Zero-Liquid Discharge Systems

Zero-Liquid Discharge (ZLD) is an advanced wastewater treatment method that eliminates all liquid waste from industrial processes, while recovering more than 95% of a plant’s wastewater for reuse. 

When left untreated and discharged into existing bodies of water, liquid waste is hazardous to the environment and threatens global access to clean water. ZLD purifies wastewater to maximize the recovery of clean, reusable water—reducing environmental impact, improving sustainability, and ensuring compliance with local discharge and water re-use regulations. In addition, ZLD systems can retrieve valuable byproduct for reuse, while isolating contaminates for proper disposal.

Benefits of Zero-Liquid Discharge from Swenson

Swenson provides streamlined Zero-Liquid Discharge systems, designed to meet the unique demands of your application. As a result, our ZLD designs provide the following benefits: 

  • Maximize clean water recovery
  • Reduce costs of raw materials due to product recovery from waste streams
  • Minimize costs of solution transportation and processing
  • Enable easy setup and relocation with skid-mounted equipment

Zero-Liquid Discharge Systems

There is no one solution for achieving zero liquid discharge, as each application presents its own unique, complex set of variables including wastewater composition, type and number of streams requiring treatment, application footprint, and more. Therefore, it is important to choose a solution provider with engineering design expertise across all major ZLD methods and technologies, including evaporation, crystallization, filtration, centrifuging, heat transfer, and drying. 

Swenson has been designing and building systems to handle waste streams for many years. Our tremendous experience, coupled with our commitment to staying at the forefront in research and development, has enabled Swenson to develop a wide range of systems to process liquid waste and deliver usable byproducts. 

In designing a ZLD system, we take many factors into consideration.

The goals of the system—volume reduction, separation, crystallization, purification, and/or product recovery—determines the system design. Following are three basic types of systems:

  • For applications requiring evaporation, an evaporator reduces wastewater solutions to manageable volumes or concentrations. Concentrated liquor is either circulated back to the process or sent to disposal.
  • For concentrated liquor that does not lend itself to crystallization but requires further processing, a spray dryer converts concentrate into a dried powder, which can be used or sent to disposal.
  • For concentrated liquor lending itself to crystallization, a crystallizer produces a crystal slurry. If further processing is required, the slurry goes to a centrifuge, which produces moist crystals that are fed to a dryer producing dry crystals.