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.     

PET bottle reverse logistics—environmental performance of California’s CRV program

Purpose

Disposable beverage bottles made of polyethylene terephthalate (PET) stand in sharp contrast to many other disposable plastic packaging systems in the US for their high level of post-consumer recovery for recycling. This is due in part to container deposit programs in several US states, such as the California Redemption Value (CRV) program. We investigate the impacts of PET bottle recycling in the CRV program to evaluate its effectiveness at reducing environmental burdens.

Methods

We develop a life cycle model using standard process LCA techniques. We use the US LCI database to describe the energy production infrastructure and the production of primary materials. We describe the inventory and logistical requirements for materials recovery on the basis of state-maintained statistics and interviews with operators and industry representatives. We report inventory indicators describing energy, freight, and waste disposal requirements. We report several impact indicators based on CML and TRACI-2.0 techniques. We apply system expansion to compare post-consumer activities to produce secondary polymer against equivalent primary production.

Results and discussion

While bottle collection is distributed across the state, processing is more centralized and occurs primarily near urban centers. The average distance traveled by a bottle from discard to recovery is 145–175 km. Recycling requires 0.45–0.66 MJ of primary energy/L of beverage, versus 3.96 MJ during the pre-consumer phase. Post-consumer environmental impacts are significantly lower than pre-consumer impacts, with the exception of eutrophication. The results are robust to model sensitivity, with allocation of fuel for bottle collection being the most significant parameter. Curbside collection is slightly more energy efficient than consumer drop-off, and is subject to smaller parametric uncertainty. Recycling has the potential for net environmental benefits in five of seven impact categories, the exceptions being smog (marginal benefits) and eutrophication (increased impacts).

Conclusions

California’s decentralized program for collecting and processing PET bottles has produced a system which generates a large stream of post-consumer material with minimal environmental impact. The selection of a reclamation locale is the most significant factor influencing post-consumer impacts. If secondary PET displaces primary material, several environmental burdens can be reduced.

Recommendations and perspectives

Our results suggest that deposit programs on disposable packaging are an effective policy mechanism to increase material recovery and reduce environmental burdens. Deposit programs for other packaging systems should be considered.     

Waste Treatment and Assessment of Long-Term Emissions (8pp)

Goal, Scope and Background The disposal phase of a product’s life cycle in LCA is often neglected or based on coarse indicators like ‘kilogram waste’. The goal of report No. 13 of the ecoinvent project (Doka 2003) is to create detailed Life Cycle Inventories of waste disposal processes. The purpose of this paper is to give an overview of the models behind the waste disposal inventories in ecoinvent, to present exemplary results and to discuss the assessment of long-term emissions. This paper does not present a particular LCA study. Inventories are compiled for many different materials and various disposal technologies. Considered disposal technologies are municipal incineration and different landfill types, including sanitary landfills, hazardous waste incineration, waste deposits in deep salt mines, surface spreading of sludges, municipal wastewater treatment, and building dismantling. The inventoried technologies are largely based on Swiss plants. Inventories can be used for assessment of the disposal of common, generic waste materials like paper, plastics, packaging etc. Inventories are also used within the ecoinvent database itself to inventory the disposal of specific wastes generated during the production phase. Inventories relate as far as possible to the specific chemical composition of the waste material (waste-specific burdens). Certain expenditures are not related to the waste composition and are inventoried with average values (process-specific burdens). Methods The disposal models are based on previous work, partly used in earlier versions of ecoinvent/ETH LCI data. Important improvements were the extension of the number of considered chemical elements to 41 throughout all disposal models and new landfill models based on field data. New inventories are compiled for waste deposits in deep salt mines and building material disposal. Along with the ecoinvent data and the reports, also Excel-based software tools were created, which allow ecoinvent members to calculate waste disposal inventories from arbitrary waste compositions. The modelling of long-term emissions from landfills is a crucial part in any waste disposal process. In ecoinvent long-term emissions are defined as emissions occurring 100 years after present. They are reported in separate emission categories. The landfill inventories include long-term emissions with a time horizon of 60’000 years after present. Results and Discussion As in earlier studies, the landfills prove to be generally relevant disposal processes, as also incineration and wastewater treatment processes produce landfilled wastes. Heavy metals tend to concentrate in landfills and are washed out to a varying degree over time. Long-term emissions usually represent an important burden from landfills. Comparisons between burdens from production of materials and the burdens from their disposal show that disposal has a certain relevance. Conclusion The disposal phase should by default be included in LCA studies. The use of a material not only necessitates its production, but also requires its disposal. The created inventories and user tools facilitate heeding the disposal phase with a similar level of detail as production processes. The risk of LCA-based decisions shifting burdens from the production or use phase to the disposal phase because of data gaps can therefore be diminished. Recommendation and Perspective Future improvements should include the modelling of metal ore refining waste (tailings) which is currently neglected in ecoinvent, but is likely to be relevant for metals production. The disposal technologies considered here are those of developed Western countries. Disposal in other parts of the World can differ distinctly, for logistic, climatic and economic reasons. The cross-examination of landfill models to LCIA soil fate models could be advantageous. Currently only chemical elements, like copper, zinc, nitrogen etc. are heeded by the disposal models. A possible extension could be the modelling of the behaviour of chemical compounds, like dioxins or other hydrocarbons.     

