ZERO LIQUID DISCHARGE TECHNOLOGY

Zero liquid discharge (ZLD) is an engineering approach to water treatment where all water is recovered and contaminants are reduced to solid waste. NanoWater ZLD treatment system typically includes 4 treatment steps:

Pretreatment and conditioning
  • Clarifier and/or reactor to precipitate out metals, hardness, and silica
  • Chemical feed to help facilitate the precipitation, flocculation, or coagulation of any metals and suspended solids
  • Ultrafiltration (UF) to remove all the leftover trace amounts of suspended solids and prevent fouling, scaling, and/or corrosion down the line of treatment
Phase-one concentration
  • Reverse osmosis (RO) to remove the bulk of dissolved solids from the water stream in the primary phases of concentration
Evaporation/crystallization
  • Brine concentrators to further concentrate the reject RO to further reduce waste volume
  • Evaporator for vaporizing access water in the final phases of waste concentration before crystallizer.
  • Crystallizer to boil off any remaining liquid, leaving you with a dry, solid cake for disposal
Filter press

It is used to concentrate secondary solid waste after pretreatment or alongside an evaporator

 

The importance of Pre-Concentration in a ZLD Process

The pre-concentration technologies have very high recoveries but usually not enough like the typical thermal evaporation technologies to drive the brine into saturation concentration levels. So why are they so important? The reason is the CAPEX/OPEX of the evaporators/crystallizers.

  • Due to the corrosive nature of the brine it takes more and more resistant metal alloys in order to resist corrosion as the concentration rises. That means that the bigger is the evaporation/crystallizer module, the bigger will be the CAPEX required (which can be 60-70% of the whole process).
  • High energy demand due to the rise of the boiling point of the brine as concentration goes higher.
Evaporation and crystallization

Evaporation and crystallization plants are required whenever there is a process: water or any other solvent has to be removed, concentration has to be increased or volume reduced, valuable and pure crystals have to be produced, by-products or impurities have to be stripped or precipitated.
NanoWater’s team consist of senior engineers in comprehensive disciplines such as: process, mechanic, electrical , projects, R&D, instrumentation and control, erection, commissioning, 2D and 3D design. Optimization of equipment process design with computational fluid dynamic: separator size, three phase flow distribution in crystallizer, axial flow pump discharge, directional guide vane to avoid abrasion. We also offer optimization of mechanical design with Finite element modeling: thickness reduction, nozzle stress on equipment

ZLD RECOVERED PRODUCT
  • ZLD can also be used to recover valuable resources from the wastewater
  • Generation of potassium sulfate (K2SO4) fertilizer from a salt mine
  • Concentration of caustic soda (NaOH) to 50 and 99% purity
  • Recovery of pure sodium sulfate (NaSO4) from a battery manufacturing facility
  • Reduction of coal mine wastewater treatment costs by recovering pure sodium chloride (NaCl) which can be sold as road salt
  • Lithium (Li) has been found in oil field brines .
  • Gypsum (CaSO4.2H2O) can be recovered from mine water and flue gas desulfurization
  • (FGD) wastewater, which can then be sold to use in drywall manufacturing
TECHNOLOGIES

Vertical Tube Falling Film Evaporators

  • Seeded Slurry (Brine Concentrators)
  • Non Seeded Evaporators

Forced Circulation Crystallizers
Sludge Dewatering

  • Filter Press
  • Centrifuge
  • Drum Dryers

 

APPLICATIONS
  • Cooling tower blowdown in heavy industry and power plants
  • Ion exchange regenerative streams particularly in food and beverage processing
  • Flue gas desulfurization blowdown, wet wastewater stream
  • Municipal potable water systems, wastewater streams
  • Process water reuse from agricultural, industrial and municipal streams
  • Various industrial wastewater streams from the textile, coal-to-chemical, food and dairy or battery industries
  • Membranes System Reject (NF,MF.UF & RO)
  • Produced water (Conventional, Fracking, SAGD)
  • Nox Injection Water
  • Integrated Gasification Combined Cycle (IGCC)
  • Mine Drainage
  • Refinery, Gas to Liquid (GTL), Coal to Chemical (CTX ) wastewaters
  • Scrubber Blowdown
  • Demineralization Waste
  • Landfill Leachate
Leading ZLD provider

NanoWater has many years of experience custom-designing and manufacturing wastewater treatment systems, so please feel free to reach out to us with your questions. For more information or to get in touch, contact us here. You can also visit our website to set up a call with an engineer or request a quote. We can walk you through the steps for developing the proper solution and realistic cost for your ZLD wastewater treatment system needs.