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Item type:Publication, Access status: with files , Decomposition of biodegradable plastic bags for kitchen waste collection in industrial compostingWith the growing awareness of microplastics in the environment, the question of microplastics as remnants of biodegradable plastic (BDP) products is gaining momentum. BDP bags for kitchen waste collection are often certified as fully compostable as proof of industrial compostability. Frequently certification is done using under standardized laboratory conditions within 12 weeks. Composting plants often process biowaste into compost in a shorter time under inhomogeneous conditions. This study investigates the decomposition behavior of commercially available BDP bags for kitchen waste collection at an industrial composting plant within a practically realistic time frame of 6 weeks. The research determines the decomposition behavior under practice conditions. Four bag types, two made from thermoplastic starch (TPS) blends and two from polylactic acid (PLA) blends underwent composting. The decomposition was evaluated by examining the remaining macro- (> 8 mm), meso- (2–8 mm), and microparticles (1–2 mm) in the compost with different methods. After 6 weeks, the mass-based decomposition rate of TPS blend bags exceeded 95%. In contrast, PLA blend bags failed to reach a decomposition rate of 90%. The study did not depict very small particles <1 mm. However, they are present. The study findings indicate that composting time and conditions, inhomogeneities, as well as the bag type are crucial factors influencing the decomposition of BDP bags. Concerns are raised about the usefulness of DIN 13432 as certification scheme for industrial conditions.Publicationtype: Journal Article58 108 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Untersuchung des Verhaltens von Beuteln aus biologisch abbaubaren Kunststoffen in der Kompostierungsanlage Neumünster(Witzenhausen-Institut für Abfall, Umwelt und Energie, 2023-04); ; ; ; Abbauversuche mit als kompostierbar zertifizierten Bioabfallsammelbeuteln wurden in einer Kompostierungsanlage mit Haupt- und Nachrotte über einen Zeitraum von bis zu sechs Wochen durchgeführt. Aussagen zum Beutelabbau wurden über die verbliebenen Makro-, Meso- und Mikropartikel getroffen. Der Praxisversuch wurde mit Laboruntersuchungen zur Beutelcharakteristik und zum Abbauverhalten im anaeroben Milieu ergänzt. Darüber hinaus wurde die aktuelle Situation der Bioabfallsammlung in deutschen Kommunen bewertet und Schlussfolgerungen für den Einsatz von BAK-Beuteln in der Praxis der Bioabfallsammlung gezogen.Publicationtype: Conference Paper67 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Untersuchung des Verhaltens von Beuteln aus biologisch abbaubaren Kunststoffen in der Kompostierungsanlage NeumünsterWaste bags made of biodegradable plastics (BDP) were tested for their degradability under industrial-scale conditions at the Neumünster composting plant. The aerated intensive rotting lasted two weeks, the naturally ventilated curing four weeks. Four different types of bags were used, two starch blends and two PLA blends. For each type, 160 bags, distributed over 8 nets, were introduced and removed after 2, 3, 4, 5 and 6 weeks, respectively. The net contents were analyzed for BDP residues, differentiating between micro (< 1 mm, 1-2 mm), meso (2-8 mm) and macro (>8 mm) particles. The BDP degradation level was determined approximately. Based on the residual particle areas, the possible maximum degree of degradation could be determined, and based on residual particle masses, the minimum degree of degradation that occurred. The actual degree of degradation will be in between. The determined residual masses were subject to uncertainties mainly due to particle impurities, the residual areas due to a neglect of the 3-dimensionality for large particles. The development of temperatures and water contents in the rotting material over the treatment period was typical for biowaste composting in most of the nets, including the expected inhomogeneities. The strongest BDP degradation occurred in all bag types in the first three weeks, with significant degradation already after two weeks. Starch blends showed a faster degradation than the PLA blends. After 4 to 6 weeks, most starch blend batches showed a degradation rate above 90%. Although most PLA blend batches had a degradation level by area above 90%, it must be assumed that their real degradation level will be partly below 90%. The minimum degradation level by mass for the bags with a drawstring was between 58 and 80%, and between 71 and 94% for those without a drawstring. Micro and meso particles were detected in all batches at all sampling times, and macro particles were detected in most. Some starch blend batches were free or almost free of macro particles, in one case already after three weeks. Besides the type of material, the thickness of the material had an influence on the BDP degradation. In the worst degraded bag type, residues of the thicker drawstrings accumulated. In addition, the rotting material moisture was significant. There were some dried-out zones with water contents below 20% in which no biodegradation activity took place and, accordingly, BDP degradation did not progress.Publicationtype: Technical Report514 1055 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Improving the quality and quantity of source-separated household food waste in areas of different socio-economic characteristics: a case study from Lübeck, Germany(2019-09); ; ; A method aiming at improving source-separation performance of household food waste (FW) was investigated in two areas with different socio-economic characteristics in Lübeck, Germany.This included the test of a new FW collection system including the distribution of small collection buckets to each household. In addition, an information event was organized and households were provided with information material includingawaste sorting guide. The study also aimed at assessing the FW avoidance potential. A method for waste composition analysis for FW from households was applied for the assessment. Both areasshowed an increase ofthe source-separation of FW from 17.4% to 60.3% (A, socio-economic lowarea) and from 16.6% to 65.7% (B, socio-economic mediumarea) respectively. Compared to the waste compositionin the bio-waste (BW) bin prior the investigation, macro-impurities (including paperwaste) reduced from around 6.1% to 0.6%(A) and from 13.6% to 