Cemex sets its sights on water-positive growth

Seb Hancox
Mar 27
5 min read

The cement manufacturer is looking to strengthen operational resilience by decoupling growth from freshwater use. GWI explores the company’s strategy to prioritise alternative water resources.

Arturo Gaytan Covarrubias Ready-mix concrete innovation and sustainability manager, Cemex Mexico GWI spoke to Arturo Gaytan Covarrubias about how Cemex is reducing its reliance on freshwater for ready-mix concrete production and improving water efficiency at its manufacturing sites. Source: Cemex

Cemex is a global leader in building materials, operating in almost 100 countries worldwide. The company is one of the world’s largest producers of cement, ready-mix concrete, asphalt, and aggregates, focusing on delivering innovative and sustainable solutions that support the construction industry's needs.

Water is essential to cement production, playing a critical role in concrete mixing, equipment cleaning, cooling systems, and dust suppression. Under its ‘Future in Action’ sustainability strategy, Cemex has committed to using alternative water sources, increasing water recycling, and becoming water-positive at priority sites in high water‑stress areas by 2030.

What are the key pillars of Cemex’s global water strategy?

Our water strategy is built upon two transformative pillars. We call the first ‘radical substitution’, and our goal here is to give water a second life by replacing freshwater with alternative sources, such as recycled water or industrial process water. The second is ‘operational efficiency’, focusing on reducing water intensity per metric tonne of cement and cubic metre of concrete produced.

Water is the soul of concrete; it provides workability and strength. Without water, there is no concrete, and without concrete, there are no cities or development. Since we cannot eliminate water from the chemical formula, our focus is on optimising every drop outside the final product, such as in equipment washing and aggregate cooling.

What are Cemex’s main sources of process water and how do you treat it?

Around 10 years ago, other industries told us that they pay municipalities to dispose of reject water from their reverse osmosis processes. In that moment, we saw an opportunity and, after running chemical analyses, we found that their reject water complied with water quality standards for ready-mix concrete. This water does not require additional treatment and is used directly in our operations.

In Mexico, where I am responsible for water management, 67% of the water we use today comes from alternative sources, while just 33% is freshwater. 10% of our total water use is prioritised for human consumption [for example in drinking water on-site], where potability is non-negotiable. We are pioneers in harnessing surplus water from industries, such as beverages, brewing, dairy, hospitality, and mining, as well as integrating treated urban wastewater. While each Cemex location has its own circumstances and legislation, our goal globally is to reduce water consumption and replace it with fresh water.

What challenges does Cemex face when using alternative water sources?

The principal barriers are the infrastructural and logistical challenges of using alternative water sources. Because the sites from which we collect water had previously disposed of it down the drain, they typically lack storage facilities or pumps. As a result, we have to transport the water from their facilities to ours by tanker, and this needs to happen quickly because ready-mix concrete is highly time-sensitive. Once it is produced, it must be used immediately, as it hardens after around two hours and can no longer be handled. Delays in collecting and transporting the water can therefore affect operations.

We also take municipal wastewater, which is more stable in quality and logistically easier to manage. Under Mexico’s National Water Law, city wastewater is considered a national good, which can prevent municipalities from being able to sell it. This legislative constraint prevents us from relying entirely on alternative water sources.

Cemex’s Key Figures

Source: Cemex

How does Cemex reuse its own water and what is it doing to improve water efficiency at its sites?

We are tackling this challenge through three main fronts: chemical innovation, digital measurement, and culture. First, we developed next-generation chemical admixtures that reduce the amount of water required in the mix without compromising quality. Second, the water we do use is treated as a critical asset. We have deployed telemetry systems to quantify specific usage and detect anomalies in real-time. Finally, we foster a culture of care through which water stewardship becomes part of our employees’ DNA, empowering them to act responsibly both at work and at home.

The cycle is circular at our plants. We treat the water used for washing concrete mixer trucks through decantation systems, allowing us to reuse it indefinitely for cleaning or even reinserting it into new concrete production. It is a zero-waste model where water circulates in a closed loop. Additionally, we have implemented rainwater harvesting and internal treatment plants for office services.

A global footprint

Cemex has roughly 1,100 ready-mix concrete plants, 50 cement-producing plants and 220 aggregate quarries around the world.

Source: Cemex

Do you pilot new technologies to improve water efficiency and water reuse?

As alternative water sources often have chemical variability, we are currently piloting real-time quality sensors that analyse these variations instantly, allowing us to adjust concrete formulations automatically to ensure maximum performance. We are also implementing vehicle identification tags that sync with water suppliers to monitor exactly who is consuming water, in what quantity, and for what specific use. As part of our focus on water reuse, we are testing new filtration technologies to optimise the recovery of rainwater and industrial runoff.

Do you have specific challenges that currently can’t be solved by existing technologies?

The major challenge is analytical agility. Currently, deep chemical analysis can take several days, and ideally, we need "on-the-go" technologies that provide results in seconds to allow for real-time decision-making on the production line. We also see an opportunity for scaling treatment technologies for medium-sized industrial facilities.

The current municipal water treatment model involves sending all wastewater to a large-capacity treatment plant, often over long distances. Once treated, the water must then be transported to a manufacturing facility, again typically in tankers. We see the future in urban treatment schemes that allow industries to utilise treated wastewater directly without the logistical and environmental costs of tanker transport. Small industries and businesses should be able to collect wastewater from their local surroundings and community, treat it, and use it on-site without having to transport it to plants outside the city and then return it.

How is Cemex working to become water-positive in water-stressed areas?

We act based on science. In collaboration with a leading university in Spain, we have mapped all our global facilities against water-stress indices. For high-risk areas, we developed a ‘Zero Freshwater and Zero Discharge Protocol’ in partnership with environmental consultancy ERM. To meet the requirements of this certification, sites must either use zero freshwater or have zero liquid discharge. This protocol is starting to be implemented across Cemex’s operations globally. In Mexico, 31 concrete plants have already been certified by AENOR (the Spanish Association for Standardisation and Certification), making them the first and only Cemex facilities worldwide to currently hold this certification. Our goal is to decouple our production growth from the use of fresh water sources in the communities in which we operate.