place by the combination of solar, artificial UV, or visible light, with a strong oxidant, ozone, or hydrogen peroxide, and in which mostly hydroxyl radical (OH) is being generated [56]. The effects of water matrix/constituents were evaluated, and it was shown that DOM, turbidity, and ions have a negative effect because of light attenuation and scattering as well as an inner filter effect, while turbidity, salinity, chloride, and (bi)carbonate ions have a negative effect due to the quenching of reactive radicals [56]. These negative effects can be achieved even with the permissible limit concentrations of water constituents; therefore, it is important to check their impact.…”

“…These negative effects can be achieved even with the permissible limit concentrations of water constituents; therefore, it is important to check their impact. On the other hand, a pH of 6.5-8.5 has a positive effect [56], and DOM can also have a positive effect because it can not only produce singlet oxygen through photosensitization, but it can also create a microenvironment for a longer lifetime of 1 O 2 and ROS generated by other light-activated PSs and AOPs [77].…”

“…As mentioned earlier for light-promoted AOPs and other photo-disinfection processes, it is also important to study the influence of water constituents on PDI for its successful application in water disinfection [56]. A favorable assumption for the use of PDI against OPPPs in DWDS is that PDI is usually more effective in clear water than those with high concentrations of DOM, while in the presence of other disinfectants, or even chemical contaminants, PDI could be even more efficient with a higher overall antimicrobial effect due to a synergistic effect [77].…”

Photodynamic inactivation of multidrug-resistant strains of Klebsiella pneumoniae and Pseudomonas aeruginosa in municipal wastewater by tetracationic porphyrin and violet-blue light: The impact of wastewater constituents

“…In a recent review (2023) on the impact of water constituents on the photoinactivation of bacteria, it was pointed out that of the nearly 11,000 publications describing inactivation of bacteria by different photo-disinfection processes in water, only the 4.4% of them described water matrix and reported the effect of water constituents [32]. While turbidity is known to have a negative effect due to light attenuation, other water constituents, such as dissolved…”