Distribution of Per- and Polyfluoroalkyl Substances (PFASs) in a Waste-to-Energy Plant─Tracking PFASs in Internal Residual Streams

Per- and polyfluoroalkyl substances (PFASs) constitute a diverse group of man-made chemicals characterized by their water- and oil-repellent properties and persistency. Given their widespread use in consumer products, PFASs will inevitably be present in waste streams sent to Waste-to-Energy (WtE) plants. We have previously observed a subset of PFASs in residual streams (ashes, treated process water, and flue gas) from a WtE plant. However, the transport and distribution of PFASs inside the WtE plant have remained unaddressed. This study is part of a comprehensive investigation to create a synoptic overview of the distribution of PFASs in WtE residues. PFASs were found in all sample types except for boiler ash. The total levels of 18 individual PFASs (Σ18PFASs) in untreated flue gas ranged from 5.2 to 9.5 ng m-3, decreasing with 35% ± 10% after wet flue gas treatment. Σ18PFASs in the condensate ranged from 46 to 50 ng L-1, of which perfluorohexanoic acid (PFHxA) made up 90% on a ng L-1 basis. PFHxA was also dominant in filter ash, where Σ18PFASs ranged from 0.28 to 0.79 ng g-1. This study shows that flue gas treatment can capture some PFASs and transfer them into WtE residues.

Co-hydrothermal carbonization of microalgae and digested sewage sludge: Assessing the impact of mixing ratios on the composition of primary and secondary char

The role of microalgae cultivation in wastewater treatment and reclamation has been studied extensively, as has the potential utility of the resulting algal biomass. Most methods for processing such biomass generate solid residues that must be properly managed to comply with current sustainable resource utilization requirements. Hydrothermal carbonization (HTC) can be used to process both individual wet feedstocks and mixed feedstocks (i.e., co-HTC). Here, we investigate co-HTC using microalgae and digested sewage sludge as feedstocks. The objectives were to (i) study the material's partitioning into solid and liquid products, and (ii) characterize the products' physicochemical properties. Co-HTC experiments were conducted at 180-250°C using mixed microalgae/sewage sludge feedstocks with the proportion of sewage sludge ranging from 0 to 100 %. Analyses of the hydrochar composition and the formation and composition of secondary char revealed that the content of carbonized material in the product decreased as the proportion of sewage sludge in the feedstock increased under fixed carbonization conditions. The properties of the hydrochars and the partitioning of material between the liquid phase and the hydrochar correlated linearly with the proportion of microalgae in mixed feedstocks, indicating that adding sewage sludge to microalgae had weak or non-existent synergistic effects on co-HTC outcomes. However, the proportion of sewage sludge in the feedstock did affect the secondary char. For example, adding sewage sludge reduced the abundance of carboxylic acids and ketones as well as the concentrations of higher molecular weight cholesterols. Such changes may alter the viable applications of the hydrochar.

Comparative characterisation and phytotoxicity assessment of biochar and hydrochar derived from municipal wastewater microalgae biomass

Microalgae, originating from a tertiary treatment of municipal wastewater, is considered a sustainable feedstock for producing biochar and hydrochar, offering great potential for agricultural use due to nutrient content and carbon storage ability. However, there are risks related to contamination and these need to be carefully assessed to ensure safe use of material from wastewater microalgae. Therefore, this study compared the properties and phototoxicity of biochar and hydrochar produced via pyrolysis and hydrothermal carbonisation (HTC) of microalgae under different temperatures and residence times. While biochar promoted germination and seedling growth by up to 11.0% and 70.0%, respectively, raw hydrochar showed strong phytotoxicity, due to the high content of volatile matter. Two post-treatments, dichloromethane (DCM) washing and further pyrolysis, proved to be effective methods for mitigating phytotoxicity of hydrochar. Additionally, biochar had 35.8-38.6% fixed carbon, resulting in higher carbon sequestration potential compared to hydrochar.

Emission of Per- and Polyfluoroalkyl Substances from a Waste-to-Energy Plant─Occurrence in Ashes, Treated Process Water, and First Observation in Flue Gas

Per- and polyfluoroalkyl substances (PFASs) are a large group of compounds commonly used as industrial chemicals and constituents of consumer products, e.g., as surfactants and surface protectors. When products containing PFASs reach their end of life, some end up in waste streams sent to waste-to-energy (WtE) plants. However, the fate of PFASs in WtE processes is largely unknown, as is their potential to enter the environment via ash, gypsum, treated process water, and flue gas. This study forms part of a comprehensive investigation of the occurrence and distribution of PFASs in WtE residues. Sampling was performed during incineration of two different waste mixes: normal municipal solid waste incineration (MSWI) and incineration of a waste mix with 5-8 wt % sewage sludge added to the MSWI (referred to as Sludge:MSWI). PFASs were identified in all examined residues, with short-chain (C4-C7) perfluorocarboxylic acids being the most abundant. Total levels of extractable PFASs were higher during Sludge:MSWI than during MSWI, with the total annual release estimated to be 47 and 13 g, respectively. Furthermore, PFASs were detected in flue gas for the first time (4.0-5.6 ng m^-3). Our results demonstrate that some PFASs are not fully degraded by the high temperatures during WtE conversion and can be emitted from the plant via ash, gypsum, treated process water, and flue gas.

Influence of hydrothermal carbonization conditions on the porosity, functionality, and sorption properties of microalgae hydrochars

Green microalgae is a possible feedstock for the production of biofuels, chemicals, food/feed, and medical products. Large-scale microalgae production requires large quantities of water and nutrients, directing the attention to wastewater as a cultivation medium. Wastewater-cultivated microalgae could via wet thermochemical conversion be valorised into products for e.g., water treatment. In this study, hydrothermal carbonization was used to process microalgae polycultures grown in municipal wastewater. The objective was to perform a systematic examination of how carbonization temperature, residence time, and initial pH affected solid yield, composition, and properties. Carbonization temperature, time and initial pH all had statistically significant effects on hydrochar properties, with temperature having the most pronounced effect; the surface area increased from 8.5 to 43.6 m² g^-1 as temperature was increased from 180 to 260 °C. However, hydrochars produced at low temperature and initially neutral pH generally had the highest capacity for methylene blue adsorption. DRIFTS analysis of the hydrochar revealed that the pH conditions changed the functional group composition, implying that adsorption was electrostatic interactions driven. This study concludes that un-activated hydrochars from wastewater grown microalgae produced at relatively low hydrothermal carbonization temperatures adsorb methylene blue, despite having low surface area.

Hydrothermal recycling of carbon absorbents loaded with emerging wastewater contaminants

Adsorption using carbon materials is one of the most efficient techniques for removal of emerging contaminants such as pharmaceuticals from wastewater. However, high costs are a major hurdle for their large-scale application in areas currently under economic constraints. While most research focuses on decreasing the adsorbent price by increasing its capacity, treatment costs for exhausted adsorbents and their respective end-of-life scenarios are often neglected. Here, we assessed a novel technique for recycling of exhausted activated biochars based on hydrothermal treatment at temperatures of 160-320 °C. While a treatment temperature of 280 °C was sufficient to fully degrade all 10 evaluated pharmaceuticals in solution, when adsorbed on activated biochars certain compounds were shielded and could not be fully decomposed even at the highest treatment temperature tested. However, the use of engineered biochar doped with Fe-species successfully increased the treatment efficiency, resulting in full degradation of all 10 parent compounds at 320 °C. The proposed recycling technique showed a high carbon retention in biochar with only minor losses, making the treatment a viable candidate for environmentally sound recycling of biochars. Recycled biochars displayed potentially beneficial structural changes ranging from an increased mesoporosity to additional oxygen bearing functional groups, providing synergies for subsequent applications as part of a sequential biochar system.

