Social acceptance, emissions analysis and potential applications of paper-waste briquettes in Andean areas.

The research assessed waste-based briquettes consumption compared to conventional fuels in the Andes. Laboratory tests were conducted together with on-field analysis in Colquencha (Bolivia). The laboratory study shows that the performances of briquettes are better in terms of PM2.5 (933.4 ± 50.8 mg kg-1) and CO emissions (22.89 ± 2.40 g kg-1) compared to animal dung (6265.7 ± 1273.5 mgPM2.5 kg-1 and 48.10 ± 12.50 gCO kg-1), although the boiling time increased due to the lower fuel consumption rate and firepower compared to shrubs. The social survey organized with 150 Bolivian citizens suggested that low-income households are not able to pay for an alternative fuel: about 40% would pay less than 4 USD per month, while methane use for cooking is positively correlated with the income level (r = 0.244, p < 0.05). On field analysis suggested that local cookstoves are not appropriate for briquettes combustion since indoor air pollution overcomes 30 ppm of CO and 10 mgPM2.5 m-3. On balance, local small manufactures can be the main target for selling waste-based briquettes to reduce shrubs and wood consumption. However, briquettes production costs seem not yet competitive to natural easy-to-obtain fuels (i.e., animal dung). The research encourages the use of cellulosic and biomass waste-based briquettes in the Andean area for cooking, heating, or manufacturing and strongly advises policy-makers to introduce economic incentives for the recovery of secondary raw materials.

Microbial Enzyme Biotechnology to Reach Plastic Waste Circularity: Current Status, Problems and Perspectives.

The accumulation of synthetic plastic waste in the environment has become a global concern. Microbial enzymes (purified or as whole-cell biocatalysts) represent emerging biotechnological tools for waste circularity; they can depolymerize materials into reusable building blocks, but their contribution must be considered within the context of present waste management practices. This review reports on the prospective of biotechnological tools for plastic bio-recycling within the framework of plastic waste management in Europe. Available biotechnology tools can support polyethylene terephthalate (PET) recycling. However, PET represents only ≈7% of unrecycled plastic waste. Polyurethanes, the principal unrecycled waste fraction, together with other thermosets and more recalcitrant thermoplastics (e.g., polyolefins) are the next plausible target for enzyme-based depolymerization, even if this process is currently effective only on ideal polyester-based polymers. To extend the contribution of biotechnology to plastic circularity, optimization of collection and sorting systems should be considered to feed chemoenzymatic technologies for the treatment of more recalcitrant and mixed polymers. In addition, new bio-based technologies with a lower environmental impact in comparison with the present approaches should be developed to depolymerize (available or new) plastic materials, that should be designed for the required durability and for being susceptible to the action of enzymes.

Can tourism support resource circularity in small islands? On-field analysis and intervention proposals in Madagascar.

Open dumping and burning of solid waste are common practices in low-income countries. On small and touristic islands, the problem is exacerbated due to the additional volume of waste amount generated by tourists. This article presents how, using Nosy Be island in Madagascar as a case study, waste recovery and recycling can be fostered by tourism to tackle the waste challenge. About 95% of the waste of Nosy Be is openly dumped, discarded to sea or openly burned. Field analysis, interviews with local stakeholders and waste flow analysis served as methodological tools to assess the current solid waste management (SWM) system of Nosy Be. Stakeholder mapping and involvement as well as first exchange among local and international actors provided the basis to identify key practice and opportunities. Research findings highlight the importance of active participation and involvement of local partners supported by international experts, to suggest how touristic centres can serve as core of circular approaches. The article presents potential circular models to be implemented in Nosy Be, taking tourism as the entry point including the aspects of financial support, separated waste flows and the interest in 'green tourism marketing'. This case study underlines how international cooperation, touristic activities and common efforts can potentially help low-income communities improve their SWM practices.

Organic waste valorization in remote islands: Analysis of economic and environmental benefits of onsite treatment options.

