ABSTRACT
ABSTRACT
The amount of solid waste generated in developing countries is rising over time due to economic growth, change inconsumer behavior, and lifestyles of people. But it is hard to manage and handle the increase of solid waste with existing waste management infrastructure. Thus, the management system of solid waste is very poor and has become a serious problem. The main purpose of this study is to quantify the volume of solid waste generated and investigate factors affecting generation and disposal of wastes in the study area. The result of this study indicated that total waste generated from households was about 97.092 kg/day. Furthermore, the study reveals that the solid waste generation rate of the town is 0.261 kg/person/day. About 57.5% of solid waste is properly disposed of to a landfill site, whereas the remaining 42.5% is illegally dumped at the roadsides and open fields.
Implications: Nowadays, in developing countries there is a high concentration of people in urban areas, causing the generation of an enormous concentration of municipal waste in urban areas. Therefore this study’s findings will be important for various policymakers and town planners. This may also serve as a benchmark for the municipal authorities of the town for whom the problem is still invisible and negligible and can push environmental protection authorities to reexamine the implementation of their policies and strategies with regard to the broader issues of human and environmental health conditions of town dwellers.
Introduction
Urbanization has been increasing in speed and scale in recent decades, with more than half the world’s population now living in urban center. At present, 54% of the world population lives in urban areas, and this is estimated to increase up to 66% or more by 2050, while the world population is expected to add 2.5 billion people to the urban population (United Nations 2014). Fast urban population growth has resulted in several land use and infrastructural challenges, including municipal solid waste management. Increasing population levels, thriving economy, rapid urbanization, and the rise in community living standards have greatly accelerated the municipal solid waste generation rate in developing countries (Minghua et al. 2009).
Currently, municipal solid waste is increasing in both quantity and composition throughout the world (Ma and Hipel 2016). Many of the world cities are generating an ever-increasing amount of waste, and the effectiveness of their solid waste collection and disposal systems is declining (EMEGHSHW, 2013). In urban centers throughout African regions, less than half of the solid waste produced is collected, and 95% of that amount is indiscriminately thrown away at various dumping sites on the periphery of urban centers, typically empty lots scattered throughout the city (Nigatu, Rajan, and Bizunesh 2011; Tewodros, Ruijs, and Hagos 2008). The main problem of waste management in the African context is, however, not only brought about by the amount of waste accumulated in the cities but also the incapability of the governments and waste management authorities to cope with the scope of the problem itself. Tanzania, for example, is faced with major problems of solid waste management with estimation of 30–50% of waste being left uncollected (Onibokun et al. 1999). In estimates for the capital city of Dar-es-Salaam, out of 3976 tons of solid wastes generated each day only 1440 tons is collected and sent to a landfill for disposal. In addition, approximately more than 70% of the daily waste generated is left near the houses, on the streets, in markets, or in drainage channels (Onibokun et al. 1999). In Kenya, the capital city of Nairobi, solid waste generation ranges from about 800 to 1000 tons per day. But the city municipality has a capacity of collecting only 400 tons daily. Likewise, in Malindi, a secondary large town in Kenya, estimates for 1991 indicate that less than 21% of waste generated reached the dumping sites. A parallel situation is also observed in Kinshasa, which is the capital and largest city of the Democratic Republic of Congo, where waste is only collected in a minority of households, while in the rest of the city it is left scattered, as in the case of Dar-es-Salaam (Onibokun et al. 1999).
Several studies have been conducted on municipal solid waste management in many cities of developing countries, such as Ethiopia, where waste management is insignificant and waste is dumped along roadsides and in open areas, threatening health and attracting vermin and posing a serious threat to the environment (Pin-Jing 2012; Onibokun et al. 1999; Tewodros, Ruijs, and Hagos 2008). Unlike in the developed world, dumping in open areas, roadsides, and valleys has been widely used in many cities of developing countries (Taewodros, Ruijs, and Hagos 2008).
In the Ethiopian perspective, the key intention of most of the investigations conducted so far on this broad agenda focuses on the effectiveness and efficiency of an already established system of the municipal solid waste management system. The researchers strongly believe that municipal solid waste management as a sector is a highly neglected sector in Robe town. Numbers of urban dwellers in Robe town are rapidly increasing over time. Urbanization and population concentration in Robe town are increasing at a rate of 6%, which is more than the regional average of 4.2%. This rapid increase of urban population accelerates solid waste generation in the town. Therefore, the primary objective of the study was to examine municipal solid waste generation and disposal systems, as well as factors that determine the solid waste generation and disposal, in Robe town.