1.2% (B). In this respect, the investigated collection system showed a significant improvement to the regular waste collection system.Publicationtype: Conference Paper327 267 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , 80 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Report on results for household food waste collection and decentralised shredding in the “Lübeck-case” : DECISIVE Deliverable D3.6 : a decentralised management scheme for innovative valorisation of urban biowasteThis study focuses on the collection and characterisation of bio-waste and in particular food waste (FW) as the core-substrate of DECISIVE. These issues are investigated in a case-study performed at the eco-settlement Lübeck-Flintenbreite (LF), which is part of the City of Lübeck (LC). Within the study, the locations are characterised, whereby LF specifically includes explanations on the settlement structures and LC focuses on the current applied collection and treatment procedures for bio-waste including source-separated bio-waste from biobins and non-separated bio-waste from residual waste bins. A waste composition analysis was carried out for wastes from bio-waste bins and residual waste bins comparing waste qualities. A special focus was placed on FW, which was distinguished into ten different fractions. Furthermore, an inventory of the technical infrastructure from LF was carried out. In LF a complete mAD system is available. It was constructed in an earlier project, but is yet to be operated. Specifically, the interface between source-separated bio-waste collection and mAD was investigated: the available decentralised shredder was operated with various source-separated bio-waste samples. Finally, scenarios for the transition of LF towards decentralised bio-waste management and the usability of the available mAD process units were evaluated.Publicationtype: Project Deliverable116 411 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Biogas and nutrients from blackwater, lawn cuttings and grease trap residues : experiments for Hamburg’s Jenfelder Au districtBackground: The project KREIS focuses on a new combination of renewable energy provision with innovative wastewater treatment, called the “Hamburg Water Cycle®” (HWC) which will be applied in Hamburg’s neighbourhood Jenfelder Au. HWC includes a separate collection of rainwater, greywater and blackwater. Vacuum toilets are used to concentrate the blackwater. Biogas will be produced from the blackwater in an anaerobic digestion process together with co-substrates. The blackwater will be transported to the anaerobic pre-treatment facility via a vacuum system. Construction of water systems started in 2013, and commercialization of houses is planned to be finished in 2018. Methods: The article focuses on research work accompanying the demonstration project. Blackwater and the co-substrates, lawn cuttings and grease trap residues from restaurants and canteens will be considered as bioresources, not as residues. To evaluate the utilization efficiency, three investigation steps were carried out: inventory to determine substrate quantities and qualities, anaerobic digestion to determine biogas production, and evaluation of digestate utilization options. Results: The daily amount of blackwater in Jenfelder Au is calculated to be about 12 m3 (dry matter (DM) 0.6 %; organic dry matter (oDM) 65 % DM; nitrogen (N) 28 % DM; phosphorus (P) 2.7 %). To increase the biogas production, co-substrates will be added. Grease trap residues (averages: DM 2 %; oDM 85 % DM; N 2.5 % DM; P 0.6 % DM) and lawn cuttings (averages: DM 30 %; oDM 80 % DM; N 2.6 % DM; P 0.3 % DM) were selected. The inventory study showed a sufficient potential of lawn cuttings within a 5-km radius. The lawn cuttings must be pre-treated for wet fermentation. Two options were investigated: press juice preparation and wet shredding of the fresh and silage lawn. Batch test was used to determine the biogas potential of the substrates with the following average results: blackwater 500 nl/kg oDM, grease trap residues 1000 nl/kg oDM, lawn cuttings 400 nl/kg oDM and lawn juice 500 nl/kg oDM. The effects of the composition of the substrate mixture and of the retention time in the reactor on biogas quantity and process stability were studied in semi-continuous operating reactors. Experiments showed that a stable process with an average biogas production of 800 nl/kg oDM is, e.g., possible with a mixture of blackwater, press juice of lawn cuttings and grease trap residues in a fresh mass ratio of 1:1:1. Furthermore, the N and P contents in digestates were determined. These nutrients are valuable for fertilization. Conclusion: It has been shown that blackwater combined with local waste streams can be used for biogas generation and that it has a potential as fertilizer. The experiments have shown that co-digestion has a positive effect on biogas yields and lawn cuttings are suitable as co-substrate. Lawn cuttings can be applied as lawn juice or lawn suspension. Ways of an integral utilization and the potential of nutrient recovery are shown in this work.Publicationtype: Journal ArticleScopus© Citations 12 602 416 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Anaerobic digestion of blackwater from vacuum toilets and kitchen refuse in a continuous stirred tank reactor (CSTR)(2007-05-22); ; ; ; The objective of this research was mesophilic anaerobic digestion of blackwater from vacuum toilets (BW) and kitchen refuse (KR) in a CSTR within an ecological sanitation system. A detailed investigation of the BW characteristics was carried out. Research on anaerobic digestion was performed with CSTR of 10 I volume at HIRT of 10, 15 and 20 days. The digestion of BW at 20 days HRT showed stable performance without inhibition effects, in spite of relatively high ammonium concentrations. The removal of total and particulate COD was 61 % and 53%, respectively, and the methane yield 10 I CH4/cap/day. The addition of kitchen refuse (KR) improved the performance of the CSTR in terms of COD removal efficiency and methane yield. At 20 days HRT the removal of total and particulate COD increased up to 71 % and 67%, respectively, and the methane yield to 27 I CH4/Gap/day. The results at 15 days HRT showed similar performance. At HRT of 10 days, the anaerobic treatment was limited but reached steady state conditions at higher VFA concentrations in the effluent, with a decrease of COD removal of 30 to 33% and of methane yields of 19 to 21 %.Publicationtype: Journal Article137