**2.4 Pyrolysis**

Pyrolysis is an age-old technique and also a Green technology in comparison to existing Sewage technologies as it is carried out in absence of oxygen resulting in toxic-free by-products. Pyrolysis thermally breaks down the sewage sludge into biogas, bio-oil, and biochar anaerobically [10]. If seen from a thermodynamic perspective, Pyrolysis is an endothermic process (100 kJ kg−1) which is carried out at temperatures fluctuating between 350–1000°C [11]. For carrying out pyrolysis effectively, Sewage management industries would require complex and expensive equipment. Thus the large-scale applications of this process are limited.
