Developments of biobased plasticizers for compostable polymers in the green packaging applications: A review

The demand for biobased materials for various end-uses in the bioplastic industry is substantially growing due to increasing awareness of health and environmental concerns, along with the toxicity of synthetic plasticizers such as phthalates. This fact has stimulated new regulations requiring the replacement of synthetic conventional plasticizers, particularly for packaging applications. Biobased plasticizers have recently been considered as essential additives, which may be used during the processing of compostable polymers to enormously boost biobased packaging applications. The development and utilization of biobased plasticizers derived from epoxidized soybean oil, castor oil, cardanol, citrate, and isosorbide have been broadly investigated. The synthesis of biobased plasticizers derived from renewable feedstocks and their impact on packaging material performance have been emphasized. Moreover, the effect of biobased plasticizer concentration, interaction, and compatibility on the polymer properties has been examined. Recent developments have resulted in the replacement of synthetic plasticizers by biobased counterparts. Particularly, this has been the case for some biodegradable thermoplastics-based packaging applications.     

Isolation of Native Soil Microorganisms with Potential for Breaking Down Biodegradable Plastic Mulch Films Used in Agriculture

Fungi native to agricultural soils that colonized commercially available biodegradable mulch (BDM) films were isolated and assessed for potential to degrade plastics. Typically, when formulations of plastics are known and a source of the feedstock is available, powdered plastic can be suspended in agar-based media and degradation determined by visualization of clearing zones. However, this approach poorly mimics in situ degradation of BDMs. First, BDMs are not dispersed as small particles throughout the soil matrix. Secondly, BDMs are not sold commercially as pure polymers, but rather as films containing additives (e.g. fillers, plasticizers and dyes) that may affect microbial growth. The procedures described herein were used for isolates acquired from soil-buried mulch films. Fungal isolates acquired from excavated BDMs were tested individually for growth on pieces of new, disinfested BDMs laid atop defined medium containing no carbon source except agar. Isolates that grew on BDMs were further tested in liquid medium where BDMs were the sole added carbon source. After approximately ten weeks, fungal colonization and BDM degradation were assessed by scanning electron microscopy. Isolates were identified via analysis of ribosomal RNA gene sequences. This report describes methods for fungal isolation, but bacteria also were isolated using these methods by substituting media appropriate for bacteria. Our methodology should prove useful for studies investigating breakdown of intact plastic films or products for which plastic feedstocks are either unknown or not available. However our approach does not provide a quantitative method for comparing rates of BDM degradation.     

Planning Biodegradable Waste Management in Stockholm

The environmental impact of the management of biodegradable waste in Stockholm, based mainly on incineration and landfilling, was compared to systems with significant nutrient recycling; large-scale composting, anaerobic digestion, and separate collection and utilization of urine. The systems' emissions, residual products, energy turnover, and resource consumption were evaluated from a life-cycle perspective, using a computerized model, ORWARE (ORganic WAste REsearch model).
Transportation was of relatively low importance to overall environmental impact, even at high rates of nutrient recycling. This is remarkable considering the geographical setting of Stockholm, with high population density and little nearby farmland. Ancillary systems, such as generation of electricity and district heating, were crucial for the overall outcome.
Increased recycling of nutrients in solid biodegradable waste in Stockholm can reduce net environmental impact, whereas separation of human urine to be spread as fertilizer cannot yet be introduced without increased acidification. Increased nutrient recycling from solid biodegradable waste inevitably increases spreading of metals on arable land. Urine is by far the least contaminated residual product. Spreading of all other residuals would be limited by their metal content.     

