SIEMENS

For many years, Turkey has been growing faster than almost any other country in the world. In 2010 its economic growth was almost nine percent, and the figure for 2011 was probably almost as high. Increases in the country’s industrial output — and in its energy and water demand — have been correspondingly large. One example of all this growth is the industrial district of Inegöl, which is in Bursa, a city of 1.9 million located roughly 150 kilometers south of Istanbul. Companies from the textile, glass, wood, and furniture industries have settled here. They have since been joined by firms from the chemicals, food & beverage, and automotive sectors. The wastewater from these companies is channeled into a 12-kilometer sewage network, which also receives around half of the wastewater produced by the inhabitants of Inegöl.

Bursa’s existing sewage treatment plant was built in 2000 with a capacity of 55,000 cubic meters per day. In 2007, due to the steady growth of the city’s industrial district, a consortium consisting of Siemens and Turkish infrastructure developer Alke was commissioned to expand the plant’s capacity to 130,000 cubic meters of water per day and equip it with a biological sludge reduction system.

The city’s demands and specifications presented a considerable challenge. For instance, the modernized treatment plant had to consume less energy, generate fewer operating costs, and produce less sludge. What’s more, it had to do all this even though there was no room to enlarge it.

Nonetheless, the complex project was successful. “In fact, the facility is Siemens’ largest biological treatment plant in Europe,” says ErsoyBulutlar, head of Siemens Water Technologies in Turkey. Thanks to the plant’s VertiCel process, a technique developed by Siemens, the biological treatment process now requires less energy. Siemens optimized the process by integrating a number of water treatment stages, including the removal and treatment of solid materials.

Aerated Solution. In order to treat wastewater, bacteria need oxygen. But adding oxygen requires a great deal of energy. Further complicating the picture is the fact that wastewater contains surfactants and other impurities against which conventional aeration systems have little effect. Fine-bubble aeration is considered to be the most energy-efficient clean water transfer process, but is significantly impacted by contaminants in untreated wastewater. To address this problem, the VertiCel process uses an optimal combination of efficient vertical disc surface aerators at the front end of the biological process, followed by fine bubble aeration in the latter stages of treatment, where most of these contaminants have been removed.

Excess biological sludge is then transferred to the facility’s “Cannibal” solids reduction system, after which biodegradable substances are broken down even further. Depending on the bacteria cultures involved, this entails alternating treatment stages, some of which require additional oxygen. As a result of this patented process, bacteria work much more efficiently and the amount of waste-activated sludge — the collection of microorganisms that decompose the organic materials in a biological treatment process — is reduced by 30 to 50 percent compared to a conventional process. Any biological solids still present following these steps are subsequently dewatered, dried and sent to a cement factory for incineration.

The use of the new technology eliminates a substantial part of waste-activated sludge and reduces drying and incineration costs. After treatment, the water is fed into a reservoir, where it is used for irrigation on farms.

Major Market. As a result of its reduced energy use and sludge-disposal costs, the Inegöl plant will save its operators approximately €1.5 million per year once the facility is running at full capacity. “That’s attractive for the companies involved, because they will have to pay part of the facility’s operating costs,” says Bulutlar. Thanks to this biological treatment plant, which saves space, water, and energy, Siemens has established a leading position in the field of wastewater purification in Turkey. “The Inegöl project demonstrates how fruitful cooperation with a globally operating supplier like Siemens can be,” says Bulutlar. “The company not only has extensive experience but also boasts a great deal of technical expertise and offers a broad range of solutions.”

“Turkey has a lot of catching up to do,” adds Bulutlar. “It would like to gradually reach the level of the European Union — an ambition that will require substantial investment.” With this in mind, the Turkish Ministry for Science, Industry, and Technology is introducing a range of incentives to spur the connection of the country’s industrial zones to water purification systems.

According to statistics from 2009, only 70 of 120 large industrial zones in Turkey have been connected to such systems. But over the next four years, Turkey’s plans call for the wastewater from 43 more industrial zones to be purified. For Siemens, Inegöl is an ideal showcase project. Not only is it located in a dynamic industrial region; it also had to overcome a wide variety of challenges.