Provision of LCI data in the European aluminium industry Methods and examples

Background, aim, and scope

The development of robust and up-to-date generic life cycle inventory data for materials is absolutely crucial for the LCA community since many LCA studies rely on these generic data about materials. LCA databases and software usually include within their package such generic LCI datasets. However, in many cases, the quality of these data is poor while the methodology and the models used for their development are rarely accessible or transparent. This paper presents the development of robust European LCI datasets for the production of primary and recycled aluminium ingots and for the transformation of aluminium ingot into semi-finished products, i.e. sheet, foil and extrusion.

Materials and methods

The environmental data have been collected through an extensive environmental survey, organised among the European aluminium industry, focusing on the year 2005 and covering EU27 countries as well as EFTA countries (Norway, Iceland and Switzerland). From this survey, European averages, i.e. foreground data, have been calculated for the direct inputs and outputs of the various aluminium processes. Using the GaBi software, the foreground data have been combined within LCI models integrating background LCI data on energy supply systems, ancillary processes and materials. For the primary aluminium production (smelters), a specific model for the electricity production has been developed. The methodology for the data consolidation and for the development of the various models is explained as well as the main differences between the new modelling approach and LCI models used in the past. An independent expert has critically reviewed the entire LCI project including data collection, models development, calculation of LCI data and associated environmental indicators.

Results

As confirmed by the critical review, the new LCI datasets for aluminium ingot production and transformation into semi-finished products have been developed though a robust methodology in full accordance with ISO 14040 and 14044. Most significant environmental data and LCI results are reported in this paper with an emphasis on energy use and the major emissions to air. The full environmental report, including the critical review report and the calculation of environmental indicators for a pre-set of impact categories, is available on the website of the European Aluminium Association (EAA 2008). Whenever possible, the updated European averages and the new LCI data are compared with previous results developed from two past European surveys covering respectively the years 2002 and 1998. For the aluminium processes related to primary production, European averages are also benchmarked against global averages calculated from two worldwide surveys covering the years 2000 and 2005.

Discussion

While some data evolutions are directly attributed to the variation of foreground data, e.g. raw materials consumption or energy use within the aluminium processes, modifications related to the system boundaries, the background data and the modelling hypotheses can also influence significantly the LCI results. For primary aluminium production, the evolution of the foreground data is dominated by the strong decrease of PFC (perfluorocarbon) emissions (about 70% since 1998). In addition, the electricity structure calculated from the refined electricity model shows significant differences compared to previous models. In the 2005 electricity model, the hydropower share reaches 58% while coal contributes to 15% only of the electricity production. In 1998, the respective share of coal-based and hydro-electricity were respectively calculated to 25% and 52%. As a result, the electricity background LCI data are then significantly affected and influence also positively the environmental profile of primary aluminium in Europe. For the semi-production processes, the reduction of process scrap production, especially for extrusion and foil, demonstrates the increase of process efficiency from 1998. In parallel, a significant reduction of energy use is observed between 1998 and 2005. However, this positive trend is not fully reflected within LCI data due to the significant contribution of the background electricity data. The choice of the electricity model plays also a critical role for these transformation processes since electricity production contributes to about 2/3 of the consumption of the non-renewable energy and to about the same level of the air emissions. In such a case, the move from the UCPTE electricity model used in the past towards the EU25 electricity model used for the development of the updated LCI data has a detrimental effect on the environmental profile of the three LCI datasets respectively related to sheet, foil and extrusion. In addition to energy and process scrap reduction, the reduction of the VOC (volatile organic compounds) emission is also a major trend in foil production. Finally, for old aluminium scrap recycling, the new LCI data show a dramatic improvement regarding energy efficiency, reinforcing the environmental soundness of promoting and supporting aluminium recycling within the aluminium product life cycles.

