# **Box  2.6  Lima, Peru—indirect use of untreated wastewater**

The Agricultural Zone of San Augustín (ZASA) is an organization of 145 families formed in 1972, who occupy an area of 540 hectares which is completely surrounded by the urban fabric of the Lima-Callao metropolitan region. ZASA annually produces more than 15,000 tons of vegetables that are sold in the markets of Lima (about 20 percent of the vegetables sold in the city). ZASA is irrigated with water from the Rimac River. However, during all but a few months a year, the flow in the river is basically domestic and industrial wastewater discharged just upstream and further degraded by garbage that is illegally dumped in the river. Under increasing pressure from the health authorities because of the significant health risks posed, and the threat of urban encroachment, ZASA is proposing to construct a waste stabilization pond system comprising 30 hectares of ponds in series (anaerobic + secondary + polishing) to achieve 1989 WHO guidelines for unrestricted irrigation. It would treat 400 l/s of raw sewage supplied directly from a nearby interceptor by the Lima water company. The treatment plant would be built by ZASA with a government line of credit (8 years at 8 percent interest). The property owners whose land is occupied by the ponds would be paid the value of their foregone farm profits by the other families. The project would be paid off in 10 years with an estimated financial rate of return of 92.2 percent and a benefit/cost ratio of 2.82, making it appear to be a financially sound and profitable venture.

_Source:_ Egocheaga and Moscoso, 2004.

# **Box  2.7  Amman, Jordan—indirect use of treated wastewater**

Jordan is one of the most water-deprived countries of the Middle East, and has some of the highest groundwater depletion rates. To meet growing water demands, more than 70 million m<sup>3</sup> of reclaimed wastewater, around 10 percent of the total national water supply, is used either directly or indirectly each year. The majority of reclaimed water is generated in the Amman Zarqua Basin. Treated effluent from the As Samra waste stabilization pond systems is discharged to the _Wadi_ Zarqua that in turn flows into the King Talal Reservoir. Irrigation water taken from the _Wadi_ is considered indirect use of reclaimed wastewater and is controlled as such. Water from the reservoir, however, is blended with other irrigation sources and is no longer considered reclaimed wastewater, and not subject to similar control.

There has been a steady evolution of the wastewater policy framework in Jordan as standards have been adapted to the needs of a severely water-constrained nation. Standards governing wastewater use have gone through four iterations. Initial standards were introduced in 1982 but were replaced in line with the 1989 WHO Guidelines; and in 1995 with a more comprehensive set of standards dealing with wastewater use and environmental discharges. Finally, in 2003 more stringent standards were promulgated following a multi-year consultation process with stakeholders. Under the new standards, groundwater recharge is permitted, but not for potable use. Jordan’s experience demonstrates that wastewater use has great potential in water-scarce areas; but that planning for wastewater use must be integrated coherently with water resources planning, environmental management, and financial arrangements.

_Sources:_ McCornick _et al_ ., 2004; Bahri, 2008a, b; Kfouri _et al_ ., 2009.

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