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| 6. |
- Ciuk Karlsson, Susanna, et al.
(author)
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Hydraulic Properties and Reduction of COD, Phosphorus and Nitrogen in a Sand Filter used for Greywater Treatment – Simulation and Verification
- 2013
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Conference paper (other academic/artistic)abstract
- A vertical flow sand filter is a simple, effective and inexpensive system for treating greywater. The performance of sand filters treating artificial greywater was tested in the laboratory over a time period of 113 days. The filters consisted of columns (0.2 m diameter) filled with sand to a height of 0.6 m. The hydraulic properties of the filters were measured as well as the inflow and outflow concentrations of COD, BOD5, total and phosphate phosphorus and total-, ammonia- and nitrate nitrogen. To get a better quantitative understanding of the treatment processes inside the filters, the HYDRUS-CW2D computer software was used to simulate the filters. The simulation of water flow through the filter could be well fitted to the measured flow by adjusting three model parameters: the air entry value, the pore size distribution index, and the pore connectivity parameter. For the COD reduction the simulated results agreed well with experimental data after an adjustment of the microbial lysis parameters of HYDRUS-CW2D. The simulated reduction of COD was 65 %, while a 72 % reduction was measured for the filters in the lab. Simulated reduction of phosphorus in the sand filter effluent corresponded well to the measured reduction: the simulated reduction of phosphorus was 72 % while the experimental filters achieved a 79 % reduction. Also, the simulated effluent concentrations of nitrate compared quite well to the measured values. Almost no reduction (4 %) in total nitrogen took place in the experimental filters, which agreed with the simulated reduction (0 %). For the phosphorus and nitrate components in HYDRUS-CW2D, so far no changes have been made to the default parameters.
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| 7. |
- Dalahmeh, Sahar, et al.
(author)
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Effects of changing hydraulic and organic loading rates on pollutant reduction in bark, charcoal and sand filters treating greywater
- 2014
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In: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 132, s. 338-345
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Journal article (peer-reviewed)abstract
- Greywater flows and concentrations vary greatly, so evaluation and prediction of the response of on-site treatment filters to variable loading regimes is challenging. The performance of 0.6 m x 0.2 m (height x diameter) filters of bark, activated charcoal and sand in reduction of biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total nitrogen (Tot-N) and total phosphorus (Tot-P) under variable loading regimes was investigated and modelled. During seven runs, the filters were fed with synthetic greywater at hydraulic loading rates (HLR) of 32-128 L m-2 day-1 and organic loading rates (OLR) of 13-76 g BOD5 m-2 day-1. Based on the changes in HLR and OLR, the reduction in pollutants was modelled using multiple linear regression. The models showed that increasing the HLR from 32 to 128 L m-2 day-1 decreased COD reduction in the bark filters from 74 to 40%, but increased COD reduction in the charcoal and sand filters from 76 to 90% and 65 to 83%, respectively. Moreover, the models showed that increasing the OLR from 13 to 76 g BOD5 m-2 day -1 enhanced the pollutant reduction in all filters except for Tot-P in the bark filters, which decreased slightly from 81 to 73%. Decreasing the HLR from 128 to 32 L m-2 day-1 enhanced the pollutant reduction in all filters, but decreasing the OLR from 76 to 14 g BOD5 m-2 day-1 detached biofilm and decreased the Tot-N and Tot-P reduction in the bark and sand filters. Overall, the bark filters had the capacity to treat high OLR, while the charcoal filters had the capacity to treat high HLR and high OLR. Both bark and charcoal filters had higher capacity than sand filters in dealing with high and variable loads. Bark seems to be an attractive substitute for sand filters in settings short in water and its effluent would be valuable for irrigation, while charcoal filters should be an attractive alternative for settings both rich and short in water supply and when environmental eutrophication has to be considered.
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| 8. |
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| 9. |
- Dalahmeh, Sahar, et al.
