Modelling incineration for more accurate comparisons to recycling in PEF and LCA

When recycling is beneficial for the environment, results from a life cycle assessment (LCA) should give incentives to collection for recycling and also to the use of recycled material in new products. Many approaches for modeling recycling in LCA assign part of the environmental benefits of recycling to the product where the recycled material is used. For example, the Circular Footprint Formula in the framework for Product Environmental Footprints (PEF) assigns less than 45% of the benefits of recycling to a polymer product sent to recycling. Our calculations indicate that this creates an incorrect climate incentive for incineration of renewable LDPE, when the recovered energy substitutes energy sources with 100–300% more climate impact than the Swedish average district heat and electricity. The risk of incorrect incentives can be reduced through allocating part of the net benefits of energy recovery to the life cycle where the energy is used; we propose this part can be 60% for Sweden, but probably less in countries without a district-heating network. Alternatively, the LCA can include the alternative treatment of waste that is displaced at the incinerator by waste from the investigated product. These solutions both make the LCA more balanced and consistent. The allocation factor 0.6 at incineration almost eliminates the risk of incorrect incentives in a PEF of renewable polymers. However, the focus of LCA on one product at a time might still make it insufficient to guide recycling, which requires concerted actions between actors in different life cycles

Incentives for recycling and incineration in LCA: Polymers in Product Environmental Footprints

For material recycling to occur, waste material from a product life cycle must be made available for recycling and then used in the production of a new product. When recycling is beneficial for the environment, the LCA results should give incentives to collection for recycling and also to the use of recycled material in new products. However, most established methods for modelling recycling in LCA risk giving little or even wrong incentives. Many methods, such as the Circular Footprint Formula (CFF) in a Product Environmental Footprint (PEF), assign some of the environmental benefits of recycling to the product that uses recycled materials. This means that the incentive to send used products for recycling will be lower. If energy recovery also provides an environmental benefit, because the energy recovered substitutes energy supplied with a greater environmental impact, the LCA results may indicate that the waste should instead be sent to incineration – even when recycling is the environmentally preferable option for the society. This study aims to increase the knowledge on the extent to which PEF results, and LCA results in general, risk giving incorrect incentives for energy recovery from plastic waste. Our calculations focus on the climate impact of the recycling and incineration of LDPE waste generated in Sweden. Since this is a pilot study, we use easily available input data only. We estimate the net climate benefit through simple substitution, where recycled material is assumed to replace virgin material and where energy recovered from LDPE waste is assumed to replace average Swedish district heat and electricity. We then apply the CFF to find whether a PEF would give the same indications. Our results show no risk of a PEF or LCA giving incorrect climate incentives for incineration of fossil LDPE. However, an LCA can wrongly indicate that renewable LDPE should be incinerated rather than recycled. Our results indicate this can happen in a PEF when the heat and electricity substituted by incineration has 40-200% more climate impact than the Swedish average district heat and electricity.Our study also aims to increase knowledge about the extent to which correct incentives can be obtained through a more thorough analysis of incineration with energy recovery – specifically, through:\ua0\ua0\ua0 1. a deeper understanding of Factor B, which in the CFF can be used to assign part of the burdens and benefits of energy recovery to