Zero Liquid Discharge (ZLD) Water Treatment


New Harquahala Generating Project ZLD water treatment plant

Fresh water scarcity and concerns for environmental impact resulting from industrial wastewater discharges place a high degree of importance on recycling and reuse of water, an increasingly valuable resource.

As regulatory issues, environmental sensitivity, and long-term water supply concerns increase, many industrial companies are considering ways to reduce their water discharges by having a Zero Liquid Discharge (ZLD) plant or integratin a ZLD system.

Veolia Water Technologies has decades of innovation using HPD® Evaporation and Crystallization technology in many wastewater treatment applications including industry experience in volume reduction and zero liquid discharge:

Veolia Water Technoloigies has the expertise to design and build wastewater reduction and ZLD facilities of any size, anywhere in the world. Delivery of a project on a lump-sum, turnkey basis ensures that customers have a single point of responsibility. Veolia also specializes in operation and maintainance of the industrial ZLD facilities for a fixed term.


Each effluent stream presents its own unique challenge when designing an entire ZLD water treatment system to efficiently and effectively minimize waste or eliminate the discharge of wastewater.

Veolia's experience in treating and managing these streams include specification and complete system design utilizing complementary water treatment expertise from Veolia Water Technologies such as deoiling, softening, clarification, and filtration for the following applications:


ZLD system with wastewater evaporator and wastewater crystallizer

Veolia offers several options in designing the optimal system to achieve each unique customer requirement for achieving zero liquid discharge or waste reduction objectives, including recovered water quality, energy consumption, minimization of capital and operating costs, and ease of operation. HPD® Evaporation and Crystallization system capacities range from around 10 gpm to greater than 1500 gpm per unit.

Falling film evaporators, sometimes called brine concentrators, are an excellent technology for efficient heat transfer, producing high-purity distillate, and achieving water recovery greater than 90%. Recovered water in a brine concentrator is suitable as cooling tower or scrubber makeup, and can be recycled to other plant processes, including demineralizer feedwater. These wastewater evaporators can be driven by mechanical vapor recompression (MVR) or with live steam depending on the relative costs of electric power and steam.

Crystallizers are designed to handle continuous crystallization of the various dissolved salts, which sometimes can be recovered as valuable by-products. Wastewater crystallizers are used to concentrate the effluent from brine concentrators, and when equipped with solids dewatering, comprise a true zero liquid discharge system. These brine crystallizers typically are driven by live steam but in some cases can use MVR technology to recycle the vapor to reduce energy usage and operating costs.