Compensatory measures to reduce GHGs in wastewater treatment plants in Southern Italy

This study evaluates Greenhouse Gas (GHGs) emissions in 183 Wastewater Treatment Plants (WWTPs) located in the Apulia region in Southern Italy. All WWTPs examined treat municipal wastewater. GHGs from each treatment unit were estimated in the current situation and compared, for the same WWTPs, to those emitted after assuming structural compensatory measures to mitigate them. Total GHGs emissions in current estimation have been estimated equal to 83 kg CO2eq/PE⋅y and equal to 62 kg CO2eq/PE⋅y after upgrade. Some compensatory mea- sures have been also discussed to lower GHGs emitted: the recirculation of sludge thickened in treatment sec- ondary; reduction of biogas systems leakage, aerobic digester and thickener coverage and new system to recovery biogas from anaerobic digester generating energy. All upgrade systems considered result in electrical energy reduction and in significant GHGs emission reduction especially for anaerobic digestion based WWTPs.