Freshwater withdrawals constitute water taken from ground or surface water sources. As global population and water demand increase, freshwater is more likely to be extracted beyond the rate at which aquifers are replenished, leading to water stressed conditions. Industry also competes for freshwater – often requiring large volumes and generating significant amounts of wastewater too, due to cleaning processes. With deep engineering and process expertise across multiple industries, GEA is well-positioned to help customers meet even the most ambitious water targets.

Water recovery and reuse in production processes

Milk is approximately 85 percent water. That means dairy processors have the potential to reuse millions of liters of water annually. Using a GEA reverse osmosis unit, condensate can be collected from an evaporation plant and the resulting water returned to the process. This greatly reduces freshwater withdrawals, minimizes manufacturing and disposal costs and mitigates CO2 emissions.

Located in Gandhinagar, India, AmulFed is Asia’s largest skim milk powder plant. It is also a near zero-water discharge facility. This feat is the result of three sets of GEA reverse osmosis polisher units which treat the condensate from an evaporation plant. From there, the water is reused for product cooling and plant cleaning, which eliminates the use of 420 million liters of freshwater annually. 

A type of membrane filtration, reverse osmosis (RO) is commonly used in dairy and food processing to concentrate solids, recover water and for “polishing.” The additional polishing step purifies the condensate resulting from the evaporation process. From there, it is suitable for watering green space or for use as toilet water. With further heat- or UV light treatment, effluent is safe to use in product-contact operations (e.g., final flushing, rinsing cans, cleaning tanks and pipework) and even as an ingredient in finished products. 

In chemical processing, manufactures may use evaporation to separate water vapor from their waste stream. After condensing, it is usable as process water. To ensure it meets quality requirements, membrane treatment, stripping or distillation are generally required. In Europe, GEA customers in the medium-density fiberboard (MDF) industry are recycling 100 percent of their condensed wastewater with GEA evaporation technology. And while the energy consumption of evaporation is significant, it can be substantially reduced with thermal or mechanical vapor recompression (MVR).

In other water-intensive processes, such as industrial recycling, materials recovery facilities can integrate a GEA sludge Decanter, which allows them to return wash water back to the process cycle. This step reduces disposal costs freshwater usage and averts potentially harmful chemicals from entering the environment.

Zero-liquid discharge for recovering water and by-products

Zero-liquid discharge (ZLD) is a process that more industries are adopting, particularly in regions where water shortages are acute. The process is commonly employed in the production of chemicals, oil and gas, power generation, mining and in water treatment plants. The benefits of ZLD are that it:

• eliminates wastewater discharges
• allows for reuse of process water, reducing freshwater withdrawals
• enables the recovery of by-products
• meets strict water reclamation & wastewater disposal regulations

GEA offers thermal and non-thermal zero liquid discharge systems which utilize crystallization technology to treat liquid effluent. Depending on requirements, GEA can provide membrane separation, decanter centrifugation, evaporation, crystallization, drying and energy recovery in this context. Our ZLD technology is successfully employed within a wastewater treatment plant at a power plant in Ciudad Juárez, Mexico. The ZLD wastewater plant converts salt-laden wastewater into pure water for internal recycling. The process leaves behind minimal dry solids for disposal, thanks to a GEA decanter centrifuge for final dewatering.  

Superior cleaning requires less water, not more

GEA product recovery and CIP systems also play an important role in minimizing freshwater usage and wastewater disposals. Product recovery, in particular pigging systems, clear process pipes of product which reduces the amount of water and chemical required during cleaning processes. For processes where storage tanks, silos or intermediate containers (IBC) are required, the removal of residues is paramount to safety and product quality. Here GEA Cleaning Technology is used across nearly all industries, ensuring product safety and hygiene and the efficient use of water and cleaning agents.