The core difference between water treatment equipment with and without EDI lies in the quality of the produced water, process principles, applicable scenarios, and operational characteristics. Compare and analyze from six dimensions:
1、 Water quality of production: significant difference in purity
Indicator with EDI device without EDI device
Conductivity ≤ 0.5 μ S/cm (usually 0.05-0.2 μ S/cm), close to theoretical pure water generally>5 μ S/cm (such as reverse osmosis water production of about 1-10 μ S/cm)
The resistivity is ≥ 1 M Ω· cm (up to 18.2 M Ω· cm), usually<1 M Ω· cm
The residual ion content almost removes all cations and anions (such as Na ⁺, Cl ⁻, Ca ² ⁺<1 ppb), and some residual ions (depending on the pre-treatment process, such as RO can remove 90-99% of ions)
Typical applications of ultrapure water include semiconductor cleaning, pharmaceutical injection water, industrial water, drinking water, and ordinary process water
Core difference: EDI achieves deep desalination through electric field driven ion migration and resin regeneration, while traditional processes (such as RO+ion exchange resin) are difficult to achieve the same purity, and the resin needs to be chemically regenerated regularly.
2、 Process principle: Does it rely on chemical regeneration
Dimension with EDI device without EDI device
Core technology EDI module (electrodialysis+ion exchange resin+electric field regeneration) single or combined process (such as sand filtration+carbon filtration+RO+resin tank)
The desalination mechanism drives ion migration through an electric field, and the resin self regenerates ions through water electrolysis. The resin adsorbs ions and needs to be regenerated regularly with acid-base agents (such as traditional mixed beds)
The use of chemical agents does not require external chemical agents (only water electrolysis produces H ⁺/OH ⁻) and relies on acid-base regenerants (such as HCl, NaOH) to generate waste acid/alkali solution
Continuous operation can run continuously for 24 hours without the need for shutdown. After resin saturation, it needs to be shut down for regeneration, which affects continuous production
Typical process comparison:
With EDI: Raw water → Pre treatment → RO → EDI → Ultra pure water
Without EDI: Raw water → Pre treatment → RO → Ion exchange resin tank → Pure water (requires periodic resin regeneration)
3、 Operating costs: pharmaceuticals, energy consumption, and maintenance
Cost item with EDI equipment without EDI equipment
The cost of pharmaceuticals is low (eliminating the need for acid-base procurement, storage, and transportation expenses) and high (requiring a large amount of acid-base consumption each year, with costs accounting for approximately 30-50% of operating expenses)
Medium energy consumption cost (approximately 0.3-0.6 kWh/m ³) Low (RO stage mainly consumes electricity, resin regeneration does not consume electricity but requires manual labor)
Low maintenance cost (regular cleaning of membrane components and resin, long replacement cycle) High (resin needs to be replaced every 1-3 years, frequent regeneration operation)
Wastewater discharge concentrated water can be recycled or treated (with a discharge volume of approximately 5-10% of the water production). Resin regeneration wastewater has high salt content and high treatment costs (with a discharge volume of approximately 20-30% of the water production)
Long term economy: EDI has a relatively high initial investment, but no chemical consumption, simple maintenance, and is suitable for high-purity water demand scenarios that require long-term operation; Traditional craftsmanship has low initial costs, but the costs of chemicals and wastewater treatment increase over time.
4、 Applicable scenarios: Water quality requirements determine technology selection
Industry/scenario with EDI equipment without EDI equipment
Semiconductor/Electronics ✅ Chip cleaning, photolithography process (requires ultrapure water) ❌ Only used for primary cleaning or non critical processes
Pharmaceutical/Biopharmaceutical ✅ Preparation of water for injection (WFI) and cell culture medium ❌ Only used for cleaning water or non sterile processes
Electricity/boiler water ✅ High pressure boiler feedwater (with extremely high anti scaling requirements) ⚪ Low and medium pressure boilers can be softened with RO (but require regular blowdown)
Food and Beverage ❌ (High cost) ✅ Production water and beverage blending water (RO is sufficient)
laboratory ✅ Precision analysis, ultra pure water experiments (such as HPLC, ICP) ❌ Only used for regular cleaning or rough solution preparation
Core Logic:
Choose EDI: When the water quality requires conductivity<1 μ S/cm or continuous production of ultrapure water is needed (such as in the semiconductor and pharmaceutical industries).
Do not choose EDI: scenarios with low water quality requirements (such as conductivity>10 μ S/cm) or limited budget that allow intermittent operation (such as domestic water purification, general industry).
5、 Equipment complexity and footprint
Dimension with EDI device without EDI device
Highly integrated system (EDI module modular design, small size) Distributed components (resin tank, regeneration system takes up a lot of space)
Save more than 50% of the floor space (such as a 10 m ³/h system occupying about 2-3 square meters), which is relatively large (systems of the same scale require 4-6 square meters)
Installation difficulty: Modular installation, standardized interfaces, short construction period requiring complex connections such as pipelines, valves, and storage tanks, long construction period
Scene adaptation:
When industrial plant space is tight, the compact design of EDI has more advantages;
In small-scale projects or renovation projects, traditional resin processes may be more compatible with existing equipment.
6、 Environmental Protection: Chemical Pollution and Sustainability
Indicator with EDI device without EDI device
No chemical pollution (no acid or alkali discharge, concentrated water can be further treated) Yes (regenerated wastewater contains high concentrations of acid, alkali, and salt, and needs neutralization treatment)
Low carbon emissions (energy consumption mainly comes from electric fields, no emissions from pharmaceutical production and transportation) and high (significant carbon emissions from acid-base production and transportation processes)
Compliance with environmental regulations (such as zero emission requirements) requires supporting wastewater treatment facilities (such as neutralization tanks)
Policy trend: With the improvement of environmental standards, industries such as chemical and pharmaceutical are more inclined to choose EDI to meet the requirements of green production and zero wastewater discharge.
Summary: How to choose?
Priority should be given to situations with EDI devices:
The required conductivity of the produced water is less than 1 μ S/cm, or it must comply with ultrapure water standards such as ASTM and ISO 3696;
Requires 24-hour continuous operation and cannot accept shutdown regeneration;
Strict environmental protection requirements, avoiding acid-base pollution (such as drinking water sources and ecologically sensitive areas);
Prioritize long-term operating costs (such as project duration>5 years, with a high proportion of pharmaceutical expenses).
Priority should be given to situations without EDI devices:
The water quality requirements are relatively low (such as conductivity>10 μ S/cm), and only basic desalination needs to be met (such as domestic water and irrigation);
The budget is limited and allows for regular manual maintenance (such as small water plants, temporary projects);
The raw water quality is good (such as low hardness of groundwater), and there is no need for deep desalination.
Key decision point: Water quality goals are the core, while cost and environmental requirements are auxiliary factors. For high value-added industries such as semiconductors, the high purity and stability of EDI are irreplaceable; In ordinary industrial scenarios, traditional processes still have cost advantages.
Post time: Jun-10-2025