Solid waste management (SWM) represents an important issue for small islands. This research evaluates the municipal SWM system of the Pelagian archipelago, in Italy. The research aims to evaluate environmental and econoemic benefits of onsite treatment plants for the valorization of the organic fraction of municipal solid waste. The sizing of the anaerobic digestion (AD) and composting plant was developed, and the characteristics of the plant were used to conduct a cost analysis and an environmental life cycle assessment. The current waste management system (S0) has been compared with the new strategy proposed (S1). Results showed that S1 leads to save more than 250,000 € y-1 due to the avoidance of organic waste final disposal and shipping, determining a payback time of about 7 years. Environmental benefits include a lowering of CO2-eq emission of more than 1100 tonnes per year and a reduction of all the six environmental impacts analysed. The outcomes represent a novel contribution to the scientific literature since the research provides the first comparison of quantitative data about environmental and cost benefits of onsite AD plants in small islands. The research underlines that onsite waste treatment systems are viable options to improve SWM systems in isolated regions.

Environmental assessment of construction and demolition waste recycling in Bolivia: Focus on transportation distances and selective collection rates.

Construction and demolition waste (CDW) management in developing countries is a global concern. The analysis of scenarios and the implementation of life cycle assessment (LCA) support decision-makers in introducing integrated CDW management systems. This paper introduces the application of an LCA in La Paz (Bolivia), where CDW is mainly dumped in open areas. The aim of the research is to evaluate the benefits of inert CDW recycling in function of the selective collection rate, defined as the amount of waste (%wt.) sorted at the source in relation to the total waste amount produced, and the distances from the CDW generation to the material recycling facility. The outcomes of the research suggest that increasing the selective collection rates (5% to 99%) spread the importance of transportation distances planning since it affects the magnitude of the environmental impacts (1.05 tCO2-eq to 20.7 tCO2-eq per km traveled). Transportation limits have been found to be lower than about 40 km in order to make recycling beneficial for all environmental impacts and for all selective collection rate, with the eutrophication potential as the limiting indicator. The theoretical analysis suggests implementing LCA with primary data and involving statistics related to the transportation of virgin materials avoided thanks to recycling. The outcomes of the research support the implementation of CDW recycling in developing countries since it has been found that material recovery is always beneficial.

Formal and informal waste selective collection in developing megacities: Analysis of residents' involvement in Bolivia.

The implementation of waste selective collection (SC) schemes in low-income countries is a challenge although it is one important way for improving environmental sustainability. The inclusion of the population is necessary for gaining effective results, and social surveys are support methods for understanding citizens' involvement and behaviour. The aim of the research is to assess the support of the citizens concerning the formal and informal recycling in a low-middle income country. The study presents a questionnaire survey conducted in 2018 in La Paz, Bolivia, where 774 citizens were interviewed for evaluating their support to the formal and informal SC systems. Two questionnaires were submitted to two different users' categories: users of the formal recyclable waste gathering points; and citizens of the neighbourhoods. Evidence of the survey shows that about 8% of the population supports the formal SC while about 48% are used to selecting their waste at home. About 79.2% of them bring the waste to the informal recycling shops or provide it to waste pickers, throwing the waste into or nearby the mixed containers in order to facilitate their collection. This research demonstrates how social inclusion is important for planning recycling systems within a developing big city, starting from the SC. Results suggest that the informal sector can be an effective means for improving the recycling behaviour of the citizens. The study can be of interest to stakeholders involved in introducing recycling policies in developing cities where the SC rate is still low, and informal waste collection exists.

Application of a life cycle assessment for assessing municipal solid waste management systems in Bolivia in an international cooperative framework.