Phosphorus release from hydrothermally carbonized digested sewage sludge using organic acids

Hydrothermal carbonization (HTC) is a treatment technique with great potential for sanitizing digested sewage sludge (SS) and converting it into valuable products. In particular, phosphorus (P) recovery from hydrothermally carbonized SS has attracted special attention in recent years. This work aims to examine the leaching efficiency of P and the consequent release of metals and heavy metals from SS hydrochars (at 180, 215 and 250 °C) using organic acids (oxalate and citrate) over a range of pH values (0-4) and extraction times (5 min-24 h). Both organic acids triggered P extraction efficiencies exceeding 75 % at the lowest pH, but only oxalate reached a nearly complete P release from hydrochars at pH > 0 and for all carbonization temperatures. Low HTC temperature (180 °C) and short extraction time (5 min) were the optimal conditions treatment for P recovery when reacted in oxalate solutions of maximal pH buffering capacity (pH = 1.4). However, oxalate leaching also transferred metals/heavy metals into the P-leachate, with the exception of Ca being retained in the solid residue from HTC as Ca-oxalate precipitate. Different characterization methods confirmed the presence of this precipitate, and provided information about the surface and morphological changes of the SS hydrochars following acid treatment. The results suggest that HTC not only a promising technique to sanitize and reduce the volume of SS, but also an efficient means for P recovery using oxalic acid, thus contributing to the circular economy of P.

Health effects of reduced occupational sedentary behaviour in type 2 diabetes using a mobile health intervention: a study protocol for a 12-month randomized controlled trial-the ROSEBUD study

BACKGROUND

Short-term trials conducted in adults with type 2 diabetes mellitus (T2DM) showed that reducing sedentary behaviour by performing regular short bouts of light-intensity physical activity enhances health. Moreover, support for reducing sedentary behaviour may be provided at a low cost via mobile health technology (mHealth). There are a wide range of mHealth solutions available including SMS text message reminders and activity trackers that monitor the physical activity level and notify the user of prolonged sitting periods. The aim of this study is to evaluate the effects of a mHealth intervention on sedentary behaviour and physical activity and the associated changes in health in adults with T2DM.

METHODS

A dual-arm, 12-month, randomized controlled trial (RCT) will be conducted within a nationwide Swedish collaboration for diabetes research in primary health care. Individuals with T2DM (n = 142) and mainly sedentary work will be recruited across primary health care centres in five regions in Sweden. Participants will be randomized (1:1) into two groups. A mHealth intervention group who will receive an activity tracker wristband (Garmin Vivofit4), regular SMS text message reminders, and counselling with a diabetes specialist nurse, or a comparator group who will receive counselling with a diabetes specialist nurse only. The primary outcomes are device-measured total sitting time and total number of steps (activPAL3). The secondary outcomes are fatigue, health-related quality of life and musculoskeletal problems (self-reported questionnaires), number of sick leave days (diaries), diabetes medications (clinical record review) and cardiometabolic biomarkers including waist circumference, mean blood pressure, HbA1c, HDL-cholesterol and triglycerides.

DISCUSSION

Successful interventions to increase physical activity among those with T2DM have been costly and long-term effectiveness remains uncertain. The use of mHealth technologies such as activity trackers and SMS text reminders may increase awareness of prolonged sedentary behaviour and encourage increase in regular physical activity. mHealth may, therefore, provide a valuable and novel tool to improve health outcomes and clinical management in those with T2DM. This 12-month RCT will evaluate longer-term effects of a mHealth intervention suitable for real-world primary health care settings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04219800 . Registered on 7 January 2020.

Removal of contaminants of emerging concern from multicomponent systems using carbon dioxide activated biochar from lignocellulosic feedstocks

Adsorption of six contaminants of emerging concern (CECs) - caffeine, chloramphenicol, carbamazepine, bisphenol A, diclofenac, and triclosan - from a multicomponent solution was studied using activated biochars obtained from three lignocellulosic feedstocks: wheat straw, softwood, and peach stones. Structural parameters related to the porosity and ash content of activated biochar and the hydrophobic properties of the CECs were found to influence the adsorption efficiency. For straw and softwood biochar, activation resulted in a more developed mesoporosity, whereas activation of peach stone biochar increased only the microporosity. The most hydrophilic CECs studied, caffeine and chloramphenicol, displayed the highest adsorption (22.8 and 11.3 mg g^-1) onto activated wheat straw biochar which had the highest ash content of the studied adsorbents (20 wt%). Adsorption of bisphenol A and triclosan, both relatively hydrophobic substances, was highest (31.6 and 30.2 mg g^-1) onto activated biochar from softwood, which displayed a well-developed mesoporosity and low ash content.

Incidence, detection and outcome of differentiated thyroid cancer in Western Sweden

Background

It is unclear whether the increasing incidence of thyroid cancer (TC) due to increased diagnosis of small and indolent tumours might mask a real increase of clinically significant cancers. The aim of this study was to correlate surgery, pathology and outcome data of individual patients to the mode of primary detection (palpation, by imaging or incidental) to assess if TC incidence has increased.

Methods

The Swedish Cancer Registry identified all patients with TC in Västra Götaland County representing approximately 1.6 million inhabitants. Clinical information was retrieved from medical records of patient cohorts from three study intervals (2001–2002, 2006–2007 and 2011–2014) comprising 60 per cent of all TC patients. Data were also obtained from the NORDCAN registry to compare of TC incidence with other Nordic countries.

Results

Between 2001 and 2014, the annualized standard incidence rate/100 000 population (ASR) of TC increased from 3.14 to 10.71 in women and from 1.12 to 3.77 in men. This was higher than the mean incidence for Sweden but similar to that in Norway and Finland. Differentiated TC (DTC) increased more than threefold. The majority of tumours (64 per cent) were detected by palpation. Larger tumours (10–20, 21–40 and greater than 40 mm) increased as much as microcarcinomas (less than 10 mm). Only 5 per cent of the tumours were detected by imaging. All disease-specific deaths (8.5 per cent of DTC in the first two cohorts) and most patients with recurrent or persistent disease (6.6 per cent of DTC cases) were diagnosed due to tumour-related symptoms.

Conclusion

DTC in Western Sweden gradually increased between 2001 and 2014. The majority of tumours were detected by palpation suggesting a real increase in the incidence of clinically significant thyroid malignancies.

Occurrence of per- and polyfluoroalkyl substances and unidentified organofluorine in leachate from waste-to-energy stockpile - A case study

Per- and polyfluoroalkyl substances (PFASs) are a diverse group of chemicals used in consumer products, which will inevitably end up in waste streams. Landfills are widely recognized secondary point sources of PFASs, but other types of waste management sites have received less attention. Therefore, in a case study presented here we investigated releases of PFASs from temporarily stored waste by determining quantities of 34 PFASs in leachate from a Waste-to-Energy stockpile (45 000 ± 2000 tonnes) during five months in 2019. We also measured extractable organofluorine (EOF) to account for PFASs not included in the target list. The mean total concentration of the 34 PFAS (Σ₃₄PFAS) was 211 ± 31 ng/L, and short-chain (C4-C7) perfluorocarboxylic acids (PFCAs) accounted for 56-60% of the total. Moreover, we found that Σ₃₄PFAS only accounted for 12% ± 4% of EOF detected in the leachate. Our results demonstrate that waste stockpiles are previously unexplored sources of PFASs in the environment, and the dominance of short-chain PFCAs is consistent with observed profiles of contaminants in landfill leachates.

Combustion by-products and their health effects: Summary of the 16th international congress

The 16th International Congress on Combustion By-Products and their Health Effects (PIC2019) was held in Ann Arbor, Michigan, from July 10 to 12, 2019. For the last 28 years, this conference has served as an interdisciplinary platform for the discussion of the formation, environmental fate, health effects, policy, and remediation of combustion by-products. The technical areas for PIC2019 included mobile and stationary sources in urban environments, open fires, indoor air pollution, and halogenated pollutants. The congress was sponsored by the National Institute of Environmental Health Sciences (NIEHS), the U.S. EPA, the School of Public Health at the University of Michigan, the Civil and Environmental Engineering Department at the University of Michigan, the Mechanical Engineering Department at the University of Michigan, the Aerospace Engineering Department at the University of Michigan, and the Climate and Space Sciences and Engineering Department at the University of Michigan. Special features of the conference included a career path and round table discussion on translating research and engaging communities.

