Monitoring of pathogenic microorganisms contamination during heat drying process of sewage sludge

Abstract

The sewage sludge from wastewater treatment plant is a potential source of infectious organism. The number and type of pathogens in sludge depends on various factors namely, the wastewater source, the type of treatment plant, and other environmental factors such as the biological medium offered by the sewage sludge. The principal sludgeborne diseases are presented followed by discussion on biological aspect of growth and occurrence. The overall objective of this work is to estimate kinetic reduction of pathogen population in sludge during different thermaldrying process including: the agitated conductive drying, drum drying, solar drying, and fry-drying. The temperature curves were reported from literature except frying data which were determined in experiment. In order to apply the temperature influence on pathogens population, kinetic parameters for the thermal inactivation (D, z-values) were chosen from literature. Values of concentrations of each pathogen were also extracted from scientific review of pathogens in bio-solids. This study conducted to resolve the survival kinetic of Hepatitis A viruses. The result showed that a concentration of 7 × 10 4 cfu/100 ml initially present in the sewage sludge is significantly reduced during the heat drying processes except the solar plant. The sewage sludge is completely disinfected when heated for 20 min, 10 min, and 10 s, respectively, during the agitated conductive process, vacuum fry-drying, and drum drying process.

Assessment of microbiological and biochemical properties of dairy sewage sludge

“…3). The presence of the above-mentioned fungi, also was found in municipal sewage sludge or in the air samples of wastewater treatment plant area and surroundings (Gotkowska-Płachta et al 2013;Romdhana et al 2009). Analyses of fungal diversity in wastes of this type were also conducted by Awad and Kraume (2011), Kacprzak and Stańczyk-Mazanek (2003).…”

Prevalence of Cryptosporidium oocysts and Giardia cysts in raw and treated sewage sludges

“…[13][14] Therefore, sludge can contain many of these parasites. [15][16][17][18] Sewage sludge is the solid, organic material which remains after wastewater is treated and discharged from a wastewater treatment plant. Sludge is treated to stabilize the organic matter and reduce the amount of human pathogens.…”

Use of an Experimental Design to Characterize the Convective Drying Behavior of Different Sludges

“…Moreover, the dried sludges are stabilized, have less odor, and are pathogen-free if the temperature and the residence time are high. [7] For incineration, drying plays a major role in increasing the net calorific value and transforming wet slurry (which can be used like coolant) into attractive fuel.…”