Assessment strategies for municipal selective waste collection schemes

Assessment of cross-media effects deriving from the application of lower emission standards for acid pollutants in waste-to-energy plants

The recent release of the new European Commission reference document on the Best Available Techniques (BAT) for waste incineration has set ambitious targets for the control of the emission of pollutants. However, an improved performance of the existing flue gas treatment systems in waste-to-energy (WtE) facilities is usually associated to an increase of cross-media effects, i.e., additional indirect environmental impacts related to the increased consumption of reactants and to the increased generation of process residues/wastewater in flue gas treatment. The present study introduces an innovative approach to assess cross-media effects deriving from more stringent acid gas emission standards in the WtE sector. By coupling simplified process modelling and life cycle analysis, the proposed methodology links the higher removal efficiency required for flue gas treatment to the impacts related to the reactants supply and waste disposal chain. An application to the Italian WtE sector exemplifies the potential of the method. The results evidence that, in case of HCl emission setpoints lower than 1 mg/Nm³, the reduction of acidifying emissions at the WtE stacks can be offset by the increase of global warming and smog formation impacts in the supply chain of flue gas cleaning reactants. In case of setpoints lower than 0.5 mg/Nm³, even within the acidification category the increase of indirect impacts more than compensates the decrease of WtE emissions. The net environmental benefit is strongly affected by the type of acid gas removal technology adopted, with dry systems typically associated with a larger increase of cross-media burdens when required to perform at higher removal efficiencies.

Review of biological risks associated with the collection of municipal wastes

In many countries, the management of household waste has recently changed with an increased focus upon waste sorting resulting in lower collection frequency for some waste fractions. A consequence of this is the potential for increased growth of microorganisms in the waste before collection, which can lead to an increased exposure via inhalation for waste collection workers. Through a review of the literature, we aimed to evaluate risks caused by waste collecting workers' exposure to bioaerosols and to illuminate potential measures to reduce the exposure. Across countries and waste types, median exposure to fungi, bacteria, and endotoxin were typically around 10⁴ colony forming units (cfu)/m³, 10⁴ cfu/m³, and 10 EU/m³, respectively. However, some studies found 10-20+ times higher or lower median exposure levels. It was not clear how different types of waste influence the occupational exposure levels. Factors such as high loading, ventilation in and cleaning of drivers' cabs, increased collection frequency, waste in sealed sacks, and use of hand sanitizer reduce exposure. Incidences of gastrointestinal problems, irritation of the eye and skin and symptoms of organic dust toxic syndrome have been reported in workers engaged in waste collection. Several studies reported a correlation between bioaerosol exposure level and reduced lung function as either a short or a long term effect; exposure to fungi and endotoxin is often associated with an inflammatory response in exposed workers. However, a better understanding of the effect of specific microbial species on health outcomes is needed to proceed to more reliable risk assessments. Due to the increasing recycling effort and to the effects of global warming, exposure to biological agents in this working sector is expected to increase. Therefore, it is important to look ahead and plan future measures as well as improve methods to prevent long and short-term health effects.

Waste pickers organizations and municipal selective waste collection: Sustainability indicators

Brazilian municipalities face several difficulties while carrying out the municipal selective waste collection (MSWC); at the same time, waste pickers organizations (WPOs) need to overcome many challenges to compete in the waste management market. In order to reach the requirements of the Brazilian National Solid Waste Policy (NSWP), it is necessary to know which factors interfere in the performance of MSWC programs and WPOs to understand the relationships between these factors. The objective of this paper was to evaluate the sustainability of MSWC programs and WPOs in the State of Espírito Santo, Brazil, and propose a new methodological strategy. For data collection, questionnaires were given to municipal civil workers from 24 municipalities and managers of 23 WPOs to calculate sustainability indicators and their correlations. Means and frequencies were calculated to analyze indicators in relation to sustainability; peer-to-peer correlation analyses were performed to the construct graphs that obtained correlation coefficients, which were applied to study the normality distribution. For each indicator, we provided necessary investments to practical solutions. As a result, a methodological proposal was presented to improve their actions, which was hierarchized by degrees of temporal urgency for their implementation. The design of the actions has great potential to improve and develop sustainability practices in WPOs and MSWC programs. Due to the low quality of primary data collected, we recommend the creation of the data control systems to continuously monitor.

