[Chile] Antofagasta Urban Sewage Reuse for Copper Mine Project Wins AIA 2026 Sustainable Management Award: 900 L/s Treatment and Reuse Plant with 160 km Water Conveyance System, Total Investment Exceeding USD 1.2 Billion, to Be Commissioned in 2028

The Industrial Association of Antofagasta, Chile (AIA) awarded the Premio AIA 2026 in the Sustainable Management category to the "Urban Wastewater–New Water Source for Mining" solution jointly developed by Econssa and Compañía Minera Zaldívar. Core of the solution: a newly built treatment and reuse plant with a recovery capacity of 900 L/s, supported by a water conveyance system of over 160 kilometers that pumps Reclaimed Water to a mining area at an altitude of 3200 meters; total project investment exceeds 12亿 USD, 2028年 commissioning, and can extend the life of the Zaldívar copper mine to 2051年.

Project Structure: One City's Sewage Becomes One Mine's Water Source

The solution is implemented by two entities working separately yet interlocking:

• Econssa (water supply and sanitation service provider) — builds a new Treatment and Reuse Plant (Planta de Tratamiento y Reúso) at Salar del Carmen, treating the Domestic Sewage of Antofagasta that was originally discharged into the sea, with a recovery capacity of 900 L/s, converting it into Reclaimed Water suitable for industrial use;
• Compañía Minera Zaldívar (water user) — builds the water conveyance system (SIA), comprising over 160 kilometers of infrastructure, lifting Reclaimed Water stage by stage via pumping stations to the mining area at an altitude of 3200 meters, replacing the original continental water source.

The project investment scale exceeds 12亿 USD, of which Zaldívar's SIA portion is approximately 9亿 USD, and Econssa's treatment and reuse plant is approximately 3亿 USD. At peak construction, 5000 workers are expected to be employed, prioritizing local labor and leaving room for regional suppliers. Construction of the water conveyance system began this year in 8月, and it is expected to be put into operation in 2028年.

Why It Matters: A Radical Example of Global Mining Decoupling from Freshwater

Mining is a typical globally high water-consuming industry. In the Atacama Desert region of northern Chile, copper mining production has long relied on continental water bodies and underground aquifers, creating direct competition with agriculture and community water use, with social license pressure rising year by year. The approach of this solution is: replace continental water sources with urban sewage, resolving this contradiction at the source.

• For the mine — María de la Luz Osses, General Manager of Zaldívar, stated that this is an "important decision: to change the water source we use to produce copper," and that this collaborative and sustainable project will replace continental water use and extend the mine life to 2051年;
• For the city — Fernando Rojas, President of Econssa, pointed out that Antofagasta will become the country's first city where water used by residents returns to the production system, while Zaldívar hands over supply to an alternative water source provided by a state-owned enterprise; "this combination relieves pressure on the aquifer and leaves reusable capacity for other industries in the region";
• For the region — the project is positioned as shared infrastructure capable of serving multiple industries. Reclaimed Water departing from Salar del Carmen will reach industrial areas such as La Negra and is set up as delivery points for enterprises with demand, rather than an exclusive pipeline for a single user.

The structure of "multiple uses of one water, cross-industry circulation" is the part of this solution with the greatest spillover value: it turns the effluent of a sewage treatment plant into the supply side of a regional industrial water market.

Engineering Highlights: Microtunneling, Remote Control and Biogas Recovery

Ultra-long-distance, large-elevation-difference water conveyance places special demands on engineering capability. Several technical choices in the project are worth the attention of peers:

• 5.3 km Micro TBM Tunnel — The water conveyance system includes a tunnel excavated using a Micro Tunnel Boring Machine (Micro TBM), a construction approach applied for the first time in Chile to address the challenges of pipeline laying under complex terrain conditions;
• Remote Control and Telemetry — The water conveyance system operates with remote control, telemetry, continuous monitoring, and early leak detection, which are critical to the long-term reliable operation of a 160 km-class pipeline;
• Anaerobic Digestion and Biogas Recovery — The treatment and reuse plant is equipped with anaerobic digesters to optimize sludge management and achieve biogas recovery and utilization, integrating the treatment process itself into the energy and resource cycle.

It is worth noting that this project is not merely a technical engineering endeavor, but rather an institutional arrangement under a Public-Private Partnership (PPP) structure: a state-owned sanitation service enterprise invests in and builds public facilities open to the region, while a mining company invests in and builds a dedicated water conveyance channel and serves as the anchor user. A clear division of risk-sharing and benefit boundaries is the prerequisite for the viability of such cross-industry water circulation projects.

What It Means for Us: TIANYI TECH's Assessment

TIANYI TECH has long served municipal and industrial park wastewater treatment and Reclaimed Water Reuse clients, with business coverage across mainland China and an expanding overseas market presence. We believe the insight this case offers to domestic clients lies not in extreme parameters such as "160 km water conveyance," but in its approach to demand organization:

First, anchoring a major user is the prerequisite for a Reclaimed Water project to succeed. High water-consuming industries such as mining, power generation, and metallurgy have stable and large-scale water demands, making them the best base-load users for Reclaimed Water pipeline networks; securing the buyer first and then building treatment facilities has a far higher success rate than "building the plant first and then finding users."

Second, quality-differentiated water supply determines project economics. This project did not pursue "treating wastewater to the highest standard," but instead determined effluent quality based on industrial use — domestic industrial park clients should likewise configure tiered systems for "high-end industrial reuse + general reuse," avoiding paying for parameters that are not needed.

Third, O&M capability for long-distance pipeline networks must be designed in from the outset. Remote control, telemetry, and early leak detection are not bonus features — they are the survival baseline for a 160 km-class pipeline. When designing Reclaimed Water Reuse systems for industrial clients, we have consistently included metering, monitoring, and intelligent O&M as standard deliverables.

For us, the global mining industry's "water transition" is opening a clear market window: whoever can provide an integrated "treatment + conveyance + O&M" solution and can turn water savings and emission reductions into verifiable data will secure a position in such cross-industry water circulation projects.

About TIANYI LIMITED: TIANYI LIMITED is deeply engaged in the fields of wastewater treatment and Reclaimed Water Reuse, committed to providing efficient, low-carbon, and sustainable water treatment solutions for municipal and industrial clients.