Special Issue "Underutilised Resources in Urban Environments"

A special issue of Resources (ISSN 2079-9276).

Deadline for manuscript submissions: closed (30 September 2019).

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editor

Dr. Sigrid Kusch-Brandt
E-Mail Website
Guest Editor
Department of Civil, Environmental and Architectural Engineering ICEA, University of Padova, 35122 Padova, Italy
Interests: biological process engineering; anaerobic digestion (biogas); organic resources; food waste; circular economy; solid waste management; environmental engineering; environmental sustainability
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue focuses on materials that occur in urban environments or are strongly influenced by urban activities, and which today are underutilised. Materials are addresses under the lens of their potential valorisation, thus fostering implementation of more circular economies. This includes for example solid material streams (e.g., urban biowaste, food waste, other organic materials such as horse manure, construction and demolition waste, used furniture), specific waste water flows, urban mining, landfill mining. Technological progress in valorisation pathways for specific materials, including novel or significantly improved processes, and progress in management procedures are relevant in this context. Studies reporting on synergies between sectors or individual entities are particularly welcome. Studies addressing underutilised resources in the urban–rural context are also of high interest.

Dr. Sigrid Kusch-Brandt
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Resources is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • underutilised resources
  • urban resources
  • urban wastes and residues
  • solid materials
  • food waste
  • circular economy
  • waste water
  • material valorisation
  • recycling
  • synergies between sectors
  • management of material flows
  • urban-rural linkages

Published Papers (11 papers)

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Editorial

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Open AccessEditorial
Underutilised Resources in Urban Environments
Resources 2020, 9(4), 38; https://doi.org/10.3390/resources9040038 - 04 Apr 2020
Cited by 2 | Viewed by 1898
Abstract
An important opportunity for more sustainable development pathways in an urbanising world is missed where resources remain underutilised, when they could be valorised in a sound and environmentally favourable mode. This Special Issue of the journal Resources was initiated to identify promising solutions [...] Read more.
An important opportunity for more sustainable development pathways in an urbanising world is missed where resources remain underutilised, when they could be valorised in a sound and environmentally favourable mode. This Special Issue of the journal Resources was initiated to identify promising solutions and specific challenges in the context of underutilised resources in urban environments. The compiled contributions address two main areas, namely the establishment of circular economy schemes based on valorising wastes that occur in urban areas and the exploitation of renewable energies. Circular economy and renewable resources hold key potential for making cities more sustainable, and the authors of this Special Issue, with their publications, enhance our understanding of how to unlock this potential. Effective regulatory frameworks and policymaking processes which balance the powers between stakeholders are required to successfully manage energy transition and the transition to more circular economies. The positive role of community engagement merits high attention. To recover valuable resources from household waste, a focus on technology and infrastructure is required but is not enough; motivational factors and knowledge of citizens are most essential elements. It also becomes evident that the need to more reliably quantify and better characterise recyclable material streams, especially where population numbers are further growing, remains. The publications compiled in this Special Issue are a rich source to identify promising solutions, challenges and research needed for the sound management of urban resource demands. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)

