Bauxite Residue Storage Efficiency
Bauxite Residue Storage Efficiency

View Graph 

Landfilled Waste
Landfilled Waste

View Graph 

Alumina Refining

Play Video


Striving for a Cleaner Environment


Alcoa has been actively managing its emissions and wastes for more than two decades. Since establishing our initial sustainability targets, we have made considerable progress toward the reduction of key emissions and wastes. These include greenhouse gases, sulfur dioxide (SO2), nitrogen oxides (NOx), and waste disposed in landfills.


We closely manage the emissions and waste we generate and continually look for innovative ways to either eliminate them at their source or effectively control them in compliance with applicable laws. We also evaluate improvements in modern technology for discharge treatment and control on a regular basis. In addition, we maintain a very robust environmental compliance tracking system that ensures rapid corrective action of any upset conditions and best practice sharing to ensure that all of our operating locations minimize the potential for unacceptable impacts to the environment.


A number of our strategic sustainability targets focus our waste efforts on what we consider our most important issues—bauxite residue and landfilled waste. We also track our mercury emissions and research cost-effective control technologies.


While we no longer have corporate targets for NOx, volatile organic compounds (VOCs), and SO2, we continue efforts to reduce these emissions in specific businesses or regions. We also track their progress on a global level.


Bauxite Residue

A byproduct of the alumina refining industry, bauxite residue is made up of two components of roughly equal quantity—sand and mud—along with some residual caustic soda. It is stored in impoundments that are capped and re-vegetated when full.


Pocos de Caldas Refinery in Brazil

A rehabilitated bauxite residue area at the Poços de Caldas Refinery in Brazil supports native flora and fauna.

Our long-term strategic targets for bauxite residue are aimed at reducing the overall footprint associated with our management of the material. These goals are:

  • From a 2005 baseline, 15% reduction in bauxite residue land requirements per unit of alumina produced by 2020; 30% by 2030;
  • Rehabilitate 30% of total residue storage area by 2020; 40% by 2030; and
  • Recycle or reuse 15% of residue generated by 2020; 30% by 2030.


To meet these goals, we have a comprehensive and ongoing research program aimed at continually improving residue storage practices to reduce potential environmental impacts. For example, we made the transition from wet storage ponds to an innovative dry stacking process in Western Australia in the 1980s. This technique has subsequently become accepted as an industry best practice.


We have also investigated ways to modify the residue, specifically decreasing its alkalinity to further lessen its potential environmental impact while also enhancing its prospects of reuse.


Examples of our advances in bauxite residue modification and reuse include:

  • The Western Australia state government is currently conducting an investigation into potential geo-sequestration of carbon dioxide (CO2) in the state’s southwest region. We have expressed interest in the project, as it could include the construction of a pipeline with the potential to deliver CO2 from the Kwinana industrial area to our Wagerup and Pinjarra refineries.
  • Alkaloam®: This fine-grained bauxite residue is carbonated through a reaction with carbon dioxide. An alkaline, Alkaloam increases soil pH similar to agricultural lime.  While traditional lime can take a number of years to effectively increase the pH of soil, Alkaloam can achieve the same result almost instantly. (View a research report on Alkaloam from the Centre for Sustainable Resource Processing.)

ReadyGrit is used in a bunker at an Australian golf course.

  • ReadyGrit (formerly known as Red Sand): This red-colored crushed rock material can be used for general fill, construction backfill, turf top dressing, bunker sand, or a material suitable in road base construction. ReadyGrit could potentially reduce our global bauxite residue volume by one-fifth while providing an environmentally sound solution to Western Australia’s declining sand supplies. Demonstration trials using the material from a pilot plant at our Kwinana Refinery continued in 2012, and we will conduct further reviews and assessments with our partners throughout 2013.
  • Alkaline clay: We have been investigating the potential use of bauxite residue to treat coal-mining overburden that generates acid. Following three years of extensive full-scale pilot testing and analysis, the Pennsylvania Department of Environmental Protection in the United States granted us a beneficial-use permit for bauxite residue to be used in this type of application. 