Formation of polybrominated dibenzofurans (PBDFs) and polybrominated diphenyl ethers (PBDEs) from oxidation of brominated flame retardants (BFRs)

Brominated aromatic rings constitute main structural entities in virtually all commercially deployed brominated flame retardants (BFRs). Oxidative decomposition of BFRs liberates appreciable quantities of bromobenzenes (BBzs). This contribution reports experimental measurements for the generation of notorious polybrominated dibenzofurans (PBDFs) and polybrominated diphenyl ethers (PBDEs) from oxidation of monobromobenzene (MBBz). In the light of developed product profiles, we map out reaction pathways and report kinetic parameters for PBDFs and PBDEs formation from coupling reactions of MBBz molecule and its derived ortho-bromophenoxy (o-BPhxy) radical using quantum chemical calculations. The identification and quantitation of product species involve the use of gas chromatograph - triple quadrupole mass spectrometer (GC-QQQMS) operating in the multiple reaction monitoring (MRM) mode. Bimolecular reactions of MBBz and o-BPhxy result in the generation of twelve pre-PBDF intermediates, of which four can also serve as building blocks for the synthesis of PBDEs. These four intermediates are denoted as pre-PBDE/pre-PBDF, with the remaining eight symbolised as pre-PBDF. The resonance-stabilised structure of the o-BPhxy radical accumulates more spin density character on its phenoxy O atom (30.9 %) in reference to ortho-C and para-C sites. Thus, the formation of the pre-PBDE/pre-PBDF structures via O/o-C couplings advances faster as it requires lower activation enthalpies (79.2 - 84.9 kJ mol^-1) than the pre-PBDF moieties, which arise via pairing reactions involving o-C(H or Br)/o-C(H or Br) sites (97.2 - 180.2 kJ mol^-1). Kinetic analysis indicates that, the O/o-C pre-PBDE/pre-PBDF adducts self-eject the out-of-plane H atoms to produce PBDEs, rather than undergo a three-step mechanism forming PBDFs. However, experimental measurements demonstrate PBDEs appearing in lower yields as compared to those of PBDFs; presumably due to H- and Br-induced conversion of the PBDEs into PBDFs following a simple ring-closure reaction. High reaction temperatures facilitate loss of ortho Br atom from PBDEs, followed by cyclisation step to generate PBDFs. PBDFs are observed in a narrow temperature range of 700-850 °C, whereas PBDEs form between 550-850 °C. Since formation mechanisms of PBDFs and polybrominated dibenzo-p-dioxins (PBDDs) are typically only sensitive to the bromination at ortho positions, the results reported herein apply also to higher brominated isomers of BBzs.

A novel hybrid organosolv-steam explosion pretreatment and fractionation method delivers solids with superior thermophilic digestibility to methane

Rising environmental concerns and the imminent depletion of fossil resources have sparked a strong interest towards the production of renewable energy such as biomethane. Inclusion of alternative feedstock's such as lignocellulosic biomass could further expand the production of biomethane. The present study evaluated the potential of a novel hybrid organosolv-steam explosion fractionation for delivering highly digestible pretreated solids from birch and spruce woodchips. The highest methane production yield was 176.5 mLCH₄ gVS^-1 for spruce and 327.2 mL CH₄ gVS^-1 for birch. High methane production rates of 1.0-6.3 mL min^-1 (spruce) and 6.0-35.5 mL min^-1 (birch) were obtained, leading to a rapid digestion, with 92% of total methane from spruce being generated in 80 h and 95% of that from birch in 120 h. These results demonstrate the elevated potential of the novel method to fractionate spruce and birch biomass and deliver cellulose-rich pretreated solids with superior digestibility.

The influence of inorganic components and carbon-oxygen surface functionalities in activated hydrothermally carbonized waste materials for water treatment

In this study, we have examined how the activation of hydrothermally carbonized sewage sludge and horse manure influences the inorganic component of these materials and surface chemistry. This was examined through statistical correlations between kinetic tests using trimethoprim, fluconazole, perfluorooctanoic acid, and copper, zinc, and arsenic and physicochemical properties. Yield and inorganic content varied considerably, with potassium hydroxide-activated materials producing lower yields with higher inorganic content. Phosphoric acid activation incorporated inorganically bound phosphorus into the material, although this showed no statistically relevant benefit. A maximum surface area of 1363 m²g^-1 and 343 m²g^-1 was achieved for the horse manure and sewage sludge. Statistical analysis found positive correlations between carbon-oxygen functionalities and trimethoprim, fluconazole, perfluorooctanoic acid, and copper removal, while inorganic content was negatively correlated. Conversely, arsenic removal was positively correlated with inorganic content. This research provides insight into the interactions with the organic/inorganic fraction of activated waste materials for water treatment.

Influence of water matrix and hydrochar properties on removal of organic and inorganic contaminants

The removal of contaminants from water using low-cost adsorbents has been widely studied, yet studies employing a realistic water matrix are still lacking. This study investigated the removal of organic compounds (trimethoprim, fluconazole, and perfluorooctanoic acid (PFOA)) and metals (As, Zn, and Cu) from landfill leachate. Additionally, tests in pure water, humic acid, and ion matrices were carried out to better understand how the water matrix affects adsorption. The hydrochars were produced from four feedstocks at three carbonization temperatures. The results show that the removal efficiencies for organic pollutants were low and metal removal by hydrochars was comparable with commercial activated carbon. The removal of all compounds from pure water was substantially lower. Tests with humic acid and ion-containing matrices could not fully explain the increased removal in the landfill leachate, which may be due to the combination of the water matrix and presence of soluble species from the hydrochars.

Extraction of active pharmaceutical ingredients from simulated spent activated carbonaceous adsorbents

Activated carbon (AC) and activated biochar (ABC) are widely used as sorbents for micropollutant removal during water and wastewater treatment. Spent adsorbents can be treated in several ways, e.g., by incineration, disposal in landfills, or reactivation. Regeneration is an attractive and potentially more economically viable alternative to modern post-treatment practices. Current strategies for assessing the performance of regeneration techniques often involve only repeated adsorption and regeneration cycles, and rarely involve direct measurements of micropollutants remaining on the adsorbent after regeneration. However, the use of regenerated adsorbents containing such residual micropollutants could present an environmental risk. In this study, the extraction of eight active pharmaceutical ingredients (APIs) commonly found in treated effluents was evaluated using 10 solvents and sorption onto three different carbon materials. An optimized extraction method was developed involving ultrasonication in 1:1 methanol:dichloromethane with 5% formic acid. This method achieved recoveries of 60 to 99% per API for an API concentration of 2 μg/g char and 27 to 129% per API for an API concentration of 1 mg/g char. Experiments using a mixture of 82 common APIs revealed that the optimized protocol achieved extraction recoveries above 70% for 29 of these APIs. These results show that the new extraction method could be a useful tool for assessing the regenerative properties of different carbon sorbents.

The impact of hydrothermal carbonization on the surface functionalities of wet waste materials for water treatment applications

Hydrothermal carbonization (HTC) is an energy-efficient thermochemical process for converting wet waste products into value added materials for water treatment. Understanding how HTC influences the physicochemical properties of the resultant materials is critical in optimizing the process for water treatment, where surface functionality and surface area play a major role. In this study, we have examined the HTC of four wet waste streams, sewage sludge, biosludge, fiber sludge, and horse manure at three different temperatures (180 °C, 220 °C, and 260 °C). The physicochemical properties of these materials were examined via FTIR, SEM and BET with their adsorption capacity were assessed using methylene blue. The yield of solid material after hydrothermal carbonization (hydrochar) decreased with increasing temperature for all samples, with the largest impact on horse manure and fiber sludge. These materials also lost the highest degree of oxygen, while HTC had minimal impact on biosludge and sewage sludge. The differences here were due to the varying compositions of each waste material, FTIR identified resonances related to cellulose in horse manure and fiber sludge, which were not detected in biosludge and sewage sludge. Adsorption capacities varied between 9.0 and 68 mg g^-1 with biosludge HTC at 220 °C adsorbing the highest amount. Adsorption also dropped drastically at the highest temperature (260 °C), indicating a correlation between adsorption capacity and HTC conditions. This was attributed to the loss of oxygen functional groups, which can contribute to adsorption. These results suggest that adsorption properties can be tailored both by selection of HTC temperature and feedstock.