A stochastic frontier analysis of the efficiency of municipal solid waste collection services in China

Governments in many developing countries, such as China, are investing a lot of human, financial and material resources to ensure that as much of municipal solid waste (MSW) as possible is collected for centralized harmless treatment and disposal. This is regarded as an effective way to alleviate the "waste siege" problem in governance caused by the continuous enormous increase in MSW quantity. Therefore, how to improve the efficiency of MSW collection service system is an important governance issue because the inputs that can be utilized to manage MSW problem are limited due to budget and resource constraints. However, studies on MSW collection efficiency in developing countries like China are under-represented in the existing literature. This paper applies a stochastic frontier analysis (SFA) approach to evaluate the efficiency of MSW collection services in 30 provinces of China from 2008 to 2017, and explore the relative importance of several factors that might influence collection efficiency. The results indicate that there exists considerable room (62.8%) to enhance efficiency since its current efficiency value is merely 0.372. With regard to influencing factors, the proportion of population aged 15-64 appears to have the greatest positive impact on efficiency, along with per capita GDP, added value of tertiary industry and education level. This paper also explores spatial variations of MSW collection efficiency across the eastern, central and western regions. These findings have policy implications and can inform the related government departments how to formulate proper policies to improve collection efficiency.

Looking beyond the banning of lightweight bags: analysing the role of plastic (and fuel) impacts in waste collection at a Portuguese city

The purpose of this work is to assess the environmental impacts of the collection of mixed municipal solid waste (MSW) in a selected neighbourhood of the Portuguese city of Aveiro. To this purpose, the main elements necessary for the collection process (carrier bags, dustbins, street containers and vehicles) were analysed applying the life cycle assessment methodology, making use of locally gathered data. The main impacts associated with this activity are mostly related to the use of polyethylene plastic bags to carry the waste from the household to the waste container, and to the fuel consumption of collection vehicle that picks MSW from street containers and transports it to the treatment facility. The impacts associated with the plastic bags were primarily due to their disposal in a sanitary landfill after use and secondarily to the consumption of fossil raw materials required for their production. Given the relative high impact of the plastic bags, alternative scenarios were tested: using bags entirely produced with recycled polyethylene and bags produced with bio-based plastics derived from starch (TPS) and from wastewater (PHA). PHA bio-based bags were found to perform slightly better than conventional high-density polyethylene (HDPE) bags, but HDPE bags with 100% recycled content remained as the environmentally best option. A sensitivity analysis was performed to check the influence of bag size. Regarding the fuel consumption by collection vehicles, a comparison was performed to check how site-specific conditions can influence the impact of this activity, resulting in remarkably higher consumptions when local data were used instead of reference databases.

Are municipal waste utilities becoming sustainable? A framework to assess and communicate progress

A framework of indicators to assess the progress towards sustainability of municipal waste management utilities is developed. Its purpose is to fulfil the need for assessing the performance of municipal waste (MW) management in a simple but comprehensive way-unlike indicators based on individual aspects such as recycling-and including aspects not well considered before, such as waste prevention. The framework is composed of a set of six single indicators, concerning the three dimensions of sustainability: reduction of effectively landfilled MW and reduction of MW generation (environmental component), balance between expenses and revenues and reduction of costs (economic component), accessibility to separate collection and number of complaints (social component). Each indicator consists of an evaluation of the current status of the variable in contrast to a previous situation, with a positive value in case of improvement or negative in case of decline. Then, the values of the individual indicators are combined to obtain a global result. This approach focuses on dynamic progress towards sustainability, complementing the common static indicators. Contrarily to the existing performance indicator schemes, the proposed framework aims at measuring the progress and not the absolute or relative achievement of a waste management utility. The framework was tested on two Portuguese municipalities, proving to be a straightforward application and reliable in guiding stakeholders. Results for the case study showed good performance on economic sustainability, while environmental and social performance were lower due to a lack of strategies for waste prevention and low source separation, affected by poor accessibility to separate collection.