Conclusions

This paper shows the development of generic LCI data about aluminium production and transformation processes which are based on robust data, methodologies and models in full accordance with ISO 14040 and 14044 standards, as confirmed by the critical review. The publishing of these LCI datasets definitely shows the commitment of the European aluminium industry to contribute in a transparent, fair and scientifically sound manner to product sustainability in a life cycle thinking perspective.

Recommendations and perspectives

Software houses and LCA practitioners are invited to update their generic European data on aluminium with the herewith datasets. Even if the quality and the completeness of these LCI data reach a high standard, some areas for data improvements have been identified, as described within the review report. Land use, water use and solid waste treatment appear as three priority areas for data refining and improvement. The land use dimension, particularly meaningful for bauxite mining, is not covered in the current LCI data while it is now integrated within many LCA studies. Up to now, the reporting of meaningful and robust data on water origins and use have not been possible due to the huge discrepancies between the surveyed sites combined with the difficulty to report coherent input and output water mass flows. The development of water data, only focussing on water-stressed areas, will most probably make more sense in the future. Finally, collecting more qualitative information about solid waste processing and treatment will help to include such operations within the system boundaries and to model their associated air, water and soil emissions.

     

煤矿固废资源化利用的生态效率与碳减排——以淮北市为例

工业固废的大量堆积产生多种环境危害,工业固废的资源化利用能够节约资源和缓解环境压力。建筑行业是能源消耗和碳排放的主要部门之一,其中建筑材料生产阶段的能耗和碳排放占有重要的地位。粉煤灰、煤矸石是常见的工业固体废物,尤其是在以煤炭为主要能源的地区。粉煤灰、煤矸石资源化利用的途径之一是用于制造新型墙体砖。本文以煤炭资源型城市淮北市的新型墙体砖(粉煤灰砌块、煤矸石砖)和传统墙体砖(粘土砖、粘土多孔砖)为案例,对墙体砖生产过程的生态效率和碳排放进行分析和比较。在淮北市墙体材料行业碳排放不增加的前提下,以最优生态效率为目标,建立线性规划模型,对淮北市4种主要墙体材料的产量进行规划。分析结果表明:新型墙体材料的生态效率高于传统墙体材料;煤矸石砖生产过程的碳排放系数高于传统墙体砖;粉煤灰砌块生产过程的碳排放系数介于粘土砖和粘土多孔砖之间。在淮北市墙体材料行业碳排放不增加的前提下,与现有的产量相比,淮北市应禁止粘土砖的生产,适当减少粘土多孔砖的产量,适当增加粉煤灰砌块和煤矸石砖的产量,以达到最优生态效率。在最优生态效率的情况下,淮北市新型墙体材料煤矸石砖对煤矸石工业固废的利用率将由目前的15.8%增加到25.2%。     

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.     

Toward Trash That Thinks: Product Tags for Environmental Management

In this article, we explore several options for linking information technology to materials and products through the use of bar codes and radio-frequency identification (RFID) tags, and the implications for product life-cycle management. We also describe tests with existing and modified tags, both on and inside products, as would be needed for environmental management applications.
Bar codes are cheap and have an existing infrastructure; RFID tags are more expensive and less widespread, but they can be read without a line of sight between the tag and the reader. Bar codes and RFID tags carrying basic product information could link to different databases for a range of applications. Product tags could increase recycling efficiency by automating the sorting of recyclables or by linking to product dismantling instructions during the recycling process. Product tags could provide incentives for good waste management, through Universal Product Code (UPC) bar-code recycling coupons or through RFID tag automatic recycling credits for curbside collection programs. Measures to encourage the development of these types of applications include moves toward competitive, market-based waste management systems, the encouragement of experimental systems, and coordination between manufacturers and waste management industries.     