OP0322-PARE HOW TO COMMUNICATE DIAGNOSTIC INFORMATION AND CUTTING EDGE SCIENCE TO PATIENTS WITH RHEUMATIC DISEASES

Background:

According to the 2017 Swedish Rheumatology Association (SRA) member strategy a recurring member survey as well as a member withdrawal survey was stipulated. The strategy was developed to evaluate to what extent SRA fulfills the requirements and expectations of its members. According to the 2019 survey, the most important output from a SRA membership, the members rank information about their diagnosis (#1) and supporting the research of these diagnoses (#2) most valuable.

Objectives:

To transfer the medical and scientific expertise of the rheumatic diagnoses into lay information in order to meet the member’s needs; to take part of the results of the cutting edge science and research progress, funded by SRA, that are relevant and important to individuals living with rheumatic conditions.

Methods:

A targeted scientific communication strategy was made consisting of lectures, interviews and scientific writing created for multi-channel distribution.

Results:

Actions taken upon the survey result

Conclusion:

As a member of SRA, regardless of rheumatic disease, the main interest is knowing more about their diagnosis and about the ongoing research in the field. Through collaborations and communicating rheumatic conditions and research within the field in lay language the patients can experience self-empowerment and the need for patient education can be met.

Disclosure of Interests:

None declared

PARE0021 TARGETED INITIATIVE TO FACILITATE THE IMPLEMENTATION OF EXISTING EFFECTIVE GOUT TREATMENT IN SWEDEN

Background:

Gout is a very painful rheumatic condition origin from excess uric acid in the bloodstream, which results in an accumulation of uric acid crystals in the joints and a severe local inflammatory response. Gout is treated in primary care and the current treatment has satisfactory results on disease management, thus patients can expect a controlled disease without flares. In Sweden however, only 30-40 % (1) of the patients receives adequate urate lowering treatment and prevent the disabling flares.

Objectives:

As a patient association, the Swedish Rheumatism Association (SRA) has identified an opportunity to use scientific evidence and data to improve awareness in both patients and physicians in order to make the existing treatment available and to shift the gout treatment from flare management to prevention.

Methods:

With SRA funding we created the Gout network, consisting of researchers, health professionals and patient research partners. Through meetings and operational support developed strategies to educate patients suffering from gout and to alert physicians in the primary care of the most recent research to aid the management of gout. We also fund a specific research project aimed to create an implementation plan to establish a treatment routine for gout in primary care with already existing resources.

Results:

A high quality patient education material is under development and consists of an information video lecture and a comprehensive online patient school providing information about the diagnosis, preventive treatment, possible life style change along with other resources that will support the gout patient, both for self-care and in relation to healthcare. For the healthcare profession we have together with a clinical research expert and a patient research partner developed a fact sheet with the latest scientific updates on gout.

Conclusion:

Accessible, high quality diagnosis information about gout is currently missing in Sweden. This collaboration initiative provides high quality facts to raise the general awareness and to educate and empower patients to get the effective therapy that is available today.

References:

[1] Incidence and prevalence of gout in Western Sweden Dehlin M, Drivelegka P, Sigurdardottir V, Svärd A & Jacobsson LTH.Arthritis Research & Therapy 18,: 164 (2016)

Disclosure of Interests:

Li Alemo Munters: None declared, Ingela Loell: None declared, Suzanna Jansson: None declared, Lennart T.H. Jacobsson Consultant of: AbbVie, Eli Lilly, Janssen, Novartis and Pfizer, Mats Dehlin: None declared

Comparative environmental assessment of end-of-life carbonaceous water treatment adsorbents

This study evaluates and compares the environmental impacts arising from the disposal of different carbonaceous sorbents used for wastewater treatment. Three different adsorption materials were considered, i.e. activated carbon, biochar and hydrochar, and three end-of-life management approaches, i.e. incineration, regeneration and landfilling. The highest overall environmental impact was of Carcinogenic effects and Freshwater Ecotoxicity due to emissions of heavy metals during production of all types of sorbents. The use of materials with higher adsorption capacities and regeneration of carbonaceous materials were considered and shown to be an efficient way for reducing the overall environmental impacts of the different adsorbents. The compensation of fossil fuel incineration by using recovered heat led to negative impacts in all categories. Recirculation of HTC process water reduced the impact on Freshwater Ecotoxicity and Eutrophication.

Novel metabolomic method to assess the effect-based removal efficiency of advanced wastewater treatment techniques

Unprecedented levels of chemicals of anthropogenic origin are currently released into surface waters globally. Wastewater treatment plant effluent has been identified as a major source, containing a broad mixture of pharmaceuticals and consumer chemicals. Therefore, there is a need for implementation of advanced wastewater treatment techniques, such as ozonation and adsorption methods, to reduce the contamination. However, there are conflicting findings on the toxicity of treated effluent and only limited possibilities for assessing the effect-based removal efficiency (EBRE) of different treatment techniques. Here, we describe a metabolomics approach to detect perturbations in fatty acid catabolic pathways as a proxy for biological effects. Metabolites in three fatty acid pathways were analyzed in a common damselfly larva (Coenagrion hastulatum) by liquid chromatography coupled to mass spectrometry. The larvae were exposed for one week to either conventionally treated effluent (activated sludge treatment), effluent additionally treated with ozone or effluent additionally treated with biochar filtration and results were compared with those from tap water control exposure. Five lipoxygenase-derived oxylipins (9,10,13-TriHOME, 9,12,13-TriHOME, 9-HODE, 9-HOTrE, and 13-HOTrE) decreased in response to conventionally treated effluent exposure. By using an additional treatment step, oxylipin levels were restored with exception of 9,10,13-TriHOME (ozonated effluent), and 9-HOTrE and 13-HOTrE (effluent filtered with biochar). In conclusion, exposure to wastewater effluent affected fatty acid metabolite levels in damselfly larvae, and a subset of the analyzed metabolites may serve as indicators for biological effects in biota in response to effluent exposure. To that effect, our findings suggest a new metabolomics protocol for assessing EBRE.

Emissions of toxic pollutants from co-combustion of demolition and construction wood and household waste fuel blends

Four different types of fuel blends containing demolition and construction wood and household waste were combusted in a small-scale experimental set-up to study the effect of fuel composition on the emissions of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), chlorobenzenes (PCBzs), chlorophenols (PCPhs) and polycyclic aromatic hydrocarbons (PAHs). Two woody materials, commercial stemwood (ST) and demolition and construction wood (DC) were selected because of the differences in their persistent organic pollutants (POPs), ash and metals content. For household waste, we used a municipal solid waste (MSW) and a refuse-derived fuel (RDF) from MSW with 5-20 wt% and up to 5 wt% food waste content respectively. No clear effect on the formation of pollutants was observed with different food waste content in the fuel blends tested. Combustion of ST-based fuels was very inefficient which led to high PAH emissions (32 ± 3.8 mg/kg_fuel). The use of DC clearly increased the total PCDD and PCDF emissions (71 ± 26 μg/kg_fuel) and had a clear effect on the formation of toxic congeners (210 ± 87 ng WHO₂₀₀₅-TEQ/kg_fuel). The high PCDD and PCDF emissions from DC-based fuels can be attributed to the presence of material contaminants such as small pieces of metals or plastics as well as timber treated with chromated copper arsenate preservatives and pentachlorophenol in the DC source.