Our research is also focused on the rehabilitation of our bauxite residue storage areas. We are improving the sustainability of the areas’ surface cover, and our locations are adopting best practice approaches to closure. Our Brazilian refinery at São Luís has completed the rehabilitation of its third residue storage area. In Western Australia, the outer slopes of dry-stacking areas are being progressively rehabilitated. Our refinery in Point Comfort, Texas, USA, is using spoil from ship-channel dredging to flatten the outer slopes of residue storage areas to enable long-term re-vegetation.


Bauxite Residue Storage Efficiency
Square meters of land required per thousand metric tons of alumina produced
Goal: 15% reductionProgress: As of Dec. 2012 


Bauxite Residue Storage Area Rehabilitation Rate
Percent of total area rehabilitated
Goal: 30% rehabilitatedProgress: As of Dec. 2012 


Bauxite Residue Reuse
Percent of total residue generated
Goal: 15% reusedProgress: As of Dec. 2012 


Bauxite Residue Generated
Metric tons per metric ton of alumina produced

Increase in 2009 was due to variations in the bauxite ore’s quality. 


Landfilled Waste

Building on our early success in waste reduction, our current strategic target is a 75% reduction in landfilled waste by 2020 and 100% by 2030 from a 2005 baseline. The goal excludes certain process waste streams from refining and power generation because the larger volumes of these materials, which include bauxite residue and fly ash, would mask our progress on reducing the landfilling of all other waste streams. We have separate programs and targets to address these large-volume wastes.


In 2012, we achieved a 25% decrease in landfilled waste from the baseline. We saw an increase in waste volumes from certain facilities that we permanently decommissioned during the year, and we worked hard to minimize these increases. For example, closure operations at the Eastalco (Maryland), Rockdale (Texas), and Alcoa (Tennessee) smelters in the United States resulted in the generation of additional landfilled waste. The cleanup from the Massena (New York, USA) casthouse fire that occurred in March 2012 also resulted in 4,800 metric tons of contaminated cleanup debris that required landfill disposal.


We are actively working with several partners interested in exploring opportunities to use our byproducts as feedstocks that meet both technical specifications and regulatory requirements. For example, we recycled record amounts of spent pot lining (SPL) in 2012 through our U.S. processing facility and implemented significant landfill diversion actions.


Landfilled Waste
Thousands of metric tons
Goal: 75% reductionProgress: As of Dec. 2012 


Total Wastes Sold or Recycled
Thousands of metric tons

Decrease between 2008 and 2010 was due to the sale of our packaging business and operational curtailments. Increase in 2011 was due to improvements in the recycling of spent pot lining and an increase in plant demolitions that resulted in significant recycled waste.


Spent Pot Lining

We continue to make progress in converting SPL—a waste from our smelting process—into an energy and raw material source for cement kilns and other industrial energy consumers. SPL is generated when the carbon and refractory lining of smelting pots reaches the end of its serviceable life.


In the last few years, we have led our industry in finding ways to transform the waste into a raw material for other industries. We work with cement manufacturers in countries around the world to implement environmentally safe processes that treat the chemicals of concern in the material and use SPL’s energy or raw material value to reduce the cost of cement production.


Through this and other efforts, we recycled 52% of the SPL we produced in 2012. The decline from the 56% recycled in 2011 was driven largely by an increase in generation due to smelter site closures where the pots have been permanently removed, as well as lingering weakness in the cement industry.


We continue to work on identifying opportunities to expand the market for this material, and this should allow for further increases in volumes recycled in the next few years. We are also developing measures to increase cell life, resulting in fewer cell failures and fewer cells that need the lining removed and replaced. This pollution-prevention effort reduces operating costs and will result in less SPL for recycling or disposal.


Spent Pot Lining Generated
Kilograms per metric ton of aluminum produced

The 2012 and 2011 generation rates do not include demolition tonnage from permanently idled smelters. The increase in 2011 was due to the additional SPL generated as a result of restarting smelters in 2011. The 2009 generation rate was considerably lower than typical years as a result of the curtailment of smelting production throughout the system.