the energy instead of the product investigated, but which in the PEF guidelines by default is set to 0, or\ua0\ua0\ua0 2. a broader systems perspective that accounts for the effects of energy recovery on waste imports and thus waste management in other countries.We estimate Factor B based on the observation that waste incineration can be described as a process with multiple jointly determining functions. Waste treatment and energy recovery both contribute to driving investments in incineration. This, in turn, defines the volume of waste incinerated, the quantity of energy recovered, and the quantity of energy substituted. We propose that expected revenues from gate fees and energy are an appropriate basis for calculating Factor B. Up-to-date estimates of the expected revenues in the relevant region should ideally be used for the calculations. Lacking such data,we suggest the value B=0.6 can be used in the CFF when modelling waste incineration in Sweden. Our PEF calculations with Factor B=0.6 indicate such a PEF will identify the environmentally best option for plastic waste management in almost all cases. However, this is at least in part luck: Factor B will vary over time and between locations, and other parts of the CFF varies between materials.To account for the broader systems perspective, we develop two scenarios based on different assumptions on whether change in Swedish waste imports affects the incineration or landfilling in other European countries. The scenarios bring a large uncertainty into the results. This uncertainty is real in the sense that it is difficult to know how a change in Swedish waste imports in the end will affect waste management in other countries. The uncertainty still makes it difficult to draw conclusions on whether renewable LDPE should be recycled or incinerated.Our suggestions for Factor B and European scenarios both make the CFF more balanced and consistent: it now recognizes that not only recycling but alsoenergy recovery depends on more than the flow of waste from the life cycle investigated. However, neither Factor B nor the broader systems perspective amends the fact that LCA tends to focus on one product at a time. This might not be enough to guide a development that requires coordinated or concerted actions between actors in different life cycles – such as increased recycling or energy recovery. Assessing decisions in one product life cycle at a time might in this context be compared to independently assessing the action of clapping one hand. This will most probably not result in an applaud.Besides a more thorough assessment of energy recovery, we also discuss the option to give correct incentives for recycling from LCA by assigning the full environmental benefit of recycling to the product that generates waste for recycling but also to the product where the recycled material is used. We find that this 100/100 approach can give negative LCA results for products produced from recycled material and recycled to a high degree after recycling, because the benefits of recycling are counted twice. The LCA results would indicate that you save material resources by producing and recycling such products without ever using them. The 100/100 approach also lacks additivity, does not model foreseeable consequences, and does not assign a well-defined environmental value to the recovered secondary material.To guide concerted actions, like recycling or energy recovery, it seems systems analysis should ideally assess the necessary actions in combination. Many situations require the environmental impacts to be estimated for a specific product or a specific action. In some cases, however, the LCA results can be calculated and presented with, for example, the following introduction:“When the material is sent to recycling, you will, together with the recycler and the actor using the recycled material, jointly achieve this net environmental benefit: …”Such joint assessment of supply and demand for secondary materials means the allocation problem is avoided. It is also consistent with the recommendation in the old SETAC “Code of Practice” to assess life cycles with recycling by studying the inputs and outputs from the total linked system

