Pharmaceutical wastewater is recognized as a “tough nut” among industrial effluents due to its high COD, strong biotoxicity, high salinity, and severe water quality fluctuations. This plan is specifically designed for small to medium-sized pharmaceutical enterprises with a daily treatment capacity of 50–300 m³. It systematically explains quality-based management + three-stage process + key equipment selection, providing a complete technical reference for engineering practice.  

1. Wastewater Characteristics and Quality-Based Management  

Core Challenges:  

- High concentration of organics: COD can reach tens of thousands to hundreds of thousands mg/L  

- Biotoxicity: Antibiotic residues inhibit or even kill activated sludge  

- High salinity: TDS > 5000 mg/L, causing microbial dehydration and death  

- Significant water quality and quantity fluctuations: Batch production, peak-to-trough ratio up to 5:1  

Quality-Based Collection Principles:  

1. Three-Stage Core Process Route  

Stage 1: Physicochemical Pretreatment (“Gatekeeper”)  

- Micro-electrolysis + Fenton oxidation: Increase B/C value (0.1 → above 0.3), degrade toxicity  

- MVR evaporation desalination: Save 60–80% energy, recover industrial salts  

- Stripping/air stripping: Remove high-concentration ammonia nitrogen or volatile solvents  

Stage 2: Enhanced Biochemical Treatment (Main COD Removal Battlefield)  

- Anaerobic (EGSB / IC reactor): IC tower OLR reaches 15–30 kg COD/m³·d, small footprint, biogas recovery  

- Aerobic (A/O or MBR): MBR sludge concentration 8–15 g/L, effluent SS ≈0, strong shock resistance  

Stage 3: Advanced Treatment (Final Compliance “Finishing”)  

- Activated carbon/resin adsorption: Remove trace toxic organics, PPCPs, pigments  

- Ozone catalytic oxidation: Completely break down antibiotic structures, decolorize, eliminate ecological toxicity  

1. Key Equipment and Scale Recommendations  

Recommended Process by Scale:

- ≤50 m³/d: Pretreatment + A/O + MBR (integrated unit)  

- 50–150 m³/d: Micro-electrolysis/Fenton + EGSB + A/O + MBR + Activated Carbon  

- 150–300 m³/d: Quality-based treatment + IC Anaerobic + MVR + MBR + Ozone Oxidation + Reuse  

4. Shock-Resistance Design and Equalization Tank  

- Equalization tank: Designed based on 8–12 hours average flow, can be enlarged to 24 hours under large fluctuations  

- Submersible agitator: 4–6 W/m³, prevent sedimentation  

- Emergency storage tank: ≥ maximum batch discharge  

- Online monitoring linkage: Automatic alarm and cutoff when COD, pH, conductivity exceed limits  

5. Typical Engineering Q&A  

Q1: Why must antibiotic wastewater be pretreated?  

Antibiotics directly kill functional microorganisms in activated sludge, causing system collapse. Fenton oxidation breaks their ring structures, and B/C value must rise above 0.3 before entering the biochemical system.  

Q2: Is solvent recovery cost-effective?  

Very cost-effective. For methanol, 100 m³/d containing 5% methanol can recover approximately 12,500 CNY per day, and the distillation tower investment can be recouped in 1–2 years, while reducing subsequent treatment load.  

Q3: How to cope with frequent product switches?  

1. Design equalization tank for the most extreme fluctuations;  
2. Use MBR to enhance buffering capacity;  
3. Reserve dosing devices;  
4. Establish a water quality database and adjust operating parameters in advance.  

6.  Expected Discharge Compliance (Reference: GB 21904-2008)

There is no “universal process” for pharmaceutical wastewater treatment; the key is to tailor the strategy to the water. The three-stage process proposed in this plan—quality-based pretreatment → IC anaerobic + MBR aerobic → ozone advanced oxidation—has been validated in multiple API and traditional Chinese medicine production sites. It is recommended to conduct preliminary small-scale tests (Jar Test, continuous small-scale test) to optimize Fenton dosing and anaerobic acclimation parameters, achieving optimal investment and operational cost balance.  

Pharmaceutical environmental professionals are welcome to exchange ideas, share, or collaborate. For the complete technical plan or engineering consultation, private messages or comments are welcome.