LC-MS/MS determination of antiretroviral drugs in influents and effluents from wastewater treatment plants in KwaZulu-Natal, South Africa

South Africa has the largest occurrence of the human immune deficiency virus (HIV) in the world but has also implemented the largest antiretroviral (ARV) treatment programme. It was therefore of interest to determine the presence and concentrations of commonly used antiretroviral drugs (ARVDs) and, also, to determine the capabilities of wastewater treatment plants (WWTPs) for removing ARVDs. To this end, a surrogate standard based LC-MS/MS method was optimized and applied for the detection of thirteen ARVDs used in the treatment and management of HIV/acquired immune deficiency syndrome (HIV/AIDS) in two major and one modular WWTP in the eThekwini Municipality in KwaZulu-Natal, South Africa. The method was validated and the detection limits fell within the range of 2-20 ng L^-1. The analytical recoveries for the ARVDs were mainly greater than 50% with acceptable relative standard deviations. The concentration values ranged from <LOD - 53000 ng L^-1 (influent), <LOD - 34000 ng L^-1 (effluent) in a decentralized wastewater treatment facility (DEWATS); <LOD - 24000 ng L^-1 (influent), <LOD - 33000 ng L^-1 (effluent) in Northern WWTP and 61-34000 ng L^-1 (influent), <LOD - 20000 ng L^-1 (effluent) in Phoenix WWTP. Whilst abacavir, lamivudine and zidovudine were almost completely removed from the effluents, atazanavir, efavirenz, lopinavir and nevirapine persisted in the effluents from all three WWTPs. To estimate the ecotoxicological risks associated with the discharge of ARVDs, a countrywide survey focussing on the occurrence of ARVDs in WWTPs, surface and fresh water bodies, and aquatic organisms, is necessary.

Using carbonized low-cost materials for removal of chemicals of environmental concern from water

Adsorption on low-cost biochars would increase the affordability and availability of water treatment in, for example, developing countries. The aim of this study was to identify the precursor materials and hydrochar surface properties that yield efficient removal of compounds of environmental concern (CEC). We determined the adsorption kinetics of a mixture containing ten CECs (octhilinone, triclosan, trimethoprim, sulfamethoxasole, ciprofloxacin, diclofenac, paracetamol, diphenhydramine, fluconazole, and bisphenol A) to hydrochars prepared from agricultural waste (including tomato- and olive-press wastes, rice husks, and horse manure). The surface characteristics of the hydrochars were evaluated via diffuse reflectance infrared spectroscopy (DRIFTS), X-ray photoelectron spectroscopy (XPS), and N2-adsorption. Kinetic adsorption tests revealed that removal efficiencies varied substantially among different materials. Similarly, surface analysis revealed differences among the studied hydrochars and the degree of changes that the materials undergo during carbonization. According to the DRIFTS data, compared with the least efficient adsorbent materials, the most efficient hydrochars underwent more substantial changes during carbonization.

Abstract P3-08-13: Serum thymidine kinase activity is an independent prognostic factor for progression-free and overall survival in women with metastatic breast cancer

Introduction:

Although prognosis and treatment of metastatic breast cancer (MBC) have improved over the last years, there is still an unmet clinical need for more precise prognostic and treatment monitoring tools. Liquid-based markers are preferred since they reflect real-time tumor progression and are not dependent on repeated invasive tissue biopsies. Thymidine kinase 1 (TK1) is an enzyme involved in nucleotide metabolism and has a fundamental role in the DNA synthesis. It can be used as a marker of cell proliferation rate and the TK1 activity has demonstrated correlations to prognosis and usefulness for treatment monitoring in different malignancies. The aim of this study was to determine serum TK1 activity (sTK1) levels measured with the DiviTum assay (Biovica, Sweden), in women with MBC scheduled for 1st line systemic therapy and to evaluate its potential for prediction of outcome and treatment monitoring.

Methods:

142 women with MBC scheduled for 1st line systemic treatment and included in a prospective monitoring trial (CTC-MBC, NCT01322893) were evaluated for sTK1 at baseline (BL) and during treatment at 1, 3 and 6 months. 132 patients had at least one follow-up sample. sTK1 activity levels were measured and correlations to important clinicopathological variables and prognosis (PFS and OS) at BL and during treatment were evaluated.

Results:

The median sTK1 level at BL was 391 u/L (range 10-35520 u/L). When comparing patients with high (above median) versus low (below median) sTK1 levels at BL, high sTK1 levels were found to be associated to worse performance status (p=0.001) and high number of metastatic sites (p=0.03). There was also a statistically significant association between high sTK1 levels and high Ki67 expression in biopsies from metastatic lesions (p=0.038). In univariable analyses high sTK1 levels correlated to worse PFS and OS (HRPFS-BL 2.32, p&lt;0.001; HROS-BL 2.54, p&lt;0.001) at BL. In multivariable analysis adjusted for clinically used prognostic factors, sTK1 was an independent prognostic factor for PFS and OS (HRPFS-BL 2.4, p&lt;0.001; HROS-BL 2.0, p=0.01). During treatment, sTK1 was significantly associated with OS from each of the four time points and onwards (BL, 1, 3, 6 months) (HROS-1m 1.93, p=0.01; HROS-3m 2.35, p=0.02; HROS-6m 2.78, p=0.002) in univariable analysis. High sTK1 levels were also associated with impaired PFS (HRPFS-1m 1.48, p=0.06; HRPFS-3m 1.52, p=0.07; HRPFS-6m 2.03, p=0.009) and these associations were significant at BL and 6 months.

Discussion:

sTK1 activity level is an independent prognostic factor for PFS and OS in patients with MBC scheduled for 1st line systemic therapy. During treatment, sTK1 is prognostic for OS evaluated from all time-points up to 6 months. The sTK1 effects observed for PFS are slightly weaker, but still propose potential usefulness for treatment monitoring. Further, sTK1 levels correlate to Ki67 expression in metastatic lesions suggesting that it can be useful as a liquid-based real-time proliferation marker. In conclusion, these results are clinically relevant for prognostication and treatment monitoring in patients with MBC. Future studies of sTK1 are justified to further elucidate in what settings this marker is most useful.

Citation Format: Larsson A-M, Jansson S, Bendahl P-O, Baker S, Bergqvist M, Aaltonen K, Rydén L. Serum thymidine kinase activity is an independent prognostic factor for progression-free and overall survival in women with metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-08-13.

Abstract P2-01-03: Improved prognostic information by serial monitoring of CTC enumeration and CTC-clusters from baseline to six months in patients with metastatic breast cancer scheduled for 1st line systemic therapy

Background: Detection and enumeration of circulating tumor cells (CTCs) allows real time monitoring of disease evolvement. In women with metastatic breast cancer (MBC), a CTC count of ≥5 CTCs is associated with decreased progression-free survival (PFS) and overall survival (OS). Serial sampling after therapy initiation has indicated that longitudinal CTC enumeration adds prognostic information, but data from long time sampling is sparse. The aim of this study was to evaluate if prospective longitudinal detection of CTC count and CTC clusters in women with newly diagnosed MBC can improve prognostication and monitoring of patients in the clinical setting.

Methods: Longitudinal blood samples were collected at baseline (BL) and after 1, 3 and 6 months in 156 women with MBC scheduled for 1st line systemic therapy. CTC enumeration and cluster detection were performed by the CellSearch® system in a prospective monitoring trial (NCT01322893). 115 patients had evaluable samples at all time-points. Primary endpoint was PFS and secondary endpoint was OS at BL in relation to CTC count and as landmark analyses during treatment. In addition, change in CTC count during therapy was compared to progressive disease (PD) versus non-PD. Structured clinical and radiological evaluation for PD was performed every 3rd month.

