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Item type:Publication, Access status: with files , Compost organic matter content varied five-fold and determined compost quality across 107 composts of the North Sea Region(Elsevier, 2026-01-15); ; 34 19 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Optimizing mechanical pretreatment of cotton textile waste to enhance enzymatic hydrolysisEnzymatic recycling processes of cotton from waste materials have gained increasing interest in recent years. Therefore, the aim of this study was to optimize the application of mechanical shear forces to end-of-life cotton-based textile suspensions, followed by an enzymatic hydrolysis to glucose. Mechanical pretreatment in a cutting mill followed by a wet-rotor-milling process was investigated by varying solids load and mill parameter settings. The results indicated that both a smaller gap width and higher solids load during mechanical pretreatment resulted in enhanced enzymatic hydrolysis. Additionally, it was found that a minimum amount of energy input while milling was necessary to enable a higher glucose yield. The relationship between energy input, enzymatic hydrolysis, and crystallinity facilitates the assessment of the effect of energy input within the milling process. Furthermore, a decrease in enzyme activity was observed with increasing solids load during enzymatic hydrolysis. Overall, the findings of this research suggest that wet milling presents a promising technology to improve the enzymatic hydrolysis of end-of-life cotton textiles.Publicationtype: Journal Article39 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Deep eutectic solvent pretreatment of cork dust : effects on biomass composition, phenolic extraction and anaerobic degradability(Elsevier, 2024-05-30); ; ; ; Aslanhan, Dicle DelalIn this study, phenolic compounds using deep eutectic solvents (DES) were extracted from cork dust, and the biogas production potential of DES-treated cork dust samples was determined. The DES treatment was carried out using choline chloride and formic acid (1:2 M ratio) at various temperatures (90, 110 and 130 °C) and treatment times (20, 40 and 60 min) at a solid-to-solvent ratio of 1:10 g mL−1. The highest total phenolic content (137 mg gallic acid equivalent (GAE) g−1 dry cork dust) was achieved at 110 °C/20 min. The extracts exhibited an antioxidant capacity of up to 56.3 ± 3.1 % 1,1-diphenyl-2-picrylhydazyl (DPPH) inhibition at a dilution rate of 100. DES treatment resulted in minimal sugar solubilization at low temperatures, while approximately 42 % of the xylan fraction in the biomass degraded under severe conditions (e.g., 130 °C/60 min). Catechin, 4-hydroxybenzoic acid and gallic acid were the major phenolics in DES extracts. The biogas yield of DES-treated cork dust increased with treatment severity. The highest biogas yield (115.1 mLN gVS-1) was observed at 130 °C/60 min, representing an increase of 125 % compared to the untreated sample. SEM images revealed that the surface structure of the samples became smoother after mild pretreatment and rougher after harsh pretreatment. Compositional and FTIR analyses indicated that a higher biogas formation potential was associated with increased cellulose content in the substrate, which could be attributed to hemicellulose solubilization in the hydrolysate. Overall, DES pretreatment effectively enhanced phenol extraction and anaerobic degradability.Publicationtype: Journal Article28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Environmentally sustainable and cost-effective recycling of Mn-rich Li-ion cells waste: Effect of carbon sources on the leaching efficiency of metals using fungal metabolites(2023-02-15); ; Metals recovery from spent lithium coin cells (SCCs) is enjoying great attention due to environmental problems and metal-rich contents such as Mn and Li. Fungi can generate many organic acids, and metals can be dissolved, but sucrose is not an economical medium. The main objective of this study is to find a suitable carbon substrate in place of sucrose for fungal bioleaching. We have developed an environmentally friendly, cost-effective, and green method for recycling and detoxifying Mn and Li from SCCs using the spent culture medium from Penicillium citrinum cultivation. Sugar cane molasses and sucrose were selected as carbon sources. Based on the extracted fungal metabolites, the effects of pulp density, temperature, and leaching time were assessed on metal dissolution. The most suitable conditions were 30 g/L of pulp density, a temperature of 40 °C, and 4 days of leaching time in spent molasses medium, which led to a high extraction of 87% Mn and 100% Li. Based on EDX-mapping analyses, it was found that the initial concentration of ∑ (Mn + C) in the SCCs powder was almost 100% while reaching nearly 6.4% after bioleaching. After bioleaching, an analysis of residual powder confirmed that metal dissolution from SCCs was effective owing to fungal metabolites. The economic study showed that the bioleaching method is more valuable for the dissolution of metals than the chemical method; In addition to improving bioleaching efficiency, molasses carbon sources can be used for industrial purposes.Publicationtype: Journal ArticleScopus© Citations 12 42 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Co-digestion of food waste and cellulose-based bioplastic: From batch to semi-continuous