Drying municipal sewage sludge with v-groove triple-pass and quadruple-pass solar air heaters along with testing of a solar absorber drying chamber.

Everyday a large amount of sewage sludge is produced in cities and proper and environmentally friendly municipal wastewater treatment is needed. Finding a convenient and affordable way for sewage sludge refinement to reduce environmental pollution or even utilization of sewage sludge will be a very attractive challenge for scientists. In the recent years, sustainable and renewable energy sources like solar energy are extensively utilized in different fields including heating, electricity generation, and drying applications. In this study, V-groove triple-pass (V-TPSAH) and V-groove quadruple-pass (V-QPSAH) solar air heaters have been designed, manufactured and tested for drying municipal sewage sludge. Also, two different types of drying chambers (DC-I: conventional, DC-II: solar absorber) have been integrated with each solar heater. Experimental and numerical methods have been applied to analyze the efficiency of developed solar air heater assisted drying systems. The system's performance has been tested in different working conditions to clarify the utilization potential of manufactured system. According to the experimental results solar air heater's average efficiency are in the range of 70.12-81.70%. In addition, obtained experimental findings are in line with numerical results. The outcomes of this study present the potential of using the developed systems in drying municipal sewage sludge to be used in multi purposes.