FeCl2 Wastewater Treatment: Dosage, Applications & 2026 Reference Pricing

FeCl2 (ferrous chloride) is a widely used wastewater treatment chemical in textile dyeing, electroplating, paper, oil & gas plants, and centralized domestic wastewater systems. Its mechanisms include coagulation-flocculation, Cr6+ chemical reduction, and Fenton AOP for breaking down organic dye molecules. Dosages range from 50 mg/L (domestic) to 500 mg/L (high-load textile dyeing), requiring Jar tests for precise determination. 2026 reference price for 30% FeCl2 solution: 3,000–5,000 VND/kg (200L drum) and 2,800–4,500 VND/kg (1,000L IBC). Loc Thien Chemicals supplies high-quality FeCl2 with delivery to Ho Chi Minh City, Binh Duong Province, and Dong Nai Province, offering free Jar tests and technical consultancy for wastewater engineers.

What is FeCl2 Wastewater Treatment? Working Mechanisms

FeCl2 — ferrous chloride or iron(II) chloride — is an inorganic salt with the formula FeCl₂, typically available as a 25–30% pale greenish-yellow solution. In wastewater treatment, FeCl2 operates via three primary mechanisms:

1. Coagulation-Flocculation

When dosed into wastewater, Fe²⁺ oxidizes to Fe³⁺ and hydrolyzes to form Fe(OH)₃ — a strongly positive-charged colloid. This colloid adsorbs and neutralizes negatively charged suspended particles, dyes, and organic matter, forming large, settleable flocs.

2. Cr6+ Chemical Reduction (Chromate Reduction)

Fe²⁺ ions in FeCl2 act as powerful reducing agents, converting toxic Cr6+ to less hazardous Cr3+ via the reaction:

3 Fe²⁺ + Cr6+ → 3 Fe³⁺ + Cr³⁺ (at pH 2.0–2.5)

Subsequent pH adjustment to 8–9 precipitates Cr³⁺ as Cr(OH)₃ for removal via sedimentation/filtration. Treated effluent meets QCVN 40:2011 Column A (Cr6+ < 0.05 mg/L).

3. Fenton Reaction (Fenton Advanced Oxidation)

Combining FeCl2 with H₂O₂ (30–35%) generates highly oxidative hydroxyl radicals (•OH) that degrade recalcitrant organic dye molecules at optimal pH 3–3.5. This is the core mechanism in FeCl2-based Fenton processes for textile wastewater.

FeCl2 Wastewater Treatment Dosage — Reference Table by Wastewater Type

Optimal FeCl2 dosage depends on pollutant load, influent pH, and treatment objectives. Below summarizes operational data from Vietnamese wastewater plants:

Note: Values are reference benchmarks. Each wastewater source has unique characteristics — conduct Jar tests for precise dosing before full-scale operation.

FeCl2 for Textile Dyeing Wastewater Treatment

Textile dyeing wastewater is complex: high pH (7–11), intense color (>500 Pt-Co), high COD (500–3,000 mg/L), and contains non-biodegradable azo/reactive dyes. FeCl2 is preferred for its high performance and cost-effectiveness.

FeCl2 Mechanisms in Textile Wastewater

• Direct Coagulation: Fe³⁺ from FeCl2 oxidation adsorbs negatively charged dye molecules, forming fast-settling flocs.
• Fenton AOP: FeCl2 + H₂O₂ (30–35%) at pH 3–3.5 generates •OH radicals that break azo dye benzene rings, achieving 90–98% decolorization and 60–85% COD reduction. Post-Fenton pH adjustment to 7–8 enables supplemental coagulation.

ZDHC Standards & International Requirements

Per ZDHC (Zero Discharge of Hazardous Chemicals) — mandatory for many global fashion brands — textile effluent must eliminate carcinogenic dyes, including aromatic amines from azo dyes. Properly operated FeCl2 + Fenton processes meet these requirements.

Details at: FeCl2 in Textile Dyeing — comprehensive technical guide for wastewater engineers.