还原可降解聚磺酸甜菜碱型纳米水凝胶的制备及载药研究

目的:制备与表征还原可降解的聚磺酸甜菜碱型纳米水凝胶,利用该纳米递药系统包载阿霉素(DOX)并初步评价其抗肿瘤性能。方法:利用回流沉淀聚合的方法合成含二硫键的聚磺酸甜菜碱甲基丙烯酸酯(PSBMA)纳米水凝胶及不含二硫键的PSBMA纳米凝胶(nd-PSBMA);通过粒度仪和透射电镜考察两种纳米水凝胶的粒径、形态以及稳定性;通过考察谷胱甘肽(GSH)对纳米凝胶溶液相对浊度的影响以评价还原环境对两种纳米凝胶的还原可降解性;利用纳米凝胶包载阿霉素(DOX),考察载药凝胶在GSH中的释药行为,并初步评价其对A549肿瘤细胞的杀伤作用。结果:以N, N'-双丙烯酰胱胺为交联剂制备了含二硫键的PSBMA纳米凝胶,其粒径在180～200 nm;同时以N, N'-双丙烯酰胺为交联剂制备了不含二硫键的n-PSBMA纳米凝胶。两种纳米凝胶与小鼠血清共孵育7天水合粒径仍无明显变化,表明磺酸甜菜碱型纳米凝胶具有良好的抗蛋白吸附能力。此外,PSBMA纳米凝胶在GSH溶液中迅速地降解,且降解速度与GSH浓度呈正相关;而nd-PSBMA纳米凝胶在GSH溶液中几乎不降解。载DOX的PSBMA纳米凝胶可在GSH作用下快速的释放药物而载DOX的nd-PSBMA纳米凝胶在GSH作用下缓慢的释放药物;体外细胞实验显示空白纳米凝胶和载药nd-PSBMA对A549细胞无明显毒性作用,但载DOX的PSBMA纳米凝胶可高效地杀死A549肿瘤细胞,其药效与游离DOX相仿。结论:还原可降解的PSBMA纳米水凝胶有望成为智能型控释药物载体。     

Rational design and characterization of bioplastics from Hermetia illucens prepupae proteins

In this study proteins extracted from prepupae of Hermetia illucens, also known as black soldier fly, are investigated as promising base for a new type of bioplastics for agricultural purposes. Design of experiments techniques are employed to perform a rational study on the effects of different combination of glycerol as plasticizer, citric acid as cross-linking agent and distilled water as solvent on the capability of proteins to form a free-standing film through casting technique, keeping as fixed the quantity of proteins. Glycerol shows interesting properties as plasticizer contributing to the formation of homogenous and free-standing film. Moreover, mechanical and thermal characterizations are performed to estimate the effect of increasing amounts of proteins on the final properties and thickness of the specimens. Proteins derived from H. illucens can be successfully employed as base for bioplastics to be employed for agricultural purposes.     

Plastics recycling: challenges and opportunities

Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3–4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide.Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel.While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it may be possible to divert the majority of plastic waste from landfills to recycling over the next decades.     

Production of alternatives to fuel oil from organic waste by the alkane-producing bacterium, Vibrio furnissii M1

AIMS: We investigated the production of alternatives to fuel oil through the bacterial metabolism of organic waste. The availability for this purpose of various sources of organic waste for hydrocarbon production by the alkane-producing bacterium, Vibrio furnissii M1, was examined. METHODS AND RESULTS: We screened 17 authentic compounds which can generally be found in organic waste for their hydrocarbon production. Carbon (3 mmol) in a 50-ml culture with acetic acid, lactic acid, butyric acid, succinic acid, malic acid, pentanoic acid, hexanoic acid glucose, xylose, starch or sucrose yielded 10-27 mg of alkanes or alkenes. The chain length of these alkanes or alkenes varied according to the culture from C14 to C27. Varying the ratio of carbon to nitrogen in the culture had no effect on the hydrocarbon production. Crude blackstrap molasses were also converted into alkanes with a conversion ratio of 20% (half of that in an authentic sucrose medium) of the total carbon consumption. CONCLUSIONS: V. furnissii M1 could produce hydrocarbons corresponding to kerosene or light oil from volatile fatty acids and sugars. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on bacterial hydrocarbon production from organic waste.     