A standardized inspection methodology to evaluate municipal solid waste collection performance

The success of separate collection of municipal solid waste, the efficiency of the other connected services and the justification of a large cost assumed by an authority, depends on the level of service provided to customers as well as the citizens' attitude towards waste management. In this paper, a semi-qualitative inspection method to evaluate both the door-to-door collection system and the conventional curbside system is proposed. The method is based on the combined evaluation of waste collection using a set of indicators and the assessment of the perception of the citizens towards collection and street cleaning services using behavioural questionnaires. The ultimate goal was to assess potential differences between door-to-door and curbside collection systems. The standardized inspection evaluation method was applied to the city of Reggio, Calabria (Italy), since both collection systems are used there. The standardized inspection evaluation proved to be simple to implement and was effective to accurately evaluate the quality of the service delivered to the citizens. The results of the behavioural survey revealed that citizens that practised door-to-door separation had a higher recycling conscience and were more satisfied with the city waste management system than the ones that practised curbside separation. According to the results of the study, there was a qualitative agreement between the results of the standardized inspection evaluation and the behavioural survey. The door to door collection system is suggested to replace the curbside collection system.

Data on urban waste collection: The case of the Apulia region in Italy

The collection of urban waste is an important step of the waste management cycle, because the collection of sorted waste that soon separates different kind of materials makes their reusing, recovering, and recycling easier and more efficient, reducing the amount of landfilled waste. In Italy, municipalities have to meet specific targets relative to the yearly percentage of sorted waste collection. Collecting and analyzing data about waste collection and the proportion of sorted waste and the specific type of waste materials is a critical activity to measure the performance and monitor the effort of the municipalities to meet targets. Raw data relative to the yearly amounts of total and sorted waste collected from 2007 to 2017, and data relative to socio-economics in 258 municipalities of the Apulia region were retrieved from public databases and were used to calculate waste statistical indicators. Data about total and sorted waste collection in Italy at the regional and country level were retrieved and analysed to compare the Apulia region and specific groups of regions. The evolution of the per capita total and sorted waste amounts was also analysed over time for Apulia and the rest of Italy. The effects of the municipality surface area, the number of inhabitants and population density on the sorted waste collection rate were investigated by performing regression analysis. These data may help policy makers and stakeholders to evaluate total and sorted waste production over time, set and assess targets, and identify best policy practices.

Benchmarking operational efficiency in waste collection: Discussion of current approaches and possible alternatives

Efficiency assessment and benchmarking are crucial for managing any organization. However, especially from a regulatory perspective, such efficiency assessment and benchmarking must be unbiased from context-specific issues and should provide an absolute rating, rather than a relative one. The current work reviews the approaches used for performance assessment and benchmarking waste collection services, revealing that the majority are biased and are not absolute, and proposes two alternative context-unbiased and absolute performance indicators, the collection capacity use (CCU) and the segregated waste collection efficiency (SWE). The proposed indicators were calculated for 246 utilities operating in Portugal. The utilities were then ranked accordingly, and their position was compared with the position attained using the equivalent performance indicators in the system currently in use by the Portuguese service regulator. The results reveal ranking differences of over 50 positions and illustrate how misleading the results from context-biased and relative metrics can be.

Multi-stage optimization approach for sustainable municipal solid waste collection systems in urban areas of Asia's newly industrialized countries

