A Technical solutions for reducing high-risk parameters, tailored to wastewater characteristics (high COD/BOD, oil content, acidic pH, etc.), include the following targeted control and reduction methods:
1. COD / BOD (Core Organic Pollutants)
Pre-treatment stage:
Oil separation + Dissolved Air Flotation (DAF): First remove floating oil and emulsified oil to reduce subsequent biochemical load.
Equalization tank homogenization: Stabilizes water quality and flow rate to prevent high-concentration shocks.
Advanced oxidation (optional): For refractory COD, employ Fenton oxidation, ozone oxidation, etc., to cleave large organic molecules into biodegradable small molecules.
Biological Treatment Stage:
Anaerobic + Aerobic Combined Process (e.g., UASB+A/O, SBR): Anaerobic stage efficiently removes high COD concentrations; aerobic stage further degrades residual BOD/COD.
Enhanced Sludge Activity: Control sludge concentration, DO, and nutrient ratio (C:N:P≈100:5:1) to boost microbial degradation efficiency.
Advanced Treatment:
Activated carbon adsorption / Sand filtration: Further removes residual refractory COD to ensure effluent compliance.
2. Oils and Grease
Source Control: Install oil separators in production sections to recover floating oil and prevent large amounts of grease entering the wastewater system.
Physical Separation:
Inclined Plate Oil Separator: Removes large particulate oil.
Dissolved Air Flotation (DAF): Achieves efficient solid-liquid separation by trapping emulsified oil with microbubbles, reducing oils below 30 mg/L.
Chemical Demulsification: Addition of demulsifiers/flocculants disrupts emulsion stability, enhancing flotation efficiency.
3. pH (Acid-Base Balance)
Online Neutralization: Install pH monitors in equalization tanks to automatically dose alkali (e.g., NaOH, lime milk) or acid, stabilizing pretreatment water pH between 6–9.
Buffer Tank Design: Increase equalization tank capacity to buffer transient pH fluctuations, preventing sudden pH changes from impacting the biological treatment system.
4. Total Suspended Solids (TSS)
Pre-treatment: Primary sedimentation tanks / air flotation tanks remove most suspended solids.
Biological End: Secondary sedimentation tanks achieve solids-liquid separation, ensuring clear effluent.
Advanced Filtration: Sand filtration / precision filtration / membrane filtration further retain residual suspended solids, maintaining TSS consistently below 100 mg/L.
5. Ammoniacal Nitrogen / Total Phosphorus
Ammoniacal Nitrogen:
Nitrification-Denitrification Process (A/O, A²/O): Nitrification in the aerobic stage converts ammoniacal nitrogen to nitrate, while denitrification in the anoxic stage reduces nitrate to nitrogen gas.
If influent ammonia nitrogen is low, optimize recirculation ratios and control carbon source dosing to ensure complete nitrification.
Total Phosphorus:
Chemical precipitation: Add iron salts / aluminum salts / calcium salts to form precipitates with phosphate ions for removal.
Biological Phosphorus Removal: Utilizes polyphosphate bacteria's ability to release phosphorus anaerobically and absorb it aerobically, removing phosphorus through sludge dewatering.
Advanced treatment can incorporate filter beds to further reduce residual phosphorus.
Operations and Management Recommendations
Online Monitoring: Install online instruments for key parameters such as COD, BOD, pH, and ammonia nitrogen to enable real-time alerts.
Process Stability: Avoid overload operation to maintain sludge activity and nutrient balance in the biological system.
Contingency Planning: Develop emergency measures for high-concentration shocks or equipment failures, such as bypassing to equalization tanks or temporary chemical dosing.
Standard Anticipation: Monitor local discharge standard upgrades and pre-reserve advanced treatment units (e.g., activated carbon, membrane filtration).
Instrumentation Locations
Adjustment Tank: Install PROBEST pH/Conductivity Analyzer to monitor pH and conductivity in real time, ensuring stable water quality post-neutralization and preventing impacts on subsequent biochemical units.
Post-Dissolved Air Flotation: Install PROBEST Oil/Turbidity Analyzer to verify oil and TSS removal efficiency, preventing high loads from entering the anaerobic section.
Post-anaerobic reactor: Install PROBEST COD/TOC online analyzer to evaluate anaerobic treatment efficiency and adjust process parameters promptly.
Post-advanced treatment (pre-discharge): Install PROBEST Total Phosphorus/Ammonia Nitrogen online analyzer to verify final effluent compliance with discharge limits and enable regulatory compliance alerts.