FeCl2 for Electroplating Wastewater — Cr6+ Reduction

Electroplating wastewater contains 50–500 mg/L Cr6+ — a Group I hazardous substance per QCVN 40:2011. FeCl2 is currently the most effective and economical Cr6+ treatment chemical.

Two-Stage Process

Stage 1 — Cr6+ Reduction to Cr3+:

• Adjust pH to 2.0–2.5 using H₂SO₄ or HCl
• Dose FeCl2 at 3 mol Fe²⁺ / 1 mol Cr6+ (practical dosage: 150–400 mg/L depending on influent Cr6+)
• Mix for 15–30 minutes until complete conversion to Cr³⁺

Stage 2 — Cr³⁺ Precipitation:

• Raise pH to 8–9 using NaOH or Ca(OH)₂
• Cr³⁺ precipitates as greenish Cr(OH)₃ flocs
• Allow 30–60 minutes quiescent settling, then sludge handling
• Treated effluent achieves Cr6+ < 0.05 mg/L (QCVN 40:2011 Column A)

Full guide: Cr6+ Treatment with FeCl2 — includes dosage calculations for actual Cr6+ concentrations.

FeCl2 for Domestic & Hospital Wastewater Treatment

In domestic and hospital wastewater, FeCl2 primarily removes total phosphorus (TP) — a critical parameter per QCVN 14:2008. Untreated phosphorus causes eutrophication in receiving waters.

FeCl2 Phosphorus Removal Mechanism

Fe²⁺ reacts with phosphate (PO₄³⁻) to form insoluble FePO₄ precipitate:

Fe²⁺ + PO₄³⁻ → FePO₄↓ (precipitate)

Concurrently, Fe³⁺ from oxidation adsorbs phosphorus via coagulation. Dosages of 50–150 mg/L achieve >90% TP removal from domestic wastewater (influent TP: 5–10 mg/L).

Hospital Applications: Hospital wastewater typically has COD 200–400 mg/L, high SS, pathogens, and pharmaceutical residues. FeCl2 aids SS and phosphorus removal during physicochemical pretreatment, enhancing overall system efficiency before biological treatment.

FeCl2 vs. PAC vs. FeSO4? Quick Comparison

Wastewater system designers often choose among three common coagulants. This comparison table facilitates quick decisions:

Conclusion: FeCl2 is optimal for heavily polluted industrial wastewater. PAC suits domestic wastewater and feedwater. FeSO4 serves as an alternative when FeCl2 is scarce. For a detailed technical comparison between FeCl2 and its ferric counterpart, see FeCl2 vs FeCl3 — Which Iron Salt to Choose? Also review our FeCl2 vs FeSO4 vs PAC analysis.

FeCl2 Dosing Procedure for Wastewater Systems

To maximize FeCl2 efficacy and ensure operational safety, adhere to this technical dosing protocol:

Step 1: Pre-Dilute FeCl2 Before Pumping

30% FeCl2 solution is highly corrosive and viscous. Dilute to 5–10% before system injection:

• Dilution ratio: 1 part 30% FeCl2 + 2–5 parts clean water
• Use HDPE or PP dilution tanks (acid-resistant)
• Equip with adjustable dosing pumps

Step 2: Check & Adjust Influent pH

Influent pH critically impacts FeCl2 performance:

• Cr6+ reduction: pH 2.0–2.5 (use H₂SO₄ or HCl for pH adjustment)
• Fenton AOP: pH 3–3.5
• Conventional coagulation: pH 6–8 (optimal for Fe(OH)₃ formation)

Step 3: Dose FeCl2 with Rapid Mixing

Inject diluted FeCl2 at the reaction tank inlet with rapid mixing (100–150 rpm for 1–2 minutes). Dose at high-turbulence zones (pipeline elbows or mixer blades).

Step 4: Slow Mixing & Sedimentation

Reduce mixing to 20–40 rpm for 15–20 minutes to grow floc size. Allow 30–60 minutes quiescent settling in lamella or vertical clarifiers.