Application of a Life Cycle Model for European Union Policy‐Driven Waste Management Decision Making in Emerging Economies

Solid waste life cycle modeling has predominantly focused on developed countries, but there are significant opportunities to assist developing and transition economies to minimize the environmental impact of solid waste management (SWM). Serbia is representative of a transition country and most (92%) of its waste is landfilled. As a Candidate European Union (EU) country, Serbia is expected to implement SWM strategies that meet EU directives. The Solid Waste Life‐Cycle Optimization Framework (SWOLF) was used to evaluate scenarios that meet EU goals by 2030. Scenarios included combinations of landfills, anaerobic digestion, composting, material recovery facilities (MRFs), waste‐to‐energy (WTE) combustion, and the use of refuse‐derived fuel in cement kilns. Each scenario was evaluated with and without separate collection of recyclables. Modeled impacts included cost, climate change, cumulative fossil energy demand, acidification, eutrophication, photochemical oxidation, total eco‐toxicity, and total human toxicity. Trade‐offs among the scenarios were evaluated because no scenario performed best in every category. In general, SWM strategies that incorporated processes that recover energy and recyclable materials performed well across categories, whereas scenarios that did not include energy recovery performed poorly. Emissions offsets attributable to energy recovery and reduced energy requirements associated with remanufacturing of recovered recyclables had the strongest influence on the results. The scenarios rankings were robust under parametric sensitivity analysis, except when the marginal electricity fuel source changed from coal to natural gas. Model results showed that the use of existing infrastructure, energy recovery, and efficient recovery of recyclables from mixed waste can reduce environmental emissions at relatively low cost.     

Charging up Battery Recycling Policies: Extended Producer Responsibility for Single‐Use Batteries in the European Union,Canada, and the United States

Extended producer responsibility (EPR) policies have proven effective at raising consumer awareness, expanding waste collection infrastructure, and shifting costs of end‐of‐life (EOL) management from municipalities to stewardship organizations. Yet, such policies have been less successful in advancing waste management programs that ensure a net environmental benefit. This article analyzes how EPR policies for single‐use batteries in the European Union (EU), Canada, and the United States address the environmental costs and benefits of EOL management. Considering these EPR policies is instructive, because single‐use batteries have high collection costs and are of relatively low economic value for waste processors. Without deliberate planning, the environmental burdens of collecting and recycling such batteries may exceed the benefits. This article considers how EPR policies for single‐use batteries integrate performance requirements such as collection rates, recycling efficiencies, and best available techniques. It argues that for such policies to be effective, they need to be extended to address waste collection practices, the life cycle consequences of EOL management, and the quality of recovered materials. Such strategies are relevant to EPR policies for other products with marginal secondary value, including some textiles, plastics, and other types of electronic waste.     

Environmental effects from a recycling rate increase of cardboard of aseptic packaging system for milk using life cycle approach

Goal, Scope and Background  Despite the well-known advantages of recycling materials to reduce solid waste or save natural resources, the recycling stage is an additional process within the life cycle that has its own energy and input requirements, as well as specific emissions. The objective of the present paper is to analyze the life cycle inventory associated with the increase in recycling rate (from 2% up to 22% at present) of the cardboard contained in the aseptic packaging for long-life milk. The main aspects of the manufacturing of the Tetra Pak aseptic package, including the filling of the product, the distribution of the conditioned product, up to the final disposal and recycling rates, were considered. Materials and Methods  This study was conducted in accordance with the general directives of the ISO 14040 series. The packaging material system was assessed using 1000 liters of milk as a functional unit, in a packaging system containing 12 units of 1 L cartons each, placed on a corrugated paperboard tray wrapped in polyethylene shrink film and arranged onto one-way wooden pallets. Brazilian inventories for energy, carton, corrugated paperboard and aluminum, based on site-collected data were employed. The final disposal of used packages was modeled using the Average Brazilian Municipal Solid Waste Management data collected for the purpose of the census of the year 2000. Results  Comparison of the total energy consumption throughout the whole life cycle of two recycling scenarios (i.e. different recycling rates) analyzed shows that the higher recycling rate led to a 6% reduction of the total energy requirement for the long-life milk package material system. The most significant reductions in the consumption of natural resources were: 8% water, 11% wood and 10% land use savings. Greenhouse gases were the main reduced air emissions and contributed with a reduction of 9.7% in GWP. Most water emissions were reduced: 10% COD, 9% BOD and 6% TSS. A unique drawback directly caused by the increase of the recycling rate was an increase of 14.4 g in TDS emissions (57%). Discussion  The reduction in energy requirements are related and limited to the proportionality among the different materials that make up the packaging system. Most emission reductions result from the replacement of virgin materials with recycled materials in the packaging system. Although the average balance of water emissions is positive, the need to improve wastewater treatment processes in the paper recycling plants to reduce TDS is highlighted as a key issue. Conclusions  It may be concluded that the increase in the recycling rate brings about a series of benefits in terms of reduction of energy and natural resource consumption, air pollutants and most water emissions. In this case, the increase of the recycling rate improved the overall environmental performance of the aseptic Tetra Pak system for milk. Recommendations and Perspectives  The authors are currently analyzing alternative recycling scenarios that will enable one to evaluate maximum reduction in GWP. Further studies could include the agriculture stages, livestock and consumer phase to broaden the environmental evaluation. ESS-Submission Editor: Dr. Andreas A. Detzel (andreas.detzel@ifeu.de)     

