MEE vs MVR Cost Comparison
Should your ZLD system use a Multi-Effect Evaporator or Mechanical Vapour Recompression? Enter your flow, TDS, and energy costs to get a data-driven CAPEX + OPEX comparison and a clear recommendation.
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Min 5,000 ppm for MEE/MVR to be relevant
MEE vs MVR: Understanding the Core Difference
In a Zero Liquid Discharge (ZLD) system, the evaporator is the largest single cost item — both in CAPEX and OPEX. Choosing between a Multi-Effect Evaporator (MEE) and Mechanical Vapour Recompression (MVR) is a decision that will affect your plant economics for 20+ years.
Both technologies achieve the same outcome: removing water from a high-TDS concentrate to produce a clean condensate and a concentrated brine for crystallisation or salt disposal. The difference is in the energy source and mechanism:
MEE (Multi-Effect Evaporator)
Uses steam as primary energy input. Feed is boiled sequentially across 3–4 effects, each at progressively lower pressure. Each kg of steam evaporates ~2.5–3.5 kg of water (for triple/quad effect). Ideal when cheap steam is available — from a captive boiler, process steam header, or waste heat.
MVR (Mechanical Vapour Recompression)
Uses electricity to drive a compressor that recompresses the vapour from evaporation back to higher pressure, re-using it as the heating steam. Energy consumption is 15–25 kWh per m³ evaporation. No steam boiler required. Ideal when power cost is low (<₹7/kWh) and steam infrastructure is absent.
The Key Decision Factor: Energy Cost
The crossover point between MEE and MVR economics is primarily driven by your energy cost structure. As a rule of thumb:
| Power Cost (₹/kWh) | Steam Cost (₹/kg) | Recommended Technology |
|---|---|---|
| < ₹5/kWh | Any | MVR — strong preference |
| ₹5–7/kWh | > ₹2/kg | MVR likely better on 10-yr TCO |
| ₹5–7/kWh | < ₹2/kg | Evaluate both — close call |
| ₹7–9/kWh | Any | MEE preferred — use available steam |
| > ₹9/kWh | Any | MEE — clear preference |
Technical Constraints: When Each Technology Is Unsuitable
Beyond economics, there are technical constraints that may rule out one option:
MEE Limitations
- • Requires steam boiler or process steam header
- • Lower single-pass energy efficiency vs MVR
- • Larger physical footprint for same capacity
- • More complex piping and multi-vessel arrangement
MVR Limitations
- • Compressor maintenance is more complex and expensive
- • Less suitable above 80,000–100,000 ppm TDS
- • Not ideal for foaming or viscous liquids
- • Higher power demand (load factor on plant DG set)
MEE and MVR in Indian ZLD Context
In India, MEE has historically dominated the ZLD evaporator market — particularly in distilleries, textile dyeing units, and pharma plants — because most industrial plants already have steam boilers for process heating. Adding MEE to an existing steam header is simpler than installing compressor infrastructure for MVR.
However, as industrial electricity tariffs have stabilised (and in some states declined with renewable PPAs), MVR is seeing growing adoption — particularly in food processing, dairy, and integrated food parks where green credentials and lower carbon footprint are increasingly important.
Spans Envirotech designs ZLD systems incorporating both MEE and MVR configurations. Our comparison tool above gives you planning-level economics; our detailed process simulation provides bankable figures. See our MEE vs ATFD comparison guide and ZLD plant overview for broader context.
Frequently Asked Questions
What is the steam consumption of a triple-effect MEE?
A triple-effect MEE consumes approximately 0.35 kg of steam per kg of water evaporated. A quad-effect MEE improves this to about 0.28 kg/kg. For a 100 KLD plant evaporating 85 m³/day (85,000 kg/day of water), a triple-effect MEE requires approximately 29,750 kg/day of steam.
What is the power consumption of MVR?
MVR consumes 15–25 kWh per m³ of evaporation. The range depends on: TDS of the feed (higher TDS = higher boiling point elevation = more compressor work), type of compressor, and operating temperature. For clean feeds at 50,000 ppm TDS, 17–20 kWh/m³ is typical. At 100,000 ppm TDS, expect 22–25 kWh/m³.
How long does MEE or MVR equipment last?
MEE equipment has a design life of 20–25 years for SS 316L construction. MVR compressors have a design life of 15–20 years with regular maintenance. Key wear items in MVR are compressor bearings and seals (4–6 year replacement cycle). In MEE, tube bundles may need replacement in 10–15 years in corrosive service.
Can MEE handle very high TDS (200,000+ ppm) concentrate?
Yes. MEE is capable of handling very high TDS — up to 250,000–300,000 ppm (near saturation) for salts like sodium chloride and sodium sulfate. This makes MEE the preferred choice for brine concentration ahead of a crystalliser. MVR struggles above 100,000–120,000 ppm due to boiling point elevation limitations.
Is MEE or MVR better for the textile industry?
Textile ZLD uses MEE more commonly because textile dyeing effluent is complex — high colour, high COD, and variable composition. MEE handles this variability better. MVR is sensitive to foaming (common in textile wastewater with surfactants) and scaling from calcium/magnesium salts. MEE can be designed with anti-scalant dosing and chemical cleaning provisions more easily.
Need a Bankable ZLD Cost Estimate?
Our process simulation team prepares detailed MEE/MVR techno-commercial proposals with feed characterisation, process design, and vendor-quoted costs.