Assessment of physicochemical parameters and trace metal elements from untreated and treated wastewater of an analysis laboratory, Yaoundé-Cameroon

ABSTRACT

The main emphasis of this study is to assess the status of daily released effluent before and after treatment with both Corn Cobs Activated Carbon (CCAC) and eggshells, with a focus on raising its pH to acceptable levels for agricultural irrigation. The physical properties of CCAC revealed that, it contained 5.82 % ash and had a point zero charge of 5.35. Before and after each treatment, the Electrical Conductivity and Total Dissolved Solids ranged from (248.3 ± 0.9) µS/cm to (285.3 ± 0.7) µS/cm and (124.00 ± 0.56) mg/L to (142.33 ± 0.34) mg/L, respectively; the pH of 6.98 ± 0.03, was found to be within the Food and Agricultural Organization of the United Nations (FAO) allowable limits for irrigation purposes. The average mean concentrations analysis of trace metal elements with Inductively Coupled plasma Optical Emission Spectrometry ranged from (0.000 ± 0.000) mg/L to (0.76 ± 0.02) mg/L for untreated and treated wastewater. After the final treatment, the concentrations of Fe2+ ions were lower than those of Zn2+, Cu2+, and Mn2+, but they were all within the FAO’s permissible limits. Similarly, the mean values for the removal efficiency of trace metal elements revealed that, Zn2+, Cu2+, and Mn2+ ions are 100 % decontaminated, whereas only 84.33 % Fe2+ ions are removed with 500 grams of eggshells. There are both positive and negative correlations between physicochemical parameters and trace metal elements. The Principal Component Analysis results of two latent factors explain 61.95 % and 29.14 % of the total variance into three groups, with all trace metal elements forming a single group. The one-way ANOVA revealed a highly significant difference between parameters and treatments at p 0.05. These findings suggest that, CCAC and eggshells have shown promising applications for industrial wastewater treatment and can be easily adopted by analytical laboratories.

KEYWORDS:

• Physicochemical parameters
• trace metal elements
• corn cob activated carbon
• eggshells
• wastewater
• adsorption
• irrigation

Acknowledgements

The authors are grateful to the Institute of Agricultural Research for Development (IRAD), Yaoundé, Cameroon. They also thank Mahamat Hamout for the time spent on schematising the overall process and AKOUTOU MVONDO Étienne for performing statistical analyses of data.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary Material

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