Municipal waste management: A complex network approach with an application to Italy

Industrial and textile waste trade: Multilayer network and environmental policy effects

Waste management is an international enterprise, and it is important to understand global flows of recyclable materials. The Pollution Haven Hypothesis (PHH) suggests that waste moves from high income nations with stringent environmental policy to low income nations with less environmentally stringent policy, by exploiting low labor and regulatory costs. This paper assesses the PHH thesis for slag/dross and textiles (SDT) wastes in PHH through novel integration of the multilayer network and gravity models. The multilayer network model generates network effect that quantifies interlayer connections of multiple waste trade networks. Instead of North-South movement of waste, North-North, South-South, and even South-North are shown. Results from the gravity model indicate that stringent waste management policies reduce both waste exports and imports. PHH is not found for slags/dross where high income countries are importing the waste, contradicting PHH. On the other hand, PHH is more evident between highly connected hubs and havens in SDT waste trade networks.

Assessing Italian household preferences for waste sorting systems: The role of environmental awareness, socioeconomic characteristics, and local contexts

Efficient Waste Management Systems (WMS) depend on citizens' willingness to sort waste and to cooperate for its improved provision. Thus, it is essential to understand what attributes individuals value the most and what drives WMS preference heterogeneity. In this paper, we investigate how individuals evaluate WMS attributes (e.g., the number of waste sorting categories, the introduction of textile sorting, and the frequency of collection per week) and how the local contexts, socioeconomics, and environmental values shape their preferences. For this purpose, we conducted a discrete choice experiment on a sample representative of the Italian population interviewed through an online panel survey. We collected information on individual's preferences for WMS attributes, environmental awareness, and socioeconomic characteristics. We analyzed the data using hybrid mixed choice models, which allowed us to integrate environmental awareness values into willingness to pay estimations. We found that individuals are willing to pay for waste sorting, even if this implies more effort on their part and increased storage space. In addition, we found that the extent to which individuals support WMS improvements strongly depends on their environmental values, experiences (which are shaped by their local context), and socioeconomic factors. Our results suggest that to increase recycling rates and citizen satisfaction, there is a need for context-specific WMS designs that acknowledge the observed heterogeneity of preferences.

Spatio-Temporal Change of Land Use in a Coastal Reclamation Area: A Complex Network Approach

Coastal ecological protection and restoration projects aimed to restore and recover the ecological environment of coastal wetland with high-intensity human reclamation activity, while the integrity of the coastal wetland system with human reclamation activity and the ability of individual land use types to control the overall system were not fully considered. In this study, a six-stage land use conversion network was constructed by using a complex network model to analyze coastal land use dynamic changes in the coastal reclamation area located in eastern China from 1977 to 2016. The results showed that land use types had gradually transformed from being dominated by natural types to artificial types, and the speed of transformation was accelerating. The proportion of un-reclaimed area decreased from 93% in 1977 to 46% in 2007, and finally fell to 8% in 2014 and 2016. Tidal flat and halophytic vegetation were the main output land use types, while cropland, woodland and aquaculture pond were the main input land use types. Cropland had the highest value of betweenness centrality, which played a key role in land use change from 1992 to 2014. The land use system of the coastal reclamation area was the most stable in 2002–2007, followed by 1984–1992, and the most unstable in 2007–2014. The Chinese and local government should carry out some measures to improve the land use in coastal wetland ecosystems, including the allocation and integration of land use for production space, living space, and ecological space, and develop multi-functionality of land use to realize the coastal high-quality development and coastal ecological protection and restoration.