Skip to main content
Log in

Landfill Leachate Treatment Through Coagulation-flocculation with Lime and Bio-sorption by Walnut-shell

  • Published:
Environmental Management Aims and scope Submit manuscript

Abstract

Due to the environmental consequences corresponding to leachate penetration, a sequence of inexpensive conventional processes proposed leachate treatment. The main objective was maximizing the COD and heavy metal removal efficiencies while minimizing generated sludge volume and material consumption rate. Walnut-shell adsorption complements lime treatment by eliminating heavy metals and low molecular-weight organic compounds. Samples gathered from Nazlou-landfill, Urmia, Iran. The relative significance of independent variables (lime and walnut-shell dosages and pH) on the removal efficiency was investigated using response surface methodology. By estimating the gradient of relative equations of the experimental results, the ideal direction of independent variable change was found as such increasing COD removal. A new variable called OSVLDR was utilized for measuring the ratio of the observed sludge volume to used lime dosage. The proposed sequence resulted in 43.24% COD removal under optimal conditions (i.e., 6.83, and 25 g/L of lime and walnut-shell dosage and pH values of 6, and 4 for two sets). Furthermore, effective removal in heavy metal concentrations was observed, i.e., 98.17, 67.45, 91.03, and 88.02% for nickel, cadmium, zinc, and lead, respectively. The results showed that a change in variables’ amount affects associated costs while making a variation at removal efficiency. Reducing the initial pH value of leachate to 3.50 might decrease the consumed raw materials and OSVLDR value, resulting in a considerable decline in material costs (by 10%). Also, the inactive walnut-shell surface with a more crushing degree was used to reduce costs in walnut-shell set experiments rather than the activated surface.

Highlights

  • Coagulation-flocculation and bio-sorption processes used for raw-leachate treatment.

  • Introducing a new parameter for calculating the amount of settled sludge (OSVLDR).

  • Ideal change direction of independent variables found using the gradient of equations.

  • More crushing walnut-shell instead of activating its surface to increase efficiency.

  • Over 43% of COD removal was achieved under optimal conditions.

  • Major metal removals were Ni 98.17%, Zn 91.03%, Pb 88.02%, and Cd 67.45%.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

Availability of Data and Materials

The datasets used and/or analyzed during the current study including codes prepared on MATLAB environment and Microsoft Excel are available from the corresponding author on reasonable request. Moreover, other data generated or analyzed during this study are included in this published article [and its supplementary information files].

References

Download references

Author information

Authors and Affiliations

Authors

Contributions

All authors contributed to the study’s conception and design. Material preparation, data collection and analysis were performed by Milad Ghaffariraad and Mehdi Ghanbarzadeh Lak. The first draft of the manuscript was written by Milad Ghaffariraad and Mehdi Ghanbarzadeh Lak commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Mehdi Ghanbarzadeh Lak.

Ethics declarations

Conflict of Interest

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ghaffariraad, M., Ghanbarzadeh Lak, M. Landfill Leachate Treatment Through Coagulation-flocculation with Lime and Bio-sorption by Walnut-shell. Environmental Management 68, 226–239 (2021). https://doi.org/10.1007/s00267-021-01489-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00267-021-01489-4

Keywords

Navigation