The total annual quantity of wastewater produced in Pakistan is 4369 MCM including 3060 MCM from municipal and 1309 MCM from industrial use. The total wastewater discharged to the major rivers is 1782 MCM and 1/3rd of all wastewater, which includes 1,438 MCM of municipal and 344 MCM of industrial effluents. Municipal wastewater is normally not treated and none of the cities have any biological treatment process except Islamabad and Karachi, and even these cities treat only a small proportion of their wastewater before disposal. It is estimated that only about 1% of municipal wastewater is treated before disposal. Disposal of untreated industrial and municipal wastewater has become one of the largest environmental problems in Pakistan