Sewage sludge is a byproduct of wastewater treatment plants. It is a kind of waste. however, it contains several valuable nutrients like phosphorous and nitrogen that are used to rich the soil as a fertilizer compound. On the other hand, it contains some harmful and toxic compounds such as pathogens, pharmaceuticals, Polychlorinated biphenyl (PCBs), Polycyclic aromatic hydrocarbons (PAHs), endocrine-disruption, hormones, and heavy metals which are contaminants and pollutants in the environment. Pyrolysis is a way to treat these contaminants and reduces the quantity of heavy metals and removes pathogens.

This project derives to pyrolysis the sewage sludge at three different temperatures 500°C,700°C, and 900°C, and evaluates the result according to the remained quantities of heavy metals and phosphorous. Each experiment was repeated three times. Then, the samples weighted and analyzed by bomb calorimeter, microwave digestion, and MP-AES.

Bomb calorimetry was used for measuring the heating value to compare the remaining heating value in the samples to the raw sewage sludge. The microwave digestion system was used for chemical processing of the samples in order to break down the samples to liquid form and then the concentration of elements such as Cd, Co, Cr, Cu, Ni, Mn, Zn, Pb, and P were measured by MP-AES. The results were gathered and compared with the Regulation by European, Union, (DirectiveE86/278/EEC), and Regulation by Swedish law, (Regulation1998:994). The raw sewage sludge was delivered from Borås wastewater treatment unit after digestion in an anaerobic fermentation process. It contained about 74% water which was dried in an oven at 105°C. The results show that Cd and Co were removed from the sewage sludge and the most amount of phosphorus remained in the resulting char. The results show that the quantity of phosphorus was almost the same between 500°C-700°C. The data shows that the amount of Pb was reduced by increasing the temperature of the pyrolysis reaction. The heating value in the char was extremely close to each other in the different range of reaction temperatures between 500°C to 900°C.