عنوان مقاله [English]
The main sources of wastewater in Iran are divided in three sections : domestic, large polluting industries and industrial estate effluents. Out of 3.9 million cubic meters of municipal wastewater, only 9% is treated in 75 wastewater treatment plants (until April 2004) and the rest (91%) is discharged directly to the sewage wells, rivers, lakes and sea, and agricultural lands without any proper treatment. The amount of industrial wastewater, from main polluting industries, is estimated over 91 million cubic meters from which only 31% treated poorly. The situation in industrial estates is the same; only 10 industrial estates have recently equipped with proper wastewater treatment plants and another 15 are under construction. The rest (over 200) are get without any treatment facilities. The total BOD loads of existing wastewater treatment plants are about 30,000 ton/yr. 76% of this load is treated by aerobic systems and 24% by anaerobic aerobic combination. Over 7 billion dollars capital inveslments are needed for wastewater collection and treatment facilities for the rest of towns. Having done so, apart form pollution prevention of water resources, about 500,000 hectars of agricultural land wille be irrigated by treated effluents. As concluding remarks, the role of government and existing challenges are dicussed and some suggestions are given.