{'fraction_non_alphanumeric': 0.025310834813499113, 'fraction_numerical': 0.021314387211367674, 'mean_word_length': 5.105691056910569, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Application of UV irradiation for polycyclic aromatic hydrocarbon removal from treated wastewater in water reclamation system

Water is one of the most important chemical compounds for humans and other living organisms. These days the problem of its insufficiency, growing pollution and poor management is crucial all over the world. New regulations proposed by the European Commission (EC) encourage water reuse (e.g., in agriculture) which results in attempts to reclaim it from treated wastewater from municipal wastewater treatment plants. Water obtained this way should correspond with microbiological and chemical requirements. Conventional wastewater treatment processes fail to remove some emerging pollutants such as polycyclic aromatic hydrocarbons (PAH). It is important to choose the right method that will allow to achieve the desired effect. Studies show that the efficiency of PAH removal from wastewater using UV irradiation may vary depending on PAH concentration in wastewater samples prior to the process. The removal of PAH is higher in the wastewater samples with an additional amount of those compounds (up to 84%) than from the samples with no added PAH standard mixture (up to 65%). It was also confirmed that the removal efficiency differs according to the number of rings of the PAH compound. The aim of this research was the assessment of PAH removal effectiveness from treated wastewater with the application of UV irradiation using low-pressure lamps with different exposure time as a part of further research considering the removal of emerging pollutants from treated municipal wastewater in order to obtain reclaimed water. The obtained results were compared with the norms standardized by the Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption. PAH removal varied from 11% to 62% after 0.5 h of UV irradiation, 19%–100% after 1 h of UV irradiation, 41%–100% after 2 h of UV irradiation and 72%–100% after 12 h of UV irradiation. PAH standardized in the Council Directive 98/83/ EC of 3 November 1998 on the quality of water intended for human consumption, that is, benzo(a) pyrene, benzo(b)fluoranthene and benzo(k)fluoranthene were removed after 1 h of UV irradiation.