Taiwan has a population of 23.12 million people and over 5.7 million households. 22.96% of domestic water is drained off to public underground sewerage systems; 13.86% is drained off to community underground sewerage systems; 11.43% to built-in sewage treatment in the buildings, and other wastewater is drained off to septic tanks. Generally, 48.25% of domestic wastewater is treated. Supposing the consumption of each individual requires a biochemical oxygen demand (BOD) of 40g/day, it is estimated that the wastewater BOD weighs 924 tonnes every day, 349 tonnes of which are drained. That is, 575 tonnes are discharged into rivers. Domestic wastewater accounts for 60% of pollutants that cause river pollution, and ranks as the major source of river pollution.
In general, domestic wastewater includes black water (fecal sewage) and gray water (wastewater from dishwashers, washing machines, sinks, and baths). Black water accounts for 32.5% of domestic wastewater, while gray water accounts for 67.5%. Domestic wastewater is categorized as organic pollutants. Construction of public underground sewerage systems is the key to minimizing domestic water pollution. The US, Japan and advanced European nations have considered the extent of public underground sewerage systems as an indicator of national competitiveness. In 1991, the extent rate of public underground sewerage systems in Taiwan was merely 3%, and after years of construction, the amount reached 10.87% in 2003. In the same year, the government incorporated the construction of public underground sewerage systems into the "Challenge 2008: National Development Plans." The "Water and Green Construction Plan" was one of the national development plans. The hook-up rate to public underground sewerage systems reached 22.58% by 2009, and 47.79% of wastewater was properly treated.
The EPA was adopted the following measures to minimize the impact of domestic wastewater on rivers:
A. Education on community drainage systems and regular inspection
"Education, inspection, and penalty" constitute the principles of helping the public understand that misconnection or inappropriate maintenance of drainage can lead to pollution and calls for inspections to be conducted.
B. Refine the management of built-in waste water treatment
The government advances programs to standardize built-in waste water treatment and regular maintenance plans for treatment facilities.
C. Encourage the recycling of domestic wastewater
The government encourages the research, development, and assessment of technologies and viability of recycling and reusing domestic wastewater. It also assists schools and government departments with installing recycling facilities to reuse water.
D. Waste minimization, source management in lieu of end control
The government will integrate education resources and raise public awareness to minimize wastewater from the source.
(Recycling domestic wastewater to water plants)
- Environmental Protection Administration, R.O.C.(Taiwan)