Application of LCA as a decision-making tool for waste management systems

Aim, Scope and Background  When materials are recycled they are made available for use for several future life cycles and can therefore replace virgin material more than just once. In order to analyse the optimal waste management system for a given material, the authors have analysed the material flows in a life cycle perspective. It is important to distinguish this approach for material flow analysis for a given material from life cycle analysis of products. A product life cycle analysis analyses the product system from cradle to grave, but uses some form of allocation in order to separate the life cycle of one product from another in cases where component materials are recycled. This paper does not address allocation of burdens between different product systems, but rather focuses on methodology for decision making for waste management systems where the optimal waste management system for a given material is analysed. The focus here is the flow of the given material from cradle (raw material extraction) to grave (the material, or its inherent energy, is no longer available for use). The limitation on the number of times materials can be recycled is set by either the recycling rate, or the technical properties of the recycled material. Main Features  This article describes a mathematical geometric progression approach that can be used to expand the system boundaries and allow for recycling a given number of times. Case studies for polyethylene and paperboard are used to illustrate the importance of including these aspects when part of the Goal and Scope for the LCA study is to identify which waste management treatment options are best for a given material. The results and discussion examine the different conclusions that can be reached about which waste management option is most environmentally beneficial when the higher burdens and benefits of recycling several times are taken into account. Results  In order to assess the complete picture of the burdens and benefits arising from recycling the system boundaries must be expanded to allow for recycling many times. A mathematical geometric progression approach manages to take into account the higher burdens and benefits arising from recycling several times. If one compares different waste management systems, e.g. energy recovery with recycling, without expanding the system to include the complete effects of material recycling one can reach a different conclusion about which waste management option is preferred. Conclusions  When the purpose of the study is to compare different waste management options, it is important that the system boundaries are expanded in order to include several recycling loops where this is a physical reality. The equations given in this article can be used to include these recycling loops. The error introduced by not expanding the system boundaries can be significant. This error can be large enough to change the conclusions of a comparative study, such that material recycling followed by incineration is a much better option than waste incineration directly. Recommendations and Outlook  When comparing waste management solutions, where material recycling is a feasible option, it is important to include the relevant number of recycling loops to ensure that the benefits of material recycling are not underestimated. The methodology presented in this article should be used in future comparative studies for strategic decision-making for waste management. The approach should not be used for LCAs for product systems without due care, as this could lead to double counting of the benefits of recycling (depending on the goal and scope of the analysis). For materials where the material cycle is more of a closed loop and one cannot truly say that recycled materials replace virgin materials, a more sophisticated approach will be required, taking into account the fact that recycled materials will only replace a certain proportion of virgin materials.     

Harnessing Catastrophe to Promote Resource Recovery and Eco-industrial Development

Hurricane Katrina devastated New Orleans, Louisiana, USA, causing widespread damage to industry, housing, and infrastructure. The area of New Orleans East was particularly devastated, including a cluster of industries, such as a major food-processing plant, manufacturing facilities, and bulk material and gas processors. Although this area was well suited for resource recovery and eco-industrial linkages, little progress has been made in implementation. This article explores New Orleans as a case study in the application of industrial ecology to disaster management. Hurricane Katrina's damage to New Orleans resulted in a significant increase in the amount of waste flowing into New Orleans East, which precipitated a massive expenditure of federal funds toward debris management. Those circumstances created an unprecedented opportunity to capitalize a resource recovery program and to establish eco-industrial relationships, both of which would have resulted in new jobs and environmental improvement. Yet straightforward opportunities for resource recovery and eco-industrial linkage were overlooked or dismissed, in spite of antilandfill activism from the environmental community and formal recommendations for recycling from scientists and other professionals. We describe the specific resource recovery and eco-industrial opportunities that were available to New Orleans East, especially those that were magnified by Hurricane Katrina, and analyze the barriers that prevented their actualization. We also provide recommendations for overcoming barriers to resource recovery and eco-industrial progress with the goal that future postcatastrophe scenarios may benefit from more effective use of relief and recovery funding.     

