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<Planning and Management of Lakes and Reservoirs:
An Integrated Approach to Eutrophication>


2.4. Approaches to Solution of Eutrophication

The causes and consequences of eutrophication of lakes and water reservoirs are discussed in detail in Chapter 1 of this publication.

Urbanization in developing countries is proceeding rapidly under severe population pressure. Treating human waste is the basis of urban sanitation, and the inability to do this starts the vicious circle of water problems and sanitation measures. Deterioration of lakes, reservoirs, and rivers near cities is particularly a serious environmental problem. Furthermore, modernization of agricultural practices brings about heavy use and run-off of nitrogen and phosphorus from chemical fertilizers, causing eutrophication of waters near the cities. Fundamental to a solution is the treatment and disposal of human wastes. Recovering urine and reusing it in agriculture is particularly important to solving the problem of the Earth's limited water resources.

An overall look at the world reveals regional differences in how people manage human waste, provide for sanitation, and deal with local water quality. The distinct regions are as follows: 1) Arabic/Iranian/Islamic cultural sphere; 2) Pan-Indian cultural sphere; 3) Chinese cultural sphere; and 4) Japanese cultural sphere.

In the Arabic/Iranian/Islamic cultural sphere, people follow the teachings of Islam by observing the principle of discarding human wastes. In this rather hot and dry region, urine is easily disposed of because it evaporates, and feces can be dispersed when it dries. In accordance with the Koran, people dispose of their excrement by washing it away and purifying with water. While this method ensures cleanliness, it burdens local waters.

The Pan-Indian cultural sphere comprises Pakistan, India, Bangladesh, Nepal, Tibet, Sri Lanka, Burma, Thailand, Cambodia, Laos, and Indonesia. Under the influence of Hinduism and Islam, people wash away their excrement, just as with the water purification mentioned above. There is no consideration for the environment at all. This cultural sphere has no Buddhist influence. However, bovine manure is used as a fertilizer and fuel.

The Chinese cultural sphere comprises China, Vietnam, Taiwan, Korea, and Japan. It is the only one of the World's four major civilizations that has reused human wastes, which was at first used to feed pigs, then later actively used as a fertilizer. Even now, farming villages actively use night soil as a fertilizer. While this is an effective way to prevent further contamination of rivers and lakes, it is now difficult in urban areas. Further, farmers now use large amounts of chemical fertilizers, which cause the eutrophication of lakes by nitrogen and phosphorus. The people in the cultural sphere of Taiwan and Korea, which may be called the Japanese cultural sphere, made, under the Japanese influence, a continuous use of night soil as a fertilizer until after the war. After the war, these countries implemented Japanese sanitation measures, with collected human wastes treated as sewage in special night soil treatment plants. The possibilities for protecting water in this Asian milieu by enhancing the good attributes of this tradition while, at the same time, overcoming its nonscientific side, should be considered.

A perspective of recycling is necessary for the effective use of the earth's limited resources. An effective measure to provide for the utilization of nitrogen and phosphorus, and to prevent the eutrophication of lakes, rivers, and enclosed seas, would require the recovery and reuse of human urine. In the Edo period, Japan made thorough and effective use of it. In the Chinese and Japanese cultural spheres, it would be possible to modify modern sewerage to achieve this. However, such modification may be quite difficult in other cultural spheres due to their religious and cultural traditions. Basically, this approach is conceivable for solving environmental problems in Asian countries with their high population densities.

The strong influence of history and religion in Asia needs to be considered in the effective incorporation of scientific findings into solutions for environmental problems. Asia has one of the keys to the dissemination and advancement of scientific understanding, which is fundamental to solving environmental problems.

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