Measuring bulky waste arisings in Hong Kong

All too often, waste authorities either assume that they know enough about their bulky waste stream or that it is too insignificant to deserve attention. In this paper, we use Hong Kong as an example to illustrate that official bulky waste figures can actually be very different from the reality and therefore important waste management decisions made based on such statistics may be wrong too. This study is also the first attempt in Hong Kong to outline the composition of bulky waste.It was found that about 342 tonnes/day of wood waste were omitted by official statistics owing to incomplete records on actual bulky waste flow. This is more than enough to provide all the feedstock needed for one regular-sized wood waste recycling facility in Hong Kong. In addition, the proportion of bulky waste in the municipal solid waste (MSW) streams in Hong Kong should be about 6.1% instead of the officially stated 1.43%. Admittedly, there are limitations with this study. Yet, present findings are suggestive of significant MSW data distortion in Hong Kong.     

Characterization of household waste in Greenland

The composition of household waste in Greenland was investigated for the first time. About 2 tonnes of household waste was sampled as every 7th bag collected during 1 week along the scheduled collection routes in Sisimiut, the second largest town in Greenland with about 5400 inhabitants. The collection bags were sorted manually into 10 material fractions. The household waste composition consisted primarily of biowaste (43%) and the combustible fraction (30%), including anything combustible that did not belong to other clean fractions as paper, cardboard and plastic. Paper (8%) (dominated by magazine type paper) and glass (7%) were other important material fractions of the household waste. The remaining approximately 10% constituted of steel (1.5%), aluminum (0.5%), plastic (2.4%), wood (1.0%), non-combustible waste (1.8%) and household hazardous waste (1.2%). The high content of biowaste and the low content of paper make Greenlandic waste much different from Danish household waste. The moisture content, calorific value and chemical composition (55 elements, of which 22 were below detection limits) were determined for each material fraction. These characteristics were similar to what has been found for material fractions in Danish household waste. The chemical composition and the calorific value of the plastic fraction revealed that this fraction was not clean but contained a lot of biowaste. The established waste composition is useful in assessing alternative waste management schemes for household waste in Greenland.     

Inconsistent pathways of household waste

The aim of this study was to provide policy-makers and waste management planners with information about how recycling programs affect the quantities of specific materials recycled and disposed of. Two questions were addressed: which factors influence household waste generation and pathways? and how reliable are official waste data? Household waste flows were studied in 35 Swedish municipalities, and a wide variation in the amount of waste per capita was observed. When evaluating the effect of different waste collection policies, it was found to be important to identify site-specific factors influencing waste generation. Eleven municipal variables were investigated in an attempt to explain the variation. The amount of household waste per resident was higher in populous municipalities and when net commuting was positive. Property-close collection of dry recyclables led to increased delivery of sorted metal, plastic and paper packaging. No difference was seen in the amount of separated recyclables per capita when weight-based billing for the collection of residual waste was applied, but the amount of residual waste was lower. Sixteen sources of error in official waste statistics were identified and the results of the study emphasize the importance of reliable waste generation and composition data to underpin waste management policies.     

Influence of assumptions about household waste composition in waste management LCAs

This article takes a detailed look at an uncertainty factor in waste management LCA that has not been widely discussed previously, namely the uncertainty in waste composition. Waste composition is influenced by many factors; it can vary from year to year, seasonally, and with location, for example. The data publicly available at a municipal level can be highly aggregated and sometimes incomplete, and performing composition analysis is technically challenging. Uncertainty is therefore always present in waste composition. This article performs uncertainty analysis on a systematically modified waste composition using a constructed waste management system. In addition the environmental impacts of several waste management strategies are compared when applied to five different cities. We thus discuss the effect of uncertainty in both accounting LCA and comparative LCA. We found the waste composition to be important for the total environmental impact of the system, especially for the global warming, nutrient enrichment and human toxicity via water impact categories.     

Factors influencing household waste management practices in Zimbabwe

Journal of Material Cycles and Waste Management - The management of household solid waste is a growing concern related to public health and environmental damage. The study examined...     