Solid waste treatment and disposal: effects on public health and environmental safety

The safety and acceptability of many widely used solid waste management practices are of serious concern from the public health point of view. Such concern stems from both distrust of policies and solutions proposed by all tiers of government for the management of solid waste and a perception that many solid waste management facilities use poor operating procedures. Waste management practice that currently encompasses disposal, treatment, reduction, recycling, segregation and modification has developed over the past 150 years. Before that and in numerous more recent situations, all wastes produced were handled by their producers using simple disposal methods, including terrestrial dumping, dumping into both fresh and marine waters and uncontrolled burning. In spite of ever-increasing industrialisation and urbanisation, the dumping of solid waste, particularly in landfills, remains a prominent means of disposal and implied treatment. Major developments have occurred with respect to landfill technology and in the legislative control of the categories of wastes that can be subject to disposal by landfilling. Even so, many landfills remain primitive in their operation. Alternative treatment technologies for solid waste management include incineration with heat recovery and waste gas cleaning and accelerated composting, but both of these technologies are subject to criticism either by environmentalists on the grounds of possible hazardous emissions, failure to eliminate pathogenic agents or failure to immobilise heavy metals, or by landfill operators and contractors on the basis of waste management economics, while key questions concerning the effects of the various practices on public health and environmental safety remain unanswered. The probable and relative effects on both public health and environmental safety of tradition and modern landfill technologies will be evaluated with respect to proposed alternative treatment technologies.     