Using a life cycle assessment (LCA) to evaluate municipal solid waste management (MSWM) systems is strongly recommended and the approach has been used in high-income contexts. However, stakeholders in low to middle income countries are not aware of the potential of this approach, mainly due to a lack of financial resources and technical ability. The present work introduces a LCA of MSWM system scenarios into a developing city using an academic licence for the LCA software that is available for use exclusively by researchers. The MSWM system in place in 2018 in La Paz (Bolivia) was assessed according to seven scenarios. The novelty of the research is twofold: the use of LCA academic licensing in a low to middle income region where LCA is unknown as planning tool; and discussing the potential of the approach in conjunction with local and international stakeholders with a view to starting MSWM projects. The results of the analysis allow for the consideration of energy recovery and materials recycling as the main methods by which the environmental impact of MSW can be reduced, as has also been reported by other LCA studies conducted with full licensing of the relevant software. Moreover, the research is the basis for cooperative development projects that will adopt the LCA approach as the main assessment tool. The study discusses the importance of cooperation between universities and local governments for implementing new strategies for MSWM assessment and planning. The research is a contribution towards improving technical knowledge in developing countries for boosting sustainable development.

Application of healthcare waste indicators for assessing infectious waste management in Bolivia.

In the developing world, healthcare waste management is a human health and environmental burden that should be solved for improving sustainability. Solutions should be introduced in the short term, concerning management, planning, financial assistance and expertise. The paper introduces an indicator set for assessing healthcare waste management in developing cities, implemented in La Paz (Bolivia) as a case study. The objective is to suggest an integrated management tool as a first assessment technique to identify the prevailing problems with a healthcare waste management system. Results suggest that, in La Paz, the application of such indicators is useful for evaluating which priorities should be addressed for improving the healthcare waste management system. The tool was applied for introducing a study necessary for the application of new management plans, especially concerning healthcare waste treatment. The method can be replicated in other contexts worldwide, with a focus on the developing world, for comparing cities, management solutions and improvements carried out along the years. The approach is of interest for boosting sustainability and human health, improving the awareness of the actors and policy-makers involved in waste management.

Introduction of the circular economy within developing regions: A comparative analysis of advantages and opportunities for waste valorization.

The introduction of effective solid waste management strategies in developing countries should be considered for improving sustainability at global level. Many barriers should be overcome, concerning the introduction of environmental policies, effective investments, social inclusion and public awareness, which are significant issues in low-middle income countries. The Circular Economy could represent the answer for improving current solid waste management activities worldwide, since denote the principle of waste valorization and recycling for boosting developing economies. This paper is focused on this theme, analyzing main opportunities for improving the current state of solid waste management in developing big cities. The solid waste management of two countries are reviewed: Romania is the emerging country where Circular Economy is becoming a future objective due to economic aids and strength regulations which the European Union (EU) established for the nations forming parts the alliance; as a comparison, Bolivia is reported for evaluating main differences founded for developing recycling systems in a no-EU country. These two case studies could be of interest for highlighting main pros and cons of the participation into a wide organization like the EU for introducing in short terms Circular Economy principles. Moreover, a theoretical Circular Economy model for developing big cities in low-middle income countries is described within the study for effectively comparing which chances can spread for these countries as regard municipal solid waste exploitation. Despite the economic level, Romania and Bolivia are both facing with many solid waste management issues although in different magnitude. For the Romanian case study, it is visible how it cannot achieve the European goals for 2020 due the need of change in public recycling behavior. Bolivia, instead, represents the case where international aids and new investments are required, considering the informal sector into the formal management system as a real opportunity for improving local recycling rate. In conclusion, the comparison suggests how external supports led to implement the principles of the Circular Economy within a developing region. The model of Circular Economy proposed is recommended for developing big cities in order to advance a new form of safe employment, encouraging the activities that are still in action (i.e. informal sector) and boosting the principles of sustainable development.

Vermicomposting process for treating animal slurry in Latin American rural areas.