The costs of household food waste in South Africa

Food waste is problematic for a number of reasons, including the loss of a potentially valuable food source or resource for use in other processes (e.g. energy generation or composting), wasted resources and emissions in the food supply chain, and problems associated with the disposal of organic waste to landfill. This paper quantifies the household food waste stream in South Africa, in order to draw attention to the magnitude of the problem. In addition, it estimates the economic (monetary) value of the wasted food, as well as the costs associated with disposing putrescible food waste to landfill, in order to highlight the associated costs to society. Costs associated with the loss of a potentially valuable food source are valued using a weighted average market price of the wasted food. Costs associated with the disposal of food waste to landfill are quantified based on estimates of the financial and external costs associated with landfilling. For household food waste alone, the costs to society associated with these two food-waste related problems are estimated at approximately R21.7 billion (approximately US$2.7 billion) per annum, or 0.82% of South Africa’s annual GDP. These costs are therefore significant, particularly considering that household food waste accounts for less than 4% of total food losses across the food supply chain.     

Chemical composition of material fractions in Danish household waste

The chemical composition of Danish household waste was determined by two approaches: a direct method where the chemical composition (61 substances) of 48 material fractions was determined after hand sorting of about 20 tonnes of waste collected from 2200 households; and an indirect method where batches of 80–1200 tonnes of unsorted household waste was incinerated and the content of the waste determined from the content of the outputs from the incinerator. The indirect method is believed to better represent the small but highly contaminated material fractions (e.g., batteries) than the direct method, because of the larger quantities included and the more homogenous material to sample from. Differences between the direct and the direct methods led to corrections in the of heavy metal concentration of a few fractions.The majority of the energy content of the waste originates from organic waste like paper, cardboard and organic fractions. The single fraction contributing most to the total energy content is the non-recyclable plastic fraction, contributing 21% of the energy content and 60% of the chlorine content, although this fraction comprises less than 7% by weight. Heavy metals originate mainly from inert fractions, primarily batteries.     

Discussion on the methodology for determining food waste in household waste composition studies

Food waste has become an increasingly discussed topic in recent years. However, there is little authoritative data on food waste quantities and composition and systematic and comparable data are missing. Household waste composition analyses, which are often carried out routinely at regular or irregular intervals, provide an opportunity for obtaining data about food waste at both local and regional levels. The results of prior waste composition studies are not really comparable due to the different classifications, definitions and methods used; in addition, these are mostly insufficiently described and not reproducible by a third party. The aim of this paper is to discuss a methodology for determining the proportion of food waste in household waste composition studies, by analysing specific problems and possible solutions. For that purpose, findings from the literature are analysed and the approach and results of a composition analysis of residual waste of a stratified sample (urban, rural area) are presented. The study suggests that in order to avoid a significant loss of information, waste should not be sieved before sorting and packed food waste should be classified into the relevant food waste category together with its packaging. The case study showed that the overall influence of the proportion of food packaging included in the food waste category, which amounted to only 8%, did not significantly influence the results and can therefore be disregarded.     

Report on hazardous household waste generation in Japan.

Surveys of over 2000 households in Japan were conducted to investigate the characteristics of hazardous household waste (HHW) generation. In Japan, about 2.5 to 4.3 kg of HHW are produced per tonne of the residential waste stream. The percentage of used batteries in HHW was over 50%. Every household using spray (aerosol) cans had more than seven cans on average. The generation of HHW, in terms of both quantities and type of waste produced, appeared to vary with dwelling type. Detached dwelling residents tended to store HHW such as used batteries, whereas apartment residents tended not to store waste. The amounts of discarded HHW were larger at the end of the year in comparison with other months. The data accumulated were used to estimate the quantities of HHW disposed off annually, and the quantities and type of waste that might be received by a typical depot collection programme in Japan.     

Consumer perspectives on household hazardous waste management in Japan

We give an overview of the management systems of household hazardous waste (HHW) in Japan and discuss the management systems and their risks. To get basic information, we conducted a survey of consumers to discover their behavior and awareness of HHW items throughout the entire life cycle, which is made up of the purchase, use, and disposal of a product. The results showed that many people hold end-of-life batteries, fluorescent lamps, empty spray cans, and others in their houses after use. Also, the results showed that a lot of such waste items were discarded in waste streams different from those stipulated by local governments. In particular, many people do not remove NiCd batteries inside products such as shavers or cordless phones before discarding. On the other hand, people’s knowledge of and concern regarding the risks, collection, and recycling of HHW were high. When information about the risks was specifically presented in the questionnaire, people tended to show a more positive intention to participate in a collection and recycling system compared to those who were not presented with such information. Our studies on NiCd batteries and fluorescent lamps showed that it is important to collect and recycle HHW to control the domestic and international flows of cadmium and mercury.     