scale investigation(2023-02-01); ; ; ; Only few studies on the behaviour of bioplastics in anaerobic co-digestion could be found in literature and most of them are conducted in batch mode. Despite the fact that continuous experiments confirm or add new insight to the findings acquired from batch ones, there is still lack of such studies. This work aims to cover this gap, carrying out a semi-continuous anaerobic co-digestion of food waste and cellulose acetate (which its behaviour under anaerobic environment is also quite unexplored). After a first evaluation of the potential methane production from each substrate at batch scale, the semi-continuous co-digestion of food waste and cellulose acetate was carried out in three configurations. During the semi-continuous process, a methane yield of 331 NmlCH4/gVS was generated from the co-digestion of food waste and cellulose acetate while bioplastics specimens achieved a weight loss of about 45 %. The results were both lower than the one obtained from batch co-digestion, although methane production rates were comparable regardless of being fed with or without bioplastics. An increase was registered after 65 days of semi-continuous process, due to the accumulation of CA specimens. This confirms the different degradation trends between bioplastics and food waste.Publicationtype: Journal Article55 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , The influence of bio-plastics for food packaging on combined anaerobic digestion and composting treatment of organic municipal waste(2022-05-01); ; ; ; The use of bio-plastic-based packaging as an alternative to conventional plastic packaging is increasing. Among the plethora of different bio-based plastics, the most relevant ones are those that, at the end of their life, can be treated with the organic fraction of municipal solid waste. Even in these cases, their impact on the waste processing and recycling is not always positive. This study aim to assess on a laboratory scale the influence on combined anaerobic digestion and composting industrial processes of a bio-based plastic film, namely cellulose acetate (CA), in pure and modified (additions of additive) forms. CA films were mixed with organic waste and subjected to: (i) anaerobic digestion; (ii) active composting and (iii) two stages of curing composting. Anaerobic digestion and composting were monitored through methane yield and oxygen uptake respectively; additionally, the bio-plastics degree of disintegration was assessed during all the processes. The final disintegration of pure and modified CA was 73.82% and 54.66%, respectively. Anaerobic digestion contributes to the disintegration of the material, while aerobic treatment appears to be nearly ineffective, especially for modified CA. The presence of cellulose acetate during anaerobic digestion of food waste increased the methane yield by about 4.5%. Bioassay confirmed the absence of possible toxic effects on the final compost from the bio-plastic treatment. Although bio-based materials are not the only solution to plastic pollution, the findings confirm the need to upgrade the organic waste treatment plants and the necessity to revise the requirements for the use of compost in agriculture.Publicationtype: Journal Article57 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , The impact of collection portfolio expansion on key performance indicators of the Dutch recycling system for Post-Consumer Plastic Packaging Waste, a comparison between 2014 and 2017The recycling network of post-consumer plastic packaging waste (PCPPW) was studied for the Netherlands in 2017 with material flow analysis (MFA) and data reconciliation techniques. In comparison to the previous MFA of the PCPPW recycling network in 2014, the predominant change is the expansion of the collection portfolio from only plastic packages to plastic packages, beverage cartons and metal objects. The analysis shows that the amounts of recycled plastics products (as main washed milled goods) increased from 75 to 103 Gg net and the average polymeric purity of the recycled products remained nearly constant. Furthermore, the rise in the amounts of recycled products was accompanied with a rise in the total amount of rejected materials at cross docking facilities and sorting residues at the sorting facilities. This total amount grew from 19 Gg in 2014 to 70 Gg gross in 2017 and is over-proportional to the rise in recycled products. Hence, there is a clear trade-off between the growth in recycled plastics produced and the growth in rejects and residues. Additionally, since the polymeric purity of the recycled plastics did not significantly improve during the last years, most of the recycled plastics from PCPPW are still only suited for open-loop recycling. Although this recycling system for PCPPW is relatively advanced in Europe, it cannot be considered circular, since the net recycling yield is only 26 ± 2% and the average polymeric purity of the recycled plastics is 90 ± 7%.Publicationtype: Journal Article292 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Anaerobic treatment of deinking sludge: Methane production and organic matter degradation(2019-02-15); ; Deinking sludge (DS) is a residue from the waste paper recycling industry. It is a by-product originating from the deinking process which is designed to remove inks and other impurities from waste papers to recover usable fibers. The