The management of animal slurry is a big issue in low-income rural areas worldwide. Bolivia suffers this issue related to collection, treatment and final disposal since the main solution applied is the open dumping. The aim of this study is to introduce a feasible treatment of animal slurry in the rural area of Carmen Pampa, where about 670 kg of dung are produced per day and disposed of in open areas. The objective is the improvement of the environmental sustainability and human health, providing an alternative solution for encouraging the circular economy. The study is focused on the vermicomposting process, a sustainable solution for low-income regions. The analysis was conducted in function of the earthworm breeds used locally ( Eisenia fetida and Lumbricus terrestris) and the application of activated bacteria (AB) for improving the process. The mass loss, the treatment time, and the growing rate of the earthworms were analyzed. The results suggest that the different breed of the worms allows gaining up to 19 days, while the use of the AB allows saving about 30 days. Moreover, the vermicomposting process reduced the mass of the slurry of about 65% for the swine's dung and the bovine's dung, and 90% of the hens' dung. Finally, experimental evidence shows that the growing rate of the E. fetida is higher than the L. terrestris (F[1,8] = 78, p < 0.05), with an average of about 193%. The data obtained could be of interest for other stakeholders who live in similar environmental, climatic, and economic conditions for improving sustainability.

The municipal solid waste management of La Paz (Bolivia): Challenges and opportunities for a sustainable development.

Municipal solid waste management (MSWM) is considered an important public health, economic and environmental concern, especially in developing countries. This paper introduces the situation of MSWM in La Paz (Bolivia) in 2016, and is based on the Wasteaware indicators and waste flow analysis, useful tools for classifying and comparing waste treatment and management plans among other countries. Taking into account the lack of technology in waste treatment and the presence of a developed informal sector, the paper analyses the main strengths and weak points for implementing a sustainable MSWM. The research conducted revealed that the MSWM of La Paz is not efficient with regard to collection, recycling (8%), financial sustainability, and equity of the service. At the same time, local Government and stakeholders are interested in implementing new MSWM methods for improving the current sanitary state of the city and many efforts were made over the last ten years. In general terms, La Paz could be considered as a good study area for developing plans for waste valorization, becoming an example for a low-middle income developing big city of Latin America. The study provided a few considerations about the affordability of the methodology applied and critically analyzed the case study proposed.

Air pollution control through biotrickling filters: a review considering operational aspects and expected performance.

The biological removal of pollutants, especially through biotrickling filters (BTFs), has recently become attractive for the low investment and operational costs and the low secondary pollution. This paper is intended to investigate the state of the art on BTF applications. After an overview on the biodegradation process and the typical parameters involved, this paper presents the analysis of a group of 16 literature studies chosen as the references for this sector. The reference studies differ from one another by the pollutants treated (volatile organic compounds [VOC], hydrogen sulphide, nitrogen oxides and trimethylamine), the geometry and size of the BTFs, and the procedures of the tests. The reference studies are analyzed and discussed in terms of the operational conditions and the results obtained, especially with respect to the removal efficiencies (REs) and the elimination capacities (ECs) of the pollutants considered. Empty bed residence time (EBRT), pollutant loading rate, temperature, pH, oxygen availability, trickling liquid flow rate, inoculum selection and biomass control strategies revealed to be the most important operational factors influencing the removal performance of a BTF.

State of the art and advances in the impact assessment of dioxins and dioxin-like compounds.

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are toxic and persistent organic pollutants that are able to enter the food chain, accumulate in the fat tissues of animals, and consequently pose a serious risk for human health. Consolidated tools for exposure assessment have been implemented during the last decades and widely used, both in the environmental monitoring and in modeling activities. Although the emissive trend and the concentrations in the environment have gradually decreased during the last 20 years, some situations are still underrated and not adequately controlled by the environmental legislation. On the other hand, a complete monitoring of all the pathways of exposure to PCDD/Fs and PCBs is technically and economically unfeasible. Therefore, this paper aims at providing an overview of the traditional approaches used to assess the impacts of PCDD/Fs and PCBs and presenting the novelties introduced during the last years. After an initial characterization of their toxicity and their effects on health, this paper focuses on activities and situations that can result in critical releases of PCDD/Fs and PCBs into the atmosphere and that can represent a hidden threat for the population. In the final part, this study presents the current methodologies for exposure assessment, summarizes the food chain models in a unified way, and puts the light on new methods that can help environmental scientists, risk assessors, and decision makers to estimate the risk related to exposure to PCDD/Fs in different contexts.

