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Municipal Wastewater Quality Control: Heavy Metal Comparative Analysis—Case Study Cover

Municipal Wastewater Quality Control: Heavy Metal Comparative Analysis—Case Study

Environmental Protection and Natural Resources
Volume 34 (2023): Issue 4 (December 2023)
By: Wiktor Halecki,  Tomasz Sionkowski,  Krzysztof Chmielowski,  Agnieszka Kowalczyk and  Konrad Kalarus  
Open Access
|Dec 2023

Figures & Tables

Figure 1.

The heavy metal content in raw and treated wastewater. The means with 95% confidence intervals. Grey bars represent raw wastewater and white bars represent treated wastewater
The heavy metal content in raw and treated wastewater. The means with 95% confidence intervals. Grey bars represent raw wastewater and white bars represent treated wastewater

Figure 2.

The heavy metal content in sewage sludge from municipal wastewater treatment. The means with 95% confidence intervals. If the upper limit of the confidence interval is below the value of the standard, it means that the standard is met, if the confidence interval overlaps the value of the standard, it means that the standard is not met, but the metal content is close to the standard, in the situation when the lower limit of the confidence interval is above the value of the standard, it means that the metal content significantly exceeds the standard. The upper bound of the confidence interval falls below the standard (red line), indicating that the metal content in the sludge is statistically significantly lower than the maximum permissible content
The heavy metal content in sewage sludge from municipal wastewater treatment. The means with 95% confidence intervals. If the upper limit of the confidence interval is below the value of the standard, it means that the standard is met, if the confidence interval overlaps the value of the standard, it means that the standard is not met, but the metal content is close to the standard, in the situation when the lower limit of the confidence interval is above the value of the standard, it means that the metal content significantly exceeds the standard. The upper bound of the confidence interval falls below the standard (red line), indicating that the metal content in the sludge is statistically significantly lower than the maximum permissible content

Figure 3.

PCA analysis results. Ordination diagrams showing the first and second ordination axes: (a) for wastewater, (b) sewage sludge. For diagram (a), circles represent raw wastewater and squares represent treated wastewater
PCA analysis results. Ordination diagrams showing the first and second ordination axes: (a) for wastewater, (b) sewage sludge. For diagram (a), circles represent raw wastewater and squares represent treated wastewater

The results of the repeated measures, analysis of variance_ “R1” represents the wastewater treatment effect, and “quarter” refers to the quarter of the year_ Significant effects are bolded_ Following symbols denote: df – degrees of freedom, F – F-statistic, p – p-value

EffectdfFp
Zn (N = 138)Intercept1948.19<0.001
Quarter31.230.302
Error133--
R117.070.009
R1*Quarter34.320.006
Error133--
Pb (N = 123)Intercept1708.47<0.001
Quarter31.880.138
Error118--
R112.090.151
R1*Quarter30.190.905
Error118--
Cd (N = 88)Intercept1411.53<0.001
Quarter30.960.414
Error83--
R112.780.099
R1*Quarter31.870.141
Error83--
Cu (N = 137)Intercept1969.36<0.001
Quarter30.260.857
Error132--
R1114.19<0.001
R1*Quarter30.100.960
Error132--
Cr (N = 121)Intercept1707.04<0.001
Quarter30.340.794
Error116--
R111.800.183
R1*Quarter32.180.095
Error116--
Ni (N = 125)Intercept1635.60<0.001
Quarter31.480.222
Error120--
R1117.16<0.001
R1*Quarter30.470.707
Error120--
Mn (N = 138)Intercept11600.64<0.001
Quarter30.160.923
Error133--
R1161.15<0.001
R1*Quarter31.280.285
Error133--

Compliance with the heavy metal content standard in sewage sludge originating from municipal wastewater treatment_ Results of the one-sample t-test relative to a constant reference value – the norm_ N denotes sample size_ SE denotes Standard error, t indicates t-statistic, and p indicates p-value

Mean [mg/l]SEReference value [mg/l]Ntp
Zn1,148.9742.392,5007031.87<0.001
Pb68.863.9075070174.48<0.001
Cd4.061.45207011.03<<.001
Cu170.827.951,10070104.35<0.001
Cr81.4611.375007036.82<0.001
Ni34.122.3330070113.89<0.001
Hg0.980.061670261.84<0.001
DOI: https://doi.org/10.2478/oszn-2023-0023 | Journal eISSN: 2353-8589 | Journal ISSN: 1230-7831
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Language: English
Page range: 127 - 134
Published on: Dec 31, 2023
Published by: National Research Institute, Institute of Environmental Protection
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year
Keywords:
Harmful effects,
heavy metal,
potentially toxic elements,
pretreatment wastewater,
sewage sludge,
wastewater treatment plant
Related subjects:
Life sciences,
Ecology

© 2023 Wiktor Halecki, Tomasz Sionkowski, Krzysztof Chmielowski, Agnieszka Kowalczyk, Konrad Kalarus, published by National Research Institute, Institute of Environmental Protection
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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