In wastewater treatment, biodegradability is a key factor. ✅It decides whether biological treatment can meet discharge standards. Here are the main indicators that affect biodegradability.
B/C Ratio — The Core Indicator
The BOD/COD ratio (B/C ratio) shows how much organic matter can be degraded by microorganisms.
- B/C > 0.3: Good biodegradability, suitable for biological treatment.
- B/C < 0.3: Few biodegradable compounds, harder to treat. ⚠️
C/N/P Ratio (Carbon, Nitrogen, Phosphorus)
Microorganisms need balanced nutrients to grow. 💧 The recommended ratios are:
- 100:5:1 → for normal biological systems
- C/N = 5–8 → for nitrogen removal systems
- C/P = 15–20 → for phosphorus control
If the balance is wrong, problems like sludge bulking or low treatment efficiency may occur.
Influent Water Quality Factors
Several water quality conditions affect biodegradability:
- High salinity → reduces microbial activity, affects floc settling.
- Unstable pH → too acidic or too alkaline can suppress microbes.
- Toxic substances or heavy metals → may poison bacteria and damage system stability. ⚠️
Process Design Matching
Treatment results also depend on process design.
- Tank size, retention time, and sludge load must be suitable.
- If design capacity is smaller than current load, effluent may fail standards.
Summary
To judge if wastewater is suitable for biological treatment, you cannot look at only one indicator. You must evaluate together:
- B/C ratio
- Nutrient balance (C/N/P)
- Water quality factors
- System design
Only with a full evaluation can discharge standards be achieved. ✅ If you have more questions, feel free to leave a message or contact us for solutions!