Life cycle assessment of a multi-material car component

Background, Aims and Scope In recent years, the automotive industry has been experiencing an increasing concern with environmental requirements. A particular focus is being given to light-weighting of cars, to reducing fuel consumption and to the use of different recycling materials. Consequently, decisions on product design and development must involve economic and technological as well as environmental considerations. In adequate conditions, the LCA methodology enables one to assist an effective integration of the environmental considerations in the decision-making process [1]. In this paper, a multi-material car component which is part of the current automotive brake system, has been modified by its original manufacturer. Such a modification included the use of a new multi-material injection moulding process and the consumption of recyclable materials. The new and the current component were comparatively assessed throughout their life cycles in order to evaluate their respective environmental impacts and, thus, to verify if the new component offers a lower environmental load. The results described in this paper are part of the outcome of a broader research project involving industrial companies, university, technological centres and research institutes based in Portugal, Spain and Germany. Main Features The car component under focus has four subcomponents whose base materials consist of steel and plastic. The LCA methodology is used to evaluate two scenarios describing the new car component, on the one hand, and the reference scenario, which consists of the existing car component, on the other. The former results from the selection of new subcomponents materials, aiming to use a new production process together with a recycling strategy. Results and Discussion The inventory analysis shows a lower energy consumption in the alternative scenario (4.2 MJ) compared to the reference scenario (6.1 MJ). Most of that energy is still non-renewable, relating in particular to crude consumption in the car use phase and in the production phase (transports and plastics production). The life cycle inventory analysis indicates also that the alternative scenario has lower air emissions of CO₂, CO, NO_x, SO_x, NM VOC and PM10, as well as lower solid wastes and water emissions of oils and BOD5. Otherwise, the water emissions of undissolved substances and COD are higher for the alternative scenario. Most of the energy consumed and the air pollutants inventoried occur as a consequence of the use phase. Otherwise, for most of the life cycle water emissions inventoried and solid wastes, the production phase is the major contributor. The impact assessment, performed with the CML method, allows one to conclude that the alternative scenario exhibits lower results in all the impact categories. Both scenarios have similar environmental profiles, being: (i) the use phase, the major contributor for the abiotic depletion, global warming, photochemical oxidation, acidification and eutrophication; and (ii) the production phase, the main contributor for ozone depletion, human toxicity, fresh water aquatic ecotoxicity, marine aquatic ecotoxicity and terrestrial ecotoxicity. The sensitivity analysis, with respect to the fuel consumption reduction value, the impact assessment method and the final disposal scenario, performed in this study allows one to confirm, as a main conclusion, that the alternative scenario is environmentally preferable to the reference scenario. Conclusion The results obtained through the application of the LCA methodology enable one to conclude that the alternative component has a lower environmental load than the reference component. Recommendations and Perspectives Considering that the time required for the inventory data collection is a critical issue in LCA practise, the insights provided by this particular case study are likely to be useful to product developers in the car component manufacturing industry, particularly to brake system manufacturers supporting the environmental design within the sector.     

Guidance for Improving Life-Cycle Design and Management of Milk Packaging

Life-cycle inventory and cost-analysis tools applied to milk packaging offer guidelines for achieving better environmental design and management of these systems. Life-cycle solid waste, energy, and costs were analyzed for seven systems including single-use and refillable glass bottles, single-use and refillable high-density polyethylene (HDPE) bottles, paperboard gable-top cartons, linear low-density polyethylene (LLDPE) flexible pouches, and polycarbonate refillable bottles on a basis of 1,000 gal of milk delivered. In addition, performance requirements were also investigated that highlighted potential barriers and trade-offs for environmentally preferable alternatives. Sensitivity analyses, indicated that material production energy, postconsumer solid waste, and empty container costs were key parameters for predicting life-cycle burdens and costs. Recent trends in recycling rates, tipping fees, and recycled materials market value had minimal effect on the results. Inventory model results for life-cycle solid waste and energy indicated the same rank order as results from previously published life-cycle inventory studies of container systems.
Refillable HDPE and polycarbonate, and the flexible pouch were identified as the most environmentally preferable with respect to life-cycle energy and solid waste. The greater market penetration of these containers may be limited by performance issues such as empty container storage, handling requirements, and deposit fees for refillables, and resealability and puncture resistance for the pouch.     

The impact of landfilling and composting on greenhouse gas emissions – A review

Municipal solid waste is a significant contributor to greenhouse gas emissions through decomposition and life-cycle activities processes. The majority of these emissions are a result of landfilling, which remains the primary waste disposal strategy internationally. As a result, countries have been incorporating alternative forms of waste management strategies such as energy recovery from landfill gas capture, aerobic landfilling (aerox landfills), pre-composting of waste prior to landfilling, landfill capping and composting of the organic fraction of municipal solid waste. As the changing global climate has been one of the major environmental challenges facing the world today, there is an increasing need to understand the impact of waste management on greenhouse gas emissions. This review paper serves to provide an overview on the impact of landfilling (and its various alternatives) and composting on greenhouse gas emissions taking into account streamlined life cycle activities and the decomposition process. The review suggests greenhouse gas emissions from waste decomposition are considerably higher for landfills than composting. However, mixed results were found for greenhouse gas emissions for landfill and composting operational activities. Nonetheless, in general, net greenhouse gas emissions for landfills tend to be higher than that for composting facilities.     

