ZLD stands for Zero Liquid Discharge and describes a treatment concept in which liquid residual streams from industrial wastewater are reduced as far as technically and economically feasible. The goal is to recover water from contaminated process media and collect the remaining substances in the smallest possible concentrate stream.

In practice, a ZLD concept often consists of several steps, such as pretreatment, filtration or ultrafiltration, evaporation technology, concentrate reduction and optional post-treatment. Depending on its quality and the application, the recovered water can be reused in the process.

Important: ZLD does not automatically mean that every application is completely wastewater-free. The right solution always depends on the medium, target quality, process requirements and economic feasibility.