The city generates 8,500 tonnes / day of solid waste. Disposal is mainly by sanitary landfill which generate 500 tonnes of methane/day or equivalent to 11,000 tonnes of carbon dioxide/day. Bangkok discharges approximately 2.4 million cubic metres/day of wastewater and only half is treated properly. Its estimated BOD pollution is at 500,000kg/day which will cause another 1,000 tonnes/day of carbon dioxide. Moreover the largest source of CO2 is from electricity generation which is estimated at 40,000 tonnes/day. see Table 1.