(author)
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Quality of greywater treated in biochar filter and risk assessment of gastroenteritis due to household exposure during maintenance and irrigation
- 2016
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In: Journal of Applied Microbiology. - : Oxford University Press (OUP). - 1364-5072 .- 1365-2672. ; 121, s. 1427-1443
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Journal article (peer-reviewed)abstract
- AimThis study evaluated treatment of greywater (GW) by a biochar filter in Jordan and assessed the annual risks of infection (Pi-annual), annual risk of disease (Pd-annual) and disease burden (in disability-adjusted life years; DALYs) of gastroenteritis caused by Salmonella spp. and rotavirus due to ingestion of GW during system maintenance and consumption of green onions irrigated with treated and nontreated GW.Methods and resultsThe biochar filter efficiently removed 93% of biochemical oxygen demand (BOD5) and 85% of solids, while removal of Escherichia coli was insignificant. Treatment of GW decreased the median Pd-annual due to ingestion of GW from 139x10(-2) to 60x10(-3) for Salmonella spp. but did not affect Pd-annual caused by rotavirus (973x10(-1) to 10). Consumption of onions irrigated with treated GW had a median Pd-annual of 125x10(-9) to 12x10(-8) for Salmonella spp. and 496x10(-4) to 437x10(-3) for rotavirus infection, which was 999 and 90% lower, respectively, than the risk when consuming onions irrigated with nontreated GW. The highest risks of gastrointestinal disease were thus associated mainly with direct ingestion of GW when maintaining the system.ConclusionsGarden produce irrigated with GW treated in biochar filter did not display intolerable risks of rotavirusbased gastroenteritis during summer season in the study area given that the produce is harvested 1 to 2days, and washed, before consumption.Significance and Impact of the StudyThis study contributes to scientific-based knowledge on the suitability of biochar filters for onsite greywater treatment and confirms the microbial safety of recycling treated greywater for garden irrigation.
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| 10. |
- Ddiba, Daniel, 1990-
(author)
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Exploring the circular economy of urban organic waste in sub-Saharan Africa: opportunities and challenges
- 2020
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Licentiate thesis (other academic/artistic)abstract
- Globally, there is increasing awareness of the importance of applying circular economy principles to the management of organic waste streams through resource recovery. In the urban areas of sub-Saharan Africa which are going to host a significant part of population growth over the next three decades, this is especially relevant. Circular economy approaches for sanitation and waste management can provide incentives to improve infrastructure and consequently contribute resources for water, energy and food that power urban livelihoods. This thesis is situated at the intersection of the circular economy on one hand and sanitation and waste management systems on the other. It aims to contribute to knowledge about the circular economy by investigating the potential contribution of resource-oriented urban sanitation and waste management towards the implementation of a circular economy in sub-Saharan Africa and the opportunities and challenges thereof.In pursuit of the above aim, the thesis employs a mixed methods approach and is operationalized in two case study locations: Kampala (Uganda) and Naivasha (Kenya). The findings reveal the quantities of resource recovery products like biogas, compost and black soldier fly larvae that can be obtained from the organic waste streams collected in a large city, demonstrate the viability of valorizing dried faecal sludge as a solid fuel for industrial applications, and identify the factors that facilitate or impede the governance capacity to implement circular economy approaches to the management of organic waste streams in urban areas in sub-Saharan Africa. The methods used for quantifying the potential for valorizing organic waste streams and for assessing governance capacity demonstrate approaches that could be applied in other urban contexts with interest in implementing circular economy principles. The discussion highlights some key implications of these findings for sanitation and waste management practices, arguing that it is time for a shift in sub-Saharan Africa from designing sanitation and waste management systems for disposal to designing them for resource recovery.
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| 12. |
- Ermolaev, Evgheni, et al.