Recycle,Bury, or Burn Wood Waste Biomass?: LCA Answer Depends on Carbon Accounting,Emissions Controls,Displaced Fuels,and Impact Costs

This study extends existing life cycle assessment (LCA) literature by assessing seven environmental burdens and an overall monetized environmental score for eight recycle, bury, or burn options to manage clean wood wastes generated at construction and demolition activity sites. The study assesses direct environmental impacts along with substitution effects from displacing fossil fuels and managed forest wood sourcing activities. Follow‐on effects on forest carbon stocks, land use, and fuel markets are not assessed. Sensitivity analysis addresses landfill carbon storage and biodegradation rates, atmospheric emissions controls, displaced fuel types, and two alternative carbon accounting methods commonly used for waste management LCAs. Base‐case carbon accounting considers emissions and uptakes of all biogenic and fossil carbon compounds, including biogenic carbon dioxide. Base‐case results show that recycling options (recycling into reconstituted wood products or into wood pulp for papermaking) rank better than all burning or burying options for overall monetized score as well as for climate impacts, except that wood substitution for coal in industrial boilers is slightly better than recycling for the climate. Wood substitution for natural gas boiler fuel has the highest environmental impacts. Sensitivity analysis shows the overall monetized score rankings for recycling options to be robust except for the carbon accounting method, for which all options are highly sensitive. Under one of the alternative methods, wood substitution for coal boiler fuel and landfill options with high methane capture efficiency are the best for the overall score; recycling options are next to the worst. Under the other accounting alternative, wood substitution for coal and waste‐to‐energy are the best, followed by recycling options.     

Accounting for transportation impacts in the environmental assessment of waste management plans

Background, aim, and scope  Many recent studies on waste management have described in detail the potential impacts of recycling and final treatment of municipal waste. In public debates, the attention has also been focused on the choice of final disposal technologies (e.g. landfilling vs. incineration). However, a comprehensive assessment of the impacts of waste collection and transport was still lacking. In the present study, we use LCA to evaluate the potential impact of the provincial waste management plan of Varese (northern Italy). Particular attention is devoted to the estimation of environmental impacts generated during waste transport. Materials and methods  A detailed Life Cycle Inventory was built for the transportation phase, based on primary data collected by interviewing the agencies involved in waste collection. To model the recycling and final disposal phase we relied on the BUWAL 250 database. Impacts were evaluated with the Eco-Indicator 99 method in its egalitarian formulation. Results  The results of our analysis reveal that the major potential impacts of the plan are associated with waste collection and transport. These impacts are partially compensated by reduced resource consumption through recycling and energy recovery through incineration. Discussion  The outputs of the LCIA were compared with those obtained by using other ecoindicators (Eco-Indicator 99 hierarchist and individualist, CML2, EPS2000). Although not comparable on a quantitative basis, they are qualitatively consistent. Conclusions  Neglecting the effects of collection and transport might result in a severe underestimation of the environmental impacts of a waste management system, especially as refers to depletion of fossil fuels, emission of respiratory inorganics and climate change. To reduce the environmental impact of waste management systems, an accurate optimisation of waste transport is required. Recommendations and perspectives  Effective waste management planning requires the explicit inclusion of waste collection and transport when comparing alternative management policies.     

Life Cycle assessment of a plastic packaging recycling system

Goal, Scope and Background.  The object of the study is the Italian system of plastic packaging waste recycling, active until 2001, that collected and mechanically recycled the post-consumer PE and PET liquid containers. The phases of collection, compaction, sorting, reprocessing and refuse disposal were individually analysed and quantified in terms of energy and material consumptions as well as of emissions in the environment. The work is the result of a joint research project with the Italian Consortium for Packaging (CONAI), carried out in co-operation with the main Italian companies active in the field. The main aim was the quantification of the real advantage of plastic container recycling and the definition of criteria, at the same time environmentally compatible and economically sustainable, for their management. Main Features  For each of the unit processes, and in order to increase the data quality, all the data of interest were collected during technical visits to several selected plants active in Italy or deduced by official documents and certificate declarations of the same companies. To allow comparison of resource consumption and environmental pollution from different management scenarios producing different products, thebasket of products method was applied. Results  The results indicates that the production of 1 kg of flakes of recycled PET requires a total amount of gross energy that is in the range of between 42 and 55 MJ, depending on whether the process wastes (mainly coming from sorting and reprocessing activities) were sent or not to the energy recovery. The same quantity of virgin PET requires more than 77 MJ. The energetic (and then environmental) saving is so remarkable, even for PE, being 40–49 MJ for the recycled polymer and about 80 MJ that for the virgin polyolefin. The calculations were made with the reasonable assumption that the final utilisation can use the virgin or the recycled polymer without any difference. Conclusions and Outlook  The analysis defined and verified a suitable tool in the field, based on objective data, for comparing different coherent scenarios of waste management politics. This allows one to propose the extension of the tool under different collection schemes, as well as for different systems of packaging recycling. As an immediate consequence of the success of the present study, the joint-research programme with CONAI has been extended for another three years. The focus will be the Italian system for paper and paperboard recycling and that for all plastic packagings. In parallel, a different study has been scheduled with reference to the integrated solid waste management of the Regione Campania, the largest and most populated area in the South of Italy.     

