Effect of sewage sampling frequency on determination of design parameters for municipal wastewater treatment plants
The uncertainty associated with the determination of load parameters, which is a key step in the design of wastewater treatment plants (WWTPs), was investigated on the basis of data sets from 58 WWTPs. A further analysed aspect was the organic load variations associated with variable sewage temperat...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IWA Publishing
2021-07-01
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| Series: | Water Science and Technology |
| Subjects: | |
| Online Access: | http://wst.iwaponline.com/content/84/2/284 |
| Summary: | The uncertainty associated with the determination of load parameters, which is a key step in the design of wastewater treatment plants (WWTPs), was investigated on the basis of data sets from 58 WWTPs. A further analysed aspect was the organic load variations associated with variable sewage temperatures. Data from 26 WWTPs with a high inflow sampling frequency was used to simulate scenarios to investigate the effect of lower sampling frequencies through a Monte Carlo approach. The calculation of 85-percentile values for chemical oxygen demand (COD) loadings based on only 26 samples per year is associated with a variability of up to ±18%. Approximately 90 samples per year will be necessary to reduce this uncertainty for estimation of COD loadings below 10%. Hence, a low sampling frequency can potentially lead to under- or overestimation of design parameters. Through an analogous approach, it was possible to identify uncertainties of ±11% in COD loading when weekly average data was used with four samples per week. Finally, a tendency to lower COD input loads with increasing temperatures was identified, with a reduction of about 1% of the average loading per degree Celsius. HIGHLIGHTS
Uncertainty of statistical measures for COD loads relating to sampling frequency.;
Determination of yearly 85-percentile values from COD loads with one weekly sample results in an up to ±13% uncertainty.;
Calculation of weekly averages of COD loads with four samples per week is associated with an uncertainty of up to ±11%.;
Relative influent COD loading decreases with higher temperatures.; |
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| ISSN: | 0273-1223 1996-9732 |