Results: Seventy-nine (52%) of 152 evaluable patients had ≥5 CTC and 14/79 patients had CTC-clusters (33 clustered CTC) at BL. Median follow-up time was 25 (7-69) months. Patients with ≥5 CTCs had inferior PFS and OS in uni-(data not shown) and multivariable analysis (HRPFS 1.91 (1.26-2.91), P=0.003) (HROS 3.57 (2.02-6.31), P&lt;0.001) at BL. Presence of clusters at BL was prognostic for OS (HROS 2.37 (1.25-4.51), P=0.008). Longitudinal landmark analysis of number of CTCs and presence of CTC clusters showed a time-dependent increase in HR during treatment for CTCs and CTC-clusters and predicted worse PFS and OS at all time-points. Stratifying patients based on CTC count and presence of clusters revealed four risk groups (0, 1-4, ≥5 CTC, ≥5 CTC + clusters) where patients with clusters had inferior PFS and OS at all time points. Change in CTC count from BL to 1 and 3 months, and from 3 to 6 months was significantly related to evaluation at 3 and 6 months (PD vs non-PD, P=0.013 (3 months), P=0.016 (6 months)) and change in CTC count from BL to 1, 3 and 6 months was also significantly predictive of both PFS and OS. Notably, survival was significantly inferior for patients with persistent CTC ≥5 during treatment.

Discussion: CTC is an independent prognostic factor for MBC patients scheduled for 1st line systemic therapy. By longitudinal monitoring during treatment, the prognostic information by presence of ≥5 CTC and clusters increases over time and supports long time monitoring of patients. Importantly, detection of CTC-clusters identifies a subgroup of patients with dismal prognosis at all time-points indicating that CTC-clusters renders important clinical information. Change in CTC count during systemic therapy is related to outcome of evaluation and prognosis at all time-points.

Citation Format: Larsson A-M, Jansson S, Bendahl P-O, Baker S, Graffman C, Lundgren C, Loman N, Aaltonen KE, Rydén L. Improved prognostic information by serial monitoring of CTC enumeration and CTC-clusters from baseline to six months in patients with metastatic breast cancer scheduled for 1st line systemic therapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-01-03.

Characterization and Photodegradation of Polybrominated Diphenyl Ethers in Car Seat Fabrics from End-of-Life Vehicles

In this study, we examined the photodegradation of decabromodiphenyl ether (BDE-209) on the surface of car seat covers from end-of-life vehicles (ELVs). Samples were collected at two car dismantling facilities in Sweden and cover car models from 1989 to 1998. The content of polybrominated diphenyl ethers (PBDEs) in nine real samples (fabric and polyurethane foam) was first characterized. Fabric samples that did not contain BDE-209 were then spiked with BDE-209 and irradiated in the laboratory and under sunlight. Photoproducts were identified using high performance liquid chromatography coupled to electrospray ionization mass spectrometer (HPLC-ESI-Orbitrap-MS), whereas volatile products were analyzed by gas chromatography-mass spectrometry (GC-MS). Similar photodegradation rates and oxidation products were observed in fabric samples irradiated in the laboratory and those collected from ELVs. Estimated half-life of BDE-209 on fabric inside vehicles ranged from 3 to 6 years. Thirteen major photoproducts were identified as lower brominated products, hydroxylated BDEs, brominated and hydroxylated dibenzofurans (PBDFs) and dioxins (PBDDs). Furthermore, several photoproducts were found to be transferable into water, particularly bromophenols and hydroxylated BDEs, and others into gas phase, such as bromomethanol and 1,2-dibromoethane. This should be taken into consideration for better estimating exposure to PBDEs and to develop strategies for ELV recycling.

Influence of pyrolysis temperature and production unit on formation of selected PAHs, oxy-PAHs, N-PACs, PCDDs, and PCDFs in biochar-a screening study

The influence of reactor type and operating conditions of the pyrolysis unit on the final concentration of toxic contaminants in biochar remains unclear. Therefore, we determined the concentrations of polycyclic aromatic hydrocarbons (PAHs), oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs), nitrogen-containing polycyclic aromatic compounds (N-PACs), polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) in biochars produced from three different feedstocks (softwood, wheat straw, and anaerobic digestate). Different scaled pyrolysis units (one batch and two continuous units) at two different temperatures (550 and 700 °C) were considered. The results revealed that the type of biomass had a significant influence on the PAH, oxy-PAH, and N-PAC content of the biochars. The configuration and type of the pyrolysis unit influenced only the wheat straw pyrolyzed at 550 °C. PCDDs and PCDFs occurred at very low levels in the biochars. In terms of PAH, PCDD, and PCDF content, the biochars assessed in this study represent a low risk to the environment, regardless of the temperature and type and size of the pyrolysis unit.

Correction to: Influence of pyrolysis temperature and production unit on formation of selected PAHs, oxy-PAHs, N-PACs, PCDDs, and PCDFs in biochar-a screening study

The correct presentation of Figs. 1, 3 and Table 3 are shown in this paper.

Fate of metals and emissions of organic pollutants from torrefaction of waste wood, MSW, and RDF

Torrefaction of municipal solid waste (MSW), refuse-derived fuel (RDF), and demolition and construction wood (DC) was performed at 220°C and a residence time of 90min in a bench-scale reactor. The levels of toxic polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) contained in emission from the torrefaction process were evaluated. In addition, main ash-forming elements and trace metals in the raw feedstock and char were determined. The use of MSW in fuel blends with DC resulted in lower PCDD and PCDF emissions after torrefaction, compared with the RDF blends. The migration of chlorine from the feedstock to the gas phase reduces the chlorine content of the char which may reduce the risk of alkali chloride-corrosion in char combustion. However, trace metals catalytically active in the formation of PCDD and PCDF remain in the char, thereby may promote PCDD and PCDF formation during subsequent char combustion for energy recovery; this formation is less extensive than when the feedstock is used.

Occurrence of brominated diphenyl ethers, dibenzo-p-dioxins and dibenzofurans in foam materials in scrapped car seats from 1985 to 2012

The purpose of this study was to evaluate the occurrence of polybrominated diphenyl ethers (PBDEs), dibenzo-p-dioxins (PBDDs) and dibenzofurans (PBDFs) in polyurethane foam (PUF) from car seats of end-of-life vehicles (ELVs) and compare the concentrations of PBDEs with the stipulated regulations in the POP Directive. The method comprised screening by X-ray fluorescence (XRF) and GG-MS analysis. Of 59 tested samples from ELVs, 17 samples showed lines above limit of detection (LOD) levels when screening by XRF. Those samples were selected as replicates and for further analysis by GC-MS. The majority of the studied samples showed low or non-detectable concentrations of PBDEs and PBDD/Fs, but two samples showed concentrations of Σ Te-HpBDEs close to the regulated level for Te-HpBDEs in waste (1000mgkg^-1); one was slightly higher (1390mgkg^-1) and the other slightly lower (570mgkg^-1). It was concluded that brominated pollutants such as Te-HpBDEs occur in low levels in automotive applications in scrapped cars produced in years when brominated flame retardants were used. However, two of the 59 samples tested showed levels close to those stipulated by regulations concerning POPs in waste.

Persistent Organic Pollutants in Streamwater: Influence of Hydrological Conditions and Landscape Type

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and hexachlorobenzene (HCB) in streamwater were measured in a remote catchment in northern Sweden and downstream to the Baltic Sea. Sampling took place at seven sites during two years and under different hydrological conditions: during the snow-free, snow-covered, and spring-flood seasons. Concentrations varied substantially between seasons and were up to 20 times higher during the spring flood compared to the preceding snow-covered period. The increase in concentrations with runoff was due to higher levels of particle-associated contaminants, while the dissolved concentrations remained stable. Particulate-contaminant concentrations were positively correlated primarily to suspended particulate matter (SPM) at sites in areas with a high land-cover fraction of sorted sediment. When upstream sampling locations were compared, a mire-dominated stream had higher concentrations and a lower retention of atmospherically deposited contaminants than a forest stream of the same catchment size. Contaminant concentrations (normalized to volume) did not increase consistently downstream despite the presence of several point sources. However, when normalized to the amount of SPM, concentrations were on average >20 times higher at the outlet in the Baltic Sea compared to the outlet from the remote catchment without point sources.

