Why is Zero Liquid Discharge Important?

In April 2024, the U.S. EPA finalized the updated ELG rule requiring coal-fired powerplants to adopt a Zero Liquid Discharge approach for FGD wastewater, Bottom Ash Transport Water, and Combustion Residual Leachate (CRL). ZLD removes the discharge pathway entirely, eliminating future compliance risk and supporting long-term operational planning.

Why Plants Turn to ZLD

Facilities move to ZLD when wastewater discharge is no longer technically, economically, or legally feasible. Common triggers include:

• Highly restrictive NPDES discharge limits
• No-discharge permits or lack of receiving waters
• Corporate or state water reuse mandates
• Residual brine streams that cannot be discharged
• Desire to eliminate long-term discharge liability

ZLD enables plants to recover nearly all water for reuse, improving operational stability and reducing freshwater demand.

How ZLD Works

A complete ZLD system integrates several treatment stages that convert wastewater into two outputs: recovered water and a stable solid byproduct. Typical components include:

Pre-Treatment

• Softening
• Clarification
• Media and membrane filtration

Concentration Technologies

• Reverse osmosis (RO)
• Brine concentrators
• Evaporation systems

Crystallization

• Converts concentrated brine into solid material
• Reduces long-term handling and disposal risk

Water Recovery & Reuse

• Treated water is recycled back into the facility
• Reduces freshwater draw and operating costs

ZLD Compliance Checklist

1. Water balance – Have you mapped all wastewater streams and recycle opportunities?
2. Permit review – Do your NPDES requirements or local conditions point toward ZLD?
3. Pilot study – Have you tested RO, evaporation, or crystallizer options at your site?
4. Residual management – Do you have a plan for handling and disposing of crystallized solids?
5. Energy/cost model – Have you modeled the CAPEX and OPEX impact of ZLD vs. advanced treatment?
6. TIMELINE – Do you have 24–36 months to design, permit, and install a full ZLD system?
7. Regulatory engagement – Have you discussed ZLD as a compliance option with your permitting authority?

Next Step: ZLD systems are complex — but with the right engineering partner, utilities can reduce risk and achieve long-term compliance.

Key Advantages of ZLD

• Eliminates discharge-related violations and fines
• Enhances water reuse and resource conservation
• Protects operations in water-stressed regions
• Reduces long-term environmental liability
• Supports corporate sustainability and compliance goals

Challenges to Plan For

ZLD is effective, but it requires thoughtful planning and engineering. Plants should consider:

• Higher capital and operating cost
• Increased energy consumption
• Larger system footprint
• Handling and disposal of crystallized solids
• Longer implementation timeline (typically 24–36 months)

Proper piloting and front-end engineering significantly reduce risk and help optimize long-term operating strategy.

Why Utilities Choose UCC Environmental

UCC Environmental delivers engineered solutions specifically for heavy industry. Our team brings:

• Proven experience in ELG-driven ZLD programs
• Deep process knowledge and full-plant water balance expertise
• Pilot testing and performance validation
• Seamless integration with existing treatment systems
• North American engineering, service, and field support

Zero Liquid Discharge FAQ’s

Next Step: Request a Site Evaluation

ZLD projects require the right technical and compliance strategy. Our engineers can review your water balance, site constraints, and treatment options to determine if ZLD is the best fit.