Zero Liquid Discharge Evaporation Equipment

Zero Liquid Discharge Evaporation Equipment Product Introduction

The zero liquid discharge (ZLD) evaporation equipment is the terminal core treatment unit in the full ZLD wastewater process. It is mainly used to treat high-salinity concentrated brine and high-concentration refractory wastewater generated by membrane systems, achieving water evaporation and salt crystallization separation through thermal energy drive. The condensate produced by evaporation can be reused in production processes, and the crystallized salt is disposed of compliantly as solid waste, ultimately achieving no liquid wastewater discharge from the entire system. It is essential equipment for enterprises in strictly environmentally regulated areas and high water-consuming enterprises to achieve zero liquid discharge. Changsha Jing'anlan Environmental Technology can match different process routes such as MVR mechanical vapor recompression, multi-effect evaporation, and forced circulation evaporation according to the concentrated brine volume, salinity, water quality composition, and plant energy conditions, providing full-process ZLD solutions from concentrated brine pretreatment to evaporation crystallization.

System Composition and Working Principle

The core principle of the evaporation equipment is to vaporize the water in the concentrated brine through heating, then condense it into clean distilled water for reuse; the dissolved salts in the water gradually concentrate as the water continuously evaporates, and crystallize out after reaching a supersaturated state, ultimately achieving solid-liquid separation of water and salts. A complete ZLD evaporation system mainly consists of five process units:

1. The pretreatment unit removes hardness, silica, suspended solids, and other scale-prone components from the concentrated brine through softening, silica removal, pH adjustment, flocculation and sedimentation processes, reducing the scaling and fouling tendency during evaporator operation and ensuring long-term stable operation of the equipment.
   

2. The preheating and heat exchange unit uses the waste heat from steam condensate and secondary steam to perform multi-stage preheating of the feed water, fully recovering thermal energy, improving overall thermal energy utilization, and reducing operating energy consumption.
   

3. The evaporation and concentration unit is the core treatment unit of the system. It heats the concentrated brine through steam or mechanically compressed thermal energy, causing continuous water evaporation. The concentrated brine continuously circulates and concentrates within the system until reaching salt saturation.
   

4. The crystallization and separation unit: the saturated concentrated brine enters the crystallizer for further evaporation, and salts precipitate to form crystal slurry. Solid-liquid separation is carried out through a centrifuge. The wet crystallized salt is collected and disposed of compliantly as hazardous waste or general solid waste, and the mother liquor is returned to the evaporation system for continued treatment.
   

5. The condensate recovery and automatic control unit: the secondary steam condenses to form clean distilled water, which is collected and reused in production processes; it is equipped with a fully automatic control system to achieve automatic operation of the entire process of feeding, heating, concentration, and salt discharge, with real-time monitoring of key parameters such as temperature, pressure, and liquid level.
   

Core Technical Advantages

1. Achieve true zero liquid discharge and completely eliminate environmental compliance risks. High-salinity concentrated brine can be fully treated and reduced to only crystallized salt and reusable distilled water, with no liquid wastewater discharged. This thoroughly avoids the risks of excessive discharge and environmental penalties, meeting the stringent environmental requirements of key regulated industries such as chemicals, electroplating, and printing & dyeing.
   

2. High water recovery rate and outstanding overall benefits. The system's distilled water recovery rate can reach over 95%. The condensed water is of excellent quality with low conductivity and can be directly reused in production processes or as boiler makeup water, greatly reducing fresh water consumption and enabling resource utilization of concentrated brine, which can offset part of the evaporation operating costs.
   

3. Flexible process selection, adaptable to various water qualities and operating conditions. The optimal process can be matched according to the characteristics of the concentrated brine and site conditions: sites without surplus steam should prioritize the MVR process for low operating energy consumption; scenarios with stable industrial steam should use the multi-effect evaporation process for lower investment costs; high-hardness, scale-prone concentrated brine should use the forced circulation evaporation process for strong anti-scaling capability.
   

4. High degree of automation with stable and reliable operation. The system is equipped with a fully automatic control system to achieve continuous and stable operation, featuring safety functions such as high/low pressure protection, liquid level interlocking, and fault alarms. It also includes an online cleaning system for regular descaling maintenance, effectively extending the continuous operation cycle and service life of the equipment.
   

Applicable Industries and Scenarios

• Industrial park zero liquid discharge projects: tailwater zero discharge projects of centralized wastewater treatment plants in chemical, printing & dyeing, electroplating, coal chemical and other industrial parks
  

• Industrial high-salinity wastewater treatment: terminal volume reduction and zero discharge treatment of high-salinity wastewater such as reverse osmosis / DTRO concentrate, nanofiltration concentrate, and chemical production mother liquor
  

• Hazardous waste liquid reduction: evaporation and volume reduction of high-concentration waste liquid, waste acid/alkali liquid, and distillation residues, greatly reducing the volume and cost of hazardous waste disposal
  

• Zero liquid discharge system integration: used in conjunction with reclaimed water reuse and membrane treatment systems to build a complete zero discharge chain of "wastewater treatment — reclaimed water reuse — concentrated brine evaporation"
  

Selection Guide

Zero-discharge evaporation equipment selection requires comprehensive consideration of four core factors: concentrated water volume, salt content, water quality composition, and on-site energy conditions:

• Process type: For scenarios with stable industrial steam, multi-effect evaporation is preferred; for scenarios without steam and with large water volumes, MVR mechanical vapor recompression is preferred; for high-hardness, high-suspended-solids concentrated water, forced circulation evaporation is preferred
  

• Treatment scale: A single unit's evaporation capacity covers 0.5t/h to 50t/h; larger scales can use multiple units in parallel
  

• Material configuration: 304 stainless steel for conventional neutral salts; 316L, titanium, and other special materials for chloride-containing, highly corrosive water quality
  

• Supporting processes: Requires simultaneous supporting concentrated water pretreatment system, crystallized salt dewatering system, and mother liquor treatment system to ensure stable operation of the entire process
  

The Jing'anlan environmental technology team can provide customized zero-discharge evaporation system solutions and operating cost estimates based on concentrated water quality test reports and on-site conditions, ensuring process suitability and economic feasibility.

Jing'anlan Service Support

• Free water quality testing and process evaluation, customized overall zero-discharge evaporation system solutions and cost estimates
  

• Professional team handles the entire process of system design, installation, and commissioning, ensuring stable water output and salt discharge
  

• Long-term supply of evaporator core components, cleaning chemicals, and spare parts
  

• Provide operation training and O&M guidance to ensure plant personnel are proficient in operating skills
  

• Provide full-chain EPC+O services from front-end wastewater treatment to terminal evaporation zero liquid discharge