A multi-stage optimization approach for sustainable collection system design for urban municipal solid waste is developed for megacities in Asia's newly industrialized countries. The approach combines four methods-analysis of waste and area characteristics, data acquisition and evaluation by GIS, mathematical projection of existing and future collection systems, and identification of most suitable alternatives through comparative multi-criteria decision analysis (MCDA). The approach is applied in Bangalore, India with 1.66 million inhabitants and 46.7-km² area of investigation, and stratified based on population density. Two possible collection mechanisms (door-to-door (D2D) and community bin (CB)) are analyzed with a varied combination of collection coverage and waste segregation level. The study results confirm that both operational and investment expenses of the collection system decrease with an increasing rate of CB collection. Moreover, overall CO₂ emissions of waste collection from the entire area of investigation decrease from 5.2 to 3.1 tons per day if the present 100% D2D collection is replaced with 100% CB collection system. Also, the increase of segregation at source contributes to the reduction of operational expenses and CO₂ emissions; for example, a 20% increase of segregation level for D2D collection system leads to a 6% reduction of CO₂ emissions. Considering all decision parameters through MCDA, a collection system comprising only CB with one separate compartment for wet waste and another combined compartment for dry and mixed waste is determined to be the most favorable approach.

Increasing the quantity of separated post-consumer plastics for reducing combustible household waste: The case of rigid plastics in Flanders

In Flanders, Belgium, rigid and soft plastics represent an interesting fraction of residual household waste as a potential 80 000 Gg a^-1 can be recycled instead of incinerated. Removing a large amount of rigid packaging and non-packaging plastics from the residual household waste fraction could contribute to the goal to reduce the amount of residual household waste to less than 150 kg capita^-1 a^-1 for the Flemish region, where currently only 20% of plastics are collected selectively in drop-off facilities. Given the wide range of plastic separation schemes across the region, it is the aim of this paper to identify whether the applied separation options have an impact on the quantity of separated plastics, and, moreover, which scheme is able to separate most plastics. Cross-sectional data for the period 2008-2012 were collected for all 308 Flemish municipalities to conduct a regression analysis. The results of the analysis show that the quantity of separated plastics differs significantly between the different separation schemes used. If municipalities change their separation schemes, Flanders as a whole would be able to collect more plastic waste to better comply with its own objectives and EU regulation on recycling. Improved separation-at-source recycling initiatives, by applying the appropriate separation scheme for plastics, may increase recycling growth.

Benefits, challenges and critical factors of success for Zero Waste: A systematic literature review

Considering the growing concern with solid wastes problems and the pressing need for a holistic approach to their management, this study developed a literature review about the subject "Zero Waste". To that end, a systematic literature review was executed, through which 102 published articles were analyzed with the aim to, initially, comprehend the concept of Zero Waste, and, then, map its benefits, challenges, and critical success factors. The results show that scholars have not reached a consensus regarding the concept of ZW. While some studies fully address this philosophy, other studies are based on just one or on some of its topics. The benefits were grouped and organized into four dimensions: benefits to the community, financial-economic benefits, benefits to the environment and benefits to the industry and stakeholders. As to the challenges, barriers were identified both in the macro environment (mainly political and cultural) and in the meso and micro environments (stakeholders, industries, and municipalities). The analysis of the articles enabled listing critical success factors, supported by a set of activities that must be carried out. Regarding future studies, it is worth noting that more empirical studies about ZW implementation are necessary, particularly with regard to educational practices designed to promote changes in user behavior.

A case study of packaging waste collection systems in Portugal - Part I: Performance and operation analysis

The need to increase packaging recycling rates has led to the study and analysis of recycling schemes from various perspectives, including technical, economic, social, and environmental. This paper is part one of a three-part study devoted to comparing two recyclable packaging waste collection systems operating in western Portugal: a mixed collection system, where curbside and drop-off collections are operated simultaneously (but where the curbside system was introduced after the drop-off system), and an exclusive drop-off system. This part of the study focuses on analyzing the operation and performance of the two waste collection systems. The mixed collection system is shown to yield higher material separation rates, higher recycling rates, and lower contamination rates compared with the exclusive drop-off system, a result of the curbside component in the former system. However, the operational efficiency of the curbside collection in the mixed system is lower than the drop-off collection in the mixed system and the exclusive drop-off system, mainly because of inefficiency of collection. A key recommendation is to ensure that the systems should be optimized in an attempt to improve performance. Optimization should be applied not only to logistical aspects but also to citizens' participation, which could be improved by conducting curbside collection awareness campaigns in the neighborhoods that have a mixed system.