Introduction

The management of solid waste continues to be a major challenge in urban areas throughout the world, particularly in the rapidly growing cities and towns of the developing world (Jing et al. 2009; Zhao et al. 2009; Guerrero et al. 2013). With the rapid economic development in Macau, along with population growth and increased prosperity and tourism in recent years, the amount of solid waste generated in Macau has also been increasing, exerting great pressure on waste management systems within Macau’s limited land area (Jin et al. 2006). The amount of solid waste generated in Macau has increased steadily over the last decade (DSEC et al. 2015; Song et al. 2013), from 232,726 tons in 2001 to 397,738 tons in 2013. The daily mean quantity per capita of solid waste generated was 1.46 kg/day in 2001 and 1.80 kg/day in 2013. Macau is currently faced with an urgent need to deal with the increasing volume of solid waste.

The European Union regulation proposes a hierarchical system based on four subsequent levels (EU (European Union) 2006): (1) reduction of solid waste production, (2) recovery of material, (3) recovery of energy, and (4) landfill disposal. There is not sufficient knowledge of this hierarchy to develop an adequate management system due to the variables relating to the environmental, social, and economic aspects along with the technical aspects (De Feo and Malvano 2009; Song et al. 2015). When choosing the most appropriate solid waste management system for a certain territory, decision makers have to take adequately into account not only the technical aspects and implementation costs but also the residents’ attitudes (Khoo 2009) . As a matter of fact, consensus of the residents is a prerequisite for the subsequent implementation of a solid waste management plan.

The establishment and implementation of relevant policies and recycling facilities must be based on consumers’ behavior and their willingness to pay (WTP) to recycle solid waste. However, the research on WTP or consumers’ behavior regarding the recycling of solid waste has attracted insufficient attention in Macau. If the Macau government wants to implement effective policies and build appropriate facilities for solving the solid waste issues, the willingness of consumers to participate in recycling activities is essential, for without this, neither government policies nor participation by producers can be effectively put in to practice. Therefore, there is a pressing need to survey the behaviors, attitudes, and WTP of residents in Macau.

Some researchers have begun to focus on the behaviors and WTP survey of environmental protection (Rahardyan et al. 2004; Brouwer et al. 2008; Afroz et al. 2013; Al-Khatib et al. 2014; Bernad-Beltrán et al. 2014; Grazhdani 2015; Otoma et al. 2013; Wang et al. 2014). Afroz et al. 2009 employed the contingent valuation method (CVM) to estimate the willingness to pay of the respondents to improve the waste collection system in Dhaka city, Bangladesh. Yoo and Kwak 2009 applied a CVM method to obtain at least a preliminary evaluation of the benefits for green electricity in Korea. Wang et al. 2011 investigated the behavior of residents toward electrical and electronic waste recycling in Beijing. Wang et al. 2014 conducted an economic analysis using CVM to estimate the WTP for municipal solid waste management in rural areas and small counties in Yunnan province. Babaei et al. 2015 evaluated their knowledge, attitudes, and practices toward solid waste reduction, source separation and recycling, collection, and WTP for solid waste services in Abadan, Iran. In addition, Jin et al. 2008 examined the public’s WTP for black-faced spoonbill conservation in Macau using the CVM. Our previous study (Song et al. 2012) also analyzed Macau residents’ behaviors, attitudes, and their WTP for recycling e-waste. The purpose of all these researches is to help policymakers make the relevant policies and laws to solve conflict between development and conservation. As mentioned in these above studies, CVM has become one of the most popular methods used by environmental and resource economists to value environmental goods and services because of its flexibility and its ability to estimate total values. CVM is a type of stated-preference approach that employs a hypothetical market system to extract WTP or willingness to accept for environmental goods (Carson 2000; Hadker et al. 1997). In this study, we adopted the CVM to quantify each household’s WTP for solid waste management in Macau.

