Anoushiravan Mohseni Bandpey; Reza Nemati; Narges Hakimi; Parviz Norouz
Volume 24, Issue 5 , September and October 2018, , Pages 333-338
Abstract
Background: Recent research has shown that an Advanced Oxidation Process known as Persulfate/UV, has a high capability in removing of persistent organic pollutants. Given that the advantages of this process are limited production of harmful byproducts and strong ability for degradation of persistent ...
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Background: Recent research has shown that an Advanced Oxidation Process known as Persulfate/UV, has a high capability in removing of persistent organic pollutants. Given that the advantages of this process are limited production of harmful byproducts and strong ability for degradation of persistent organic thus it seems this process be also suitable for disinfection of municipal wastewater treatment plant effluents.
Materials & Methods: After collection, the effluent samples were transferred to the lab. Then the disinfection experiments were carried out in a 1 L sterile reactor with 0.5 L of sample and various doses were injected. The direct method was used to measure the microbial populations (thermo-tolerant coliforms).
Results: The result of this research indicated that Persulfate and UV irradiation cannot be able to meet the needs of thermo tolerant coliforms inactivation, but simultaneous using of them (Persulfate/UV) could inactivated approximately 5 logs thermo-tolerant coliforms (Persulfate dose <30 mM). While Persulfate (without UV irradiation) even with 300 mM could inactivated less than 3 logs thermo-tolerant coliforms.
Conclusion: The results of this research show UV irradiation has a strong synergistic effect on persulfate disinfection efficiency. Due to the restriction of the use of sulfur compounds in wastewater treatment, it seems that the use of UV irradiation with less amounts of persulfate can largely improve this restriction and significantly reduce the economic and environmental impact of traditional disinfectants.
Hasan Alidadi; Raziyeh Novrozian Ostad; Habobollah Esmaeli
Volume 23, Issue 1 , May and June 2016, , Pages 40-47
Abstract
Background & Objectives: Common methods for water disinfection are using chlorine which can efficiently control microbial agents. Researches in recent decades have shown a relationship between the disinfection of water and disinfection by-products. Nanotechnology in the last decades has provided ...
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Background & Objectives: Common methods for water disinfection are using chlorine which can efficiently control microbial agents. Researches in recent decades have shown a relationship between the disinfection of water and disinfection by-products. Nanotechnology in the last decades has provided opportunities for discovering the bactericide property of metal nanoparticles. Among all anti-microbial nanoparticles, silver is the most applicable one. Therefore, the aim of this study was to evaluate the effect of nanosilver on inactivating of the heterotrophic bacteria in contaminated waters. Materials & Methods: This bench-scale experimental study was carried out in a batch system on artificially contaminated water samples prepared by adding 10 ml effluent to 90 liters of distilled water. In each run, the nanosilver (30-180 μgL-1) was added to 6 containers of contaminated water and then a sample was taken every 20 minutes for a 100-minute period. Numbers of heterotrophic plate count (HPC) were determined for all samples according to the standard methods book instructions (21st edition). Results: Results revealed that the heterotrophic bacteria inactivation significantly increased with increasing the contact time of nonosilver (P=0.001), but there was no significant correlation between the nanosilver concentrations and heterotrophic bacteria inactivation (P=0.13). The maximum heterotrophic bacteria inactivation (83.6%) was achieved within 100 minutes of contact time for 180 μgL-1 of nanosilver. Conclusion: Nanosilver treatment is effective in heterotrophic bacteria inactivation in contaminated water and can be advised as a new method for water disinfection.