How to Remove Sulfates from Water

Pollution characteristics and risk thresholds

Geological dissolution leads to sulfate enrichment in natural water bodies (concentrations often reach 100-500 mg/L)

Causes gastrointestinal discomfort when exceeding 250 mg/L (national standard limit 250 mg/L)

Easily reduced to hydrogen sulfide under high temperature environment (threshold for rotten egg smell 0.05 mg/L)

Core removal process comparison

1. Reverse osmosis membrane separation system

Brackish water grade polyamide composite membrane (desalination rate > 99.2%)

System recovery rate: single stage 60-75%, double stage 80-85%

Concentrated water sulfate is concentrated to 3000 mg/L (subsequent disposal is required)

2. Ion exchange process

Strongly alkaline anion resin (working exchange capacity ≥ 1.2 eq/L)

Cl⁻ type resin selectively replaces SO₄²⁻ (penetration point ≥ 200 mg/L)

Regeneration cycle: 2000-5000 bed volumes (10% NaCl solution)

3. Distillation refining device

Multi-effect vacuum evaporator (steam consumption 0.35kg/kg water)

Condensate sulfate <5mg/L (can be almost completely removed)

Applicable to small high-concentration scenarios (>1000mg/L)

Key parameters for engineering selection

Grading treatment of influent sulfate concentration:

<300mg/L: ion exchange is preferred

300-1000mg/L: reverse osmosis process is recommended

>1000mg/L: distillation + ion exchange coupling

System anti-scaling control:

Automatic dosing of antiscalants (aminophosphonic acid, 1-3mg/L)

Calcium Ion concentration limit <50mg/L

Water quality assurance and resource utilization

Sulfate stability in water production <20mg/L (12 times better than the national standard)

Ion exchange regeneration waste liquid to produce anhydrous sodium sulfate (purity>98%)

Reverse osmosis concentrated water electrolysis to recover sulfuric acid (concentration ≥30%)

Operation economic analysis

Cost of water treatment per ton:

Reverse osmosis system: 0.32-0.45 yuan

Ion exchange: 0.18-0.28 yuan

Distillation process: 1.8-2.5 yuan

Equipment life cycle:

Membrane element>5 years (regular chemical cleaning)

Resin bed>8 years (anti-oxidation protection)

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