Research

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Open AccessFeature PaperArticle
Estimating the Generation of Garden Waste in England and the Differences between Rural and Urban Areas
Resources 2020, 9(1), 8; https://doi.org/10.3390/resources9010008 - 16 Jan 2020
Cited by 4 | Viewed by 2828
Abstract
Garden waste arising from private households represents a major component of the biodegradable municipal waste stream. To design effective waste valorisation schemes, detailed information about garden waste is a prerequisite. While the biochemical composition of this material is well documented, there is a [...] Read more.
Garden waste arising from private households represents a major component of the biodegradable municipal waste stream. To design effective waste valorisation schemes, detailed information about garden waste is a prerequisite. While the biochemical composition of this material is well documented, there is a lack of knowledge regarding both the quantities arising, and quantities entering the services operated by waste management authorities. This work studied the quantities of garden waste arisings at urban and rural households along with the disposal methods used. A door-to-door interview survey, an analysis of kerbside collections of garden waste, and an assessment of materials brought by citizens to a waste recycling site were carried out in Hampshire, UK. If extrapolated nationally, the results indicate that households in England produce an average of 0.79 kg of garden waste per day, or 288 kg per year. On a per capita basis, this corresponds to an annual arising of 120 kg per person, out of which around 70% enters the collection schemes of the waste management authorities. The quantity generated by rural and urban households differed substantially, with rural households producing 1.96 ± 1.35 kg per day and urban households 0.64 ± 0.46 kg per day. Rural households adopted self-sufficient methods of garden waste management such as home composting or backyard burning to a much greater extent compared with urban households. Less than half of the generated rural garden waste entered services operated by the waste collection authorities, while urban households strongly relied on these services. A detailed breakdown of the disposal routes chosen by urban and rural householders can support authorities in tailoring more effective waste management schemes. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
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Open AccessArticle
Assessment of Household Solid Waste Generation and Composition by Building Type in Da Nang, Vietnam
Resources 2019, 8(4), 171; https://doi.org/10.3390/resources8040171 - 05 Nov 2019
Cited by 4 | Viewed by 2864
Abstract
This study assesses the quantity and composition of household solid waste (HSW) in the City of Da Nang and proposes a transparent and standardised method for its assessment through a combination of very-high-resolution (VHR) satellite imagery, field surveys, questionnaires, and solid waste measurements [...] Read more.
This study assesses the quantity and composition of household solid waste (HSW) in the City of Da Nang and proposes a transparent and standardised method for its assessment through a combination of very-high-resolution (VHR) satellite imagery, field surveys, questionnaires, and solid waste measurements on the ground. This was carried out in order to identify underutilised resources and to obtain discrete planning values at city level. The procedure proved to be a suitable method for reliable data gathering. To describe HSW generation, 818 valid datasets, subdivided into five building types, and their location were used. The average HSW generation rate was 297 g per capita per day. Within a total of 19 subcategories, organic waste had a share of 62.9%. The specific generation and composition of HSW correlates positively with both the building type and the spatial location within the city. The most HSW (509 g per capita per day), by far, was generated in the ‘villa-type’ building while in the ‘basic-type’ building, this was the least (167 g per capita per day). Taking into account the number of individual buildings, the total HSW generation in Da Nang in 2015 was estimated between 109,844 and 164,455 tonnes per year, which corresponds to about one-third to one-half of the total municipal solid waste. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
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Open AccessCommunication
Recovery and Valorisation of Energy from Wastewater Using a Water Source Heat Pump at the Glasgow Subway: Potential for Similar Underground Environments
Resources 2019, 8(4), 169; https://doi.org/10.3390/resources8040169 - 30 Oct 2019
Cited by 3 | Viewed by 2432
Abstract
An installation of a Water Source Heat Hump (WSHP) at Glasgow’s Underground Station, has been using the subsurface wastewater ingress to heat the office at St. George’s Cross station. The performance of the Glasgow Subway’s new heating system was observed for a few [...] Read more.
