Assessing the performance of a waste management system towards a circular economy in the Global South: The case of Marrakech (Morocco).

Waste management is essential for the safety and wellbeing of any society; it also helps to tackle global problems, such as climate change and resource scarcity. To support the evolution of waste management systems (WMSs) towards a circular economy (CE), assessment methods are applied. This paper shows, using the case of Marrakech (Morocco), how a novel holistic approach called WMS development stage concept (WMS-DSC) is applied to assess WMSs and determine measures promoting a CE. The approach enables a simplified derivation of measures that are useful to municipal decision makers and consists of five stages; stage 1 is equal to a WMS lacking essential WM elements and stage 5 describes a functioning CE. The approach was specifically designed to be transferable to other Global South cities through the categorization into these universal stages. The results from the WMS-DSC show that components related to energy recovery and waste recycling are classified in stage 1. For the latter, a slight development towards stage 2 can be assumed due to the planned activities in Marrakech. The components "collection and transport" and "prevention and reuse" are mainly in stage 2. Nevertheless, the components "governance", "sector and market" and "waste disposal" are assigned to stages 2 and 3 with a stronger trend towards stage 4. The results show that in Marrakech and Morocco, CE is still in its infancy, and with this current state, it is hard to achieve. However, 33 measures were determined to improve the WMS of Marrakech and promote a CE.

Approach to assess the performance of waste management systems towards a circular economy: waste management system development stage concept (WMS-DSC).

In this paper a novel holistic approach to assess the performance of waste management systems (WMSs) is presented. The so called WMS development stage concept (WMS-DSC) can be used by practitioners or decision makers to assess primarily the WMS at the municipal level. The WMS categorization into development stages notably enables a clear identification of symptoms, the causes of possible waste mismanagement and potential measures for improvement. The concept can be used to (i) assess the status quo of a WMS and, based on this, identify possible measures for implementation; (ii) check whether relevant system conditions to implement a specific measure are met; (iii) monitor the progress of a WMS; and (iv) compare the WMSs of different cities. The concept consists of five development stages: stage 1 - absence or lack of essential elements of waste management; stage 2 - reliable collection and improved landfill sites; stage 3 - separate collection and sorting; stage 4 - expansion of the recycling industry; and stage 5 - circular economy (CE), waste as a resource. While stage 1 describes the absence of or a very immature and malfunctioning WMS, stage 5 stands for a fully implemented CE. By equating the highest stage to the objectives that have evolved today globally for a sustainable CE, this concept can be used to identify targets and the most suitable steps for an individual WMS towards a future best practice of CE.•A holistic approach to assess waste management systems' performance is presented.•A benchmarking tool to estimate the circular economy (CE) evolvement in cities.•Usable for cities both in the Global North and South to identify CE potentials.

Evaluation of a quick one-step sample preparation method for the determination of the isotopic fingerprint of rapeseed (Brassica napus): Investigation of the influence of the use of 2,2-dimethoxypropane on compound-specific stable carbon and hydrogen isotope analyses by gas chromatography combustion/pyrolysis isotope ratio mass spectrometry.

RATIONALE: Gas chromatographic analyses for vegetable oils require transesterification, which generally involves multiple steps, mainly to generate fatty acid methyl esters (FAMEs). A quick method based on acid-catalyzed transesterification using 2,2-dimethoxypropane (DMP) enables the conversion in one step, in a single reactor. For compound-specific stable carbon and hydrogen isotope analyses (C- and H-CSIA) of individual fatty acids (FAs) in oil, the verification of this one-step method has not yet been reported. METHODS: In this study, we evaluated the feasibility of the one-step method for C- and H-CSIA of individual FAMEs in rapeseed samples. The focus was on the investigation of the influence of methanol, which was produced from the reactions of DMP with glycerol and water during transesterification, on the accuracy of isotope composition of FAMEs, consequently of the FAs. The reproducibility of the one-step method was assessed by the measurement of the FAMEs from rapeseed and rapeseed oil. For the C- and H-CSIA of individual FAMEs, a gas chromatography combustion/pyrolysis isotope ratio mass spectrometry system was used. RESULTS: Our results showed that no significant differences arise in the carbon and hydrogen isotope compositions of the selected main FAMEs produced with and without DMP except for the H-CSIA value of C18:3. The reproducibility of the one-step method for rapeseed was in the range of ±0.1 mUr to ± 0.3 mUr for C-CSIA and ±1 mUr to ±3 mUr for H-CSIA of the main FAMEs. CONCLUSIONS: DMP improves the transesterification efficiency without influencing the accuracy of the C- and H-CSIA of FAMEs. The performance of the one-step method for rapeseed samples for the determination of C- and H-CSIA values of FAMEs is satisfactory. Thus, the applicability of the one-step method for isotopic fingerprint analyses of FAs in oilseeds is reported for the first time.

Techno-economic and environmental assessment of methane oxidation layer measures through small-scale clean development mechanism - The case of the Seychelles.