Influence of feeding mixture composition in batch anaerobic co-digestion of stabilized municipal sludge and waste from dairy farms.

Waste anaerobic co-digestion applications are particularly useful in Southern Mediterranean areas where large quantities of agricultural waste materials and waste from agro-industries are produced. This waste can be added to urban waste together with the sludge produced by wastewater treatment processes, which, when combined, guarantee the supply of organic matrixes for treatment throughout the year. The implementation of facilities to service vast areas of the agricultural economy and which are heterogeneous in terms of production can provide a good solution. We present an experimental investigation into the anaerobic co-digestion of municipal sludge and bio-waste produced in the Mediterranean area. We conducted anaerobic treatability tests, with measures of biogas production and pH of the mixture in digestion. Our main aims were to identify an optimal mix of substrates for the production of biogas, and to analyse the influence on the composition of biogas and the variation in pH values of the substrates. This analysis was conducted considering the variation of the input, in particular due to the addition of waste acids, such as biological sewage sludge.

Automotive shredder residue: a survey of the hazardous organic micro-pollutants spectrum in landfill biogas.

In this study, we report an extensive set of analytical results on the quality of the biogas produced by a landfill of automotive shredder residues. In particular, the investigation was directed towards the identification of a spectrum of polycyclic aromatic hydrocarbons (16 compounds) and a wide range of volatile organic compounds (35 compounds). This article highlights the most important indications of toxicological concern for the detected compounds. Among the polycyclic aromatic hydrocarbons, chrysene shows the highest concentration, followed by pyrene and benzo(b)fluoranthene. Dibenz(a,h)anthracene, the most carcinogenic of the tested compounds, displayed results below the limit of analytical detectability. Benzo(a)pyrene, another typical carcinogenic compound, was detected at low concentrations. With regard to volatile organic compounds, the survey revealed a relevant concentration of toluene (found in fuels and paint thinner) significantly higher than the other compounds. Noticeable amounts of hexane, trichloromethane, and acetone were also found.

Comparative application of different risk assessment models and implications on resulting remediation options.

The issue of contaminated soils and their productive recovery is a quite controversial environmental and economic problem with important consequences for its social, public health and sustainability aspects. The sheer number and characteristics of the polluted sites are so large and varied, and the definition of priorities related to their remediation interventions so site-dependent, that proper characterization and final environmental quality goals reflect a strategic importance. One of the possible approaches to site specific approach and site priority ranking can be that of carrying out, respectively, absolute and comparative analysis procedures. An important aspect to be solved is represented by the necessity to consider not only the potential risk to public health, but also the best possible financial return from the investments for remediation, especially when carried out with public money. In this paper, different contaminated sites' risk assessment approaches are considered, compared and their applicability to support sustainable policies discussed using a case study.

Calculating specific denitrification rates in pre-denitrification by assessing the influence of dissolved oxygen, sludge loading and mixed-liquor recycle.

This article presents the results of an experimental study on the correlation among the specific denitrification rate (SDNR), the dissolved oxygen concentration (DO), the F:M ratio (F:M) and the mixed-liquor (ML) recycle in the pre-denitrification reactors fed by domestic sewage. The experimental curves reveal a 28.8-32.0% reduction in the SDNR at 20 degrees C (SDNR(20 degrees C)) with DO equal to 0.1 mgO2 L(-1) and F:M in the range 0.2-0.4 kgBOD5 kgMLVSS(-1) d(-1). The SDNR reduction increases to 50.0-55.9% with DO = 0.3 mgO2 L(-1). A mathematical correlation of these results and an equation for calculating SDNR(20 degrees C) as function of the F:M as well as the average DO and BOD5 in the total flow rate fed in the denitrification stage are proposed. The conducted experience gives useful suggestions for practical usage, in particular regarding the denitrification reactor design, and represents a good starting point for future applications with the aim to optimize the biological process in domestic sewage treatment plants.

Treatment of slaughterhouse wastewaters using anaerobic filters.

