Evaluation of Greenhouse Gas Emission from Septic Tank under Tropical Climate: A Case Study in Hanoi, Vietnam

摘要

Globally, 2.8 billion people rely on onsite sanitation, and this number is expected to grow to 5 billion by 2030 (Strande et al., 2014). In 2006, IPCC proposed CH_4 emission factor (EF) of septic systems. By using the EF, global CH_4 emission from septic systems was estimated as 73.5 MtCO_2-eq/yr， accounted for 19% of total greenhouse gas (GHG) emission of the wastewater sector. However, this EF was not based on septic systems but anaerobic processes in domestic wastewater treatment plants. There are only 2 studies monitored GHG emission from septic systems in USA. EFs of CH4 calculated from these previous studies were 2.4 times smaller than the IPCC's EF. Geographically, majority of septic tanks (STs) is used in developing countries where under tropical climate. Further, typical septic systems in developing countries receive only blackwater while septic systems in developed countries receive both black and greywater. This study monitored and evaluated GHG emission from blackwater STs in a tropical climate region, as a case study of Hanoi, Vietnam.