Shan Shan Chung

Evaluating sustainability in waste management: the case of construction and demolition, chemical and clinical wastes in Hong Kong

Abstract This paper intends to set out clearly defined criteria for evaluating sustainability in solid waste management and have them illustrated by a modern Chinese city—Hong Kong. Following a thorough literature review, four evaluative criteria are derived: environmental desirability, economic optimization, social acceptability and equity and administrative diligence. These four criteria are then applied in the context of Hong Kong for the evaluation of the management performance of construction and demolition waste, clinical waste and chemical waste. Although the need to attain sustainability is compelling in Hong Kong, our analysis shows that the management of construction and demolition waste, clinical waste and chemical waste has failed in almost all the sustainability criteria. In terms of controlling the environmental impact from waste management, only end of pipe treatment is adequately delivered but preventive waste management programs are far from adequate. In terms of waste management economics, economic incentives have yet to be instituted for most waste generators. Thus, the present levels of waste generation in Hong Kong far exceed social and economic optimal. Furthermore, although Hong Kong has been commended by having an efficient government, the ability of the government to induce environmentally responsible behavior from private waste generators is weak and thus failing the administrative diligence criterion as well. In the management of the three types of waste, the welfare of future generations is often sacrificed for the narrower, sectoral or district community interests. The myopic environmental welfare view in the Hong Kong community is a logical result of the minimal effort devoted to build up social capital stock and environmental citizenship culture. The main causes for the unsatisfactory waste management performance in Hong Kong is closely related to the governance style of the government rather than some general causes such as a lack of technological know-how or financial constraints.

Generation of and control measures for, e-waste in Hong Kong

While accurately estimating electrical and electronic waste (e-waste) generation is important for building appropriate infrastructure for its collection and recycling, making reliable estimates of this kind is difficult in Hong Kong owing to the fact that neither accurate trade statistics nor sales data of relevant products are available. In view of this, data of e-products consumption at household level was collected by a tailor-made questionnaire survey from the public for obtaining a reasonable e-waste generation estimate. It was estimated that on average no more than 80,443 tones (11.5 kg/capita) of waste is generated from non-plasma and non-liquid crystal display televisions, refrigerators, washing machines, air-conditioners and personal computers each year by Hong Kong households. However, not more than 17% of this is disposed as waste despite a producer responsibility scheme (PRS) not being in place because of the existence of a vibrant e-waste trading sector. The form of PRS control that can possibly win most public support is one that would involve the current e-waste traders as a major party in providing the reverse logistics with a visible recycling charge levied at the point of importation. This reverse logistic service should be convenient, reliable and highly accessible to the consumers.

Characterisation of municipal solid waste and its recyclable contents of Guangzhou

Waste characteristics are essential data for waste disposal facilities planning and waste management policy formulation. However, waste composition studies are rarely carried out in mainland Chinese cities and even when it does, the methodologies used are not stringent. A year-long field survey on the physical components of waste and the recyclable in the waste stream has been conducted in Guangzhou to fill the information gap and to provide further experience for waste characterization study in mainland China. It was found that the ash content in the waste stream has decreased considerably. But the proportion of plastic materials in the waste stream has increased and is now comparable to its more urbanized cities. Although this lends support to the recent controls on expanded polystyrene food containers implemented by the Guangzhou environmental protection bureau, more detailed analysis shows that the focus should not only be on disposable food containers, but also on film plastic waste. Furthermore, the abundance of composite materials in the waste stream solicits attention from the waste management authority to step up the monitoring of their generation pattern and to consider imposing control measures.

Evaluating waste management alternatives by the multiple criteria approach

Abstract In the past, justifications on decision making in the environmental (including waste management) field have always been qualitative and implicit in Hong Kong. The use of multiple criteria analysis (MCA) in waste management decision making has the advantage of rendering subjective and implicit decision making more objective and transparent. An additional merit of MCA is its ability to accommodate quantitative and qualitative data. In this paper the MCA approach is made use to find out the preferred waste management option(s) for Hong Kong (HK). Landfilling, waste to energy, composting and source separation of municipal solid waste (MSW) are analysed by the MCA. It is found that source separation is the most preferred option. Waste to energy is found to have a better overall performance than landfilling (with methane recovery). Composting of solid waste is found to be very land intensive and should only be used with care. Incineration without energy recovery is the least desirable option. Landfilling of solid waste although is not the best option, it is indispensable in a waste management system. Thus, it should only be practised in a limited extent. It is also demonstrated in this paper that dominance pairwise comparison is not sensitive to weighting differences. Thus, if decisive criteria exist, then they should be considered prior to the use of dominance pairwise comparison.

