Evaluating the potential for denitrification in permeable interlocking concrete pavements

Authors

  • Luke P Brown Civil Engineering Department, University of Cape Town, Rondebosch, 7700, Cape Town, South Africa
  • Neil P Armitage Civil Engineering Department, University of Cape Town, Rondebosch, 7700, Cape Town, South Africa https://orcid.org/0000-0003-3704-3648

DOI:

https://doi.org/10.17159/wsa/2024.v50.i3.4086

Keywords:

denitrification, nitrogen removal, permeable interlocking concrete pavers (PICP), stormwater, sustainability

Abstract

This research explored the denitrification potential of a submerged zone incorporated into the present permeable interlocking concrete pavement (PICP) design. The following three main factors controlling denitrification were investigated through a laboratory study: (i) detention time, (ii) inclusion of a carbon source (newspaper), and (iii) submerged zone depth. The study used 10 columns, each fully packed with 50–63 mm washed aggregate and including a 1.5 m deep submerged zone. Columns were paired according to detention time (1, 2, 5, 10 and ‘varied’ days) with one set including newspaper, the other set not. All columns were loaded with synthetic stormwater over a 4-month period. Samples were taken from different submerged depths (0, 300, 600, 900, 1200 and 1 500 mm) and analysed for concentrations of ammonia (NH3), nitrate (NO3) and phosphate (PO43−) every 10 days. This study found that 10 – or more – days detention and the provision of a carbon source had the most significant impact on denitrification – providing an overall mean NO3 and nitrogen removal above 41% and 59%, respectively. Moreover, a submerged depth of 300 mm was sufficient to achieve a minimum NO3 removal of 41% in columns which included a carbon source and had 10 days detention. Generally, an increase in detention time resulted in an increase in NH3 and PO43− removal with overall mean values of 86% and 30%, respectively, achieved with 10−day detention periods.

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Published

2024-07-31

Issue

Section

Research paper

How to Cite

Evaluating the potential for denitrification in permeable interlocking concrete pavements. (2024). Water SA, 50(3 July). https://doi.org/10.17159/wsa/2024.v50.i3.4086