Degrémont is a world specialist in water treatment plants and makes an important contribution towards sustainable development. The company’s South African operations are headed up by deputy managing director, Dumi Luthuli.

According to Luthuli, Degrémont’s main field of expertise is in designing, building and commissioning of installations for:

• drinking water production
• desalination by reverse osmosis
• wastewater treatment and re-use for industrial, agricultural or drinking purposes
• sludge treatment.

Luthuli has been with the organisation for eleven years. He started off as a young engineer, and his dedication is an indication of Degrémont’s advanced technologies, expertise and commitment to innovation.

One of the most significant projects that Luthuli has been involved in is the Lower Ruvu Water Treatment Plan in Tanzania. The city of Dar-es-Salaam with a population of 2.7 million is drinking water that is produced from the plant built by Degrémont.

Melbourne desalination plant

One of the most recent projects that the company has been involved in is the Melbourne plant, Australia’s largest seawater desalination project designed under a public-private partnership.

An important milestone in the development of the Melbourne project is the completion of the planting of the largest green roof of its kind in the southern hemisphere. The green roof is an important part of the plant’s design, helping to integrate the desalination plant into the landscape and minimising visual impacts on the coastline.

The reverse osmosis building is the biggest of the 29 buildings on the site. Its green roof spans 26 000m², bigger than the playing surface of the Melbourne Cricket Ground.

The completion of planting on this roof is another significant milestone achieved successfully by Thiess Degrémont. “It’s a credit to the team that the planting has been completed in just over eight months, despite challenging weather conditions,” said Project Director for Thiess Degrémont, John Barraclough. Planting of a second, smaller green roof on the screen and feed building will commence soon.
The desalination plant’s green roof system features over 100000 indigenous ground covers, tussocks and low growing shrubs. Twenty-five different species have been carefully chosen to suit the coastal climate conditions of the site.

Desalination by reverse osmosis: a sustainable alternative

Abundant water is present on earth in different forms. However, 97.2% of the water is salt water, and therefore unfit for consumption. Fresh water is therefore a rare resource which should be preserved. It is increasingly unevenly distributed over our planet. While some regions benefit from considerable surpluses, others, on the contrary, are suffering from increasing shortages every year (the Gulf States, Australia, the Mediterranean basin, China). Thus, to make seawater (and brackish water) drinkable, desalination has gradually made its appearance as a solution for the future, in particular for countries which have coasts ⁽¹⁾. Two processes, distillation and reverse osmosis, are now widely used. It is desalination by reverse osmosis, which was chosen by Degrémont “as it fits into the perspective of sustainable development”, says Miguel Angel Sanz, Director of Development and Innovation at Degrémont for the Iberian Peninsula, Africa and Latin America. This technique operates by filtration of water under high pressure through semi-permeable membranes. Less expensive and consuming less energy, it represents a more ecological solution which limits greenhouse gas emissions.

Declared the desalination business of the year in 2010,⁽²⁾Degrémont has designed innovation control techniques to prevent discharges of brine having impact on the environment.

Brine discharge, considered to be the process main disadvantage for the environment and marine ecosystems is completely controlled, emphasises Sanz. “Thanks to a system of diffusers capable of diluting salinity quickly, rapid return to the concentrations of the natural environment is obtained.” Finally, he notes that, “the waters are discharged at the same temperature as that of the marine environment, without disturbing it, and thus preserve biodiversity.”

Faced with increasing shortage of water resources, desalination thus proves to be a sustainable alternative, able to answer ever increasing needs for household and industrial water.

(1)      About 40% of the world’s population lives lessthan 100km from the coast.

(2)      Global Water Awardsrewardwhat the leaders of the international water sector has recognised as the most remarkable accomplishments of the past year.

Degrémont, a subsidiary of SUEZ ENVIRONNEMENT, now has over 250 reverse osmosisdesalination plants in the world. 20 million people consume this water which has been made drinkable.