Materials and methods
Philosophical foundation of the study
In any study, there is a need to clearly set up the philosophical foundation of the research, ontology, epistemology, and theoretical perspective prior to selecting a methodology. Ontology is the beginning point of any research, after which the epistemology and methodological position logically flow. Ontology is the study the nature of existence of reality and its characteristics (Creswell, 2007). From two contrasting ontological traditions (ontology of being and ontology of becoming) this study employed the “being” ontology. In this form of ontology, the reality is seen as being composed of clearly formed entities with identifiable properties and represented by symbols, words, and concepts (Gray, 2004). Epistemology is one of the core branches of philosophy and is concerned with the theory of knowledge. Epistemology affords a philosophical background for deciding what kinds of knowledge are legitimate and adequate (Gray, 2004). Among the three epistemological positions (objectivism, constructivism, and subjectivism), this study employed objectivism and constructivism from the ontology of being. The position of objectivist reality is that reality exists in the external world independently of human consciousness and this reality is single (Gray, 2004;Knox, 2004). The theoretical perspective closely linked to objectivism that is adapted for this study is positivism. This is because positivism is congruent with objectivism. The process of research in positivism is deductive, which focuses on testing theory (Creswell, 2009; Creswell & Piano Clark, 2011; Gray, 2004). This process of research is, therefore, strongly associated with a quantitative research approach, in which a linear regression model was applied to measure the determinants and factors affecting the amount of solid waste generated and its disposal in Robe town.
The position of constructivists about truth and reality in the social world is that realities do not exist in the external world; rather, they are created by the subject’s interactions with the world where we live and work, and realities are multiple (Creswell, 2009; Gray, 2004; 2009). Consequently, meaning is constructed, not discovered (Creswell, 2009). Therefore, the goal of the the researcher is investigating the socially and culturally influenced multiple views of research participants and the process of interaction among individuals (Creswell, 2009; Creswell & Piano Clark, 2011). A theoretical perspective closely linked with constructivism is phenomenology. Phenomenology holds that any attempt to understand social reality has to be grounded in people’s experiences of that social reality (Gray, 2004). The inductive process of research is a bottom-up process that focuses on generating theory through interconnecting broader themes developed from multiple views of participants (Chen et al. 2011; Creswell & Piano Clark, 2011). This process of research is associated with a qualitative research approach. Therefore, the perception, values, and attitude of households with respect to municipal solid waste were studied using this method.
Description of study area
The study was conducted in Robe town, located in South Eastern Ethiopia. Robe town is located about 430 km to the southeast of the national capital, Addis Ababa. The total area of the town is 8024 km2. Robe town is located at 07°08’00”N and 40°00’00”E. Population size of the town, according to CSA (2007), was about 54,337. After a period of 8 years from the CSA report, the population size of the town has shown a drastic change so that now it is estimated to be 73,859. According to the national survey made by CSA in 2007, the total number of households in Robe town is about 13,471. The town is divided into three administrative kebeles, namely, Oda Robe, Beha Biftu, and Chefe Donsa, consisting of about 5351, 2172, and 5948 households, respectively. Generally, the town is growing at an alarming rate of 6% per year, far more than the national average growth rate of 4.2% per year (Oromia Planning Bureau, 2016). Robe town is the administrative center of Bale Zone, which is one of the geographically largest, most economically significant, and most climatically conducive zones in Ethiopia. Currently, the town is serving as a center for numerous governmental and nongovernmental institutions. The combined effect of the economic and ecological importance of the town is attracting more people from different areas of the country (see Table 3).
Research design, sampling, and data collection
A mixed research approach was used for this study since effective research on municipal solid waste generation and disposal makes use of both quantitative and qualitative research approaches on the bases of quantitative and qualitative philosophical foundations of research, respectively. Two stages of sampling techniques were used to select sample households. in the first stage, Oda Robe Kebele from Robe town was purposively selected. In the second stage, 372 households were selected from 13,471 households of the town using a systematic sampling technique. To determine the representative sample sizes for the total target population of this study, researchers used the formula designed by Yemane (1967). According to Yemane, having a confidence level of 95% with a sampling error of 5%, the sample size n is determined as follows: 
(1)
where N is total households.
A formal sample survey used to be used to collect primary data for the study. Therefore, a structured and unstructured questionnaire was used to collect primary data from urban households. Observation and interview were also used to collect complementary data.