Modeling Biowaste Flows for Life‐Cycle Assessment: Calculation of the Potential and Collected Weight of Kitchen and Garden Waste

This article presents an integrative approach to calculating the weight of potential biowaste and collected biowaste materials, as the basis for a life‐cycle assessment (LCA) of biowaste management. Biowaste contains kitchen and garden (yard) waste of households. This approach could be used for waste management planning and for the implementation of biowaste schemes. Case studies and examples in the literature are analyzed to model the mass of the flow of biowaste. This article defines relevant operands, presents the main assumptions, and describes the calculation principles. Spatial aspects and the uncertainties related to the inclusion of this aspect are explicitly considered in the calculation of the weight of the potential biowaste. We also present the calculation principles for obtaining the weight of (1) biowaste used in home composting, (2) the organic portion of residual waste, (3) biowaste separately collected by a bring system, and (4) biowaste separately collected by curbside collection (known in some areas as kerbside collection). By choosing the biowaste potential in kilograms per capita year (kg/cap yr) as the functional unit, previously ignored options within the biowaste system could be assessed. For example, widening the system boundaries allows LCA studies to assess the contribution of private and public transport of waste to ecological impact categories. It allows examining the effects of supporting home composting through financial incentives and the introduction of a separate collection system. This study focuses on the comparison of different collection types and on the characteristics of the area under investigation. It also incorporates the behavior of the inhabitants of households and includes a sensitivity analysis of relevant operands. This approach is being included in an LCA assessing biowaste management options.     

Wrapping Up Greenhouse Gas Emissions An Assessment of GHG Emission Reduction Related to Efficient Packaging Use: An Assessment of GHG Emission Reduction Related to Efficient Packaging Use

The use of packaging materials results in greenhouse gas (GHG) emissions through production and transport of materials and packaging and through end-of-life management. In this article, we investigate the potential reduction of GHGs that are related to packaging. For this purpose, we use the dynamic MATTER-MARKAL model in which the western European energy and materials system is modeled. The results show that GHGs related to packaging can technically be reduced by up to 58% in the period 1995–2030. Current European packaging directives will result in a 10% emission reduction. Cost-effective improved material management 1 that includes lightweighting, reusable packages, material recycling, and related strategies can contribute a 22% GHG emission reduction. An additional 13% reduction becomes cost effective when a GHG emission penalty of 100 euros per metric ton 2 (EUR/ton) is introduced (1 EUR 0.9 USD). Generally speaking, improved material management dominates the gains that can be achieved without a penalty or with low GHG emission penalties (up to 100 EUR/ton CO2 equivalent). By contrast, the reduction of emissions in materials production and waste handling dominate when high GHG penalties are applied (between 100 and 500 EUR/ton CO2 equivalent). Given the significant technical potential and the low costs, more attention should be paid to material efficiency improvement in GHG emission reduction strategies.     

LCA application to integrated waste management planning in Gipuzkoa (Spain)