This study used a survey questionnaire to explore the residents’ attitudes and WTP concerning solid waste management in Macau, with the intent of gathering information about three areas: (1) public perception of the local environment, (2) the residents’ attitudes on solid waste management in Macau, and (3) the residents’ WTP for recycling solid waste in Macau.

Material and methods

Questionnaire survey

In this study, we defined one household as the basic research unit. The questionnaire mainly contained four sections: (1) the first section comprised some general questions regarding public environmental perception, (2) the second section formulated some questions about the knowledge and attitudes of respondents on solid waste recycling, (3) a description of the WTP was included in the third part, and (4) the last part of the questionnaire collected socioeconomic data on the respondents.

The data used in this analysis comes from a 2011 questionnaire survey of households in Macau, which was conducted on 2–5 July 2011. The study area was restricted to all of Macau (29.9 km2). The total number of households in Macau in 2011 was 172.6 thousand.

There were three methods that could have been used to conduct the survey: face-to-face interview, telephone interview, or mail. Of these methods, we chose to use face-to-face interviews with well-trained interviewers because the quality of data obtained by this method has been found to be the highest—the most complete, comprehensive, and meaningful. In this study, a 250 sample size was conducted during the survey process.

Willingness to pay for recycling solid waste

Existing methods for estimating WTP include continuous CVM (represented by open-ended questions) and discrete CVM (represented by dichotomous choice questions) (Zhen et al. 2011). In continuous CVM, the interviewees are free to answer the open-ended questions by filling out the maximum amount they are willing to pay; also, it is easy for data analysis. The disadvantage is that it is sometimes difficult for the respondents to give the appropriate answer when they do not have enough background information about the research object. On the other hand, for the discrete CVM, the respondents are required to give their willingness only by choosing either “yes” or “no,” and they do not need to indicate the specific amount of money, thereby avoiding the problem of inconsistency between the stated WTP and actual amount the respondent is willing or able to pay.

To acquire the necessary data for both WTP and the specific amount, we used the single-bound dichotomous CVM method in this study. During the questionnaire, the interviewees were asked, “Are you willing to pay for the solid waste management in Macau?” The answer included “Yes, I am” and “No, I am not,” and for those people who agreed to pay, the following value choices were given: 10, 20, 30, 40, 50, 60, 70, 80, 90, ≥100 MOP per month ($1 ≈ 8 MOP).

Results and discussion

The socioeconomic characteristics of the respondents

A total of 250 personal interviews were administered in 2011 by trained interviewers at respondents’ homes; the sample response rate through the face-to-face interviews was 95.60 %.

Table 1 reports the descriptive statistics for the main socioeconomic characteristics of the respondents. Comparing with the Macau census data on the characteristics of the Macau population as a whole, the survey data was found to be close to the Macau average. The mean age of the respondents was 38.96 years. Only 33.33 % of respondents were male, which indicated that the women in Macau were more willing to accept the survey comparing with the men. The average number of household members was 3.70, and the average educational level was high school. The average income level was around 16,513 MOP/month.

Table 1 The basic information of the surveyed households
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Public perception of the local environment

Public environmental awareness is one of the most important indicators for displaying national civilization. It reflects many aspects of environmental status, such as people’s knowledge, personal consideration and behavior, public capacity, and the local citizens’ attitude toward sustainable society as a whole, etc. All of the information is useful for decision makers, environmentalists, educators, and businessmen in planning for social sustainable development.

As shown in Table 2, the public perceptions of the local environment are presented. The study found that all of respondents concerned about the environmental issues in Macau and the vast majority (80.8 %) of respondents often paid close attention to the environmental issues. Most residents acquired the environmental information through the TV and newspaper (49.7 %) and the environmental activities (26.5 %). From Table 2, it can be also known that the government also pays an important role on the environmental information spreading in Macau. About 87.4 % respondents ever participated in the environmental activities, which indicated that the Macau residents owned a high environmental awareness.