Collection and transportation cost of household solid waste in Kuwait

The specific aim of this funded research project was to examine and evaluate the efficiency and the effectiveness of the municipal solid waste collection and transportation system in the State of Kuwait. The contract resources of the seven contracting firms, the annual contract budgets, and the district area and population of each service contract are presented. Service efficiency and effectiveness indicators for each collection/disposal contract are also computed and discussed. The cost of collection and transportation of household waste in Kuwait is also compared with those of a number of urban areas in other nations. The low energy and manpower costs are mainly responsible for the favorable cost of management, collection and transportation of residential waste in Kuwait.     

Comparative analysis of hazardous household waste in two Mexican regions

Household hazardous waste (HHW) generation in two Mexican regions was examined, a northern region (bordering with the USA) and a central region. The aim of this work was to determine the dynamics of solid waste generation and to be able to compare the results of both regions, regarding consumption patterns and solid waste generation rates. In the northern region, household solid waste was analysed quantitatively. In order to perform this analysis, the population was categorized into three socioeconomic strata (lower, middle, upper). Waste characterization revealed the presence of products that give origin to household hazardous waste. In the northern region (Mexicali city), household hazardous waste comprised 3.7% of municipal solid waste, the largest categories in this fraction were home care products (29.2%), cleaning products (19.5%) and batteries and electronic equipment (15.7%). In the central region, HHW comprised 1.03% of municipal solid waste; the main categories in this fraction were represented by cleaning products (39%), self care products (27.3%), and insecticides (14.4%). In Mexicali, the socioeconomic study demonstrated that the production of HHW is independent of the income level. Furthermore, the composition of the solid waste stream in both regions suggested the influence of another set of variables such as local climate, migration patterns and marketing coverage. Further research is needed in order to establish the effect of low quantities of HHW upon the environment and public health.     

Analysis of collection systems for sorted household waste in Spain

This work analyses the separate collection systems used in Spanish towns with between 5000 and 50,000 inhabitants. The study looks at the systems and their efficiency by means of the indicators fractioning rate, quality in container rate and separation rate. The results obtained are compared with those from a similar study conducted earlier that was applied to towns and cities with populations over 50,000. It can be concluded that the most widely implemented system in Spain involves the collection of mixed waste from kerbside bins and picking up paper/cardboard, glass and lightweight packaging from drop-off points. Findings show that the best system is the one that collects mixed waste, organic material and multiproduct waste door-to-door, and glass from drop-off points. The indicator separation rate made it possible to establish beta regression models to analyse the influence of the following logistic variables: inhabitants per point (people/pt), time (years) and frequency of collection (freq). From these models it can be seen that people/pt has a negative effect on all the fractions, while freq and years have a positive effect in the case of paper.     

WEEE and portable batteries in residual household waste: Quantification and characterisation of misplaced waste

A total of 26.1 Mg of residual waste from 3129 households in 12 Danish municipalities was analysed and revealed that 89.6 kg of Waste Electrical and Electronic Equipment (WEEE), 11 kg of batteries, 2.2 kg of toners and 16 kg of cables had been wrongfully discarded. This corresponds to a Danish household discarding 29 g of WEEE (7 items per year), 4 g of batteries (9 batteries per year), 1 g of toners and 7 g of unidentifiable cables on average per week, constituting 0.34% (w/w), 0.04% (w/w), 0.01% (w/w) and 0.09% (w/w), respectively, of residual waste. The study also found that misplaced WEEE and batteries in the residual waste constituted 16% and 39%, respectively, of what is being collected properly through the dedicated special waste collection schemes. This shows that a large amount of batteries are being discarded with the residual waste, whereas WEEE seems to be collected relatively successfully through the dedicated special waste collection schemes. Characterisation of the misplaced batteries showed that 20% (w/w) of the discarded batteries were discarded as part of WEEE (built-in). Primarily alkaline batteries, carbon zinc batteries and alkaline button cell batteries were found to be discarded with the residual household waste. Characterisation of WEEE showed that primarily small WEEE (WEEE directive categories 2, 5a, 6, 7 and 9) and light sources (WEEE directive category 5b) were misplaced. Electric tooth brushes, watches, clocks, headphones, flashlights, bicycle lights, and cables were items most frequently found. It is recommended that these findings are taken into account when designing new or improving existing special waste collection schemes. Improving the collection of WEEE is also recommended as one way to also improve the collection of batteries due to the large fraction of batteries found as built-in. The findings in this study were comparable to other western European studies, suggesting that the recommendations made in this study could apply to other western European countries as well.     

