The plant uses water between two and seven times in cooling towers (semi-closed circuits) and nine times in steam production (via condensate return).
Tarragona is in a water-stressed area (Figure 4), i.e., one in which more than 60% of the naturally available water sources are already exploited. In total, around 20% of all BASF sites are located in such water-stressed areas. Last year, the company sourced around 7% of its worldwide water supply from these areas.
"By the year 2020, we want to introduce water management to the EWS standard at all sites where water is scarce," says Ulrich von Deessen, head of BASF's competence center, environment, health and safety, Ludwigshafen.
Chemical makers in other water-stressed areas also are taking action. For instance, Sabic, Riyadh, Saudi Arabia, aims to significantly reduce its consumption of fresh water from the current level of 124 million m3/yr. The goal is to cut by 2025 fresh-water use intensity (m3 water used/metric ton of product sales) from the 2010 level of 3. It's implementing a number of water conservation and reduction projects in plants located in water-scarce regions such as Saudi Arabia, Brazil and Spain.
For example, at the Al-Jubail and Yanbu complexes in Saudi Arabia, the company has developed a seawater cooling system to minimize use of desalinated water. This is Sabic's only seawater cooling system and has been purposely designed not only to save desalinated water but also to minimize damage to plant equipment and prevent any possible toxic chemical leaks to the seawater environment.
The company has reduced water usage at its Campinas, Brazil, facility by 20% while increasing production by 16%. This was achieved by improving the integrity of underground water supply pipelines and reusing treated industrial wastewater.
At its Cartagena, Spain, plastics plant, Sabic uses micro-filtration to clean and reuse process wastewater from multiple sources within the complex. In the last six years, this has saved more than 850,000 m3 of raw potable water and over $1.2 million in associated costs.
Since 2010, DSM has been working to optimize water use at its engineering plastics compounding site in Pune, India. The company says that the Pune facility is one of the first in the group to have completely eliminated release of waste water. A treatment and checking regime allows the waste water to serve for gardening purposes. This year the facility, through a combination of increased process water recycling and strict monitoring of potential leakages, has slashed by two-thirds the amount of water used in the manufacture of thermoplastic polyester and polyamide compounds.
Seán Ottewell is Chemical Processing's Editor at Large. You can email him at email@example.com.