Households' source separation behaviour and solid waste disposal options in Ghana's Millennium City

Journal of Environmental Management 259 (2020) 110055

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Journal of Environmental Management journal homepage: http://www.elsevier.com/locate/jenvman

Research article

Households’ source separation behaviour and solid waste disposal options in Ghana’s Millennium City Hamdiyah Alhassan a, *, Paul Adjei Kwakwa b, Ebenezer Owusu-Sekyere c a

Department of Agricultural and Resource Economics, University for Development Studies, P.O. Box TL 1882, Tamale, Ghana Presbyterian University College, Ghana, School of Business and Economics, P.O. Box 59 Abetifi, Eastern Region, Ghana c Department of Development Studies, University for Development Studies, Ghana b

A R T I C L E I N F O

A B S T R A C T

Keywords: Source separation Multinomial logistic regression Ghana Solid waste disposal

Poor solid waste management has increasingly taken a hegemonic position in urban policy discourse in Ghana. Often, the discourse centers on free market principles and inflexible waste management laws that promote privatization and deregulation. Recently however, source separation is dominating discussions on policy alter­ natives. This study investigates determinants of households’ source separation behaviour and solid waste disposal options among residents of Ghana’s ‘Millennium City’- Accra using logit and multinomial logit regression models respectively. The logit regression estimates show that households’ source separation behaviour is determined by gender, income, monetary incentives, attitude, compound house dummy, type of service pro­ vider and other household location variables. The multinomial logit estimates reveal that gender, age, age square, income, household size, employment, housing type, and attitude predicted household disposal options. We argue that to win the ‘garbage war’, source separation should be promoted by the Accra Metropolitan As­ sembly as this may enhance positive attitudes towards proper waste management.

1. Introduction Households remain one of the greatest solid waste generators in the world. Their commitment to engage in solid waste management (SWM) practices is therefore crucial in the direction of having sustainable and quality environment (World Bank, 2018). Geared towards an under­ standing of households’ SWM practices, empirical studies have been carried out in the past to ascertain the determining factors of house­ holds’ SWM behaviour (Alhassan et al., 2018). Evidence suggests a number of factors influence households’ SWM behaviour but such fac­ tors are country or area specific and therefore makes it difficult to have a one-size fit-all factors. Thus, identifying the drivers of households’ SWM behaviour for specific area of interest cannot be over emphasized. From the foregoing, the objective of this paper is to investigate the de­ terminants of household source separation behaviour and solid waste disposal options in the Accra Metropolitan Area of Ghana. Since the dawn of Sustainable Development Goals (SDGs), environ­ mental sustainability has been on the radar of international and aca­ demic communities. The reason is that sustainable environment has implications on agricultural productivity, peaceful society, water secu­ rity, energy security and human health (Oteng-Ababio et al., 2017). A

significant factor that accounts for environmental deterioration is urban pressure. With majority of the world’s population living in urban areas, urban waste has increased (World Bank, 2018). The increased urban waste in various compositions follows the population pressure, munic­ ipal expansion, economic development, improvement of people’s living (Li, 2007) and changing life style of urban population (Gutberlet, 2017). From all indications, the urban growth process is not going to cease in the coming years. It is therefore imperative that society found a way to maximize the associated benefits while managing the environmental deteriorating effect through the implementation of sustainable solid waste policies (Kwakwa et al., 2018). Statistics reveal that global waste has witnessed an increment from 5.6 million tonnes in 1997 to 7.65 million tonnes in 2007 representing about 28% growth and the projection is that by 2020 it will increase by 30% (Tan et al., 2015). Also, according to Hoornweg and Bhada-Tata (2012), urban solid waste in 2012 saw about 48% increase over the past 10 years amounting to 1.3 billion tones and it is expected to reach 2.2 billion tonnes by 2025 (Maskey, 2018). The Sub-Saharan Africa (SSA) region generated 174 million tonnes of waste or 0.46 kg per person each day in 2016. Although this figure is the lowest globally, it is expected to triple by 2050 (World Bank, 2018). Further, waste

* Corresponding author. E-mail address: [email protected] (H. Alhassan). https://doi.org/10.1016/j.jenvman.2019.110055 Received 6 August 2019; Received in revised form 29 October 2019; Accepted 30 December 2019 Available online 9 January 2020 0301-4797/© 2020 Elsevier Ltd. All rights reserved.

