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Lead and zinc removal with storage period in porous asphalt pavement

Y Zhao, C Zhao

Abstract


Porous asphalt pavements have been used as an effective technique to overcome road runoff challenges, and to improve efficiency of rainwater utilisation in urban areas. Using porous asphalt pavements with reservoir storage and harvesting facilities is an important consideration for the  future. This study monitored changes in water quality indicators, such as pH, conductivity, and concentrations of lead and zinc, for water stored in porous asphalt pavement models with basalt-, limestone- and  ‘basalt+limestone’-filled reservoir structures. The research discusses  findings over a 696-h storage period following artificial rainfall. Total lead and zinc concentrations were remarkably reduced throughout the initial  flush, showing, on average, reductions of 90% and 80.5%, respectively. This pattern was consistent throughout the storage period, producing  average reductions in lead and zinc of 99.98% and 79%, respectively, over 696 h. Conductivity and pH levels increased in all pavement models after the 696-h storage. The results obtained confirmed the potential of using porous asphalt pavements with reservoir structures to remove heavy  metals from road runoff. This can be applied to future research on the removal mechanisms of porous asphalt pavements in relation to heavy metals in road runoff.

Keywords: heavy metals, road runoff, porous asphalt pavement, retention




http://dx.doi.org/10.4314/wsa.v40i1.8
AJOL African Journals Online