Goal, Scope and Background  Gipuzkoa is a department of the Vasque Country (Spain) with a population of about 700,000 people. By the year 2000 approximately 85% of municipal solid waste in this area was managed by landfilling, and only 15% was recycled. Due to environmental law restrictions and landfill capacity being on its limit, a planning process was initiated by the authorities. LCA was used, from an environmental point of view, to assess 7 possible scenarios arising from the draft Plan for the 2016 time horizon. Main Features  In each scenario, 9 waste flows are analysed: rest waste, paper and cardboard, glass containers, light packaging, organic-green waste, as well as industrial/commercial wood, metals and plastics, and wastewater sludge. Waste treatments range from recycling to energy recovery and landfilling. Results  Recycling of the waste flows separated at the source (paper and cardboard, glass, light packaging, organic-green waste, wood packaging, metals and plastics) results in net environmental benefits caused by the substitution of primary materials, except in water consumption. These benefits are common to the 7 different scenarios analysed. However, some inefficiencies are detected, mainly the energy consumption in collection and transport of low density materials, and water consumption in plastic recycling. The remaining flows, mixed waste and wastewater sludge, are the ones causing the major environmental impacts, by means of incineration, landfilling of partially stabilised organic material, as well as thermal drying of sludge. With the characterisation results, none of the seven scenarios can be clearly identified as the most preferable, although, due to the high recycling rates expected by the Plan, net environmental benefits are achieved in 9 out of 10 impact categories in all scenarios when integrated waste management is assessed (the sum of the 9 flows of waste). Finally, there are no relevant differences between scenarios concerning the number of treatment plants considered. Nevertheless, only the effects on transportation impacts were assessed in the LCA, since the plant construction stage was excluded from the system boundaries. Conclusions  The results of the study show the environmental importance of material recycling in waste management, although the recycling schemes assessed can be improved in some aspects. It is also important to highlight the environmental impact of incineration and landfilling of waste, as well as thermal drying of sludge using fossil fuels. One of the main findings of applying LCA to integrated waste management in Gipuzkoa is the fact that the benefits of high recycling rates can compensate for the impacts of mixed waste and wastewater sludge. Recommendations and Outlook  Although none of the scenarios can be clearly identified as the one having the best environmental performance, the authorities in Gipuzkoa now have objective information about the future scenarios, and a multidisciplinary panel could be formed in order to weight the impacts if necessary. In our opinion, LCA was successfully applied in Gipuzkoa as an environmental tool for decision making.     

Quantum Dots as alternatives to organic fluorophores for Cryptosporidium detection using conventional flow cytometry and specific monoclonal antibodies: lessons learned.

BACKGROUND: Significant developments in biological applications are occurring through the incorporation of Quantum Dots (QDs) as biological labels. The demonstration of QDs unique optical properties may have important implications for the study of environmental samples, where microorganisms of interest need to be isolated away from the background debris. METHODS: Flow cytometric analysis was used to determine the fluorescence intensity of oocysts after mAb staining by QDs or organic fluorophore conjugates. In addition, the level of non-specific binding to detrital particles within a control water concentrate was estimated using the optimal staining concentration determined for each mAb analyzed. RESULTS: Under 488 nm excitation, oocysts stained with QD-conjugates exhibited significantly lower fluorescence intensity than organic conjugates. Moreover, the level of non-specific binding by QD-conjugates to detrital particles present in the water concentrate was significantly higher that of the organic conjugates. CONCLUSIONS: While QDs are noted for their superior spectral characteristics, they have been shown here to be unsuitable for conventional flow cytometric detection of Cryptosporidium. Therefore, we conclude that in their current form, QD's are severely limited for fluorescent detection of pathogens in environmental applications.     

Wood Plastic Composites Prepared from Biodegradable Poly(butylene succinate) and Burma Padauk Sawdust (Pterocarpus macrocarpus): Water Absorption Kinetics and Sunlight Exposure Investigations

Wood plastic biocomposites of biodegradable poly(butylene succinate) (PBS) and Padauk sawdust was successfully prepared by using a twin screw extruder and an injection molding machine.The effects of water absorption and sunlight exposure on some properties of the composites were investigated.Water absorption of PBS composites was found to follow the Fick's law of diffusion,while the diffusion coefficient increased with increasing wood content.Maximum water absorption of around 4.5％ was observed at 30 wt.％ sawdust.Optical micrograph indicated the swelling of wood particles by around 1％-3％ after 30 days of water immersion.The tensile and flexural strengths reduced slightly both under the water immersion and sunlight exposure.After 90 days of exposure,the composites clearly looked paler than the non-weathered ones.Thermal scan indicated the reduction of crystalline region due to the plasticization effect derived from water molecules.     