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Journal of Environmental Management 259 (2020) 110055

qualitative in nature without establishing any relationships between SWM practices and certain variables of interest. As a result, this study does an econometric analysis on solid waste source separation behav­ iour and disposal options of households in Ghana’s capital, Accra. The contributions of this study to the literature are four folds: a) it is the first study to the best of our knowledge to estimate the drivers of households’ disposal behaviour econometrically in Ghana; b) the study examines the effect of monetary incentive on solid waste separation behaviour; c) it also investigates the possible effect solid waste separation may have on solid waste disposal behaviour; and d) to the best of our knowledge, this is the first study to econometrically examine the effect of socioeconomic, socio-psychological and situational factors on household solid waste disposal and source separation behaviour in a single study. The rest of the paper is organised as follows; Section 2 reviews relevant literature, Section 3 describes the data and method used, Section 4 explains and discusses the result of the study, and Section 5 concludes and offers policy recommendations.

generation in urban areas of SSA which stands at 0.74 kg per person each day is higher than the regional average (World Bank, 2018). This development presents a worrying situation since about 20–50% of municipal budget spent on urban waste management in developing countries including SSA countries is able to collect about 40–70% of the waste generated (The World Bank, 2016). The situation in Ghana is not different from other developing coun­ tries. Ghana generates 0.51kg/capita/day which is higher than the regional average of 0.46kg/capita/day (World Bank, 2018). Efforts by city authorities in Ghana to manage solid waste has been stifled by numerous challenges including poor public attitude, inadequate infra­ structure, inadequate equipment, and poor maintenance culture (Badoe, 2014). Many of these challenges are financial related. Thus, the financial stance of the authorities is a major setback to managing the urban waste in the country. For instance (Oteng-Ababio, 2011) has documented that it costs authorities in Accra US$307,340 and US$163,910 in a month on solid waste haulage and maintenance of dump sites respectively; and in Kumasi about US$491,730 is spent monthly on solid waste collection and disposal. However, this amount is still not enough as common signposts to the cities are mountains of solid waste, streets littered and choked drains (Owusu-Sekyere, 2019). With such a huge financial constrain, it becomes necessary to pro­ mote solid waste reduction, reuse, recycling and recovery. Generally, the issue with solid waste is not the quantity being generated but rather the inability on the part of the government to keep up with its man­ agement (Oteng-Ababio, 2011; Kyere et al., 2019). Thus, it becomes a concern when the increasing quantities are not matched by increasing government expenditure. Such a situation only encourages indiscrimi­ nate disposal practices. It is for this reason that emphasis is placed on recycling and reuse (Afroz et al., 2011; Oteng-Ababio, 2014), and proper solid waste disposal (Fobil et al., 2008; Oteng-Ababio, 2013; Miezah et al., 2015). The literature highlights that source separation promotes recycling, reuse, and recovery of solid waste which also helps to reduce solid waste at landfill sites (Afroz et al., 2011; Almasi et al., 2019). This will also help to reduce environmental pollution (Rahji and Oloruntoba, 2009; Matter et al., 2013). Source separation also creates room for more land space and it reduces cost (Chen et al., 2017; Al-Khateeb et al., 2017). It also prevents rag pickers from getting hurt; it prevents the formation of leachate and methane gases that may degrade the envi­ ronment (Chintan Environmental Research and Action Group, nd). It is therefore no wonder that some developing countries have geared towards source separation and proper disposal of solid waste (Afroz et al., 2011; Almasi et al., 2019). The numerous advantages associated with solid waste separation at source could be the reason for upsurge in advocacy by policy makers, environmentalists and the government of Ghana towards effective SWM. Fact is Ghana has recently mounted strong campaign towards recycling and recovery as contained in the Environmental Sanitation Policy (2010). The policy sees the need for waste separation to achieve effective waste reuse, recovery, reduction and recycling. The success of this policy would require the involvement of all sectors especially households who are key solid waste generators in the country. However, available literature suggests there is no formal system to encourage households to practice solid waste segregation at source (Alhassan et al., 2018). The implication is that government of Ghana’s effort to dealing with the solid waste menace may not be realized if situations at the household level do not change. As a step towards improving households SWM in the country, it is necessary to have knowledge on the drivers behind household’s solid waste separa­ tion and disposal behaviour. However, research to unravel the drivers of such behaviour in the country is limited. To this end the current study models the drivers of households’ solid waste separation and disposal behaviour in Ghana. Although studies on solid waste separation and disposal in Ghana are abound (see for instance, Alhassan et al., 2018; Amfo-Otu et al., 2013; Oteng-Ababio et al., 2017; Boamah, 2011; Puopiel, 2010; Douti et al., 2017; Gyimah, 2018) such studies have largely been descriptive and

