Case Study: Electrochemical Mineralization Of High-Cod API And Formulation Wastewater With Electro Oxidation Modules
Project Profile: Henan Specialty Pharmaceutical Facility
Industry Sector: Advanced Active Pharmaceutical Ingredient (API) Synthesis & Specialty Formulation
Facility Compliance Standard: International Good Manufacturing Practice (GMP) Certification
Design Hydraulic Throughput: 600 m³/day continuous (25 m³/hour operational average)
Effluent Composition: High-strength specialty API process synthesis rinse streams, manufacturing vessel spray-ball wash water, floor sanitization lines, and low-strength auxiliary utility blowdown matrices.
Core Engineering Objective: Complete degradation and deep chemical oxidation of non-biodegradable, toxic pharmaceutical residues to transform recalcitrant compounds, maximize downstream biodegradability, and meet stringent sewer network discharge thresholds.
The Engineering Challenge
The manufacturing facility produces highly complex, specialty active pharmaceutical ingredients. Because these organic molecules are synthesized to resist biological breakdown, the plant’s raw rinse wastewater exhibits extreme toxicity. Conventional biological treatment systems cannot handle this matrix directly; the high active antimicrobial concentration kills the activated sludge biomass, leading to immediate system failure, biofouling, and permit violations.
To bypass this bottleneck and ensure steady compliance with regional environmental sewer networks, the facility required a reliable advanced oxidation step capable of breaking open stable heterocyclic rings and aromatic cores without requiring massive, ongoing chemical dosing or generating toxic secondary chemical sludge.
The Solution: Modular Anodic Oxidation
Evoaeo engineered and deployed an integrated, skid-mounted electro oxidation system with Boron-Doped Diamond (BDD) anode based electro oxidation electrode assembly. BDD anodes provide extraordinary physical-chemical advantages over conventional electrode materials like platinum (Pt), iridium oxide (IrO₂), lead dioxide (PbO₂), or tin oxide (SnO₂):
Extraordinary Oxygen Overpotential: Possessing an Oxygen Evolution Potential (OEP) of 2.3 to 2.7 V vs. SHE, BDD minimizes energy-wasting water splitting and drives the direct generation of highly reactive, surface-bound hydroxyl radicals (•OH).
Extreme Chemical Inertness & Lifespan: Resistant to fouling, passivation, and surface corrosion under extreme chemical loads, eliminating frequent consumable replacement costs.
Sludge-Free Operation: The mineralization loop operates cleanly without requiring hazardous iron catalysts or massive acid/base adjustments, producing zero hazardous secondary solid waste.
EPC & Controls Integration
The core electrochemical reactors, titanium-substrate BDD electrode configurations, and current distribution matrices were engineered and manufactured at the Evoaeo production facility. To achieve seamless facility integration, our engineering team manage to pull off comprehensive automated system process controls, SCADA programming, and local hydraulic integration loops were executed in direct alignment. This collaborative approach allowed facility operators to track real-time flow velocities, pH drift, liquid levels, and process temperatures directly from centralized control offices.
In-Field Performance Data
Following a rapid timeline—12 days for customized equipment fabrication, 3 days for on-site mechanical installation, and 10 days for system commissioning—the electro oxidation system achieved stable operation.
The table below documents the verified analytical field performance data from regular operational testing runs:
| Wastewater Parameter Matrix | Influent Concentration (Raw Entry) | Effluent Target Value (Post-EO Treatment) | Absolute Destruction & Removal Efficiency | Operational Compliance Status |
|---|---|---|---|---|
| Chemical Oxygen Demand (COD_Cr) | 17,890 mg/L | ≤ 320 mg/L | 98.21% Removal | Fully Compliant with Network Limits |
| Ammonia Nitrogen (NH₃-N) | 830 mg/L | ≤ 35 mg/L | 95.78% Removal | Fully Compliant with Discharge Codes |
| Hydrogen Ion Exponent (pH) | 6.6 – 7.3 | 6.2 – 8.7 | Optimized Neutral Range | Fully Stabilized |
Chemical Oxidation Mechanism: The deep drop in Chemical Oxygen Demand and Ammonia Nitrogen is driven directly by the continuous generation of non-selective hydroxyl radicals at the BDD anode interface. The electrophilic •OH radicals systematically strike the complex API molecules:
Aromatic Ring Cleavage: Radicals attack carbon-carbon and carbon-halogen matrices, opening stable rings and turning complex molecules into basic aliphatic organic acids.
True Mineralization: These intermediate short-chain carboxylic acids are then completely oxidized into harmless carbon dioxide (CO₂), water (H₂O), and stable inorganic mineral salts, optimizing the water’s downstream biodegradability profile.