Data analysis technique
Both quantitative and qualitative techniques were employed to analyze municipal solid waste generation and disposal conditions. Qualitative data were analyzed in a descriptive way, while quantitative data were analyzed using linear regressions. Linear regression was used to analyze determinants of solid waste generation and factors responsible for proper disposal of solid waste in Robe town. Linear regression was also used to show the relationship between dependent variables and independent variables. Furthermore, tables and percentages were used in the analysis technique.
Results and discussion
General background of respondents
Table 1 illustrates the general characteristics of the respondents. Of the total respondents, 35% (130) were male and the remaining 65% (242) were female. Most of the respondents were female, as solid waste management encourages the participation of females.
Table 1. General background of sample households (N = 372).
As far as the education level of respondents is concerned, most of the respondents (34%) had no formal education, and 66% of respondents acquire some level of formal school education: 19.1% attended primary school, 17.2% attended secondary school, 11.3% had a diploma, and 18.3% had a degree and above. The average age of households was 43.15 years with standard deviation 10.481. The average family size of households was 5.14 and the standard deviation was 3.33. Regarding job categories, 29% of the respondents were government employees, and 71% were self-employed.
Factors affecting solid waste generation in Robe town
Solid waste generation varies in different countries, cities, and municipalities, in developing countries. One important requirement in waste management is the provision of a record of waste generation in terms of quantity and composition (Cheru 2010). This enables the management to deal better with the amount and the various categories of waste provided. However, it is difficult to get waste generation statistics in quantities, as well as composition, for all the countries including Ethiopia.
The study indicated that about 97.092 kg of solid waste is generated daily from the town. The result of the study further indicates that the generation rate of the town was estimated to be 0.261 kg/person/day. Furthermore, the study shows that out of the total solid waste generated in the town, only 57.5% is properly disposed to the landfill site, whereas the remaining 42.5% is illegally dumped at the roadsides and in open fields and stormwater drainage canals.
Some scholars have recognized factors influencing the principles of the waste management systems. According to Sujauddin, Sm, and Hoque (2008), cited in Guerrero, Maas, and Hogland (2013), the generation of waste is influenced by family size, education level, and monthly income. Shekdar (2009) suggests that the quantity of solid waste generated is lower in countries with lower gross domestic product (GDP). Table 2 analyzes factors affecting solid waste generation, using a linear regression model.
Table 2. Coefficient of determination of solid wastes.
As illustrated in Table 2, R2 is 0.78, which indicates that 78% of the variation independent variable (solid waste generation) explains the variation in the independent variables. But the remaining 22% of total variation in solid waste generation is unexplained. This means that 78% of total variation in the dependent variable is explained by the variables in the equation (sex, levels of income, house ownership condition, family size, and reuse and recycling and knowledge of compost preparation). The result reveals that the explanatory variables are strongly correlated with the dependent variable. Thus, as indicated in the table, the p values of six independent variables are less than 0.05 (p < 0.05) and we can conclude that the overall model is statistically significant and the independent variables have a combined effect on the dependent variable.
Therefore, based, on the regression coefficients of dependent and independent variables the equation can be written as follows: 
(2)
(3)
Female respondents change the amount of solid waste generated by −12.963 times compared to males. This indicates that female households provide lower waste by a factor of 12.963 versus that of the males (if other factors remain constant, it can be expressed as 
). For a 1-unit change in average income level, solid waste generated is increased by 0.014 units (1 unit change in x2 causes 0.14 unit change in y). If a household lives in a private house, waste generated decreased by 17.423 units.
Similarly, as family size increased by 1 unit, the amount of solid waste generated increased by 4.43 units, so a 1-unit change in X4 changes the dependent variable (Y) by 4.43 units. If respondents reuse and recycling of solid waste (SW) increases by 1 unit, the amount of solid waste is reduced by −12.461 units. And finally, when respondents know about compost preparation, the total solid waste generated from individual households is decreased by −3.275 units.
Determining factor of proper disposal of solid wastes in Robe town
Tewdeos, Ruijs, and Hagos (2008) analyzed the factors that influence household waste disposal decision making. Results showed that the supply of waste facilities significantly affects waste disposal choice. Inadequate supply of waste containers and longer distance to these containers increase the probability of waste dumping in open areas and roadsides relative to the use of communal containers. Insufficient financial resources limiting the safe disposal of waste in well-equipped and engineered landfills and absence of legislation are mentioned by Pokhrel and Viraraghavan (2005).