Table 2 Public perception of the local environment
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In regard to Macau environment, most respondents (92.4 %) expressed their satisfactions on the current situation, while only 7.5 % were not satisfied. Similar surveys in Ningbo, Qingdao, and Zhuhai city of mainland China showed that the satisfaction rate was 49.9, 72, and 83.8 %, respectively (Huang et al. 2006). The percentage of Macau’s citizens who are satisfied with their local environmental quality is relatively higher than with the coastal city in mainland China. Our surveys also revealed four major perceived environmental problems in Macau area: water pollution (10.6 %), air pollution (25.1 %), solid waste pollution (50.2 %), and noise pollution (14.1 %). Most respondents thought that the solid waste pollution in Macau should be paid more attention, and in future, the government should make more effective measures to improve the management and treatment of solid waste.

Residents’ attitudes toward solid waste management in Macau

Many environmental studies examined environmental attitudes as a factor to explain environmental behavior. The questionnaire survey has been popularly used by environmental researchers as a tool to measure general environmental concern or a world view as well as environmental beliefs, attitudes, and values. The public participation is a wholly accepted crucial element for the success of any waste management programs including source reduction and recycling, which due to its economic and environmental issues has gained more attention around the world in recent years.

The experiences from developed countries show that source separation of solid waste should be the first step for handling this issue. Therefore, some questions in the survey were designed to obtain local public opinions and attitudes toward the handling of solid waste. The survey data revealed the respondents’ positive attitudes toward source separation as shown in Table 3. Firstly, 73.5 % respondents selected “After source separation, solid waste was treated and recycled based on their characteristics” as the most effective way of solid waste treatment. Secondly, about 97.9 % respondents thought that the source separation was very necessary for the sustainable management of solid waste in Macau. Thirdly, most of respondents (95.7 %) were willing to sort the solid waste at home, if the government required them to do it. In addition, the reasons for the poor source separation in Macau were also investigated in our study. The results (Fig. 1) show that the low environmental awareness maybe the most primary reason, accounting for 50.5 % of the total respondents. Note that, “lack of classification collection systems and facilities” and “spend a lot of time” were also two important reasons to influence the implementation of source separation. In future, in order to improve the source separation of solid waste, further improving the residents’ environmental awareness will be more effective.

Table 3 Residents’ attitudes toward source separation in Macau
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Fig. 1
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The reasons for poor source separation in Macau

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In this study, we also did some investigations on the residents’ behaviors toward solid waste recycling in Macau, as shown in Table 4. Of the respondents, 98.8 % expressed willingness to contribute their efforts to the local environmental protection, while only 1.2 % respondents said no, who thought that the solid waste recycling belonged to the government’s responsibility. For the question on how to improve the solid waste recycling in Macau, “More environmental activities and propaganda to enhance residents’ environmental awareness” was considered as the most effective methods, accounting for about 38.5 % respondents, followed by “Increasing the environmental control facilities.” It can be noted that about 20.3 % respondents selected the environmental legislation as the more effective way.

Table 4 Residents’ behaviors toward solid waste recycling
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Residents’ WTP for recycling solid waste in Macau

The WTP

For the Macau residents, if they are willing to pay more for the solid waste management and recycling, they can get back more good services, e.g., better collection, better recycling, less annoyance with solid waste spreading all over the city, and good environmental quality. Based on interviewers’ comments, the WTP elicitation procedures were well within the respondents’ abilities. The total percentage of yes responses was 85.4 %, much higher than that of the no responses (14.6 %). The protest rate seems relatively low, compared with some previous studies (Song et al. 2012; Cho et al. 2005; Jin et al. 2006). This indicated that the Macau residents owed the stronger willingness to improve the solid waste management in Macau.

Table 5 presents the distribution of responses to the valuation questions, indicating the total number of respondents at each bid level, ranging from 10 to 100 MOP per month. More respondents intended to pay for 10, 50 and 100 MOP, accounting for 19.2, 20.5, and 17.2 %, respectively. These estimates are very possible to represent the minimum expected WTP of respondents under our e questionnaire.