(author)
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Greenhouse gas emissions from small-scale fly larvae composting with Hermetia illucens
- 2019
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In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 96, s. 65-74
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Journal article (peer-reviewed)abstract
- Fly larvae composting is an emerging waste treatment alternative with great potential to increase revenue from food waste management. For wider implementation, fly larvae composting has to be evaluated in comparison with conventional systems, based on direct greenhouse gas (GHG) emission data for the treatment process, which are currently limited. This study evaluated direct emissions of CO2, CH4, N2O and NH3 from composting of food waste using black soldier fly (BSF) larvae (Hermetia illucens). Use of BSF larvae-associated bacteria in 7-day pre-treatment and seeding at larvae treatment start were evaluated and compared to larvae treatment without bacteria addition. The treatments were performed in a set of 14-day laboratory-scale experiments. Mean substrate reduction was 49 +/- 8% and bioconversion ratio was 24 +/- 8% (both dry matter basis). Direct GHG emissions from the fly larvae treatment process were generally very small, with emissions of CH4 and N2O equivalent to 0.38 kg CO2-equivalents per ton food waste treated assuming global warming potential over 100 years, while mean total CO2 emissions were 96 g CO2 per kg food waste treated. Additional emissions could be expected to occur in the pre-treatment process, which did not provide any significant improvement in bioconversion ratio or reduction in total GHG emissions during treatment. Similarly, use of BSF larvae-associated bacteria did not significantly improve process efficiency. No NH3 emissions were detected, as reflected in total N mass balance over the treatment cycle. The results show that total direct GHG emissions from food waste treatment by fly larvae composting are lower than those from conventional food waste treatment, and that pre-treatment and seeding of food waste with BSF larvae-associated bacteria do not further reduce total GHG emissions. (C) 2019 Elsevier Ltd. All rights reserved.
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| 13. |
- Ermolaev, Evgheni, et al.
(author)
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Model selection for waste conversion efficiency and energy demands in a pilot for large-scale larvae treatment
- 2019
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In: Linköping electronic conference proceedings. - : Linköping University Electronic Press. - 1650-3686 .- 1650-3740. ; , s. 118-124
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Conference paper (peer-reviewed)abstract
- Implementations of conversion systems for segregated food waste into larval biomass are reliant on stability of production environment and predictable outcomes. However, the knowledge is currently lacking for large scale implementation modelling allowing to adjust the process for reaching a stable production quality and predicting the treatment capacity and output product quantity. This study contributed to the development of such knowledge and investigated models for prediction of larvae mass gain in the conversion process, food waste degradation due to larval and microbial activity, heat production based on metabolic activity in the conversion process. These models were used to evaluate the amount of heat produced and compared to the demand for water removal for achieving a minimal total solids content (50%) in the treatment residue for easy larvae separation by sieving. Based on these models’ predictions and measurements of the conversion efficiency it was established that, assuming no heat loss from the system, the heat generated by the process was sufficient to achieve a desirable total solids content in the residue after 14 days of treatment. An exponential heat production from waste degradation can be expected, and thus, for wetter food waste, the treatment period can be expanded to achieve the desired residue total solids content.
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| 14. |
- Ewald, Nils, et al.
(author)
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Fatty acid composition of black soldier fly larvae (Hermetia illucens) - Possibilities and limitations for modification through diet
- 2020
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In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 102, s. 40-47
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Journal article (peer-reviewed)abstract
- Black soldier fly larvae (Hermetia illucens; BSFL) can convert organic wastes into a nutrient-rich biomass suitable in animal feed, which could be a way to achieve more sustainable production of food. However, little is known about how the diet fed to BSFL affects their nutritional value, especially their fatty acid composition. In this study, BSFL were fed 11 diets based on four different organic waste sources (mussels, bread, fish and food waste). Fatty acid and proximate composition (dry matter, crude fat, crude protein and ash) were analysed in the diets, in two-week-old larvae and substrate residues. Larval weight, survival and feed conversion were also recorded. The diet was found to affect all parameters investigated. Irrespective of diet, the larval fat consisted mainly of lauric acid and other saturated fatty acids and these were found to be synthesised by the larvae. However, both the fatty acid composition of the substrate, and the larval weight were found to affect the fatty acid profile of the larvae. In general, larvae with a higher weight contained a higher percentage of saturated fatty acids and a lower percentage of unsaturated fatty acids, such as eicosapentaenoic (EPA) and docosahexaenoic acid (DHA). It was concluded that the possibilities to tailor the fatty acid composition of the BSFL through the diet are limited; thus, the BSFL fat may not be suitable to replace fish oil, but has potential of inclusion in other food, feed and fuel products. (C) 2019 The Authors. Published by Elsevier Ltd.
