Dredged sediments as a resource for brick production: Possibilities and barriers from a consumers’ perspective
Introduction
Dredged sediments consist of soil material originating from deepening, broadening and maintaining of public waterways and from the establishment of new shipping infrastructure. In Flanders (Belgium), approximately 12,000 kton of dredged sediments has to find a destination every year (Nielsen et al., 2010). A possible application is the use of dredged sediments as a raw material in brick production.
Despite the fact that several examples (e.g., Agostini et al., 2007, Hamer and Karius, 2002, Xu et al., 2014) show that this application is feasible, some economical, technical and social limitations interfere with the actual use of dredged materials in brick production in Flanders. With respect to technical issues, the problem of dewatering of sediments as a very energy-demanding and costly process seems to have been partly solved. In the AMORAS project (Dockx and De Broe, 2008) mechanical dewatering using chamber filter presses is used as an economically viable alternative for lagooning. It also enables to properly control the dewatering process. This mechanical dewatering process yields an end product of superior quality, and it opens up new applications for re-use, such as the partial replacement of clay in bricks (Dockx and De Broe, 2008). At the moment, it is not completely clear why the beneficial use of dredged sediments as a secondary resource in brick manufacturing is not applied on a commercial scale. Based on a review of relevant literature, the feasibility of brick production from dredged sediments as well as the potential environmental impacts associated with bricks will first be discussed. Besides technical and environmental aspects concerning the (re)use of dredged sediments, the legal framework in Flanders will briefly be addressed. These represent essential components of the supply side of the market. When the feasibility of brick production from dredged sediments is addressed, consumers’ acceptance and willingness to pay for bricks produced from dredged sediments are important factors to gain insight into the demand side. Until now, information on this topic is still scarce. The present study will focus on the consumer demand for bricks produced from dredged sediments, investigating the most relevant aspects that influence the potential market success of this kind of product from a consumers point of view.
Although the present study was performed in Flanders, the outcome of this study is interesting for any region or organization that has to deal with dredged sediments.
Section snippets
Overview of the supply side: legal, technical, environmental and economic aspects
First we give a brief overview of the relevant legislation in Flanders. Next we discuss the technical and economic feasibility of using dredged sediments in brick production as well as its environmental impact.
The demand side: market potential and consumers’ attitude
Environmental behavior of consumers is typically influenced by a number of different factors. We distinguish two main categories: individual and contextual factors (Tanner and Kast, 2003, Kollmuss and Agyeman, 2002). Individual factors include (1) specific attitudes, (2) perceived risks, (3) knowledge, and (4) personal norms. Contextual factors, on the other hand, reflect the social, economic, or physical environment within which people act.
Firstly, a consumer survey by Mainieri et al. (1997)
Methods
In the present study, the limitations and barriers to develop a market for bricks made from dredged sediments were analyzed from the consumers’ point of view, based on interviews and on a survey held in 2011 in Flanders (Belgium). The survey dealt with consumers’ willingness to pay for bricks produced from traditional raw materials and from (contaminated) sediments.
The aim of the present survey was to investigate whether there exists a market for bricks produced from dredged sediments and to
Results and discussion
In this section we first present the general characteristics of our respondents and discuss their risk perception. We also perform a factor analysis in order to identify the constructs underlying respondents environmental attitudes. Next we analyze the factors that influence demand for sedibricks and finally we discuss the potential to promote sedibricks as a green product.
Conclusions
Technical problems, such as the dewatering of dredged sediments, have been solved during the last few years, and many different valorisations options, including brick production, have proven to be feasible. Thus, the supply side does not imply specific barriers to stimulate the development of the market for sedibricks. However, the expansion of the demand side of the market seems to lag behind. In Flanders, the real valorisation of dredged sediments is still very limited and consumers are
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