Unclosed coastal landfills in small island developing states are major sources of greenhouse gases and other environmental impacts. This is a major problem for sustainable waste management systems mainly due to the lack of economic resources. The clean development mechanism (CDM) appears as a possibility to facilitate sustainable financing. Implementing a methane oxidation layer (MOL) emerges as a feasible technical option for this kind of small landfills since landfill gas extraction is usually not viable. This paper presents a techno-economic and environmental assessment of MOL implementation in the Providence landfill (Seychelles) as a small-scale CDM measure. Results show that the MOL measure could avoid by 2030 between 94 and 20 kt CO2 eq. Concerning profitability, results clearly show that it depends on the existence of stabilized biomass material within the island. Thus, the MOL measure starts to be profitable in some scenarios for certified emission reductions (CER) prices higher than 26 €/t CO2 eq. that seem possible depending on the emissions' market development. When not profitable under CDM, the MOL measure might be used to reduce CO2 emissions from the domestic climate effort under the Paris Agreement since the unitary abatement costs is between 10 and 423 €/t CO2 eq. Moreover, the MOL measure contributes to the sustainable development goals (SDG) achievement - mainly SDG8, SDG13, and SDG14. Finally, results call for a prompt action in Seychelles since the sooner the MOL is implemented after the landfill is closed, the more profitable.

Nitrogen in Life Cycle Assessment (LCA) of agricultural crop production systems: Comparative analysis of regionalization approaches.

Assessing reactive nitrogen (Nr) flows resulting from agricultural crop production systems (ACPS) with LCA requires regionalization. However, methodological approaches for regionalized LCA of ACPS may not necessarily reflect a comprehensive picture of Nr compounds and their complex interaction with the environment. This study presents a comprehensive analysis of the consideration of Nr in methodological approaches for regionalized LCA applied to ACPS. We conducted a review comprehending scientific literature on regionalization approaches applied to ACPS and compared these with general requirements of LCA and the scientific background of the N-cycle following the LCA framework. Special focus was placed on the analysis of process-based models (PBM) and life cycle impact assessment (LCIA) methods. We derived key factors relevant for a regional assessment of N flows in LCA and compared these to 23 regionalization approaches applied to ACPS. Main obstacles identified to conduct a regionalized LCA for ACPS involved the consideration of different regional scales and thus a missing common regionalization approach suitable for ACPS. Although, N related key-factors were mainly considered by the analyzed approaches in the different LCA phases, critical points involved the consideration of N field emissions and N impact assessment. Based on these findings, practical recommendations were given. Our comprehensive review provides relevant requirements for an improved regional N assessment in regionalized LCA of ACPS and aims to present a realistic picture when comparing different alternatives considering N specific regional impacts.

Extraction of medium chain fatty acids from organic municipal waste and subsequent production of bio-based fuels.

This paper provides an overview on investigations for a new technology to generate bio-based fuel additives from bio-waste. The investigations are taking place at the composting plant in Darmstadt-Kranichstein (Germany). The aim is to explore the potential of bio-waste as feedstock in producing different bio-based products (or bio-based fuels). For this investigation, a facultative anaerobic process is to be integrated into the normal aerobic waste treatment process for composting. The bio-waste is to be treated in four steps to produce biofuels. The first step is the facultative anaerobic treatment of the waste in a rotting box namely percolate to generate a fatty-acid rich liquid fraction. The Hydrolysis takes place in the rotting box during the waste treatment. The organic compounds are then dissolved and transferred into the waste liquid phase. Browne et al. (2013) describes the hydrolysis as an enzymatically degradation of high solid substrates to soluble products which are further degraded to volatile fatty acids (VFA). This is confirmed by analytical tests done on the liquid fraction. After the percolation, volatile and medium chain fatty acids are found in the liquid phase. Concentrations of fatty acids between 8.0 and 31.5 were detected depending on the nature of the input material. In the second step, a fermentation process will be initiated to produce additional fatty acids. Existing microorganism mass is activated to degrade the organic components that are still remaining in the percolate. After fermentation the quantity of fatty acids in four investigated reactors increased 3-5 times. While fermentation mainly non-polar fatty acids (pentanoic to octanoic acid) are build. Next to the fermentation process, a chain-elongation step is arranged by adding ethanol to the fatty acid rich percolate. While these investigations a chain-elongation of mainly fatty acids with pair numbers of carbon atoms (acetate, butanoic and hexanoic acid) are demonstrated. After these three pre-treatments, the percolate is brought to a refinery to extract the non-polar fatty acids using bio-diesel, which was generated from used kitchen oil at the refinery. The extraction tests in the lab have proved that the efficiency of the liquid-liquid-extraction is directly linked with the chain length and polarity of the fatty acids. By using a non-polar bio-diesel mainly the non-polar fatty acids, like pentanoic to octanoic acid, are extracted. After extraction, the bio-diesel enriched with the fatty acids is esterified. As a result bio-diesel with a lower viscosity than usual is produced. The fatty acids remaining in the percolate after the extraction can be used in another fermentation process to generate biogas.

Closed-loop recycling of construction and demolition waste in Germany in view of stricter environmental threshold values.

Recycling of construction and demolition waste contributes decisively to the saving of natural mineral resources. In Germany, processed mineral construction and demolition waste from structural engineering is used nearly exclusively in civil engineering (earthwork and road construction sector) as open-loop recycling. Due to the planned stricter limit values for the protection of soil and water, however, this recycling path in civil engineering may no longer be applicable in the future. According to some new guidelines and standards adopted recently, recycled aggregates may also be used for concrete production in the structural engineering sector (closed-loop recycling). Wastes from the structural engineering sector can thus be kept in a closed cycle, and their disposal on a landfill can be avoided. The present report focuses on the determination of maximum waste volumes that may be handled by this new recycling option. Potential adverse effects on the saving of resources and climate protection have been analysed. For this purpose, materials flow analysis and ecobalancing methods have been used.