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| 15. |
- Fidjeland, Jörgen, et al.
(author)
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Ammonia sanitisation of sewage sludge using urea
- 2013
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In: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 68, s. 1866-1872
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Journal article (peer-reviewed)abstract
- The aim of the study was to develop a simple, low-cost treatment for sewage sludge using urea as a sanitising agent. Sewage sludge was spiked with Enterococcus faecalis and Salmonella typhimurium, treated with 0.5, 1, 1.5 and 2% w/w urea at laboratory scale, and the viability was monitored during 4 months of storage at 4, 10 and 22 degrees C (only 0.5%). A linear relationship was identified between Salmonella spp. inactivation rate and ammonia (NH3) concentration. Temperature had a positive impact on Salmonella spp. inactivation at higher temperatures, but in the range 4-10 degrees C temperature influenced this inactivation merely by its impact on the ammonia equilibrium. Enterococcus spp. was more persistent and a lag phase of up to 11 weeks was observed. Higher temperature and ammonia concentration reduced the lag phase duration significantly, and also had a clear effect on the inactivation rate for the treatments with 0.5% urea at 22 degrees C and 2% urea at 4 and 10 degrees C. Urea sanitisation of sewage sludge can give a 2 log(10) reduction of Enterococcus spp. and more than a 5 log(10) reduction of Salmonella spp. within 6 weeks with either 0.5% w/w urea at 22 degrees C or 2% urea at 10 degrees C.
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| 17. |
- Guidini Lopes, Ivã, et al.
(author)
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Dynamics of black soldier fly larvae composting – Impact of substrate properties and rearing conditions on process efficiency
- 2023
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In: Waste Management. - 0956-053X .- 1879-2456. ; 172, s. 25-32
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Journal article (peer-reviewed)abstract
- Inadequate organic waste management have detrimental impact on the environment and on public health. Black soldier fly (BSF) larvae composting is a biological treatment for biodegradable waste that align with circular economy principles. The bioconversion efficiency of bio-waste into larval biomass is influenced by various factors, such as substrate type and the process parameters employed in the larval rearing process. In this study, the influence of these parameters on survival, material reduction (Mat.Red), waste-to-biomass conversion efficiency (BCE) and larval yield per rearing unit was investigated through two sets of experiments. In Experiment 1, the impact of larval density in five distinct rearing substrates was evaluated, while the effect of larval feed dose and substrate depth was assessed in Experiment 2, using a model substrate (dog food). In Experiment 1 it was found that higher larval density lead to an increase in BCE and larval yield, up to a threshold (around 6.25 larvae cm−2). Surpassing this threshold led to the production of smaller larvae, while the yield remained relatively consistent. In Experiment 2 it was found that supplying the substrate in a shallow layer (1–1.5 cm depth) and providing a low feed dose (0.1 g volatile solids (VS) larva–1) led to higher BCE and Mat.Red, albeit with a reduced overall yield per unit. Increasing feed load and substrate depth reduced the conversion efficiency, Mat.Red and larval survival. This study enhances the understanding of the effect of various process parameters used in the BSF larvae treatment, and how they interrelate.
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| 18. |
- Gunnarsson, Matilda, et al.