From Table 4, R-squared is 0.717, which indicates that 71.2% of total variation in the dependent variable is explained by independent variable in the equation. The remaining 28.8% of total variation solid waste disposal is unexplained. This means that 71.2% of the variation in the dependent variable (solid waste disposal) is explained by independent variables such as access to training, municipality supervising, average income, accessibility to the small-scale enterprise, participation in cleanup campaign, and the level of education and awareness of respondents.
Table 3. Coefficients of variables that determine the generation of municipal solid waste in Robe town.
Table 4. Coefficient of determination of linear regression analysis of solid waste disposal.
There are seven explanatory variables (Table 5) that are considered in this study: 
(4)
Table 5. Linear regression result of factors determine municipal solid disposed in Robe town).
Table 6. current condition of Robe town municipal solid waste practices.
Table 7. Effort made by municipality to provide municipal solid waste management (SWM) services in Robe town.
where 
is the disposal of solid wastes, and
are explanatory variables indicated in Table 4.
are estimated regression coefficients associated with the explanatory variable.
is constant (error estimates). Thus, the linear regression model depicts the disposal of solid wastes in the study estimated as a function of
(5)
The effect of each independent variable on the dependent variable (solid waste disposal) is described by using an unstandardized beta coefficient. Thus, unstandardized beta coefficients illustrated that any change in an independent variable can bring change in the dependent variable by their individual coefficients. Accordingly, a 1-unit change in education levels of respondents changes total solid average waste properly dumped by 3.019 units (
). The more educated households are, the higher the waste disposal will be. This result indicates a 1-unit change in educational level will bring 3.019 unit changes in the independent variable. Similarly, a 1-unit change in average income levels changes the dependent variable 0.015 units (
). Lack of awareness and training decreases the amount of SW properly disposed of by −1.667 (
) and −2.384 (
) units, respectively. Another factor that affects the proper disposal of SW is the participation of households in the cleaning up campaign. Participating in the cleaning up campaign is increasing the proper disposal of SW by 7.6 (
) units compared to nonparticipant groups (Table 3).
The results of the study revealed that about 42.5% of respondents illegally dispose of solid wastes into a different environment. The major reasons behind this illegal disposal of solid waste of residents are a lack of commitment and clear and adequate awareness as well as training about a proper solid waste management system. Furthermore, there is a lack of door-to-door solid waste collection service, and absence of public solid waste containers. According to information obtained from respondents, 55.1% of the town residents did not have awareness of rules and regulations of solid waste management and its consequences on environment and health. For instance, illegal solid waste disposal by residents also closed and damaged drainage systems and forced liquid waste to stand on street sides. It also pollutes the air, water, and soil, and the combination of these may affect the beauty of the town and bring health problems. A study conducted by Alie in 2015 revealed that in Dassie town 76% of solid waste generated in the town is not properly dumped. Similarly, research conducted by Bizatu in 2008 revealed that about 66% of solid waste in Kersa town is dumped in open space. A study conducted by Mengistu and Assegid in 2014 also shows that in Adama town about 65% of households had no training on the method of handling solid wastes.
The result of this study indicates that in Robe town about 40.3% of households were unsatisfied and 30.4% of households were very unsatisfied with the current condition of municipal solid waste management (MSWM) practice in Robe town.
Generally, about 70.7% of households were not satisfied with current MSWM practice. Similarly, 58.6% of households regarded efforts made by the municipality to provide efficient SWM service as very weak. This weak waste management service in the study areas resulted from weak municipal waste management efforts and absence of supervision from municipal offices, shortage of budget, the absence of responsibility at each level in communities and institution, and limited access to training and community participation in solid waste management service and low coordination of stakeholders.
Conclusion and recommendation
The results of the study illustrated that the amount of solid waste generated from that town is high, which is estimated to be about 97.092 kg/day, and the generation rate of the town is 0.0261 kg/person/day. In the results of this study, solid waste generation of the town is affected by sex, average income, family size, house ownership, and reuse, recycling, and composting. Disposal of solid waste is also affected by education level, average income, the level of awareness of households, accessibility to training, municipal supervision, and participation of households in the cleanup campaign. This study shows that households have low levels of awareness toward solid waste management and associated problems. The solid waste disposal system of Robe town is an open dump, which is very poor and below the standard, and therefore, solid waste management is very insignificant due to the combined factors that arose from municipality and communities of the town. Thus, to overcome the problems of solid waste generation and disposal of Robe town, the municipality must strongly work on waste reduction measures like reducing, recycling, reusing, and composting. The municipality has to deliver to fill the gap trainings on how to separate wastes by their composition. Thus, the municipality must deliver training to raise the awareness of households. There is no appropriate landfill site for solid waste management. Accordingly, the municipality must think about and build a well-standardized landfill enabled to control leachate material and gasses outgoing from the site.