中国餐厨垃圾处理的现状、问题和对策

餐厨垃圾具有高水分、高盐分、高有机质含量、组分时空差异明显、危害性与资源性并存的特点。目前国内外常用的餐厨垃圾处理技术如焚烧、卫生填埋、生态饲料、厌氧消化、好氧堆肥和蚯蚓堆肥等,通常存在着资源化利用效率低、经济效益不够理想的缺陷。总结相关文献及报道,中国在餐厨垃圾资源化处理上存在"行政瓶颈"和"技术瓶颈"两大方面的问题:"行政瓶颈"的解决之道在于完善管理及处理体系,各级政府部门切实重视、加大投入,强力推进垃圾分类投放;而对于"技术瓶颈",除综合运用多种现有处理技术外,开发新技术提高餐厨垃圾的资源化循环利用程度,是关键所在。     

Assessing hydrologic alteration: Evaluation of different alternatives according to data availability

The natural flow regime of rivers across the world has been largely modified. Understanding the extent to which the flow regime deviates from natural conditions is necessary for designing sound management and restoration measures. In this regard, ‘Indicators of Hydrologic Alteration’ is currently considered one of the most effective approaches for assessing hydrologic alteration (HA). However, several generalized drawbacks such as the climatic variability between the pre- and post-impacted series and the scarcity of hydrological data in many impaired rivers should be addressed. In this study, a protocol with the following five alternative designs based on data availability is presented: (1) Paired-Before–After Control–Impact (BACIP), (2) Before–After (BA), (3) Control–Impact (CI), (4) Hydrological Classification (HC) and (5) Predicted Hydrological indices (HP). BACIP compares the status of the impacted gauge before and after the perturbation is started, in addition to controlling for natural climatic changes. Hence, it has been considered as the reference benchmark for all other designs. When this protocol was applied to 11 reservoirs situated in the northern third of the Iberian Peninsula, the BA design was able to correctly identify most of the non-significant HA but failed in almost one quarter of the significant alterations. Similarly, BACIP and CI showed an agreement of >80%. This suggests that the method is suitable when proper data are unavailable for BACIP or BA. In addition, our results indicated that the critical thresholds for HA varied depending on the hydrological index being considered. Significant HAs ranged from <5% for the number of days with increasing and decreasing flows to >64% for the duration of low-flow pulses. To delineate adequate thresholds, further research combining hydrological analyses with the biological response to the HA is warranted. Finally, the application of HC and HP designs revealed a significant degree of uncertainty related to the intra-class variability and the predictive error of the models. Therefore, 25% of the analysis could not be evaluated. However, in the evaluable cases, the HC and HP designs correctly assessed >75% of the HA, which highlighted the potential of this method in cases of scarce streamflow data.     

Integrated municipal waste management systems: An indicator to assess their environmental and economic sustainability

Tools based on Life Cycle Thinking (LCT) are routinely used to assess the environmental and economic performance of integrated municipal solid waste (MSW) management systems. Life Cycle Assessment (LCA) is used to quantify the environmental impacts, whereas Life Cycle Costing (LCC) allows financial and economic assessments. These tools require specific experience and knowledge, and a large amount of data.The aim of this project is the definition of an indicator for the assessment of the environmental and economic sustainability of integrated MSW management systems. The challenge is to define a simple but comprehensive indicator that may be calculated also by local administrators and managers of the waste system and not only by scientists or LCT experts.The proposed indicator is a composite one, constituted by three individual indicators: two of them assess the environmental sustainability of the system by quantifying the achieved material and energy recovery levels, while the third one quantifies the costs. The composite indicator allows to compare different integrated MSW management systems in an objective way, and to monitor the performance of a system over time.The calculation of the three individual indicators has been tested on the integrated MSW management systems of the Lombardia Region (Italy) as well as on four of its provinces (Milano, Bergamo, Pavia, and Mantova).