(author)
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Estimating environmental and societal impacts from scaling up urine concentration technologies
- 2023
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In: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 382
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Journal article (peer-reviewed)abstract
- There is a growing trend for nutrient recovery from wastewater as part of the transition to a circular economy. Most nutrients in household wastewater originate from urine and one way to facilitate reuse of these nutrients is to concentrate the urine into fertiliser products. Urine concentration technologies are still in the development phase and not implemented at scale. The aim of this study was to provide guidance to technology developers and policymakers by assessing the environmental and societal impacts of urine concentration technologies. In particular, it includes practical aspects such as worker safety, space availability and local fertiliser needs that have not been included in previous studies. Future scenarios on implementing three different urine concentration technologies (alkaline dehydration, nitrification-distillation, ion-exchange with struvite precipitation) in a planned residential area in Malmö, Sweden, were developed. The technologies were evaluated using multi-criteria assessment (MCA), with environment, technical, economic and health sustainability criteria derived from the Sustainable Development Goals (SDGs). It was found that all urine concentration technologies performed well against many of the sustainability criteria examined and can contribute to achieving SDGs, especially regarding nitrogen recovery. Specific areas for further development were identified for each technology. An impact assessment on scaling up demonstrated that nitrogen emissions to surface water were significantly reduced when more than 60% of urine in Malmö city was subjected to urine concentration. Nitrogen and phosphorus recovered from recycling only 15–30% of urine in Malmö could supply 50% of Malmö municipality's fertiliser demand.
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| 19. |
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| 20. |
- Isibika, Alice, et al.
(author)
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Co-composting of banana peel and orange peel waste with fish waste to improve conversion by black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae
- 2021
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 318
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Journal article (peer-reviewed)abstract
- Black soldier fly (BSF) larvae composting is a promising waste treatment that can add value to available biodegradable waste. However, substrates that have low protein content and contain complex molecules (e.g. fruit peels) are not easily degraded by the larvae. This study evaluated the impact on the BSF larvae composting efficiency of co-composting different mixtures of banana and orange peels with incremental increase of fish waste. Mixtures (in total 50 distinct mixtures) of varying proportions of banana peels, orange peels and fish waste were evaluated. BFSL fed on orange peel and banana peel mixtures, containing no fish waste, resulted in a lower biomass conversion efficiency (4.5% +/- 1.3) on a volatile solids (VS) basis (BCEvs). Co-composting the fruit peels with fish waste increased the biomass conversion efficiency and the highest BCEvs (25%) was attained when 75% fish waste was included. However, the BCEvs varied greatly (18.0% +/- 5.8), likely due to varying fish waste composition. A 25% fish waste inclusion resulted in more than twice as high BCEvs (12.3% +/- 2.1) compared to when no fish waste was included. As the conversion efficiency variance increased with increasing fish waste inclusion, it was recommended to keep the inclusions of the fish waste to around 25% of the total mixture, in order to increase the reliability of the BSF larvae composting efficiency.
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| 21. |
- Isibika, Alice, et al.
(author)
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Food industry waste - An opportunity for black soldier fly larvae protein production in Tanzania
- 2023
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 858
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Journal article (peer-reviewed)abstract
- Black soldier Ily larvae composting is an emerging treannent option with potential to improve biowaste valorization in cities of low-income countries. This study surveyed the current generation and management status of food industry biowaste and their availability and suitability as potential feedstock for black soldier Ily larvae (BSFI.) composting treatment in three Tanzania cities, Dar es Salaam, Mwanza, and Dodoma. Biowaste-generating food industry companies (n = 29) in the three cities were found to produce banana peels, mango seeds, sunflower press cake, brewery waste, and coffee husks in large quantities (similar to 100,000-1,000,000 kg y(-1)). Around 50 % of these companies (16/29), primarily vegetable oil companies (10/11), either sold or gave away their waste as animal feed, while most companies (9/11) with unutilized food industry waste landfilled the generated biowaste. Multi-criteria analysis based on substrate availability criteria identified banana peels, mango seeds, and coffee husks with total score points of a >= 10/12 as the most suitable feedstock for BSFL composting. However, multi-criteria analysis based on physicalchemical criteria identified brewery waste and sunflower press cake with total score points of a >= 11/15 as the most suitable feedstock. Combined availability and physical-chemical properties of individual biowastes showed that all identified types of food industry biowaste can be suitable feedstock for producing BSFL biomass for protein production, but certain waste streams needed to be mixed with other waste streams prior to BSFL-composting to ensure sufficient availability and provide a balanced nutritional profile compared with the single-source biowastes. This study concluded that large volumes of food industry waste are being generated from food industry companies in Tanzania and there is need to establish new biowaste management interventions for resource recovery. Furthermore, for interested stakeholders in the waste management business, multi-stream BSFI.-composting can be a suitable solution for managing and closing nutrient loops of the unutilized food industry biowaste in Tanzania and in other similar settings globally.
