Information on all three aspects of wastewater is available from only 5 countries China, India, Japan, Republic of Korea, and Vietnam. Partial data are available for 14 countries, including Bangladesh, Bhutan, Cambodia, Laos, Malaysia, Maldives, Mongolia, Myanmar, Nepal, Pakistan, Philippines, Singapore, Sri Lanka, and Thailand.
Only about 32% of the wastewater generated in Asia is treated,
Japan has adopted a comprehensive strategy for treated wastewater use. In 2009, 0.2 cubic kilometers of treated wastewater were used in the country. More than half was used for environmental purposes, such as landscape irrigation, recreation, and river maintenance. Wastewater use in agriculture and industry is not substantial, accounting only for 7% and 1% of the treated wastewater, respectively. In addition, more than 3% of the treated wastewater is used for toilet-flushing. Japan's wastewater use strategy is somewhat unique, as it is focused on meeting urban water needs, rather than providing water primarily for agricultural uses.
An estimated 1.3 million ha are irrigated with wastewater in China, while an estimated 9,500 ha are irrigated with untreated wastewater in Vietnam. At least 2% of the agricultural land around most Vietnamese cities is irrigated with wastewater, and much of that land is planted in rice.
An estimated 32,500 ha are irrigated with wastewater in Pakistan. Most of the wastewater is untreated, and yet there are no clear regulations in Pakistan regarding which crops may be irrigated with wastewater. Direct use of untreated wastewater is also common in India, where in 1985, an estimated 73,000 ha were irrigated with wastewater.
The increasing demand for plant nutrients in Asia provides an incentive for farmers and public officials to develop safe methods for distributing and managing wastewater for use in agriculture. Projections
|Contact: Terry Collins|
United Nations University