Spent Pot Lining Recycled/Reused

The decrease in 2012 was due to lingering weakness in the cement industry and significant one-time remediation tonnage resulting from the permanent closure of several smelters for which recycling capacity was not available.


Air Emissions

We continue to pursue opportunities to reduce our various air emissions. (See the Climate Protection section for a discussion on greenhouse gases.)


The bulk of our mercury emissions occur in our refining operations because mercury is a naturally occurring element found in the bauxite we process in refining. There is considerable variation in the concentration of mercury depending on the source of the bauxite used, which creates a challenge for optimizing potential solutions aimed at reducing emissions.


We continued to research technology and operational solutions to achieve our strategic target of an 80% reduction in mercury emission intensity by 2020 and 90% by 2030 from a 2005 baseline. In 2012, our intensity decreased 15% from the prior year but remained above our 2005 baseline, mainly because of the increasing levels of mercury in the bauxite available to us today.


In addition to mercury, we continue to identify innovative measures to reduce the emission of other pollutants, such as SO2, NOx, VOCs, and fluoride. In 2012, these emissions declined slightly.


Mercury Emission Intensity
Grams per metric ton of alumina produced
Goal: 80% reductionProgress: As of Dec. 2012 


Mercury Emissions
Thousands of kilograms

Data change from prior reporting was due to improved measurements for mercury emissions at the refineries.


SO2 Emissions
Thousands of metric tons

Data changes from prior reporting were due to improved measurement and reporting methods.


NOx Emissions
Thousands of metric tons

Data changes from prior reporting were due to improved measurement and reporting methods and changes in the operation of the power utility at our Warrick Operations in Indiana (USA).


VOC Emissions
Thousands of metric tons

Data changes from prior reporting were due to improved measurement and reporting methods.


Fluoride Emissions
Kilograms per metric ton of aluminum produced

Data changes from prior reporting were due to improved measurement methods and database management at the operating locations.


Ozone-Depleting Substances

We continue to eliminate ozone-depleting substances from our process operations. In newly acquired facilities, elimination of these substances is a high priority. We do continue to use halon gas as a fire suppressant in several locations throughout the world, and these systems will continue to be phased out. There have been no documented releases from a halon system since 2004.


We are replacing some halon systems with FM 2000, which is not an ozone-depleting substance but does have a high global-warming potential. We continue to search for other substitutes that will address that concern as well.


We require all Alcoa locations to operate in compliance with all applicable environmental laws and regulations. Our corporate compliance function facilitates our goal of zero non-compliance incidents by tracking actual or potential issues and ensuring that matters of non-compliance are corrected with sustainable solutions.


In 2012, 48% of our operating locations operated without any environmental non-compliance incidents, which is a decrease from 70% in 2011. Special internal compliance reviews conducted at several operating locations contributed to the decrease.


We implemented an environmental permit review process in 2011 to ensure that permit applications, draft permits, and final permits are effectively reviewed, commented on, and submitted in accordance with regulatory requirements. This beginning-to-end process facilitates receipt of final permits with conditions that are fully understood and achievable and will allow for timely legal appeal of permit terms and conditions that are not achievable. In 2012, we continued to work with our operating locations to populate our permit database to enable enhanced tracking of environmental permit activity.


Environmental Incident Rate
  Spills Over 20 Liters Spills Over 2,000 Liters Environmental Incident Rate per Location
2008 807   0 8.8
2009 760   4 10.0
2010 599   2 9.2
2011 560   4 7.3
2012 562   9 10.1


Environmental Capital Expenditures

We maintain a robust review process for all capital projects. Corporate environmental staff members review all requests for capital exceeding US$2 million to ensure that the work to be carried out incorporates best practices and the completed project minimizes additional impact on our environmental footprint.


Capital expenditures for environmental purposes fluctuate from year to year based on the number and type of projects implemented. Our expenditures increased slightly in 2012 over the prior year and continue to be focused on environmental control system improvements.  These included improvements to material storage, management of impurities, water management systems, and control equipment.


Environmental Capital Expenditures
Millions of US dollars