aim of this study was to investigate the possibility of anaerobic digestion (AD) of DS in order to produce methane (CH4) by degrading organic matter. DS differs clearly from common AD substrates due to its specific composition. The focus was laid on comparing various inocula in order to find appropriate microbial consortia. Three inocula from different origins were investigated. After sludge and inocula characterization, batch AD at a mesophilic (37 °C) condition was performed for 21 days to determine biogas and CH4 potentials as well as sludge biodegradability in comparison to cellulose. The highest average CH4 yield achieved in the 21 days of the batch experiment was 167 NmL/g organic dry matter (oDM). However, the CH4 potentials from all experiments did not have a wide range (average 160 NmL/g oDM; standard deviation ±5.0 NmL/g oDM). The highest organic matter degradation achieved was 31%. It can be stated that conventional AD inocula are usable to degrade DS, but that a significant part of the oDM was anaerobically not degradable. The overall CH4 yields were lower compared to top AD substrates such as energy crops, but in a similar range like residue-based AD substrates such as manure. Since actual DS management is cost-intensive and affecting the profitability of waste paper industry significantly, AD as a management option with an energetically valuable output is a very promising option.Publicationtype: Journal Article316 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Assessment of plastic waste materials degradation through near infrared spectroscopy(2018-12); ; Plastic waste is a relevant challenge for waste management sector and further technological means have to be urgently researched. The evaluation of plastic waste quality through non-destructive, cost-effective and mature technologies could be without any doubt a key issue. This study is aimed at the assessment of Near Infrared (NIR) spectroscopy for the generation of global degradation-prediction models able to forecast plastic ageing. The degradation of Polyethylene terephthalate (PET), Acrylonitrile Butadiene Styrene (ABS), Polypropylene (PP) and Polyethylene (PE) was achieved by thermal ageing (at 85 °C, 105 °C and 120 °C and durations ranging from 4 to 504 h), to simulate environmental outdoor conditions. Experimental data obtained for each plastic material were elaborated through partial least square (PLS) regression to obtain empirical models. For all inspected plastic materials, a good correspondence between the variation in absorbance units and the change in chemical bonds vibrations was observed. The PLS models were afterwards calibrated (taking into account the different ageing conditions; first separately then including the ageing factors combined). A high accuracy (R2 equal to 0.85-1.00) was observed in predicting ageing for PET and ABS, while the correspondence showed a 30% decrease for PE and PP. This study proves that NIR spectroscopy can be recommended as an effective tool to investigate plastics degradation, with some limitations for specific polymers that need further investigations.Publicationtype: Journal Article180 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Aeration of the teuftal landfill: Field scale concept and lab scale simulation(2016-09-01); ; ; ; Long lasting post-closure care (PCC) is often the major financial burden for operators of municipal solid waste (MSW) landfills. Beside costs for the installation and maintenance of technical equipment and barriers, in particular long term treatment of leachate and landfill gas has to be paid from capital surplus. Estimations based on laboratory experiments project time periods of many decades until leachate quality allows for direct discharge (i.e. no need for further purification). Projections based on leachate samples derived from the last 37 years for 35 German landfills confirm these assumption. Moreover, the data illustrate that in particular ammonium nitrogen concentrations are likely to fall below limit values only after a period of 300 years. In order to avoid long lasting PCC the operator of Teuftal landfill, located in the Swiss canton Bern, decided to biologically stabilize the landfill by means of a combined in situ aeration and moisturization approach. In December 2014 the aeration started at a landfill section containing approximately 30% of the total landfill volume. From summer 2016 onwards the remaining part of the landfill will be aerated. Landfill aeration through horizontal gas and leachate drains is carried out for the first time in field scale in Europe. The technical concept is described in the paper. Parallel to field scale aeration, investigations for the carbon and nitrogen turnover are carried out by means of both simulated aerated landfills and simulated anaerobic landfills. The results presented in this paper demonstrate that aeration is capable to enhance, both carbon mobilization and discharge via the gas phase. This effect comes along with a significant increase in bio-stabilization of the waste organic fraction, which positively affects the landfill emission behavior in the long run. In terms of leachate pollution reduction it could be demonstrated that the organic load decrease fast and widely independent of the adjusted aeration rates whereby ammonium nitrogen load efficiently decrease later and only under higher aeration rates.Publicationtype: Journal Article94