Groundbreaking decanter

“For the first time in history, it might actually be worth replacing an old decanter with a new one before the old one is completely worn out,” says Bent Madsen, manager, Process & Technology, Product Centre Decanters at Alfa Laval. Madsen has worked on the development of the Alfa Laval Aldec G3. “It is quite unique that the investment in a new decanter pays off before the lifetime of the old decanter is up.”

Two new features make this possible – the Alfa Laval Power Plates and the Alfa Laval Slimline design. The Power Plates reduce the loss of kinetic energy when the liquid leaves the bowl, reducing flow-related power consumption by up to 20 percent. The Slimline design features a smaller conveyor diameter, which means there is room for more liquid in the pond, and the pressure on the bowl wall can be higher. This paves the way to either a drier cake or less use of polymer. The smaller discharge radius can save an additional 20 percent in power costs, and a drier cake helps solids handling and saves on transport costs.

“This is a product for customers who focus on their operational costs,” says Brian Munch, business manager, Environment Technology at Alfa Laval. “Sometimes it’s just a matter of making a simple calculation to know the actual impact on the operational costs.”

The development of the Aldec G3 began some years back. Alfa Laval determined to develop an extraordinary product that would really make a difference, focusing on both reducing power consumption and improving performance. “The large power consumption of decanters actually disturbs the separation process, so we figured if we could reduce power consumption we would improve the result as well,” explains Madsen.

The final solution featuring the Power Plates and the Slimline design is actually quite simple – so simple in fact that the Alfa Laval Aldec G3 is often met with initial scepticism. When it was launched at a municipal wastewater exhibition in Munich, Germany, in September 2010, the customers invited to the launch couldn’t believe that such a simple solution could make such a difference. “They first wondered ‘Can that really be true?’” says Munch. “We have been facing a challenge of how slim we could make the conveyor design without loosing its stiffness. But we have found a new way of doing this.”

The results speak for themselves. The Alfa Laval Aldec G3 has been tested in full scale at a wastewater treatment plant in Chicago, in the United States, with great results. And the first customers to buy and install the Aldec G3 have already seen the promised results.