Title: Wastewater Production, Treatment and Use in Pakistan

Pakistan, once a water-surplus country, is now a water deficit country. The water availability has decreased from 1,299 m3 per capita in 1996-97 to 1,100 m3 per capita in 2006 and it is projected to less than 700 m3 per capita by 2025. Therefore, search for other non-conventional water resources for irrigation i.e. wastewater, has become important. In Pakistan, domestic and industrial wastewater is either discharged directly to a sewer system, a natural drain or water body, a nearby field or an internal septic tank. Mostly, this wastewater is 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 (<8%) of their wastewater before disposal. The wastewater used for irrigation is valued by farmers, mainly because of its nutrient contents and reliability of supply and exert positive impacts on agriculture land values, households, monthly income and employment due to reuse of wastewater despite of the ill effects of wastewater irrigation on soil physical and chemical properties in addition to contamination of human food chain and related health risks. Limited information is available in this regard. There seems no national policy in effect on sustainable use of wastewater in this country. Problems of wastewater disposal tend to stem from distortions due to economy-wide policies, failure of targeted environmental policies and institutional failures. Thus laws and regulations have been formulated about treatment and disposal of wastewater but their implementation due to lack of resources and skilled manpower is the real issue. There is hardly any well organized study which focused on risk assessment in a systematic way. Some of the systematic work has been done by IWMI and Pak-EPA with financial aid from foreign donors. Therefore, a well-coordinated program is necessary to create awareness among different sections of the society including the general public, organizations, industrialists and farmers. 1. Water availability and use: Pakistan has become a water deficit country due to depleting ground and surface water resources, loss in surface shortage, prevailing droughts and shift of fresh water from agriculture to more pressing domestic as well as industrial uses (Ensink et al., 2004). Therefore, search for other non-conventional water resources for irrigation i.e. wastewater has become important. The recent statistical data shows that the Indus System and its tributaries provide an average 142 MAF of water annually. Out of which nearly 96 MAF is utilized for irrigation, 36 MAF flows to sea and about 10 MAF is consumed by the system losses which include seepage, evaporation and spill during floods. Presently, 40.5 MAF groundwater is being pumped annually and about 36% of the groundwater is classified as highly saline and 60-80% as saline (Anonymous, 2011). Overall water availability has decreased from 1,299 cubic meters (m3) per capita in 1996-97 to 1,100 m3 per capita in 2006. It is projected that water availability will be less than 700 m3 per capita by 2025 against the international standard of 1500 m3 per capita (Pak-SCEA 2006). The renewable water resources are estimated at 248 billion m3/year. Surface runoff is estimated at 243 billion m/year, while groundwater resources are about 55 billion m/year, most being the base flow of the river system. Of which 96.8% is withdrawn for agricultural purposes, 1.6% for domestic use and another 1.6% for industrial use. Pakistan would need more additional water in future to meet irrigation and other requirements of the people. This was not possible unless new storage dams were built. 2. Wastewater production and treatment: 2.1. Wastewater Production Total discharge of wastewater for 14 major cities of Pakistan, computed on the basis of 1998 population census, is about 1.83 × 10 7 m 3 h −1 (FAO, 2002). Latest estimates reveal (PWSS, 2002 & Table 1) that total quantity of wastewater produced in Pakistan is 962,335 million gallons (4.369 x 10 9 m 3 /yr) including 674,009 million gallons (3.060 x 10 9 m 3 /yr; a figure of 5.54 x 10 9 m 3 /yr for the year 2011) from municipal and 288,326 million gallons (1.309 x 10 9 m 3 /yr) from industrial use. The total wastewater discharged to the major rivers is 392,511 million gallons (1.782 x 10 9 m 3 /yr and 1/3rd of all wastewater), which includes 316,740 million gallons (1.438 x 10 9 m 3 /yr) of municipal and 75,771 million gallons (0.344 x 10 9 m 3 /yr) of industrial effluents. Petrochemicals, paper and pulp, food processing, tanneries, refineries, textile and sugar industries are major industrial contributors to wastewater pollution in Pakistan (UNIDO, 2000). It has also been estimated that around 2,000 million gallons of sewage is being discharged to local surface water bodies every day (Pak-SCEA 2006). The industrial sub-sectors of paper and board, sugar, textile, cement, polyester yarn, and fertilizer produce more than 80% of the total industrial effluents (WB-CWRAS Paper 3, 2005). Table 1: Sector wise estimated wastewater production in Pakistan Sr. No. Source Volume 10 6 m 3 y -1 Percent %