世界发展银行-Wastewater-_-From-Waste-to-Resource-_ndash_-The-Case-of-Arequipa,-Peru_7页_1mb

Wastewater: From Waste to Resource - The Case of Arequipa, Peru

Core Content

The case study of Arequipa, Peru, highlights a successful public-private partnership (PPP) that transformed wastewater from a pollutant into a valuable resource. The initiative, known as La Enzolada, is a wastewater resource recovery facility designed to treat and reuse municipal sewage for industrial and agricultural purposes.

Main Points

Context and Challenges

• SEDAPAR S.A. is a public service enterprise in Arequipa, providing water and sanitation to over 1.1 million people with more than 94% water coverage and 80% sanitation coverage.
• Arequipa Department is vast (63,345 km²), arid, and has deep valleys and high mountains, making water infrastructure development challenging.
• The Chili River, a key water source for the region, was heavily polluted due to untreated wastewater from Arequipa city, which threatened both the environment and public health.
• Cerro Verde, the largest copper mine in Peru, needed additional water for its expansion but faced challenges due to the region's water scarcity and poor wastewater treatment capacity.

Proposed Solution

• La Enzolada is a water resource recovery facility designed, financed, built, and operated by Cerro Verde under a PPP agreement with SEDAPAR.
• The facility treats wastewater from Arequipa city and reuses it for mining operations (1 m³/second) while returning the rest to the Chili River for downstream agricultural use.
• The plant uses trickling filters, which are more energy-efficient than activated sludge, especially at high altitudes (over 2,000 meters above sea level).

Financial Structure

• Cerro Verde financed the CAPEX (capital expenditure) and OPEX (operating expenditure) of the project, including the wastewater treatment plant, pumping station, and conveyance pipelines.
• The project was structured over 29 years, with ownership and management transferred to SEDAPAR at the end of the contract.
• SEDAPAR saved over $615 million by not having to build and operate the wastewater treatment plant itself, with savings of $538 million in construction and $77 million in operation and maintenance.

Benefits

• Environmental Benefits: Improved water quality in the Chili River, reduced pollution, and the return of aquatic life.
• Social Benefits: Reduction in waterborne diseases, better health for downstream communities, and improved irrigation for farmers.
• Economic Benefits: Cost-effective water supply for Cerro Verde compared to alternatives like desalination, which would have cost at least four times more.

Stakeholder Engagement

• Continuous engagement with local and regional stakeholders was crucial for the project's success.
• Cerro Verde implemented a community relations program and collaborated with a multisectoral water users' committee.
• The company has contributed to other water infrastructure projects, including the Bamputañe dam, Pillones dam, and La Tomilla II potable water plant.

Key Information

• La Enzolada started operations in December 2016 and has a current capacity of 1.8 m³/second, with plans for two future expansions to 2.1 m³/second (2029) and 2.4 m³/second (2036).
• The PPP agreement allowed Cerro Verde to take on most of the project risks, including technical, financial, and operational, which were deemed less costly than not expanding the mine.
• The cost per cubic meter of water via La Enzolada is $0.68–$0.80, significantly lower than the $2.5/m³ for desalination and pumping.
• Some farmers expressed dissatisfaction due to reduced water availability for irrigation, leading to ongoing discussions on compensation.

Lessons Learned

• Stakeholder engagement is essential for the success of water reuse projects, especially in communities affected by water source changes.
• Favorable national PPP regulations can encourage private sector participation in innovative waste-to-resource projects.
• Water scarcity can drive the economic viability of wastewater reuse, particularly in regions where alternative water sources are expensive or inaccessible.
• Mitigating social risks is a complex challenge that requires inclusive dialogue and compensation mechanisms for affected groups.

Conclusion

The La Enzolada project exemplifies how well-structured PPPs can address both business and social needs. It demonstrates the potential of wastewater reuse to improve environmental quality, public health, and water security in water-scarce regions. The collaboration between Cerro Verde and SEDAPAR has led to significant economic and social benefits, while also setting a precedent for future waste-to-resource initiatives.