Determinação de parâmetros cinéticos da inativação térmica de Escherichia coli em lodo de esgoto

Abstract

ResumoO presente trabalho objetivou determinar parâmetros cinéticos da inativação térmica de Escherichia coli em lodo de esgoto. Os ensaios foram realizados em laboratório pelo método do frasco de três bocas nas temperaturas de 45, 50, 55, 60 e 65ºC. Os resultados indicaram que a cinética de inativação térmica deste microrganismo pode ser descrita por um modelo de primeira ordem. A resistência da bactéria é reduzida consideravelmente em temperaturas acima de 55ºC.A energia de inativação encontrada foi 2,48x10 5 J.mol -1 . O tempo de redução decimal D 55°C foi de 3,61 minutos e o coeficiente térmico z foi 8,3ºC.Palavras-chave: lodo de esgoto; Escherichia coli; inativação térmica; parâmetros cinéticos. AbstractThe present study aimed to determine the kinetic parameters of thermal inactivation of Escherichia coli in sewage sludge. The tests were performed in the laboratory using the three-neck flask method at temperatures of 45, 50, 55, 60 and 65ºC. The results indicated that the thermal inactivation kinetic of this microorganism can be described by a first order model. The resistance of bacteria is greatly reduced at temperatures above 55ºC. The inactivation energy was found 2.48x10 5 J.mol -1 . The decimal reduction time D 55°C was 3.61 minutes and the thermal coefficient z was 8.3ºC.

Progress on the Use of Hydroponics to Remediate Hog Farm Wastewater after Vermifiltration Treatment

“…Thus, the present results reinforce the suggestion that DWC hydroponic systems can pose a risk of pathogen proliferation. Coliforms and other bacteria can be removed from wastewaters by a variety of chemical and physical techniques, such as chlorination, ozonation, ultraviolet light [67], percolation and membrane techniques [68], nanoparticles and photocatalysis [69], or simply by storage in holding ponds [70,71]. Wastewater disinfection either before or after use in hydroponic systems is advisable whenever coliforms and other pathogens are cause for concern.…”

Biofertilizers from wastewater treatment as a potential source of mineral nutrients for growth of amaranth plants

“…Different studies demonstrate the efficiency of microalgae in disinfecting the environment by varying the conditions such as pH and oxygen concentration, and by intra-algal competition for nutrients and light [25,84,85]. Moreover, exposure to the sunlight and the drying process at temperatures above 55˚C inactivate bacteria such as Escherichia coli and disinfect the effluent [86][87][88], thus ensuring the safety of products derived from sewage treatment for use in agriculture. The sludge generated from domestic sewage tends to have concentrations below the safety standards established by CONAMA [89,90].…”