The importance of protecting the environment against pollution is an objective which gained international acceptance in the recent years. According to the first principle of the Declaration of the United Nations Conference on the Human Environment which took place in Stockholm in 1972, "man .... bears a solemn responsibility to protect and improve the environment for present and future genera­ tions". The United Nations again in their desire to improve the sanitation conditions allover the world decided to proclaim the period between 1981-1990 as the "International Drinking Water Supply and Sanitation Decade." Although attempts have been made by inter­ national organizations to prevent pollution, it is difficult to say that these attempts gave satisfactory results in developing countries. The most common reasons of failure are: a) To find solutions