Adapting Stand‐Alone Renewable Energy Technologies for the Circular Economy through Eco‐Design and Recycling

Renewable energy (RE) technologies are looked upon favorably to provide for future energy demands and reduce greenhouse gas (GHG) emissions. However, the installation of these technologies requires large quantities of finite material resources. We apply life cycle assessment to 100 years of electricity generation from three stand‐alone RE technologies—solar photovoltaics, run‐of‐river hydro, and wind—to evaluate environmental burden profiles against baseline electricity generation from fossil fuels. We then devised scenarios to incorporate circular economy (CE) improvements targeting hotspots in systems’ life cycle, specifically (1) improved recycling rates for raw materials and (ii) the application of eco‐design. Hydro presented the lowest environmental burdens per kilowatt‐hour of electricity generation compared with other RE technologies, owing to its higher efficiency and longer life spans for main components. Distinct results were observed in the environmental performance of each system based on the consideration of improved recycling rates and eco‐design. CE measures produced similar modest savings in already low GHG emissions burdens for each technology, while eco‐design specifically had the potential to provide significant savings in abiotic resource depletion. Further research to explore the full potential of CE measures for RE technologies will curtail the resource intensity of RE technologies required to mitigate climate change.     

城市生活垃圾代谢的研究进展

城市代谢是导致城市发展、能量生产和废物排放的社会、经济和技术过程的总和。生活垃圾管理系统是一类典型的、具备社会、经济、自然要素的复杂系统,它不仅同管理体制、技术水平和居民素质有关,也贯穿生产、消费、流通、还原过程,更和水体、土壤、大气、生物、矿产等自然环境紧密联系。综述了近年来基于城市生态系统代谢思路,在生活垃圾碳、重金属、营养元素和能量的城市代谢等方面的研究进展,分析了未来该领域研究需重点关注的方向。生活垃圾在城市生态系统中的能量流动、物质循环、代谢效率等方面的研究,可为生活垃圾管理系统的评价、规划、工程、管理研究提供科学基础。     

Quantity,Components, and Value of Waste Materials Landfilled in the United States

The current system of production and consumption needs end‐of‐life disposal to function, but the linkage between upstream production‐consumption with the downstream landfill as terminus is, at best, a tenuous, one‐way relationship, suggesting a partial system failure. A starting point to fix this link is to confront, systematically, the messy “black box” that is mixed waste landfilling, interrogate its contents locally, and determine a baseline that can be used to scale up results. Here, we develop a detailed model characterizing landfilled municipal solid waste (MSW) in the United States across the dimensions of material quantity, quality, location, and time. The model triangulates measurements spanning 1,161 landfills (representing up to 95% of landfilled MSW) and 15,169 solid waste samples collected and analyzed at 222 sites across the United States. We confirm that landfilled quantities of paper (63 million megagrams [Mg]), food waste (35 million Mg), plastic (32 million Mg, textiles (10 million Mg), and electronic waste (3.5 million Mg) are far larger than computed by previous top‐down U.S. government estimates. We estimate the cost of MSW landfill disposal in 2015 (10.7 billion U.S. dollars [USD]) and gross lost commodity value of recyclable material (1.4 billion USD). Further, we estimate landfill methane emissions to be up to 14% greater (mass basis) than the 2015 U.S. inventory. By principally relying on measurements of waste quantity and type that are recorded annually, the model can inform more effective, targeted interventions to divert waste materials from landfill disposal, improve local, regional, and national emission estimates, enhance dissipative loss estimates in material flow analyses, and illuminate the dynamics linking material, energy, and economic dimensions to production, consumption, and disposal cycles.