An installation of a Water Source Heat Hump (WSHP) at Glasgow’s Underground Station, has been using the subsurface wastewater ingress to heat the office at St. George’s Cross station. The performance of the Glasgow Subway’s new heating system was observed for a few months. The energy output readings are being presented. An average coefficient of performance (CoP) of 2.5 and a 60% energy input reduction for the heating system based on the old heating system’s energy demand indicates the actual system’s performance. The purpose of this research is to detect the likelihood of implementing the same setup in similar underground environments where the excess wastewater may support a viable and eco-friendly heating system. Fifteen cities across Europe have been identified and presented, with the adequate water quantities, where similar heating systems may be applied. The output of this study indicates not only the financial benefit but also the energy and carbon reduction of this trial. It highlights main subjects which were encountered in such a challenging subway system. Future steps to commercialize the excess heat energy output are explored together with opportunities to promote the same setup in similar cases. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
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Open AccessArticle
Particle Size Distribution in Municipal Solid Waste Pre-Treated for Bioprocessing
Resources 2019, 8(4), 166; https://doi.org/10.3390/resources8040166 - 21 Oct 2019
Cited by 5 | Viewed by 2688
Abstract
While it is well known that particle size reduction impacts the performance of bioprocessing such as anaerobic digestion or composting, there is a relative lack of knowledge about particle size distribution (PSD) in pre-treated organic material, i.e., the distribution of particles across different [...] Read more.
While it is well known that particle size reduction impacts the performance of bioprocessing such as anaerobic digestion or composting, there is a relative lack of knowledge about particle size distribution (PSD) in pre-treated organic material, i.e., the distribution of particles across different size ranges. PSD in municipal solid waste (MSW) pre-treated for bioprocessing in mechanical–biological treatment (MBT) was researched. In the first part of this study, the PSD in pre-treated waste at two full-scale MBT plants in the UK was determined. The main part of the study consisted of experimental trials to reduce particle sizes in MSW destined for bioprocessing and to explore the obtained PSD patterns. Shredders and a macerating grinder were used. For shear shredders, a jaw opening of 20 mm was found favourable for effective reduction of particle sizes, while a smaller jaw opening rather compressed the wet organic waste into balls. Setting the shredder jaw opening to 20 mm does not mean that in the output all particles will be 20 mm or below. PSD profiles revealed that different particle sizes were present in each trial. Using different types of equipment in series was effective in reducing the presence of larger particles. Maceration yielded a PSD dominated by very fine particles, which is unsuitable for composting and potentially also for anaerobic digestion. It was concluded that shredding, where equipment is well selected, is effective in delivering a material well suited for anaerobic digestion or composting. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
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Open AccessArticle
Sustainable Extraction and Characterisation of Bioactive Compounds from Horse Chestnut Seed Coats for the Development of Bio-Based Additives
Resources 2019, 8(2), 114; https://doi.org/10.3390/resources8020114 - 19 Jun 2019
Cited by 3 | Viewed by 2801
Abstract
Background: To protect renewable packaging materials against autoxidation and decomposition when substituting harmful synthetic stabilizers with bioactive and bio-based compounds, extracts from Aesculus hippocastanum L. seeds were evaluated. The study objectives were to determine the antioxidant efficacy of bioactive compounds in horse chestnut [...] Read more.
Background: To protect renewable packaging materials against autoxidation and decomposition when substituting harmful synthetic stabilizers with bioactive and bio-based compounds, extracts from Aesculus hippocastanum L. seeds were evaluated. The study objectives were to determine the antioxidant efficacy of bioactive compounds in horse chestnut seeds with regard to different seed fractions, improve their extraction, and to evaluate waste reuse. Methods: Different extraction techniques for field samples were evaluated and compared with extracts of industrial waste samples based on total phenolic content and total antioxidant capacity (2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS)). The molecular weight distribution and absorbance in ultraviolet range (UV) of seed coat extracts were determined, and the possibility of extracts containing proanthocyanidins was examined. Results: Seed coat extracts show a remarkable antioxidant activity and a high UV absorbance. Passive extractions are efficient and much less laborious. Applying waste product seed coats leads to a reduced antioxidant activity, total phenolic content, and UV absorbance compared to the field sample counterparts. In contrast to peeled seed extracts, all seed coat extracts contain proanthocyanidins. Discussion: Seed coats are a potential source of bioactive compounds, particularly regarding sustainable production and waste reuse. With minimum effort, highly bioactive extracts with high potential as additives can be prepared. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
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Open AccessArticle
Renewable Energy as an Underutilised Resource in Cities: Germany’s ‘Energiewende’ and Lessons for Post-Brexit Cities in the United Kingdom
Resources 2019, 8(1), 7; https://doi.org/10.3390/resources8010007 - 31 Dec 2018
Cited by 10 | Viewed by 3721
Abstract
Renewable energy remains an underutilised resource within urban environments. This study examines the ongoing German Energiewende (energy transition) as an example of renewable energy being treated as a necessary resource for urban development. It departs from existing literature by operationalising the Advocacy Coalition [...] Read more.