In this paper, a laboratory-scale experimentation allowed comparing the performances of two upflow anaerobic packed-bed filters filled with different packing materials and operating at mesophilic conditions (30 degreeC) for treating slaughterhouse wastewaters. Methane production was experimentally evaluated considering different volumetric organic loading rates as well as feeding overloading conditions. Although filter performances declined with loading rates higher than 6 kg CODin m-3 d-1 , the chemical oxygen demand (COD) removal efficiency remained always above 60%. The experimental results allowed for determining kinetic parameters for bacterial growth rate and methane production, following Monod and Chen-Hashimoto models, respectively. Results demonstrated that the reactors reached a cellular retention time significantly greater than the hydraulic retention time. The kinetic parameter values (Ks, l/max) revealed the low microorganisms' affinity for the substrate and confirmed the moderate biodegradability of slaughterhouse wastewater. The kinetic analysis also allowed the comparison of the filters performances with another anaerobic system and the assessment of the parameters useful for real-scale plant design. The system design, applied to a medium-sized Argentinean slaughterhouse, demonstrated to (i) be energetically self-sufficient and (ii) contribute to the plant's water heating requirements.

When solid recovered fuel (SRF) production and consumption maximize environmental benefits? A life cycle assessment.

Solid recovered fuel (SRF) from non-recyclable waste obtained from source separation and mechanical treatments can replace carbon coke in cement plants, contributing to the carbon neutrality. A life cycle assessment (LCA) of the SRF production from non-recyclable and selected waste was conducted in an Italian mechanical treatment plant to estimate the potential environmental impacts per ton of SRF produced. The analysis would contribute to evaluate the benefits that can be obtained due to coke substitution in best- and worst-case scenarios. The avoided impacts achieved were assessed, together with an evaluation of the variables that can affect the environmental benefits: SRF biogenic carbon content (in percentage of paper and cardboard); transportation distances travelled from the treatment plant to the cement kiln; the renewable energy used in the mechanical facility. On average, about 35.6 kgCO2-eq are generated by the SRF transportation and production phase. These impacts are greatly compensated by coke substitution, obtaining a net value of about -1.1 tCO2-eq avoided per ton of SRF. On balance, the global warming potential due to SRF production and consumption ranges from about -542 kgCO2-eq to about -1729 kgCO2-eq. The research recommended the use of SRF to substitute coke in cement kilns also in low densely-populated areas to mitigate environmental impacts and achieve carbon neutrality at a global level.

Environmental impact scenarios of organic fraction municipal solid waste treatment with Black Soldier Fly larvae based on a life cycle assessment.

Biowaste treatment with Black Soldier Fly (BSF) larvae is an alternative option for organic waste valorization. Its environmental impacts should be assessed and compared with conventional treatment options. The research aims to evaluate the treatment of organic fraction of municipal solid waste (OFMSW) with BSF larvae through a life cycle assessment (LCA). This study employed data inventories from literature and aimed to provide a wide range of production parameter values to identify the potentialities of BSF treatment in the best-case and worst-case scenarios. The SimaPro9, the database Ecoinvent3.5, and the impact assessment method IMPACT 2002+ have been employed for the analysis. A sensitivity analysis of relevant parameters was conducted, considering the avoided impacts that can be obtained thanks to the exploitation of larvae proteins for bioplastics or fishmeal production. Research findings highlight six main environmental impact indicators: respiratory inorganics (kg PM2.5-eq), ozone layer depletion (kg CFC-11-eq), terrestrial ecotoxicity (kg TEG soil), land occupation (m2 organic arable), global warming (kg CO2-eq), and non-renewable energy (MJ primary). The most relevant process generating impacts is BSF breeding, followed by boiling, storage, and OFMSW treatment. The environmental performance is better when the conventional fishmeal substituted, thanks to BSF larvae production, is made from areas 10,000 km far, implementing a 100% renewable energy scenario, reducing the energy consumption by 50%, increasing the lifespan of the equipment to 15 years, and products are employed locally. The current study represents the first attempt to evaluate the global higher or lower environmental impact scenario related to OFMSW treatment through BSF larvae.