Zero Liquid Discharge Etp

Zero Liquid Discharge (ZLD) is a treatment process designed to remove all the liquid waste from a system. The focus of ZLD is to reduce wastewater economically and produce clean water that is suitable for reuse (e.g. irrigation), thereby saving money and being beneficial to the environment.

The specific technologies that will make up a facility’s ZLD treatment system will vary greatly depending on (1.) the volume of dissolved material present in the waste, (2.) the system’s required flow rate, and (3.) what specific contaminants are present, but will generally consist of a three-step process with the following “blocks” of treatment:

1. Pretreatment and conditioning; removes simple things from the wastewater stream that can be filtered or precipitated out, conditioning the water and reducing the suspended solids and materials that would otherwise scale and/or foul following treatment steps.

2. Phase-one concentration. Concentrating is usually done with membranes like reverse osmosis (RO), brine concentrators, or electrodialysis. These technologies take this stream and concentrate it down to a high salinity and pull out up to 60–80% of the water. Zero Liquid Discharge System, Zero Liquid Discharge Plant, zld system, zero liquid discharge plant, zld plant, zero liquid discharge water treatment system

3. Evaporation/crystallization. After the concentration step is complete, the next step is generating a solid, which is done through thermal processes or evaporation, where you evaporate all the water off, collect it, and reuse it. The leftover waste then goes from an evaporator to a crystallizer, which continues to boil off all the water until all the impurities in the water crystallize and are filtered out as a solid.