Renewable energy remains an underutilised resource within urban environments. This study examines the ongoing German Energiewende (energy transition) as an example of renewable energy being treated as a necessary resource for urban development. It departs from existing literature by operationalising the Advocacy Coalition Framework (ACF), taking a policy systems approach to analyse (and explain) the cases of three German cities—Munich, Berlin, and Freiburg. This approach helps draw lessons for future UK energy scenarios by placing more abstract conceptions of Sustainable Energy Transitions (SETs) within the context of UK cities, post-Brexit. By discussing five main themes: the shift from government to governance; the need to break ‘carbon lock-in’; renewable energy innovation as an underutilised resource; developing governance strategies for renewable energy resources; the shift from policy to practice, the study yields a detailed reconceptualisation of approaches to renewable energy resource-use policy. The novelty of this study lies in its response to these challenges, taking a policy systems approach to energy governance. The article concludes with a proposed integrated framework. The framework, which is based on multi-scalar and multi-stakeholder integrated energy governance strategy, reconsiders the way in which renewable energy resources are seen in current governance terms in the UK. The framework presents a new approach to renewable energy resource-use policy that embraces innovation, responsible governance, and inclusive processes, (alongside thinking beyond simply technical solutions) to considering the socio-economic impacts of policy decisions in cities. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
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Open AccessFeature PaperArticle
Value Chain Actors and Recycled Polymer Products in Lagos Metropolis: Toward Ensuring Sustainable Development in Africa’s Megacity
Resources 2018, 7(3), 55; https://doi.org/10.3390/resources7030055 - 04 Sep 2018
Cited by 2 | Viewed by 2004
Abstract
Polymer recycling is one of the major areas that need adequate intervention in any megacity’s effort toward sustainable development. However, megacities in Africa face various challenges in general waste management and also lag behind in developing efficient waste-to-wealth services. Therefore, this study examined [...] Read more.
Polymer recycling is one of the major areas that need adequate intervention in any megacity’s effort toward sustainable development. However, megacities in Africa face various challenges in general waste management and also lag behind in developing efficient waste-to-wealth services. Therefore, this study examined the difficulties experienced by the actors involved in the value chain of polymer recycling in the Lagos megacity. Thirty in-depth interviews and four key informant interviews were conducted with value chain and supporting actors, while 400 questionnaires were administered among residents of Lagos metropolis. The study found that negative public perception, lack of adequate capital, poor health conditions, inefficient infrastructure, and technological difficulties are some of the problems in polymer recycling in the megacity. Therefore, social label redefinition, effective dissemination of recycling information, an efficient loan system, import duty relaxation, and stakeholder involvement are recommended. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
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Open AccessArticle
Identifying Challenges and Barriers to Participating in the Source Separation of Waste Program in Tabriz, Northwest of Iran: A Qualitative Study from the Citizens’ Perspective
Resources 2018, 7(3), 53; https://doi.org/10.3390/resources7030053 - 29 Aug 2018
Cited by 7 | Viewed by 2133
Abstract
There are many problems with the waste management systems (WMSs) in developing countries. In order to provide applicable strategies for improving the WMSs in these countries, there is a need to identify the barriers and challenges at the community level. Our aim in [...] Read more.
There are many problems with the waste management systems (WMSs) in developing countries. In order to provide applicable strategies for improving the WMSs in these countries, there is a need to identify the barriers and challenges at the community level. Our aim in the present study was to explain the challenges and barriers in front of the citizen’s participation in the Source Separation of Waste (SSW) program in Tabriz, Iran. In this qualitative research, 13 citizens were invited to participate and were then interviewed. Data were analyzed with the content analysis approach. MAXQDA10 was applied to facilitate the organization of data. Four core categories of the barriers to sourcing the separation of household waste were identified: (a) problems in the collecting system of waste; (b) a lack of responsibility among citizens; (c) insufficient awareness among citizens, and (d) the expectation of receiving incentives. The findings of the study indicated the potential infrastructure barriers that may hinder in-process household solid waste separation attempts. Recycling investors, environmental health policymakers, and stakeholders should take into account these barriers while designing, implementing, and/or reorienting the Source Separation of Waste (SSW) programs. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
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Other

