Engineered system · Water & Wastewater Treatment
Zero Liquid Discharge (ZLD) Systems
Plan every stream, including what remains.
A liquid-discharge objective is a whole-site water and residue question. Recovery stages and residual handling must be considered together.
Project vision
Zero liquid discharge is a treatment train built so that no wastewater leaves the site. Effluent first passes through conventional treatment, then membranes recover most of the water as clean permeate. The concentrated reject that remains is boiled down in evaporators and dried into solids. The result is reusable water on one side and a dry residue on the other, with no liquid stream to a drain or river.
Industries look at ZLD for many reasons: tighter disposal rules, consent conditions in sensitive river basins, rising water costs, or simply a shortage of fresh water. We design the full chain to suit your effluent, from pre-treatment through membrane recovery to evaporation and drying, and we can operate and maintain it under an AMC.
Illustrative application narrative · no completed installation or measured result is asserted.
Typical business & operational challenges
A typical operational situation
Concentrated streams, energy demand and residue disposal can be missed when the focus stays only on water recovery.
Our solution
Zero Liquid Discharge (ZLD) Systems is considered around the actual duty, available inputs and operating arrangement. The scope starts with water and salt balance. It also considers recovery-stage evaluation. It also considers thermal options where appropriate. It also considers residue-management planning.
Our approach
Map all water and concentrate streams
Review chemistry and feasible recovery routes
Assess energy and residue handling
Define integrated scope and acceptance criteria
Features & deliverables
- Water and salt balance
- Recovery-stage evaluation
- Thermal options where appropriate
- Residue-management planning
Selection and inclusion are confirmed through the approved proposal and design.
Expected operational benefits
A clearer basis for water and salt balance and residue-management planning, supported by an operating approach suited to the application. Actual performance depends on the final design, conditions and operation.
Technology options & engineering basis
Assess energy and residue handling. Equipment, interfaces and operating requirements are selected after the input review.
Information to bring to the discussion
Source or process analysis, flow and load variation, target quality, space, utilities and operating constraints.
How it works, stage by stage
Pre-treatment
Oil and grease trap, equalisation and neutralisation prepare the raw effluent.
Clariflocculation
A flash mixer and primary clariflocculator remove suspended solids and part of the pollutant load.
Biological treatment
Aeration breaks down organics, followed by a secondary clariflocculator to settle the biomass.
Filtration
Pressure sand and activated carbon filters polish the water ahead of the membranes.
UF and RO
Ultrafiltration protects the RO, which recovers clean water and leaves a concentrated reject.
Evaporation (MEE)
A multiple-effect evaporator boils off water from the reject, reusing steam across effects.
Drying (ATFD)
An agitated thin film dryer turns the concentrate into dry solids for disposal.
Options
Membrane-led ZLD
UF and RO recover most of the water, keeping the volume sent to evaporation as small as possible.
Thermal ZLD
Evaporators and dryers handle high-salt streams that membranes cannot treat economically.
Hybrid ZLD
Membranes and thermal stages combined, sized to balance capital cost, energy and recovery.
Where it is used
- Pharma (API)
- Textiles & dyeing
- Distilleries
- Paper & pulp
- Specialty chemicals
- Pesticides
- Petrochemicals
- Biotech
Visual story
The needPlan every stream, including what remains. Concentrated streams, energy demand and residue disposal can be missed when the focus stays only on water recovery.
Read the full voiceover script
- The need Plan every stream, including what remains. Concentrated streams, energy demand and residue disposal can be missed when the focus stays only on water recovery.
- The response Zero Liquid Discharge (ZLD) Systems begins with the application. Map all water and concentrate streams. Review chemistry and feasible recovery routes.
- The work Assess energy and residue handling. Then define integrated scope and acceptance criteria. The details belong to the agreed configuration and scope.
- The next step Start with water and salt balance, and define what success needs to look like. Discuss your application with ZEAL.
Questions before the next step
Does a ZLD label establish zero discharge?
No. The claim requires a defined site boundary, complete stream accounting and verified operating evidence.
What is needed for an enquiry?
Water and salt balance, application details, available records, site constraints and the required delivery scope.
Is ZLD compulsory for our unit?
It depends on your industry, location and consent order. Regulators have asked several sectors, particularly in the Ganga basin, to adopt ZLD, so check your consent conditions and we will help you read them.
What drives the running cost of a ZLD plant?
Mostly the energy and steam used by the evaporator and dryer. That is why we push as much recovery as possible through the membranes first, so less water has to be boiled off.
What happens to the dry solids?
The salts and sludge are collected and sent for disposal through an authorised facility, as your consent requires. Some streams allow salts to be recovered and reused.
Bring us your application.
Share your requirement and the information you already have. ZEAL can help clarify the options and the information needed for the next step.