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| 22. |
- Isibika, Alice, et al.
(author)
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Pre-treatment of banana peel to improve composting by black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae
- 2019
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In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 100, s. 151-160
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Journal article (peer-reviewed)abstract
- Use of black soldier fly (Hermetia illucens (L), Diptera: Stratiomyidae) larvae (BSFL) is among the solutions being explored to shift the value chain in organic waste management by producing valuable products. Although BSFL consume a range of substrates, nutrient-imbalanced materials with high hemicellulose and lignin content, e.g. manure and banana peel, yield low conversion into larval biomass. This study explored pre-treatment methods to improve the nutrient composition and digestibility of banana peel to achieve higher substrate conversion into BSFL biomass. The pre-treatment methods evaluated were microbial, chemical (non-protein nitrogen), heat-based, and combinations of these. All pre-treatments tested except heating resulted in more efficient BSFL conversion in terms of final larvae weight. The low BSFL responses in pre-treatments were caused by the observed high amounts of tannins and phenolic compounds mainly from the heating pre-treatment. Waste to biomass conversion ratio correlated negatively with substrate volatile solids (VS) and positively with the decrease in VS in pre-treatment. Microbial - 14 days pre-treatments provided the optimum pre-treatment time for the microorganisms to achieve maximum degradation of the substrates, facilitating larval assimilation of the released nutrients. Rhizopus oligosporus-14 days and ammonia + Rhizopus resulted in the most efficient BSFL treatment, measured as protein produced per kg incoming material. (C) 2019 The Author(s). Published by Elsevier Ltd.
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| 23. |
- Khalil, Sammar, et al.
(author)
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Fertiliser effect on Swiss chard of black soldier fly larvae-frass compost made from food waste and faeces
- 2021
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In: Journal of insects as food and feed. - 2352-4588. ; 7, s. 457-469
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Journal article (peer-reviewed)abstract
- Inadequate organic waste management can have adverse health effects and pollute the environment. If the energy and nutrients in organic waste were to be used efficiently, they could increase food security. Composting using black soldier fly (BSF) larvae can convert organic waste into two valuable products: organic fertiliser, in the form of treatment residues, and animal feed protein, in the form of larvae. To demonstrate the feasibility of using BSF treatment residues as organic fertiliser, more knowledge is needed about the effect of BSF larvae-frass compost on plant growth and performance. This study examined the effect on growth of Swiss chard of five fertiliser treatments: (1) BSF larvae-frass compost of human faeces (BSF-F); (2) BSF larvae-frass compost of food waste (BSF-FW); (3) cow manure (CM), the most commonly used organic fertiliser globally; (4) an inorganic fertiliser containing nitrogen, phosphorus and potassium (NPK); and (5) a negative control with no fertiliser. The results revealed that BSF larvae-frass compost of human faeces and food waste gave comparable yields to inorganic fertilisers, and significantly higher yields than the unfertilised control. The percentage increase in fresh weight of leaves in the treatments compared to the unfertilised control were 132% for BSF-FW, 115% for BSF-F, 118% for NPK and 86% for CM. Principal component analysis ( PCA) showed that all treatments involving fertiliser gave differences in soil nutrient concentrations. PCA also revealed a positive correlation between soil nitrate concentration and yield. Thus, using BSF larvae-frass compost as fertiliser could be a way of efficiently returning plant nutrients in faeces and organic waste to the food chain.