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Open AccessBook Review
Urban Renewable Energy on the Upswing: A Spotlight on Renewable Energy in Cities in REN21’s “Renewables 2019 Global Status Report”
Resources 2019, 8(3), 139; https://doi.org/10.3390/resources8030139 - 02 Aug 2019
Cited by 19 | Viewed by 3037
Abstract
Published in June 2019, the new edition of the annually updated Renewables Global Status Report (GSR) compiles the most recent developments and trends in the adoption of renewable energies worldwide and in specific regions, countries and sectors. The report represents a rich resource [...] Read more.
Published in June 2019, the new edition of the annually updated Renewables Global Status Report (GSR) compiles the most recent developments and trends in the adoption of renewable energies worldwide and in specific regions, countries and sectors. The report represents a rich resource for reliable and up-to-date information about individual renewable energy sources and their use. The analysis also covers a review of energy policies. Renewable energy policies still strongly concentrate on the power sector, while transport and heating and cooling are given less attention. Most investment in renewable energy today happens in developing and emerging countries, which is a major change to the situation some years ago. The 2019 edition of the GSR report includes a feature on renewable energy in cities, which highlights the importance of prioritising the urban context in order to achieve more sustainable schemes of energy supply and consumption. More than half of the global population today lives in cities, but around two-thirds of energy consumption happens in an urban environment. The GSR 2019 identifies that cities already are among the most active players in the adoption of renewable energies. One interesting finding is that in more than 100 cities worldwide at least 70% of the electricity already comes from renewables. This includes cities in both developed and developing countries. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
Open AccessCase Report
Mandatory Recycling of Waste Cooking Oil from Residential and Commercial Sectors in Taiwan
Resources 2019, 8(1), 38; https://doi.org/10.3390/resources8010038 - 18 Feb 2019
Cited by 13 | Viewed by 3180
Abstract
Waste cooking oil (WCO) has been considered a low-cost and renewable feedstock for the production of biodiesel and biobased products if it can be economically and efficiently collected and recycled. The objective of this case study is to review the scientific background of [...] Read more.
Waste cooking oil (WCO) has been considered a low-cost and renewable feedstock for the production of biodiesel and biobased products if it can be economically and efficiently collected and recycled. The objective of this case study is to review the scientific background of WCO recycling in the literature in connection with the regulatory and promotional measures in Taiwan under the authorization of a legal waste management system. Furthermore, the updated information about the on-line reporting WCO amounts in Taiwan is also analyzed to illustrate its significant increase in the recycling status of WCO officially designated as one of the mandatory recyclable wastes since 2015. Finally, an overview of available utilization of WCO as biodiesel, fuel oil, and non-fuel related uses is briefly addressed in this paper. It shows that the collected amounts of WCO from residential and commercial sectors in Taiwan significantly increased from 1599 tonnes in 2015 to 12,591 tonnes, reflecting on the WCO recycling regulation effective since 2015. Practically, the most important option for this urban mining is to reuse WCO as an energy source for the productions of biodiesel and auxiliary fuel. Other non-fuel related uses include the production of soaps/detergents, C-18 fatty acids, and lubricants. However, the reuse of WCO as a feed additive should be banned to prevent it from re-entering the food chain. Full article
(This article belongs to the Special Issue Underutilised Resources in Urban Environments)
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