Mechanistic evaluation of polychlorinated dibenzo-p-dioxin, dibenzofuran and naphthalene isomer fingerprints in microwave pyrolysis of biomass

Isomer distribution patterns of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and naphthalenes (PCNs) were investigated in microwave-assisted pyrolysis (MAP) products of woody biomass. The feedstocks included bark and impregnated wood. The results indicated that isomer distributions in MAP are more selective compared to those reported from wood burning and waste incineration. Favored formation of 4-MoCDF and highly selective chlorine substitution at the 2,4-position observed during MAP suggested a preferred formation pathway of PCDFs involving (chloro)phenol precursors followed by subsequent chlorination. The PCDD distribution was dominated by isomers typically formed from chlorophenol condensation at relatively low temperature. The PCN isomer distributions showed a tendency for sequential chlorination from non-substituted naphthalene at successive positions. The presence of isomers such as 1-MoCDD, 4-MoCDF, 1,2,3-TriCN with low thermodynamic stability indicates that kinetic factors may be important in the MAP process.

14th congress of combustion by-products and their health effects-origin, fate, and health effects of combustion-related air pollutants in the coming era of bio-based energy sources

The 14th International Congress on Combustion By-Products and Their Health Effects was held in Umeå, Sweden from June 14th to 17th, 2015. The Congress, mainly sponsored by the National Institute of Environmental Health Sciences Superfund Research Program and the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning, focused on the "Origin, fate and health effects of combustion-related air pollutants in the coming era of bio-based energy sources". The international delegates included academic and government researchers, engineers, scientists, policymakers and representatives of industrial partners. The Congress provided a unique forum for the discussion of scientific advances in this research area since it addressed in combination the health-related issues and the environmental implications of combustion by-products. The scientific outcomes of the Congress included the consensus opinions that: (a) there is a correlation between human exposure to particulate matter and increased cardiac and respiratory morbidity and mortality; (b) because currently available data does not support the assessment of differences in health outcomes between biomass smoke and other particulates in outdoor air, the potential human health and environmental impacts of emerging air-pollution sources must be addressed. Assessment will require the development of new approaches to characterize combustion emissions through advanced sampling and analytical methods. The Congress also concluded the need for better and more sustainable e-waste management and improved policies, usage and disposal methods for materials containing flame retardants.

Assessment of chemical and material contamination in waste wood fuels--A case study ranging over nine years

The increased demand for waste wood (WW) as fuel in Swedish co-combustion facilities during the last years has increased the import of this material. Each country has different laws governing the use of chemicals and therefore the composition of the fuel will likely change when combining WW from different origins. To cope with this, enhanced knowledge is needed on WW composition and the performance of pre-treatment techniques for reduction of its contaminants. In this study, the chemical and physical characteristics of 500 WW samples collected at a co-combustion facility in Sweden between 2004 and 2013 were investigated to determine the variation of contaminant content over time. Multivariate data analysis was used for the interpretation of the data. The concentrations of all the studied contaminants varied widely between sampling occasions, demonstrating the highly variable composition of WW fuels. The efficiency of sieving as a pre-treatment measure to reduce the levels of contaminants was not sufficient, revealing that sieving should be used in combination with other pre-treatment methods. The results from this case study provide knowledge on waste wood composition that may benefit its management. This knowledge can be applied for selection of the most suitable pre-treatments to obtain high quality sustainable WW fuels.

Size fractionation of waste-to-energy boiler ash enables separation of a coarse fraction with low dioxin concentrations

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) formed in modern Waste-to-Energy plants are primarily found in the generated ashes and air pollution control residues, which are usually disposed of as hazardous waste. The objective of this study was to explore the occurrence of PCDD/F in different grain size fractions in the boiler ash, i.e. ash originating from the convection pass of the boiler. If a correlation between particle size and dioxin concentrations could be found, size fractionation of the ashes could reduce the total amount of hazardous waste. Boiler ash samples from ten sections of a boiler's convective part were collected over three sampling days, sieved into three different size fractions - <0.09 mm, 0.09-0.355 mm, and >0.355 mm - and analysed for PCDD/F. The coarse fraction (>0.355 mm) in the first sections of the horizontal convection pass appeared to be of low toxicity with respect to dioxin content. While the total mass of the coarse fraction in this boiler was relatively small, sieving could reduce the amount of ash containing toxic PCDD/F by around 0.5 kg per tonne input waste or around 15% of the collected boiler ash from the convection pass. The mid-size fraction in this study covered a wide size range (0.09-0.355 mm) and possibly a low toxicity fraction could be identified by splitting this fraction into more narrow size ranges. The ashes exhibited uniform PCDD/F homologue patterns which suggests a stable and continuous generation of PCDD/F.

PCDDs, PCDFs and PCNs in products of microwave-assisted pyrolysis of woody biomass--Distribution among solid, liquid and gaseous phases and effects of material composition

Microwave-assisted pyrolysis (MAP) of lignocellulosic biomass is a technique that could potentially be used to produce and upgrade renewable energy carriers. However, there is no available information about the formation of dioxins and other organic pollutants in MAP treatment of woody biomass. In this study, MAP experiments were conducted in lab-scale using virgin softwood, bark, and impregnated wood as feedstocks. The non-condensable gas, liquid (fractionated into aqueous and oil phases), and char fractions generated during pyrolysis were collected and analysed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and naphthalenes (PCNs). The concentrations of PCDDs, PCDFs and PCNs in the pyrolysis products ranged from 0.52 to 43.7 ng kg(-1). All investigated compound groups were most abundant in the oil fraction, accounting for up to 68% (w/w) of the total concentrations. The highest PCDD, PCDF and PCN concentrations were found from the pyrolysis of bark, which has relatively high contents of chlorine and mineral matter, followed by impregnated wood, which contains organic and metal-based preservatives. The homologue profiles of all three compound groups were dominated by the less chlorinated homologues. The homologue abundance decreased as the degree of chlorination increased. This trend was observed for all three feedstocks.

Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits.

Multivariate relationships between molecular descriptors and isomer distribution patterns of PCBs formed during household waste incineration

The congener-specific concentrations of mono- to deca-chlorinated biphenyls (PC1-10B) in post-combustion zone flue gases from a laboratory-scale fluidized bed reactor were evaluated and correlated with a set of physicochemical properties and chlorine substitution descriptors. The objective was to identify parameters that affect post-combustion zone polychlorinated biphenyl (PCB) formation and interpreting observed correlations by using principal component analysis (PCA), and bidirectional orthogonal projections to latent structures (O2PLS). Both physicochemical variables and chlorine substitution descriptors were shown to have significant effects on the PCB congener distribution; however, the physicochemical descriptors were more influential in all-homologue models, whereas the chlorine substitution descriptors had a greater impact in single-homologue models, which suggests that PCB formation in general may be under thermodynamic control, whereas the distribution of isomers within homologues is more sensitive to chlorine substitution parameters. The EHOMO and ELUMO variables notably influenced both the PCA and the O2PLS models, which indicate that reactivity and polarization in the molecular structures of the PCBs is of importance.

The effects of fuel composition and ammonium sulfate addition on PCDD, PCDF, PCN and PCB concentrations during the combustion of biomass and paper production residuals

The use of waste wood as an energy carrier has increased during the last decade. However, the higher levels of alkali metals and chlorine in waste wood compared to virgin biomass can promote the formation of deposits and organic pollutants. Here, the effect of fuel composition and the inhibitory effects of ammonium sulfate, (NH4)2SO4, on the concentrations of persistent organic pollutants (POPs) in the flue gas of a lab-scale combustor was investigated. Ammonium sulfate is often used as a corrosion-preventing additive and may also inhibit formation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). In addition to PCDDs and PCDFs, polychlorinated naphthalenes (PCN) and biphenyls (PCB) were also analyzed. It was found that the flue gas composition changed dramatically when (NH4)2SO4 was added: CO, SO2, and NH3 levels increased, while those of HCl decreased to almost zero. However, the additive's effects on POP formation were less pronounced. When (NH4)2SO4 was added to give an S:Cl ratio of 3, only the PCDF concentration was reduced, indicating that this ratio was not sufficient to achieve a general reduction in POP emissions. Conversely, at an S:Cl ratio of 6, significant reductions in the WHO-TEQ value and the PCDD and PCDF contents of the flue gas were observed. The effect on the PCDF concentration was especially pronounced. PCN formation seemed to be promoted by the elevated CO concentrations caused by adding (NH4)2SO4.

