Design influent quality.
Influent concentrations for municipal sewage, shown as industry statistics rather than standard values, with the common design range alongside.
Basis: industry statistics, not a national-standard value
GB 50014-2021 does not specify typical influent values — it covers design principles, effluent standards and process parameters. The columns below are operational statistics, not standard values. Source: influent-quality characteristics of 127 wastewater treatment plants (industry literature). The common design range column is industry design practice. Industrial wastewater discharged to a sewer is governed separately by GB/T 31962-2015. For export projects the concentrations are back-calculated from the UK load method of 60 g BOD and 8 g ammonia-N per person per day.
Design influent quality
Values in mg/L. The first two data columns report the same survey from two different angles; the last column is design practice.
| Parameter (mg/L) | National statistical mean | 80% of plants below | Common design range |
|---|---|---|---|
| COD | 220 | 282 | 250–450 |
| BOD₅ | 81.6 | 105 | 100–200 |
| SS | 148.5 | 210.8 | 150–250 |
| NH₃-N | 22.8 | 27.6 | 25–40 |
| TN | 30.4 | 36.4 | 30–50 |
| TP | 3.7 | 3.3 | 3–5 |
Industry statistics, not a national-standard value. GB 50014-2021 does not give typical influent values.
How to use and notes
- Treat every figure here as an industry statistic, not a national-standard value. GB 50014-2021 does not give typical influent values.
- Where a project has measured influent data, use the measured data; this chart is a planning default only.
- The statistical mean is the average of the surveyed plants; the 80% column is the value below which 80% of those plants fall. They answer different questions and should not be interchanged.
- Industrial wastewater, or sewage with a high industrial fraction, needs its own sampling; GB/T 31962-2015 governs discharge to a municipal sewer.
- For export projects, the organic and ammonia loads are usually derived from per-person loads (60 g BOD and 8 g ammonia-N per person per day) rather than from the concentrations above.
- Factory confirmation pending: the design influent range the equipment accepts and the pretreatment recommended outside that range: [to be confirmed with factory].