Step 5: Verify Results & Adjust Dosage

Analyze post-settling samples for target parameters (COD, color, Cr6+, TP...). If QCVN non-compliant, increase FeCl2 dosage by 10–20% and repeat Jar testing. Document results in operational logs.

2026 FeCl2 Wastewater Treatment Price Reference

30% FeCl2 solution prices in Vietnam fluctuate with iron and HCl feedstock costs. Below are 2026 reference prices for operational budgeting:

Estimated Chemical Costs: At 200 mg/L dosage and 500 m³/day flow rate, daily consumption ≈ 100 kg FeCl2/day × 4,000 VND/kg ≈ 400,000 VND/day. Compared to PAC (400–800 VND/m³), FeCl2 offers significant cost savings for industrial wastewater.

Order high-quality FeCl2 at: Purchase 25-30% FeCl2 — fast delivery to Ho Chi Minh City, Binh Duong Province, Dong Nai Province, and nationwide.

Where to Buy FeCl2 for Wastewater Treatment?

Loc Thien Chemicals specializes in supplying 25–30% FeCl2 solution to wastewater treatment plants across Southern Vietnam:

Why Choose Loc Thien?

• Quality Assurance: 25–30% FeCl2 with batch-specific COA (Certificate of Analysis). Also supply FeCl3 40-42% — compare at FeCl2 vs FeCl3
• Three Warehouses: Ho Chi Minh City — Binh Duong Province — Dong Nai Province, same-day delivery for orders before 2 PM
• Free Technical Support: Engineer consultations for dosage optimization and chemical dosing system design, on-site Jar testing
• Complimentary Jar Testing: Submit water samples for FeCl2 efficacy evaluation and dosage optimization
• Flexible Packaging: 200L drums, 1,000L IBCs, 5–25 ton tanker trucks. See full supply details at FeCl2 Supply — Color, Specifications & Applications
• Long-Term Contract Benefits: 3–8% discounts for regular orders and annual contracts

Contact Information

• Website: hoachatlocthien.com
• Ho Chi Minh City Warehouse: Serves Industrial Zones in Binh Chanh, Cu Chi, Thu Duc
• Binh Duong Warehouse: Supplies VSIP, My Phuoc, Dong An, Song Than Industrial Zones
• Dong Nai Warehouse: Covers Bien Hoa, Long Thanh, Nhon Trach Industrial Zones

Frequently Asked Questions

📖 Complete FeCl2 & FeCl3 Guide:

• FeCl2 & FeCl3 Comparison
• FeCl2 Supply & Applications
• What is FeCl3?

Conclusion

FeCl2 (ferrous chloride) is a versatile, cost-effective wastewater treatment chemical suitable for most Vietnamese industrial effluents. From textile dyeing (90–98% decolorization via Fenton AOP) to electroplating (Cr6+ reduction to QCVN 40:2011 Column A standards) and domestic wastewater phosphorus removal (>90% TP), FeCl2 delivers performance at competitive costs.

Key Takeaways:

• FeCl2 dosage: 50–500 mg/L depending on wastewater type — requires Jar testing for precision
• Fenton AOP: pH 3–3.5, 30–35% H₂O₂, achieves 90–98% decolorization
• Cr6+ reduction: 3 mol Fe²⁺/mol Cr6+, pH 2–2.5, followed by pH 8–9 precipitation
• Pre-dilute FeCl2 to 5–10% before system injection
• 2026 price reference: 2,800–5,000 VND/kg depending on packaging

📞 Need FeCl2 pricing or technical consultation?

Call/Zalo: +84 979 891 929 — quote within 15 minutes with current batch COA

Or visit: FeCl2 Product Page — detailed specifications, COA sample, and delivery options

Loc Thien Chemicals — direct FeCl2 manufacturer since 2016. 6 warehouses nationwide, 20 tanker trucks, batch-specific documentation. Free Jar testing for first-time buyers.