Drop in Conductivity of Sewage Sludge in the Process of Autothermal Thermophilic Aerobic Digestion

The article presents research on the assessment of electrolytic conductivity changes of sludge during the process of its autothermal thermophilic aerobic digestion (ATAD), which takes place in a two-stage installation system, operating in a municipal sewage-treatment plant. In the years 2012–2014 sludge was studied and the results were analyzed. Thickened sludge in the intermediate tank, which was then directed to installation reactors, was examined. Conductivity was measured in each tank. In this manner collected results made it possible to follow the changes of this index at consecutive stages of the system. The results were statistically analyzed and it was determined to what degree, as a result of an objective process, the values of processed sludge conductivity would change. The conclusions from the carried-out studies and from own experiments are also presented