Use of selected waste materials in concrete mixes

A modern lifestyle, alongside the advancement of technology has led to an increase in the amount and type of waste being generated, leading to a waste disposal crisis. This study tackles the problem of the waste that is generated from construction fields, such as demolished concrete, glass, and plastic. In order to dispose of or at least reduce the accumulation of certain kinds of waste, it has been suggested to reuse some of these waste materials to substitute a percentage of the primary materials used in the ordinary portland cement concrete (OPC). The waste materials considered to be recycled in this study consist of glass, plastics, and demolished concrete. Such recycling not only helps conserve natural resources, but also helps solve a growing waste disposal crisis. Ground plastics and glass were used to replace up to 20% of fine aggregates in concrete mixes, while crushed concrete was used to replace up to 20% of coarse aggregates. To evaluate these replacements on the properties of the OPC mixes, a number of laboratory tests were carried out. These tests included workability, unit weight, compressive strength, flexural strength, and indirect tensile strength (splitting). The main findings of this investigation revealed that the three types of waste materials could be reused successfully as partial substitutes for sand or coarse aggregates in concrete mixtures.     

Fungal survival during anaerobic digestion of organic household waste

Anaerobic digestion of organic waste yields energy rich biogas and retains nutrients (N, P, K, S, etc.) in a stabilised residue. For the residue to be used as a soil fertiliser, it must be free from pollutants and harmful microorganisms. Fungal survival during sanitation and anaerobic treatment of source-separated organic household waste and during aerobic storage of the residue obtained was investigated. Decimal reduction times were determined for inoculated fungi (Aspergillus flavus and Aspergillus fumigatus, Penicillium roqueforti, Rhizomucor pusillus, Thermoascus crustaceus and Thermomyces lanuginosus). Several different fungal species were found after waste sanitation treatment (70 degrees C, 1 h), with Aspergillus species dominating in non-inoculated waste. Anaerobic waste degradation decreased the diversity of fungal species for processes run at both 37 and 55 degrees C, but not total fungal colony forming units. Fungi surviving the mesophilic anaerobic digestion were mainly thermotolerant Talaromyces and Paecilomyces species. T. crustaceus and T. lanuginosus were the only inoculated fungi to survive the thermophilic anaerobic degradation process. Aerobic storage of both types of anaerobic residues for one month significantly decreased fungal counts.     

Municipal solid waste management in Malaysia: Practices and challenges

Rapid economic development and population growth, inadequate infrastructure and expertise, and land scarcity make the management of municipal solid waste become one of Malaysia’s most critical environmental issues. The study is aimed at evaluating the generation, characteristics, and management of solid waste in Malaysia based on published information. In general, the per capita generation rate is about 0.5–0.8 kg/person/day in which domestic waste is the primary source. Currently, solid waste is managed by the Ministry of Housing and Local Government, with the participation of the private sector. A new institutional and legislation framework has been structured with the objectives to establish a holistic, integrated, and cost-effective solid waste management system, with an emphasis on environmental protection and public health. Therefore, the hierarchy of solid waste management has given the highest priority to source reduction through 3R, intermediate treatment and final disposal.     

Source separation of household waste: a case study in China

A pilot program concerning source separation of household waste was launched in Hangzhou, capital city of Zhejiang province, China. Detailed investigations on the composition and properties of household waste in the experimental communities revealed that high water content and high percentage of food waste are the main limiting factors in the recovery of recyclables, especially paper from household waste, and the main contributors to the high cost and low efficiency of waste disposal. On the basis of the investigation, a novel source separation method, according to which household waste was classified as food waste, dry waste and harmful waste, was proposed and performed in four selected communities. In addition, a corresponding household waste management system that involves all stakeholders, a recovery system and a mechanical dehydration system for food waste were constituted to promote source separation activity. Performances and the questionnaire survey results showed that the active support and investment of a real estate company and a community residential committee play important roles in enhancing public participation and awareness of the importance of waste source separation. In comparison with the conventional mixed collection and transportation system of household waste, the established source separation and management system is cost-effective. It could be extended to the entire city and used by other cities in China as a source of reference.