Volume 94, Issue 1 e1672
RESEARCH ARTICLE

Effectiveness of ozonation with zirconium and tin tetrachloride for stabilized anaerobic landfill leachate treatment

Siti Nor Farhana Zakaria

Siti Nor Farhana Zakaria

Faculty of Engineering, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia

School of Civil Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, Pulau Pinang, Malaysia

Contribution: Data curation (lead)

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Hamidi Abdul Aziz

Corresponding Author

Hamidi Abdul Aziz

School of Civil Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, Pulau Pinang, Malaysia

Solid Waste Management Cluster, Science and Technology Research Centre, Universiti Sains Malaysia Engineering Campus, Nibong Tebal, Pulau Pinang, Malaysia

Correspondence

Hamidi Abdul Aziz, Solid Waste Management Cluster, Science and Technology Research Centre, Universiti Sains Malaysia Engineering Campus, 14300 Nibong Tebal, Pulau Pinang, Malaysia.

Email: [email protected]

Contribution: Conceptualization (lead), Funding acquisition (lead), Methodology (lead), Supervision (lead)

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Motasem Y. D. Alazaiza

Motasem Y. D. Alazaiza

Department of Civil and Environmental Engineering, College of Engineering (COE), A'Sharqiyah University (ASU), Ibra, Oman

Contribution: Validation (equal)

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First published: 03 December 2021
Citations: 3

Abstract

Landfill leachate can threaten the environment and human life. Therefore, this study aims to investigate the efficiency of ozone (O3), O3 with zirconium tetrachloride (O3/ZrCl4), and O3 with tin tetrachloride (O3/SnCl4) in remediating the stabilized anaerobic landfill leachate (SAL) from Alor Pongsu, Perak. Hydroxyl radical (OH•) is an important oxidizing agent in the ozonation process. Its presence was tested using tert-butyl alcohol. Results showed that using ZrCl4 and SnCl4 in ozonation boosted the generation of hydroxyl radical, thereby enhancing the oxidation process and pollutant removal inside the sample. The O3/ZrCl4 mix at chemical oxygen demand (COD) to ZrCl4 ratio of 1:1.5, pH 8–9, and 90-min reaction time resulted in the highest reduction rates of COD and color at 91.9% and 99.6%, respectively. All results demonstrated that the optimum performance occurred at alkaline conditions (pH > 8), proving that OH radicals primarily oxidized the pollutants through an indirect reaction pathway. The biodegradability (biochemical oxygen demand/COD) ratio was also considerably improved from 0.02 (raw) to 0.37 using O3/ZrCl4, compared with using O3 alone and using O3/SnCl4, which only recorded 0.23 and 0.28, respectively, after the treatment. The study demonstrated that O3/ZrCl4 was the most efficient combination.

Practitioner Points

  • The O3/ZrCl4 recorded the highest COD and color removals.
  • The O3/ZrCl4 combination also recorded higher OH• concentrations.
  • The biodegradability of leachate (BOD5/COD ratio) improved from 0.02 to 0.37.

Graphical Abstract

In this study, a combination of O3/ZrCl4 and O3/SnCl4 in SAL treatment was investigated. Three factors were varied; dosage of ZrCl4 and SnCl4, pH of sample and reaction time. The performances were evaluated based on colour, COD and BOD5/COD ratio. O3/ZrCl4 was the best combination that effectively removed COD and colour, up to 91.9% and 99.6%, respectively, and improved the leachate biodegradability in terms of the BOD5/COD ratio.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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