Effects of regional differences in waste composition on the thermal formation of polychlorinated aromatics during incineration

Two artificial wastes (A and B) whose contents reflect regional differences in municipal solid waste composition, were used to investigate the thermal formation of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and naphthalenes (PCNs) during incineration. Flue gas samples were simultaneously collected at three ports in the post-combustion zone corresponding to flue gas temperatures of 400, 300, and 200 °C. The combustion of Waste B, which had a higher chlorine and metal content than Waste A, produced greater levels of highly-chlorinated homologues, as demonstrated by a higher degree of chlorination. The total concentrations of PCDDs, PCDFs, PCBs, and PCNs formed in the combustion of both wastes increased as temperature decreased along the convector. There were no significant differences in total concentrations between Waste A and Waste B combustion at specific temperatures, with exception of PCDFs at 400 °C. Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) modeling, used to evaluate the data for all compound groups, suggest that during flue gas quenching at temperatures of 400 °C low-chlorinated homologues are preferentially formed in the presence of copper, which is known to be a very active catalyst for this process. At 300 and 200 °C, the formation of highly-chlorinated homologues is favored.

Reduction of PCDD, PCDF and PCB during co-combustion of biomass with waste products from pulp and paper industry

The use of waste wood as an energy carrier has increased during the last decade. However, elevated levels of alkali metals and chlorine in waste wood compared to virgin biomass can cause increased deposit formation and higher concentrations of organic pollutants. In this study, we investigated the effect of the ChlorOut technique on concentrations of organic pollutants. Ammonium sulfate was injected into the combustion system to inhibit formation of KCl (which causes deposits) and persistent organic pollutants, namely polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs). The results showed that concentrations of the toxic congeners of PCDD, PCDF and PCB decreased in the presence of ammonium sulfate.

Accurate sampling of PCDD/F in high temperature flue-gas using cooled sampling probes

In a laboratory-scale combustion reactor, flue-gas samples were collected at two temperatures in the post-combustion zone, 700°C and 400°C, using two different water-cooled sampling probes. The probes were the cooled probe described in the European Standard method EN-1948:1, referred to as the original probe, and a modified probe that contained a salt/ice mixture to assist the cooling, referred to as the sub-zero probe. To determine the efficiency of the cooling probes, internal temperature measurements were recorded at 5cm intervals inside the probes. Flue-gas samples were analyzed for polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs). Samples collected at 700°C using the original cooling probe showed higher concentrations of PCDD/Fs compared to samples collected using the sub-zero probe. No significant differences were observed between samples collected at 400°C. The results indicated that artifact formation of PCDD/Fs readily occurs during flue-gas sampling at high temperatures if the cooling within the probe is insufficient, as found for the original probe at 700°C. It was also shown that this problem could be alleviated by using probes with an enhanced cooling capacity, such as the sub-zero probe. Although this may not affect samples collected for regulatory purposes in exit gases, it is of great importance for research conducted in the high-temperature region of the post-combustion zone.

Relationships between congener distribution patterns of PCDDs, PCDFs, PCNs, PCBs, PCBzs and PCPhs formed during flue gas cooling

The congener patterns of mono- to octa-chlorinated dibenzo-p-dioxins (PC(1-8)DD), dibenzofurans (PC(1-8)DF), naphthalenes (PC(1-8)N), mono- to deca-chlorinated biphenyls (PC(1-10)B), di- to hexa-chlorinated benzenes (PC(2-6)Bz) and mono- to penta-chlorinated phenols (PC(1-5)Ph) in flue gas samples collected simultaneously at 450°C, 300°C and 200°C in the post-combustion zone during waste incineration in a laboratory-scale reactor in a previous study, were in this study evaluated using principal component analysis (PCA). To our knowledge this is the most comprehensive chemical and multivariate analysis to date of the thermal formation of dioxins. The PCA indicated that different formation pathways occur in the temperature regions 450-300°C and 300-200°C, and reflected a chlorination effect of PCDF and PCDD between 450°C and 200°C which could not be discerned or was less pronounced for the other compound groups. Toxic equivalents (TEQs) of PCDDs, PCDFs and PCBs, as well as total TEQ values (TEQ(Total)) were also calculated, and correlations between changes in levels of specific congeners and the TEQs were explored in the PCA. Levels of four HxCDF congeners and 1,2,3,4,8-, 1,2,3,7,8-PeCDF and 2,3,4,7,8-PeCDF showed the strongest correlations with TEQ(Total) (R(2)≥0.9). In addition, levels of 1,2,4-TriCBz correlated strongly with TEQ(Total) (R(2)>0.7), supporting previous reports that it may be a potential indicator of the TEQ.

Characterisation and fingerprinting of PCBs in flue gas and ash from waste incineration and in technical mixtures

Congener patterns of mono- to deca-chlorinated biphenyls (PC1-10B) were evaluated in (a) waste incineration flue gases collected in the post-combustion zone of a laboratory-scale fluidized-bed reactor, (b) ashes from two different MSW incineration plants, and (c) published data of eight Aroclor formulations. The congener patterns of the flue gases, ashes, and Aroclor mixtures clearly differed from each other, likely reflecting differences in formation pathways. The flue gas congener patterns were largely dominated by the least chlorinated congeners, whereas the ashes displayed more evenly distributed patterns. The most abundant congeners indicated a preference for 3,3',4,4'-oriented substitution, which may be related to de novo-type formation involving perylene. Principal component analysis confirmed that congener patterns differed among the three matrices and also distinguished flue gases collected at 200 °C from those collected at 300 °C and 450 °C. This distinction could be partly explained by the degree of chlorination, although the substitution status of the ortho-position, and substitution in the 3,3',4,4'-positions also seemed to be influential. Injecting biphenyl into the post-combustion zone of the reactor did not alter the patterns, indicating that availability of the backbone structure is not a limiting factor for PCB formation.

Effect of injection of di- and tricyclic aromatic compounds on post-combustion formation of polychlorinated dibenzo-p-dioxins and dibenzofurans

The formation of mono- to octachlorinated dibenzo-p-dioxins (PC₁₋₈DD) and dibenzofurans (PC₁₋₈DF) was studied using a model waste in a laboratory-scale combustion reactor with simultaneous collection of flue gas at three different temperatures (450 °C, 300 °C, and 200 °C) in the post-combustion zone. To investigate the influence of chlorination reactions and the effects of carbon backbone-containing compounds present in the flue gases, five aromatic compounds were injected into the flue gas, namely dibenzofuran (DF), biphenyl (BP), naphthalene, phenanthrene and fluorene. The injection of DF induced a reduction in the concentration of PC₃₋₅DD, but did not significantly influence the concentration of PCDF. A reduction in the concentration of PC₃₋₅DD was also observed during the injection of fluorene, which is structurally very similar to DF. The injection of biphenyl, naphthalene and phenanthrene had less pronounced effects on the formation of PCDD and PCDF. A possible explanation of the observed changes during injection of DF and fluorene, based on homologue profiles and affected congeners, involves formation of radical species from fluorene and/or dibenzofuran. The fluorene radical is stabilized by the delocalization of electrons across the aromatic ring structure and has the propensity to react with highly abundant hydrogen chloride, whereas the molecular species would require reaction with Cl₂ or chlorine radicals.