Reuse of materials from a Sustainable Drainage System device: Health, Safety and Environment assessment for an end-of-life Pervious Pavement Structure.

Pervious pavement systems can have a life span of about 20years but, at end-of-life, it becomes necessary to evaluate the state of the infrastructure to determine whether they pose a health and safety risk to workers during dismantling, and also determine potential reuse of the waste material generated. In this paper, we report of an investigation conducted to evaluate whether Pervious pavement systems are hazardous to human health at end-of-life and also to assess the mobility of the stormwater pollutants trapped in the system as a measure of their potential release to receiving systems such as water-bodies and groundwater systems. After decommissioning, the pervious pavement structure was sampled for analysis including Gas Chromatography, inductively coupled plasma spectroscopy and, leachate analysis. Results show that carcinogenic risks were significantly below the regulatory limit of 1×10-6 while, the hazard quotients and cumulative hazard indices were also below regulatory value of 1, based on United States Environmental Protection Agency standards. Furthermore, mean concentrations of benzene, toluene, ethylbenzene and xylene were significantly less than the UK soil guideline values. The results of the leachate analysis show that the metals of concern, Pb, Zn, Cr, Ni, Cd and Cu were all below the threshold for reuse applications such as irrigation purposes as they were all below the regulatory limits such as Food and Agriculture Organization and, United States Environmental Protection Agency standards. Finally, the evaluation of potential reuse and recycling purposes indicate that wastes generated from the dismantling of the PPS are within limits for recycling as aggregates for other civil engineering projects as per European Union standards. This has potential to enhance UK's drive to achieve the target of 70% level of construction & demolition waste recovery for reuse and recycling by the year 2020 as per European Union Water Framework Directive.