@article{(Open Science Index):https://publications.waset.org/pdf/9731, title = {Contribution of On-Site and Off-Site Processes to Greenhouse Gas (GHG) Emissions by Wastewater Treatment Plants}, author = {Laleh Yerushalmi and Fariborz Haghighat and Maziar Bani Shahabadi}, country = {}, institution = {}, abstract = {The estimation of overall on-site and off-site greenhouse gas (GHG) emissions by wastewater treatment plants revealed that in anaerobic and hybrid treatment systems greater emissions result from off-site processes compared to on-site processes. However, in aerobic treatment systems, onsite processes make a higher contribution to the overall GHG emissions. The total GHG emissions were estimated to be 1.6, 3.3 and 3.8 kg CO2-e/kg BOD in the aerobic, anaerobic and hybrid treatment systems, respectively. In the aerobic treatment system without the recovery and use of the generated biogas, the off-site GHG emissions were 0.65 kg CO2-e/kg BOD, accounting for 40.2% of the overall GHG emissions. This value changed to 2.3 and 2.6 kg CO2-e/kg BOD, and accounted for 69.9% and 68.1% of the overall GHG emissions in the anaerobic and hybrid treatment systems, respectively. The increased off-site GHG emissions in the anaerobic and hybrid treatment systems are mainly due to material usage and energy demand in these systems. The anaerobic digester can contribute up to 100%, 55% and 60% of the overall energy needs of plants in the aerobic, anaerobic and hybrid treatment systems, respectively. }, journal = {International Journal of Environmental and Ecological Engineering}, volume = {3}, number = {6}, year = {2009}, pages = {144 - 148}, ee = {https://publications.waset.org/pdf/9731}, url = {https://publications.waset.org/vol/30}, bibsource = {https://publications.waset.org/}, issn = {eISSN: 1307-6892}, publisher = {World Academy of Science, Engineering and Technology}, index = {Open Science Index 30, 2009}, }