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

Identification of Obstacles to Implementing Sustainability in the Civil Construction Industry Using Bow-Tie Tool

The construction industry is responsible for causing a large adverse impact on the environment. To minimize these impacts, sustainable practices are being sought mainly in the area of the wastage of and the waste from raw materials. Many obstacles and difficulties are encountered when trying to implement sustainable practices in civil construction. Thus, a study to identify what the obstacles are to implementing such practices is necessary. Therefore, the objective of this study is to present an assessment of the main obstacles to implementing sustainability in civil construction for which the bow-tie tool is used. Three cases were analyzed: construction material waste, the wastage of plaster and planning a sustainable construction project. Results showed that the lack of planning for sustainable construction projects, the lack of compliance with technical standards and the lack of technical knowledge of the workforce and of standardization are among the main obstacles to implementing sustainability in civil construction. This study offers a structured methodology to identify causes, consequences and obstacles related to events that affect the implementation of sustainable practices. It provides a visualization of the scenario investigated through the diagram generated, facilitating its understanding and analysis.

State of a sustainable drainage system at end-of-life: assessment of potential water pollution by leached metals from recycled pervious pavement materials when used as secondary aggregate

Sustainable drainage systems (SuDS) have emerged as an effective and attractive approach for stormwater management, prevention of water pollution and flood control due to its sustainable, environmentally friendly and cost-effective approaches. One of the SuDS devices widely used to infiltrate, store and treat surface runoff which allows it to recharge groundwater is the pervious paving systems (PPS). Previous studies have demonstrated relatively high pollution removal efficiencies typically ranging from 98.7% for total hydrocarbons to 89% of COD. Although a small number of the studies have assessed the performance characteristics of the PPS system in long-established installations in terms of retention of pollutants, hydrological features, biodegradation of pollutants etc., none has assessed the risk of potential groundwater and soil pollution by pollutants such as metals retained in the PPS materials either as a disposed waste material (in the case of used geotextiles) or during re-use as secondary aggregates. Thus, this study evaluated potential risks associated with the decommissioning and beneficial use of wastes produced during the disassembly of a PPS. The authors believe that this was the first PPS to be addressed in this way. The method involved the determination of leachable concentrations of 14 metals in the PPS samples made up of extracts from the model profile which included the geotextile fibre (G), dust alone (D), aggregates and dust (AD), aggregates alone (AA) and pavement blocks (P) which were analysed and compared with two different groups of regulatory threshold limits. The results showed that the measured concentrations of all the metals were below the appropriate threshold values for irrigation purposes as specified by FAO and USEPA. Furthermore, results all indicated that the dismantled materials were all below EU LFD WAC limits for inert waste, indicating relative ease of disposal and suitability for use as recycled aggregate. This, admittedly limited data, indicates that recycling of aggregates from demolition wastes arising from end of life PPS would not be limited by the potential leaching of heavy metals, including re-use within another PPS. This would minimise dependence on virgin aggregates and hence reduce rate of exploitation of natural resources and improve sustainability score card of SuDS.

SUSTAINABILITY INDICATORS FOR END-OF-LIFE CHEMICAL RELEASES AND POTENTIAL EXPOSURE

Understanding the chemical risk to environment and human health is an important issue when a waste management strategy and a control risk system is analyzed and selected. This is even more important at the end-of-life (recycling, recovery and disposal) scenario for a chemical due to the uncertainty in respect of the most susceptible receptors (e.g., workers), pathways (e.g., groundwater), routes (e.g., inhalation) and hazard (e.g., cancer) associated to a chemical exposure. Hence, selecting a group of sustainability performance indicators for estimating the chemical risk when evaluating end-of-life scenarios is a crucial task. Therefore, this manuscript focuses on a critical analysis of the sustainability indicators taxonomy which are used to assess chemical risk to the environment and human health during end-of-life scenarios. The insights from performing an extensive literature search in the largest database of peer-reviewed literature provide that chemical intake, hazard quotient, hazard index, and carcinogenic risk have been the most commonly used for human health chemical risk. In addition, previous research has been less focused on environment chemical risk, with ecological risk index being the most widely used indicator for. The most employed human health chemical risk sustainability indicators are part of a methodology suggested by U.S. Environmental Protection Agency for chemical risk assessment.