Table 5 Distribution of responses by bid amount
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From Table 6, through analyzing the survey data, we can see that the mean WTP value per household in Macau was 38.5 MOP/month. When expanding the sample to all Macau households, one critical concern is the external generalization of the sample values to those for all of Macau. Based on the total number of households in Macau, it can be deduced that the annual WTP value of Macau as a whole would be approximately 79.7 million MOP, with a range (at the 95 % confidence interval) from 70.6 million MOP to 88.6 million MOP. This conclusion could be used as reference values to design a conservation payment scheme and determine the total required funding to promote the solid waste management in Macau.

Table 6 Estimation of the WTP in Macau
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Relationships between WTP and household characteristics

The regression model has been developed to explore the influence factors on WTP. Here, respondents selected their WTP for solid waste management with two alternatives: 1—willing to pay and 0—not willing to pay, thereby making the dependent variable of the regression model non-continuous. In this study, logistic regression was selected as our evaluation method. The definitions of the variables used in our logistic regression are presented in the description for Table 1. The logistic regression was performed using SPSS 19.0, and the results were given in Table 7. The data from Table 7 indicate that only education level is statistically significant at 5 % significance level. Moreover, the coefficient of education level are positive, which support the hypothesis that the probability of the respondents’ saying yes to the WTP question increases with education level. Other variables, such as respondents’ age, gender, number of members, and income in the household, were not statistically significant. This shows that these characteristics have little influence on respondents’ WTP.

Table 7 Relationships between WTP and household characteristics
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Conclusions

Increasing public attention has been brought to bear on the environmental impacts of solid waste management in Macau. In this study, we discussed residents’ behaviors and willingness to pay for solid waste recycling through a questionnaire survey and have provided some basic information for the future solid waste management in Macau. Overall, the survey was relatively successful in eliciting the residents’ attitudes and their WTP values for solid waste management.

The results indicated that Macau residents owned a relatively high environmental awareness. In Macau, all respondents concerned about the environmental issues in Macau, and about 87.4 % respondents ever participated in the environmental activities. In regard to Macau environmental quality, most respondents (92.4 %) expressed their satisfactions on the current situation, and the solid waste management and treatment should attract more concerns in future.

The survey data also revealed the residents’ positive attitudes toward source separation in Macau. Most of respondents (95.7 %) were willing to sort the solid waste at home, if the government required them to do it. The Macau residents also showed that the primary reason for the poor source separation was due to the lower environmental awareness.

In our study, most respondents (85.4 %) provided positive answers to the questions about WTP and freely gave their views and perceptions about issues. These survey results support the hypothesis that the probability of the respondents’ saying yes to the WTP question increases with education level. The monthly mean WTP was 38.5 MOP per household, and the annual WTP was approximately 79.7 million MOPs for all of Macau.

Under ordinary circumstances that simply take into consideration the market-based value, the solid waste problem cannot be properly assessed. Therefore, for the purpose of developing new policies of solid waste management, the results of our study can help managers develop more effective environmental management policies for solid waste disposal. Moreover, although most residents in Macau are aware of the management necessity and the potential environmental risk of solid waste, there is a need for educational campaigns to promulgate the proper methods to recycle and reuse the solid waste for the residents. And it is necessary to enrich elementary education in environmental protection and resource conservation to foster the solid waste recycling habits from the child.

Although our survey was relatively successful, there are still some limitations, e.g., (1) only 250 samples were conducted in our survey. In future, more sample size should be done for higher credibility. (2) The consumption habits and lifestyles of the residents often associate with the waste management and will be possible to influence the effectiveness of solid waste management. (3) As the tourist and gaming city, Macau will receive millions of visitors every year. The attitudes and behaviors of visitors will also be very important for the waste management. In future, further research should pay more attention to the above three points.