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| 24. |
- Korbelyiova, L., et al.
(author)
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Paper vs leaf : Carbon footprint of single-use plates made from renewable materials
- 2021
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In: Sustainable Production and Consumption. - : Elsevier. - 2352-5509. ; 25, s. 77-90
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Journal article (peer-reviewed)abstract
- Plastic pollution of the natural environment world-wide is ubiquitous. More than 80% of marine litter is made of plastics, 70% of which originates from disposable items, so plastic disposables need to be replaced with disposables made from renewable materials. However, it is important to investigate the environmental impact of renewable alternatives through their life cycle, in order to support sustainable consumption and production. In this study, the carbon footprint of disposable plates made from two different renewable materials (paper, tree leaves) were analysed using life cycle assessment. The leaf plate was produced in India and the paper plate in Finland, but both were used and disposed of in Sweden. The results showed that the leaf plate had higher carbon footprint, due to long-distance transport and use of fossil fuel-based electricity for production. Scenario analysis indicated that the emissions associated with the leaf plate were lower when replacing air freight with sea transport and with economies of scale in expanded production. For the paper plate, the processing stage was shown to contribute most life cycle emissions. These could be lowered by applying a biodegradable coating. In comparison the leaf plate had the benefit of being biodegradable, but this benefit was not enough to compete with the paper plate which was consider the less environmentally damaging alternative. However, in order to increase sustainability in the food supply chain, it will not be enough to just improve the material use for single use plates, especially since the idea of single use materials could be seen as less sustainable, but improved materials have the potential to offset the anticipated growth of the food service sector where single use items are widely used.
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| 25. |
- Lalander, Cecilia, et al.
(author)
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A comparison in product-value potential in four treatment strategies for food waste and faeces – assessing composting, fly larvae composting and anaerobic digestion
- 2018
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In: GCB Bioenergy. - : Wiley. - 1757-1693 .- 1757-1707. ; 10, s. 84-91
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Journal article (peer-reviewed)abstract
- Municipalities are expected to provide solid waste management, which is funded by tax revenue or/and waste treatment fees. In many low- and middle-income countries, municipalities struggle to provide an adequate level of service, and in these places, the informal sector plays a major role in the collection and treatment of solid waste. In contrast to the plastic and metal fraction, the organic fraction is not managed by the informal sector, primarily because it has low or no financial value and treatment would cost more than the possible revenue. If the organic fraction could be converted to valuable products, the treatment could bear its own cost and this could act as an incentive to collect and treat this fraction. In this study, the potential product value generated through four treatment strategies treating food waste and faeces was compared in a Swedish context: (i) thermophilic composting; (ii) black soldier fly treatment (BSF treatment); (iii) anaerobic digestion (AD); and (iv) BSF treatment followed by AD (BSF + AD). In order to assess the AD strategies, the biomethane potentials of the substrates were assessed. Food waste had the highest biomethane potential, while BSF-treated faeces had the lowest (417 and 188 NmL g VS-1, respectively). Thermophilic composting yielded the lowest value product (organic fertilizer; 26 (sic) t(-1) treated food waste) and BSF treatment + AD the highest total value of products (animal feed, vehicle gas and organic fertilizer; 215 (sic) t(-1) treated food waste). The treatment costs were not taken into account here; the total value gives an indication of the cost margin for the different strategies studied. In places with an existing AD plant, BSF treatment + AD strategy is the most economically viable. In places where no such plant exists, BSF treatment is likely to be the most economically favourable treatment.
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