Unsorted Waste Research Articles

The impact of an efficient collection sites location on the zoning phase in municipal solid waste management

In this paper, we study two decisional problems arising when planning the collection of solid waste, namely the location of collection sites (together with bin allocation) and the zoning of the service territory, and we assess the potential impact that an efficient location has on the subsequent zoning phase. We first propose both an exact and a heuristic approach to locate the unsorted waste collection bins in a residential town, and to decide the capacities and characteristics of the bins to be located at each collection site. A peculiar aspect we consider is that of taking into account the compatibility between the different types of bins when allocating them to collection areas. Moreover, we propose a fast and effective heuristic approach to identify homogeneous zones that can be served by a single collection vehicle. Computational results on data related to a real-life instance show that an efficient location is fundamental in achieving consistent monetary savings, as well as a reduced environmental impact. These reductions are the result of one vehicle less needed to perform the waste collection operations, and an overall traveled distance reduced by about 25% on the average.

It Wasn't Me! Visibility and Free Riding in Waste Sorting

Free riding problems can be more severe in multiple-person social dilemmas than in two-person dilemmas, since agents can hide their actions behind the veil of anonymity. In this paper, we use field data on waste sorting to study the effect of visibility in social dilemmas. We compare the sorting behavior of households sharing (or not) their bin for unsorted waste. Since households have to pay a fee proportional to their unsorted waste production, sharing the bin means sharing the fee. We find that, on average, household unsorted waste production is higher if three or more households share the same bin. Surprisingly, when only two households share the same bin, and therefore the household sorting behavior can be identified, unsorted waste production decreases compared to users not sharing the bin. Our interpretation is that shame and fear of punishment may play a role between the two sharing users.

The application of LCA to alternative methods for treating the organic fiber produced from autoclaving unsorted municipal solid waste: case study of Catalonia

Despite efforts to increase the selective collection of municipal solid waste (MSW) in developed countries, the amount of unsorted waste remains high, with the consequent difficulty of material recovery and recycling. In 2010, 61% of the MSW generated in the European Union (EU) ended up in landfill and incineration facilities. Autoclaving is a novel technology that can be used to treat unsorted MSW, producing organic fibers that can be composted. The life cycle analysis (LCA) was used to assess the effectiveness of autoclaving unsorted MSW and various alternative methods for treating organic fibers produced through this process. The alternative methods that were considered included composting in tunnels, composting in confined windrow and composting in turning windrow as well as anaerobic digestion. The environmental assessment results were compared to those associated with incineration and landfill. The results of this study showed that autoclaving with sorting, digesting anaerobically and composting had the lowest impact values for eutrophication and the global warming potential. It was also found that autoclaving is justified only if the products of the process, that is, polyethylene terephthalate, ferrous and non-ferrous metals, are recycled to avoid virgin material production and if the remaining mixed plastic wastes are incinerated for energy recovery.

Evaluating Unit-Based Pricing of Residential Solid Waste: A Panel Data Analysis

Municipalities introduced unit-based pricing (UBP) with the aim of achieving a decrease in household waste generation and for the replacement of unsorted waste with recycling. Although many studies have shown that UBP has a short-run effect on recycling, few works have tackled the long-run effect on waste generation and recycling. By using panel data for 665 Japanese cities over 8 years, we examine the long-run effect of UBP on waste generation and recycling. The estimation results in waste generation suggest that there is a rebound effect, though a small one. We confirm that the effect of UBP on recycling sustains for the long run. We also find that the short- and long-run responses to an economic incentive for recycling activities differ with income groups. Recycling among the high-income group has not been promoted by implementation of UBP, but people in that group are willing to participate in recycling without an economic incentive. In contrast, recycling activity within the low-income group is strongly motivated by UBP for many years.

Assessment of the applicability of the Pay As You Throw system into current waste management in Estonia

PurposeThis paper aims to assess the current waste management situation in Estonian municipalities and outlines the main constraints hindering the implementation of the Pay‐As‐You‐Throw (PAYT) system into the existing waste management model.Design/methodology/approachData pertaining to the treatment methods of municipal solid waste (MSW) and the ability to implement the PAYT system were gathered from 150 of the 226 local municipalities, whilst statistical data related to the amounts of MSW generated and separately collected at a municipal level were obtained from the Estonian Environmental Information Centre.FindingsThe results of the study showed that 39 per cent of the municipalities sort waste before landfilling. To increase the sorting ability of inhabitants, 43 per cent of those municipalities that responded to the questionnaire suggested enhancing awareness among people in regard to waste handling. It was found that people are not economically motivated to sort their waste due to the fact that differences in charges between separately collected and unsorted waste are negligible. It was estimated that implementing the PAYT system in one rural municipality would increase the cost of emptying containers by approximately 20‐45 per cent.Practical implicationsResults of the study can be used in countries with a comparable economic situation to improve their current economic and legislative context in the field of sustainable waste management.Originality/valueThe novelty is that the authors aimed to assess the possibility of implementation of the Pay‐As‐You‐Throw system in practice, using Estonian municipalities as a case area, including economic feasibility and willingness of stakeholders to apply the system.