Integrated economic and environmental assessment of waste policy instruments

The need for new policy instruments supporting the on-going transition from end-of-pipe waste treatment to resource management has been recognized in European policy. Instruments need to be carefully assessed before implementation to promote the desired changes and avoid problem shifting. Mathematical models may assist policy makers in such assessments. This paper presents a set of soft-linked models for assessing the economic and environmental impacts of policy instruments for both the prevention and management of waste and discusses its strengths and limitations. Consisting of (1) a macro-economic model, (2) a systems engineering model for waste management and (3) a life cycle assessment model for waste management, the set is primarily suited to assessing market-based instruments and environmental regulations. Considerable resources were needed for developing and using the set, and there are clear limits as to what can be addressed. However, if only one of the models had been used, neither the range of instruments nor the scope of impacts would have been possible to cover. Furthermore, soft-linked models allow many disciplines to contribute within one harmonized framework. Such integrated assessments may become increasingly useful for continuing the implementation of policy for sustainable governance of society’s material resources

Mediation by Thyroid Hormone in the Relationships Between Gestational Exposure to Methylmercury and Birth Size

Our previous studies have linked gestational methylmercury exposure, originating from seafood, to changes in maternal thyroid hormones and infant birth size in a Swedish birth cohort. Herein we aimed to determine associations between maternal thyroid hormones and infant birth size and elucidate if maternal hormones could mediate the relationship between methylmercury and lower birth size. In 515 women, without known thyroid disease, we assessed metal exposure by erythrocyte mercury concentrations (mainly methylmercury, reflecting exposure over the past months) in early third trimester measured with inductively coupled plasma-mass spectrometry. Plasma concentrations of total and free thyroxine (tT4 and fT4) and triiodothyronine (tT3 and fT3), and thyroid-stimulating hormone (TSH) were measured at an accredited clinical laboratory. In multivariable-adjusted linear regression models, maternal tT3 (per 1\ua0nmol/L increase) was positively associated with birth weight (B: 125\ua0g; 95% CI 36, 214) and length (B: 0.59\ua0cm; 95% CI 0.21, 0.97). Maternal fT4 was inversely associated with birth weight (B: −\ua033\ua0g; 95% CI −\ua057, −\ua09.5), driven by obese women (n = 76). Causal mediation analyses suggested that a doubling of erythrocyte mercury (> 1\ua0\ub5g/kg; n = 374) was associated with a mean tT3-mediated decrease in birth weight of 11\ua0g (95% CI −\ua025, −\ua01.6) and in birth length of 0.1\ua0cm (95% CI −\ua00.12, −\ua00.01), both equivalent to about 12% of the total effect. To conclude, tT3 was positively associated with infant birth size. Reduced tT3 levels appeared to mediate a minor part of the inverse association between methylmercury exposure and birth size

A Swedish comment on ‘review: the availability of life-cycle studies in Sweden’

The article entitled ‘Review: the availability of life-cycle studies in Sweden’ by Croft and colleagues (January 2019, volume 24, issue 1, pages 6–11) has puzzled many researchers in Sweden. The stated purpose of the article is to review the availability of water and carbon footprinting studies and life-cycle assessment (LCA) studies in Sweden. Despite its title and purpose suggesting otherwise, the article appears to be about the accessibility of life-cycle case studies from Sweden in South Africa. It is problematic that the article claims to be a review in the title and text, but is presented by the journal as a commentary. We believe that the article’s method is unclear and that its title and results are misleading. The authors of the article found only 12 academic papers, 10 academic theses, 8 company reports, and 1 presentation. This result significantly underestimates the actual production and availability of Swedish LCA case studies

Kontaktperson – en avlönad vän i behov av stöd?

Denna uppsats har sitt ursprung i att Kontaktpersonsverksamheten LSS Majorna i Göteborg tog kontakt med institutionen för socialt arbete vid Göteborgs universitet. De hade en önskan om att några studenter skulle ta på sig uppgiften att undersöka om deras stödinsatser i form av handledning, feedback och utbildning var tillräckliga. Vi tyckte att uppdraget var intressant då vi alla tre har erfarenheter från människobehandlande organisationer och på nära håll sett hur viktiga dessa mellanmänskliga relationer är. Vi har genomfört en kvantitativ studie och vår datainsamlingsmetod bestod i att skicka ut enkäter till 112 kontaktpersoner inom kontaktpersonsverksamheten LSS Majorna. Det övergripande syftet med denna studie har varit att undersöka om kontaktpersonerna får de verktyg i form av handledning, feedback och utbildning de behöver för att utföra sina uppdrag på ett bra sätt. Undersökningen visar på att kontaktpersonsverksamheten LSS i Majorna i hög grad erbjuder tillräckligt med handledning, feedback och utbildning som kontaktpersonerna behöver för att känna att de kan utföra sina uppdrag på ett tillfredsställande sätt. Det finns dock vissa förbättringsområden. Av dessa kan nämnas att flera respondenter önskade mer riktade utbildningar om specifika utbildningar, såsom autism och Downs syndrom. Vidare visar resultatet på ett samband mellan civilstånd och behov av stöd, då de som lever tillsammans med en partner har mindre behov av handledning och ser färre svårigheter i uppdraget. Resultatet visar även på att det finns en tydlig skillnad mellan könen i förhållande till att bland annat söka och ta emot de stödinsatser som erbjuds