Systematic evidence mapping to assess the sustainability of bioplastics derived from food waste: Do we know enough?

Data Availability Statement: Not applicable.Copyright © 2022 by the authors. The production of bioplastics from food loss and waste (FLW), termed FLW-derived bioplastics, is considered an attractive alternative to first-generation bioplastics. To our knowledge, a clear understanding of the sustainability performance of FLW-derived bioplastics from environmental, economic, technical, and social aspects is still lacking. This systematic evidence mapping aims to fill this gap by undertaking a reality check on the life cycle sustainability performance of FLW-derived bioplastics from a multidimensional perspective underpinned by systems thinking approach to assess their potential to revolutionise the plastics economy. Results revealed that FLW-derived bioplastic production is highly complex and uncertain. The low technological readiness of FLW valorisation processes and the under-researched logistics of FLW management on a regional scale currently withhold advancement in this field. Nonetheless, progress is looming, and ensuring that FLW-derived bioplastics production enables the transition toward a sustainable bioeconomy is critical. Innovation in both the food and plastics value chains is urgently needed to address their challenges and mitigate pollution. Yet, any steps forward need to be holistically calculated to yield sustainability benefits and prevent unintended consequences.This research received no external funding

Statistical quantification of sub-sampling representativeness and uncertainty for waste-derived solid recovered fuel (SRF): Comparison with theory of sampling (ToS)

The level of uncertainty during quantification of hazardous elements/properties of waste-derived products is affected by sub-sampling. Understanding sources of variability in sub-sampling can lead to more accurate risk quantification and effective compliance statistics. Here, we investigate a sub-sampling scheme for the characterisation of solid recovered fuel (SRF) - an example of an inherently heterogeneous mixture containing hazardous properties. We used statistically designed experiments (DoE) (nested balanced ANOVA) to quantify uncertainty arising from material properties, sub-sampling plan and analysis. This was compared with the theoretically estimated uncertainty via theory of sampling (ToS). The sub-sampling scheme derives representative analytical results for relatively uniformly dispersed properties (moisture, ash, and calorific content: RSD ≤ 6.1 %). Much higher uncertainty was recorded for the less uniformly dispersed chlorine (Cl) (RSD: 18.2 %), but not considerably affecting SRF classification. The ToS formula overestimates the uncertainty from sub-sampling stages without shredding, possibly due to considering uncertainty being proportional to the cube of particle size (FE ∝ d3), which may not always apply e.g. for flat waste fragments. The relative contribution of sub-sampling stages to the overall uncertainty differs by property, contrary to what ToS stipulates. Therefore, the ToS approach needs adaptation for quantitative application in sub-sampling of waste-derived materials

Stability and maturity of biowaste composts derived by small municipalities : correlation among physical, chemical and biological indices

Stability and maturity are important criteria to guarantee the quality of a compost that is applied to agriculture or used as amendment in degraded soils. Although different techniques exist to evaluate stability and maturity, the application of laboratory tests in municipalities in developing countries can be limited due to cost and application complexities. In the composting facilities of such places, some classical low cost on-site tests to monitor the composting process are usually implemented; however, such tests do not necessarily clearly identify conditions of stability and maturity. In this article, we have applied and compared results of stability and maturity tests that can be easily employed on site (i.e. temperature, pH, moisture, electrical conductivity [EC], odor and color), and of tests that require more complex laboratory techniques (volatile solids, C/N ratio, self-heating, respirometric index, germination index [GI]). The evaluation of the above was performed in the field scale using 2 piles of biowaste applied compost. The monitoring period was from day 70 to day 190 of the process. Results showed that the low-cost tests traditionally employed to monitor the composting process on-site, such as temperature, color and moisture, do not provide consistent determinations with the more complex laboratory tests used to assess stability (e.g. respiration index, self-heating, volatile solids). In the case of maturity tests (GI, pH, EC), both the on-site tests (pH, EC) and the laboratory test (GI) provided consistent results. Although, stability was indicated for most of the samples, the maturity tests indicated that products were consistently immature. Thus, a stable product is not necessarily mature. Conclusively, the decision on the quality of the compost in the installations located in developing countries requires the simultaneous use of a combination of tests that are performed both in the laboratory and on-site

Fast and fine-tuned corrections when the target of a hand movement is displaced

To study the strategy in responding to target displacements during fast goal-directed arm movements, we examined how quickly corrections are initiated and how vigorously they are executed. We perturbed the target position at various moments before and after movement initiation. Corrections to perturbations before the movement started were initiated with the same latency as corrections to perturbations during the movement. Subjects also responded as quickly to a second perturbation during the same reach, even if the perturbations were only separated by 60 ms. The magnitude of the correction was minimized with respect to the time remaining until the end of the movement. We conclude that despite being executed after a fixed latency, these fast corrections are not stereotyped responses but are suited to the circumstances