We want to sort! Assessing households’ preferences for sorting waste

There are two major ways in which solid waste can be sorted and recycled – at the household level, when households are required to sort waste into a given number of categories, or in specialised sorting facilities. Traditionally, it has been thought that sorting at the household level is an inconvenience, as it uses space and requires time and effort. Our study provides empirical evidence to the contrary, indicating that home sorting is a net source of utility for some people. Through a carefully designed choice experiment we collected stated choices from members of a Polish municipality with respect to the way their waste is sorted and how often it is collected. In the hypothetical scenario employed, respondents were informed that waste will be sorted anyway – if not at the household level then at a specialised sorting facility. Interestingly, analysis shows that a large group of people are willing to sort waste at the household level even if unsorted waste would be collected at no extra cost. For a minority, increased home sorting of waste would, however, impose a loss of utility. Overall, our results indicate that most respondents preferred to sort waste themselves if given the choice. We provide a few possible explanations of this perhaps surprising result, including the desire to promote a green external image, and a concern about the effectiveness of separation activities performed by others.

Waste disposal sites as sources of mercury in the atmosphere in the coastal zone of the Gulf of Gdańsk (southern Baltic Sea)

Abstract Elemental mercury re-emission into the air from an old burial ground in Gdańsk Letnica and from a modern landfill in Gdańsk Szadółki resulted in noticeably increased TGM concentrations from the urban background level of 1.9 ng m−3 to a maximum value of 164.4 ng m−3. Hgtot concentrations in the soil of the burial ground ranged from 37.3 to 4817.3 ng g−1 and in the surrounding water: from 22.0 to 55.0 ng dm−3. The highest Hgtot concentrations in the modern landfill (Gdańsk Szadółki) were reported for the unsorted waste: 36.1–972.8 ng g−1. Laboratory experiments on the re-emission of Hg(0) into the air showed that emission from soil was stimulated by solar radiation and from the water — additionally by turbulent mixing.

Experimental Sorting of Municipal-Like Waste in the Hospital “Civico”, Palermo (IT)

An experiment of source sorting - based management of Health Care Waste (HCW) was carried out in 2011 in 4 Departments of the Public Hospital “Civico” (Palermo, IT), where the basic mandatory separation between hazardous and non-hazardous waste was already going on since year 2000.The experiment consisted in weighing every day for 15 days 4 predefined fractions collected in the Infirmaries (namely paper, plastics, glass and unsorted fraction), and the bags with unsorted waste from the patient’s stay room. Furthermore, in 1 of the 4 Departments also the boxes of Infectious Waste (IW) were weighed for a week.As a result a weighted average value of 0.56 kg of Municipal-like Waste (MLW) per bed and per day was obtained for the Infirmaries of the 4 Departments (1.89 kg for the whole Department). The potentially recoverable waste fractions of MLW were about 65.7 %, the balance being unsorted waste.The actual production of IW − monitored in just one of the Departments, OU 1− brought to a generation rate of 0.74 kg/bed-day with a range 0.50−1.00. This production represents the 54 % of total waste from that Infirmary but just 34 % of the overall waste stream from the Unit. This pilot experiment confirms the wide finding that IW are a minor part of the overall waste stream produced in a health care structure.

Capacitated location of collection sites in an urban waste management system

Urban waste management is becoming an increasingly complex task, absorbing a huge amount of resources, and having a major environmental impact. The design of a waste management system consists in various activities, and one of these is related to the location of waste collection sites. In this paper, we propose an integer programming model that helps decision makers in choosing the sites where to locate the unsorted waste collection bins in a residential town, as well as the capacities of the bins to be located at each collection site. This model helps in assessing tactical decisions through constraints that force each collection area to be capacitated enough to fit the expected waste to be directed to that area, while taking into account Quality of Service constraints from the citizens’ point of view. Moreover, we propose an effective constructive heuristic approach whose aim is to provide a good solution quality in an extremely reduced computational time. Computational results on data related to the city of Nardò, in the south of Italy, show that both exact and heuristic approaches provide consistently better solutions than that currently implemented, resulting in a lower number of activated collection sites, and a lower number of bins to be used.