A material flow analysis on current electrical and electronic waste disposal from Hong Kong households

A material flow study on five types of household electrical and electronic equipment, namely television, washing machine, air conditioner, refrigerator and personal computer (TWARC) was conducted to assist the Government of Hong Kong to establish an e-waste take-back system. This study is the first systematic attempt on identifying key TWARC waste disposal outlets and trade practices of key parties involved in Hong Kong. Results from two questionnaire surveys, on local households and private e-waste traders, were used to establish the material flow of household TWARC waste. The study revealed that the majority of obsolete TWARC were sold by households to private e-waste collectors and that the current e-waste collection network is efficient and popular with local households. However, about 65,000 tonnes/yr or 80% of household generated TWARC waste are being exported overseas by private e-waste traders, with some believed to be imported into developing countries where crude recycling methods are practiced. Should Hong Kong establish a formal recycling network with tight regulatory control on imports and exports, the potential risks of current e-waste recycling practices on e-waste recycling workers, local residents and the environment can be greatly reduced.

Waste reduction and recycling strategies for the in-flight services in the airline industry

Abstract Air transport is one of the worlds fastest-growing industries. Todays worldwide tourism and international exchange of goods and services would not be possible without aircraft. Solid waste management and disposal is one of the most significant issues in the environmental management of the airline industry. In this study, a waste composition analysis was conducted for in-flight service waste, and potential waste minimisation measures were evaluated. The total in-flight waste was estimated to be up to 500 kg per flight, including food waste, and galley and cabin waste. The waste composition analysis showed that paper (mainly newspaper, meal menu cards, etc.) was the largest component, ranging from 32 to 71% by weight of the total galley and cabin waste. Another major component was plastic items. Transparent polystyrene drinking cups and food covers accounted for up to 13% of the total weight. Aluminium cans accounted for up to 4% of the total waste. These recyclable materials can be sorted on board to facilitate the waste reduction and recycling programme. The proposed on board sorting and collection programmes can achieve a recycling rate of as much as 45–58% of the total galley and cabin waste from in-flight services.

Projection of waste quantities: The case of e-waste of the People’s Republic of China:

Although waste quantification and projection are important data for waste management, the reliability of their results is difficult to verify. The present study attempted to identify the best waste quantification methods using e-waste quantification studies of mainland China as case studies. Large discrepancies in the predicted amounts of e-waste generated were found no matter whether the same or different methods of estimation are used. Moreover, even when agreements between studies were found, the agreed figures were not necessarily the correct figures. However, since without hindsight it is not possible to tell whether a projection figure is accurate, the convergence rule and a prudent approach to counting on studies conducted with meticulous scientific procedures should be adopted. Two worrying trends are noted. First, the transparency of data collection and computation methods in these studies was not high; second, irresponsible citation practices were found to have already spread to academic studies. As a result, leading organizations in the academic community should consider establishing a platform devoted to the reporting of false or dubious citations.

Diving associated coral breakage in Hong Kong: differential susceptibility to damage.

We conducted the first quantitative assessment of coral breakage along a gradient of diving activities in Hong Kong, the most densely populated city in southern China. A survey of six 1 × 25 m transects at seven sites revealed a total of 81 broken corals, among which 44% were branching, 44% plate-like and 12% massive. There were 3-19 broken colonies per site. At most study sites, the percentage of broken corals exceeded the recommended no-action threshold of 4%, suggesting that management intervention is justified. There was a significant positive correlation between the number of broken coral colonies and the number of divers visiting the site. The branching Acropora and the plate-like Montipora suffered from much higher frequency of damage than their relative abundance, raising the concern that the cumulative impact of such differential susceptibility to breakage may affect coral community composition.

Using plastic bag waste to assess the reliability of self-reported waste disposal data

Direct waste analysis (DWA) and the material flows approach are the two standard methods to quantify aggregated waste streams and analyze waste composition. Yet, with the increasing application of producer responsibility measures, product-based waste data rather than aggregated waste data are becoming important. It is over this requirement that both approaches fail to some extent in delivering the type and quality of information that is needed. This study uses plastic bag waste as an illustration to show how self-reported questionnaire survey data may be used to assess disposal quantities of product-based waste types. The estimates from a large-scale questionnaire survey with over 4,100 completed cases were verified against DWA data of the same year in Hong Kong. It was found that self-reported data give systematically lower figures (on the order of 1.3-5 times) than those obtained from standard methods such as DWA for Hong Kong and the UK. However, it is demonstrated that self-reported data can be internally consistent. Also, the magnitude of underestimation may not be as considerable as it appears since the data from DWA are not themselves entirely accurate owing to the difficulties in obtaining a pure load of waste for field analysis and the variable moisture contents or contamination levels in waste material.

Assessing the Social Carrying Capacity of Diving Sites in Mabul Island, Malaysia

Abstract This study has explored social carrying capacity of an underwater environment based on divers’ perceived crowding. Two dimensions were assessed, the number of divers seen and the proximity of diver. Data were obtained from a survey of 132 divers dived in Mabul Island, Malaysia during 2013–2014. Photographs depicting four levels of diver number and four levels of diver proximity in different combinations were shown to the respondents for assessing their acceptability. Between the two variables, the “number of divers” was the most influential factor for divers’ perceived crowding. Divers would start to feel unacceptably crowded if 8–9 divers were visible to them at one time. Based on this, it is likely that the use level of diving sites in Mabul Island has already exceeded its social carrying capacity. Implications for future research and diving tourism management for Mabul Island are also discussed in the paper.