Efficacy of a solar still in destroying virus and indicator bacteria in water for human consumption

Abstract

Natural water distillation can destroy and/or inactivate microorganisms that are sensitive to heat and ultraviolet radiation (UV). This method is currently used to provide fresh water in ships and in the desalination of brackish water. For the development of this research, a pilotscale solar still was built and installed in the southern region of Brazil, in order to assess its efficiency in water disinfection, which was based on the most probable number (MPN) of total coliforms and Escherichia coli, in addition to the DNA copy number of human adenovirus type 5 (HAdV-5) in raw, undistilled samples and in treated distilled water. Results showed that the distillation process removed 100% of total coliform and Escherichia coli and 4.5 log (99.997%) of HAdV-5, which meets the microbiological standards for drinking water according to national Brazilian regulations, as well as USEPA and HEALTH CANADA requirements.

Aplicação da destilação solar na potabilização de águas contaminadas

“…Portanto, este estudo confirma que existem certas temperaturas (aquelas na faixa microbiana ideal de crescimento) que pode prejudicar a desinfecção solar. Nascimento et al (2018) construíram um destilador solar em escala piloto para verificar a eficiência do equipamento (Figura 8) na desinfecção de água. A destilação natural da água pode destruir e/ou inativar microrganismos que são sensíveis ao calor e a radiação UV-A.…”

Sources, fates and treatment strategies of typical viruses in urban sewage collection/treatment systems: A review

“…Recent work on the reliability of solar stills for wastewater treatment found that 90% of the virus can be removed by heating the WWTP effluent to 70 °C and denaturing proteins at high temperatures [17] , and the pilot-scale solar could remove 4.5 log (99.997%) of HAdV-5 in the distillation process [222] . Furthermore, the emergence of nanotechnology improved the distillation mechanism greatly, and might help alleviate water issues by solving the technical challenges that removing viruses [223] , creating potential avenues for addressing the virus concerns via the combination traditional desalination and emerging materials.…”

O paradoxo da Escherichia coli como bioindicador

“…O processo respiratório é aeróbio ou anaeróbio facultativo, fermentando lactose e produzindo gás a uma temperatura de 35ºC, entre 24 e 48 horas. Estes coliformes fazem parte da microbiota natural do trato gastrointestinal de alguns animais endotérmicos, incluindo o homem (Funasa, 2013;Mueller & Tainter, 2022).…”

“…No entanto, a presença e a quantidade de colônias são indicativos da qualidade higiênico-sanitária de um produto (Silva & Melo, 2021). Por fazer parte da flora natural do intestino (bactéria comensal), os coliformes não são patogênicos; porém, quando encontrada fora do trato intestinal, algumas linhagens ou a proliferação destes microrganismos podem ser a causa de doenças intestinais e extraintestinais em humanos, como as infecções do trato urinário e a pneumonia (Lopes Neto et al, 2021;Mueller & Tainter, 2022).…”