COLIPHAGES
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Outflows from secondary stages of conventional me-chanical-biological wastewater treatment plants (WWTPs) still contain significant concentrations of faecal pollution indicators suggesting the potential presence of pathogenic organisms. The decrease in the concentration of somatic coliphages and bacterial indicators of faecal pollution during the technological stages (coagulation, sand filtra-tion, membrane ultrafiltration, sorption on granular acti-vated carbon, disinfection, accumulation) of a semi-operational plant designed for multi-stage tertiary treat-ment or rather recycling of treated wastewater was moni-tored and discussed. During the tertiary treatment, faecal bacteria indicators were better removed than somatic coliphages, hence the inclusion of somatic indicators among faecal pollution indicators in water quality control for reuse is entirely appropriate. Subsequent tertiary treat-ment, including disinfection, is essential for safe reuse of treated water.
- MeSH
- biologické modely MeSH
- kolifágy genetika izolace a purifikace fyziologie MeSH
- koně krev virologie MeSH
- krev virologie MeSH
- střeva virologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Disinfection aims at maximal inactivation of target organisms and the sustainable suppression of their regrowth. Whereas many disinfection efforts achieve efficient inactivation when the effect is measured directly after treatment, there are questions about the sustainability of this effect. One aspect is that the treated bacteria might recover and regain the ability to grow. In an environmental context, another question is how amenable surviving bacteria are to predation by omnipresent bacteriophages. Provisional data suggested that bacteria when subjected to sublethal heat stress might develop a phage-resistant phenotype. The result made us wonder about the susceptibility to phage-mediated lysis for bacteria exposed to a gradient of chlorine and UV-LED disinfection strengths. Whereas bacteria exposed to low sublethal chlorine doses still underwent phage-mediated lysis, the critical chlorine Ct of 0.5 mg min/L eliminated this susceptibility and induced phage resistance in the cells that survived treatment. In the case of UV, even the smallest tested dose of 2.8 mJ/cm2 abolished phage lysis leading to direct regrowth. Results suggest that bacteria surviving disinfection might have higher environmental survival chances directly after treatment compared to non-treated cells. A reason could possibly lie in their compromised metabolism that is essential for phage replication.
- MeSH
- bakteriolýza účinky léků účinky záření MeSH
- chlor fyziologie MeSH
- dezinfekce MeSH
- Escherichia coli * účinky léků účinky záření virologie MeSH
- fyziologický stres MeSH
- kolifágy izolace a purifikace fyziologie MeSH
- mikrobiální viabilita účinky léků účinky záření MeSH
- počet mikrobiálních kolonií MeSH
- průtoková cytometrie MeSH
- ultrafialové záření * MeSH
- vysoká teplota * MeSH
- Publikační typ
- časopisecké články MeSH
