Fate and Effects of Fry-Drying Application on Municipal Dewatered Sludge

Abstract

The present experimental investigation examined the applicability of fry-drying technology for municipal dewatered sludge by using waste engine oil for frying. The process was studied in a 100–180°C temperature range for 2 to 20 min frying times. The cakes were shaped in a diameter range of 1 to 3 cm with 3-cm-length prior to the frying. Experimental points were determined by the Box–Wilson experimental method. Statistical analysis was employed for determining the response function coefficients for variables. The response functions were as dry solids content (DS), volatile solids content (VS), and low heating value (LHV). Experimental and predicted results indicated good agreement with high correlation coefficients. The results showed that fry-drying is an alternative, fast process for sludge drying. In addition, it makes fry-dried sludge as a product with noteworthy LHV. This study provides further insight into the fry-drying of municipal dewatered sludges.

Keywords:

• Dewatered sludge
• Fry-dry technology
• Sludge cake
• Sludge drying
• Waste oil

ACKNOWLEDGMENTS

The authors acknowledge the Department of Mining Engineering at Dokuz Eylul University, which provided extensive use of the bomb calorimeter in the Chemistry Laboratory. The authors thank the personnel of the Izmir Cigli Municipal Wastewater Treatment Facility for their valuable help during the sampling of the sludges.