Opportunities regarding the use of technologies of energy recovery from sewage sludge

Based on the global need to efficiently eliminate highly produced amounts of sewage sludge, alternative technologies are required to be practically developed. Reduction of sewage sludge waste quantities with energy recovery is the most important and modern practice, with least possible impact on the environment. Appropriate technologies for treating and disposal sewage sludge are currently considered: incineration, gasification and pyrolysis. The main products generated during the pyrolysis process are bio-gas, bio-oil and bio-residue, providing sustainable fuels/ biofuels and adsorbents. Compared to other disposal methods of sewage sludge, pyrolysis has advantages in terms of the environment: waste in small quantities, low emissions, low level of heavy metals. From a technological point of view, pyrolysis is the most efficient in relation to its final products, pyrolysis oil, pyrolysis gas and solid residue that can be transformed into CO2 adsorbent with the help of chemical and thermal activation processes. The incineration process of sewage sludge has a number of disadvantages both environmentally and technologically: organic pollutants, heavy metals, toxic pollutants and ash resulting from combustion that needs a disposal process. A comparison of different types of sewage sludge elimination for the energy recovery is described in the present paper.

Automated summary

Efficiently eliminating large amounts of sewage sludge requires the development of practical alternative technologies, with a focus on reducing waste quantities and energy recovery. Current technologies for treating and disposing of sewage sludge include incineration, gasification, and pyrolysis, with pyrolysis offering environmental advantages and sustainable fuel production.