Evaporating wastewater seems expensive and energy-intensive, but it doesn’t have to be. Companies can recoup their investment within three to five years if they filter the condensate and reuse it as process water. Bernard De Jonghe, a GEA expert in separation techniques for the chemical industry, talks about the sustainable possibilities of evaporation technology, during the interaction with Mayur Sharma.
Q. Bernard, why is wastewater evaporation so expensive?
Bernard: Evaporation is a separation technique that demands a substantial investment while at the same time seemingly wastes a lot of energy. So it’s our job to properly inform the customer about the various possible techniques so that we can be sure evaporation is the right choice. With larger customers who have the requisite expertise in-house and know that an evaporator is what they need, it’s simply a question of taking a quick look at their decision process and endorsing the outcome.
The investment is considerable, but the equipment is very robust and is built to last a generation and more. The energy consumption of evaporation can be optimized with thermal or Mechanical Vapour Recompression (MVR). You’d be amazed at how efficiently water can be evaporated!
Another thing is that the composition of wastewater is variable – unlike that of milk or sugar, for instance. No two batches of wastewater are the same. So it has to be thoroughly tested, as we need to be sure we’re using the right physical parameters to correctly dimension our equipment. Testing is done in three stages: 1) in the lab, 2) in a pilot plant and 3) during a continuous endurance test for 3-6 weeks. Only then can we give the customer realistic and reliable information about the solution, including energy consumption and purchase price.
Q. But they can recoup the investment, can’t they?
Bernard: Yes, that’s right. The evaporation process produces condensed water, which they would like to recycle in the plant as process water. But to do this, the water has to meet the quality requirements for process water. That calls for techniques like membrane treatment, stripping, distillation, etc. We have experience with separation techniques in the food industry – which has to meet the most rigorous standards – and can use it to advise companies in the chemical industry. MDF manufacturers such as Spanolux and Unilin completely recycle their condensed water, for instance.
This kind of exercise inevitably involves a financial analysis: what are the tax benefits? How much can we save if we have much less or no waste to dispose of if we no longer need to pump water, etc.? Those savings will be weighed against the investment and energy costs. Depending on the industry, companies want to be able to write off the investment within three to five years.
Q. Do you think the need for recycling will increase?
Bernard: Absolutely. Water is becoming a precious resource. We as a society are going to have to think about how we deal with water. Companies with drilling wells sometimes pump up large quantities of groundwater. But more and more often they’re being denied access to the water table as a result of taxes levied by the government, which wants to use the groundwater as drinking water. We’re seeing that not just in Belgium, but throughout Western Europe. Other sectors will follow, such as the waste-processing, metallurgical and textile industries, for example. Some companies are resorting to diluting water, but that’s just a temporary fix.
Q. Finally, why should I choose GEA for wastewater evaporation equipment?
Bernard: I believe that GEA is second to none when it comes to the product experience. Our technical center in Karlsruhe, where 15 people constantly run tests, is a crucible of ideas and ensures that we’re at the cutting edge of technology. What’s more, we can quickly check all the details of the project together with the customer. And the customer knows that GEA has the right expertise in-house. Last but not least, we’re well organized and can successfully manage major projects because we have excellent resources in Germany in the areas of process technology, automation, equipment manufacturing, and structural steelwork.
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