Study on Dry-basis Separation Test for Urban Residential Waste

Abstract Since its implementation in 2000, China's urban domestic waste separation pilot program has achieved little success. The root cause lies in the lack of moisture control for crude waste from the source. If wet-basis waste is placed in bags, collected by waste bins/cans and transferred by vehicles, waste is difficult to be separated for collection, transport and disposal, and a large amount of materials lose the value of recycling. High moisture and rapid reproduction of microbes leads to serious pollution, collection and transfer of daily waste upon generation and soaring transport cost. Unsorted waste also greatly increases the difficulty in collection, transport and disposal. The study on dry-basis separation test helps achieve the separation and temporary storage of domestic waste through moisture control, facilitating the low-frequency placement, collection and transport of domestic waste. Based on the test, a new concept of low-frequency direct transport and separation of domestic waste on a dry basis is raised, and corresponding key technical equipment to be developed is specified.

Issues of Roadside Disposal Habit of Municipal Solid Waste, Environmental Impacts and Implementation of Sound Management Practices in Developing Country “Nigeria”

The municipal solid wastes in Nigeria contain all sources of unsorted wastes, such as commercial refuse, construction and demolition debris, garbage, electronic wastes etc, which are dumped indiscriminately on roadsides and any available open pits irrespective of the health implication on people. The aim is to emphasize various waste management options, which integrated waste management disclosed the hierarchy of waste management options, environmental impacts of those options where studied under health and social effects, and the legislation of Extended Producer Responsibility were suggested where by product take back by manufacturers, especially when remanufacturing and reuse is available to ensure sound management practice in developing country Nigeria.

Thermal waste treatment for sustainable energy

Waste disposal, energy production and pollution minimisation are key problems that must be addressed for sustainable cities of the future. In a world with finite resources witnessing a population explosion, much effort is being made to change the way in which developed societies consume energy and materials and dispose of waste. This paper reviews the current UK practices of segregation and treatment of municipal solid waste (MSW) with focus on advanced thermal treatment technologies. MSW is segregated either at source or at dedicated facilities across the country. The residues of waste segregation can be thermally treated for energy recovery. Direct incineration of unsorted waste is currently the main route practiced by the energy from waste (EfW) industry. Typical MSW incinerators can burn wastes with a wide range of calorific values without any waste pre-processing. However, these incineration systems have low energy efficiency and suffer from unfavourable public opinion. Consequently, gas clean-up technologies associated with waste incinerators have been developed further, especially for dioxin removal and fly ash treatment. The two main alternatives to incineration are gasification of pre-processed waste and production of solid recovered fuel (SRF) from mechanical and biological treatment (MBT). Both processes have potentially higher energy efficiencies than incineration and more flexibility in the use of primary products. Further technology developments with regulatory drivers are required to compete with incineration. Another route available for EfW is pyrolysis, producing cheap and storable fuel products. Pyrolysis is suitable only for specific types of waste material. Pyrolysis of waste wood can produce a good-quality char that can be readily burned in coal-fired power plants or other higher energy efficiency thermal systems.

EXPERIMENTAL INVESTIGATION OF BIODEGRADATION PROCESSES IN FOOD WASTE WITH DIFFERENT AMOUNTS OF MOISTURE

The today's world faces a rapid increase of population and thus a growing amount of generated waste. Unsorted municipal waste is transported to landfills. The negative environmental impact of a landfill is related with generated odours, polluted leachate and waste itself. Most of present landfills do not meet minimal environmental and sanitary requirements, i e most of landfills do not have an installed leachate collection system. In Lithuania waste management is related with many problems. The municipal waste collection system is inefficient, and the equipment is outdated. Large amounts of recyclable waste materials mixed with other wastes are still disposed in landfills. Aiming to use anaerobic digestion technologies for organic waste and minimize their negative environmental impact, recyclables need to be separated. The paper gives information about experimental investigation with fruit, vegetable and meat waste humidified with addition of moisture to 75 %, 79 % and 85 %. The experiment lasted for 60 days, and the concentration of methane and oxygen as well as temperature changes in vessels were observed. The results showed that in 50 l containers of mixed waste set with moisture to 85 % higher amounts of methane were produced than in those humidified with less water.

Mass Burning of MSW With Energy Recovery

There are four or five options for the final disposition of municipal waste, each with its own drawbacks and limitations. One system has been proven by 25 yrs or more of successful operation in Europe and some record of success in the U.S. This is mass burning of unsorted waste in a refractory or water wall furnace with a heat recovery boiler. Heat recovery is a misnomer as actually these systems should be referred to as municipal waste fired boilers or mass burning systems. Municipical waste-mass burning systems are appropriate for waste quantity from about 200 tons/day to about 3,000 and is a logical alternative to landfilling as the final disposition of municipal solid waste. Mass burning has the advantages of 90% volume reduction to a completely odorless inert product, potential for recovery of valuable heat energy and existing technology to remove dust and pollutants from the flue gas to meet the most severe environmental requirements.