| Characteristics | Value |
|---|---|
| Gender (%) | |
| Male | 35 |
| Female | 65 |
| Age (years) | |
| Mean | 43.15 |
| SD | 10.481 |
| Education (%) | |
| No formal education | 34.1 |
| Primary | 19.1 |
| Secondary | 17.2 |
| diploma | 11.3 |
| Degree and above | 18.3 |
| Family size (number) | |
| Mean | 5.14 |
| SD | 3.33 |
| Job categories (type) | |
| Employee | 29 |
| Private | 71 |
| R | R squared | Adjusted R squared | Change statistics | ||
|---|---|---|---|---|---|
| R2 change | F change | Sig. F change | |||
| .885 | 0.783 | 0.780 | 0.783 | 216.793 | 0.000 |
| Unstandardized coefficients | Standardized coefficients | 95% Confidence interval for B | |||||
|---|---|---|---|---|---|---|---|
| Model | B | Std. error | Beta | t | Sig. | Lower bound | Upper bound |
| (Constant) | 52.814 | 2.503 | 21.097 | .000 | 47.891 | 57.737 | |
| Sex(x1) | −12.963 | 1.608 | −.272 | −8.063 | .000 | −16.125 | −9.801 |
| Average Income(x2) | .014 | .001 | .575 | 16.814 | .000 | .012 | .016 |
| House Ownership(x3) | −17.423 | 1.284 | −.408 | −13.567 | .000 | −19.949 | −14.898 |
| Family Size(x4) | 4.430 | .814 | .144 | 5.442 | .000 | 2.829 | 6.031 |
| Reuse/ Recycle (x5) | −12.461 | 1.301 | −.261 | −9.580 | .000 | −15.019 | −9.903 |
| Composting(x6) | −3.275 | 1.198 | −.072 | −2.733 | .007 | −5.632 | −.918 |
| R | R square | Adjusted R square | Change statistics | ||
|---|---|---|---|---|---|
| R2 change | F change | Sig. F change | |||
| 0.847 | 0.717 | 0.712 | 0.717 | 130.141 | 0.000 |
| Unstandardized coefficients | Standardized coefficients | 95% Confidence interval for B | Collinearity statistics | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Model | B | Std. error | Beta | t | Sig. | Lower bound | Upper bound | Tolerance | VIF |
| (constant) | 16.940 | 2.387 | 7.095 | .000 | 12.245 | 21.635 | |||
| Level of education (X1) | 3.019 | .511 | .226 | 5.903 | .000 | 2.013 | 4.025 | .538 | 1.859 |
| Average income (X2) | .015 | .001 | .676 | 20.552 | .000 | .013 | .016 | .728 | 1.374 |
| Awareness (X3) | −1.677 | .529 | −.100 | −3.173 | .002 | −2.716 | −.638 | .792 | 1.262 |
| Accessibility of training (X4) | −2.384 | 1.419 | −.053 | −1.680 | .004 | −5.174 | .406 | .801 | 1.248 |
| Municipal supervision (X5) | 6.573 | 1.349 | .149 | 4.872 | .000 | 3.920 | 9.226 | .844 | 1.184 |
| Accessibility to MSE (x6) | −20.199 | 1.436 | −.489 | −14.068 | .000 | −23.023 | −17.376 | .653 | 1.532 |
| Participation on cleanup campaign (x7) | 7.600 | 1.348 | .189 | 5.638 | .000 | 4.949 | 10.251 | .702 | 1.425 |
| Current condition of MSW practice | Frequency | Percent |
|---|---|---|
| Satisfactory | 10 | 2.7 |
| Fair | 99 | 26.6 |
| Unsatisfactory | 263 | 70.7 |
| Very unsatisfactory | 113 | 30.4 |
| Total | 372 | 100.0 |
| Efforts made by municipality to provide efficient SWM services | Frequency | Percent |
|---|---|---|
| Very weak | 218 | 58.6 |
| Weak | 77 | 20.7 |
| Fair | 65 | 17.5 |
| Strong | 12 | 3.2 |
| Total | 372 | 100.0 |
Acknowledgment
The authors are appreciative of the Robe town administrative bodies and town municipal authorities, town beautification office, and Robe town administrators for their collaboration and providing permission to carry out this study.