2. Literature review The consumer utility maximization theory has been one of the main theories that underline studies on waste management (Alhassan et al., 2017). The theory contends that economic agents are rational and utility maximizing agents who make decisions by making use of all relevant information available and choose an option that provides maximum net benefits taking into consideration the budget constraint (Ben-Akiva and Lerman, 1991). The implication is that economic agents choose to adopt solid waste management behaviour based on the expected net benefit, given the available socioeconomic and situational factors. Empirical Studies on the effect of socioeconomic factors abound although the results are mixed. Alhassan et al. (2018) found that income decreases source waste separation intention among households in Ghana, and Huhtala (2010) found that willingness-to-pay for recycling decreases with income among residents in Helsinki, Finland. On the other hand, Dwivedy and Mittal (2013) noted that income increases household e-waste recycling behaviour in India. Saphores et al. (2006) revealed that the educated are more likely to participate in recycle in California. Also, Alhassan et al. (2017) found that education has a pos­ itive effect on willingness-to-pay for improved solid waste management among households in Ghana while Meneses and Palacio (2005) reported that education has no significant effect on recycling. Also, Alhassan et al. (2018) and Ekere et al. (2009) found that females in Ghana and Uganda respectively are more likely to participate in source separation as they are traditionally responsible for domestic waste management. However, Hage et al. (2009) found no link between gender and recycling. Abebaw (2008) found that education influenced household choice of solid waste disposal options. A related study by Binyaruka (2015), Sama and Mbwange (2017) confirmed that education influence households’ choice of solid waste disposal option. Income has also been observed to have significant influence on household choice of solid waste disposal option by Abebaw (2008) in Ethiopia, Sama and Mbwange (2017) in Tanzania. In addition, while Abebaw (2008), Binyaruka (2015), and Sama and Mbwange (2017) reported that gender and age have signifi­ cant effects on household disposal choice, Tadesse et al. (2007) found no significant relationship between household disposal decision and age. Some researchers (Jenkins et al., 2003; Kipperberg, 2007; Sheau-T­ ing et al., 2016; Wang et al., 2018; Sotamenou et al., 2019) have made a case for situational factors to be very influential when it comes to waste management behaviour. Situational factors measure the time, space and effort required to undertake waste separation behaviour. In effect, where the situation makes it easier and more convenient, households tend to practice proper waste management and vice versa. Kipperberg (2007) also reported that convenience is an important driver of Nor­ wegian recycling behaviour. Saphores et al. (2006) observed that proximity to the drop-off center increased recycling. Sheau-Ting et al. (2016) found that information on how to separate waste increase 2

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Journal of Environmental Management 259 (2020) 110055

Generally, Accra metropolis has been classified into three residential areas, namely, low, middle and high-income areas (Songsore, 2003). The low-income areas are sub-divided into indigenous and migrant low-income area and are associated with heavily congested neighbour­ hood with poor infrastructure and services. Majority of the residents live in compound houses which are poorly maintained and lack in-house facilities (toilets, bathrooms, water supply, etc). In addition, access to most homes by vehicles is also impossible as the road network is poor. In the middle-income areas, the compound housing type dominates but they are of higher quality and less congested compared to the low-income areas. Consequently, there is limited use of outdoor public facilities such as water and toilet. In contrast, the high-income areas are well-planned with clean surroundings. The residents in these areas are comparatively of high socio-economic status, with higher education. The community is not congested, with good road network and infra­ structure; it has a high amount of single houses, with high walls making constant interaction quite less. In this study a three-staged sampling design was used to randomly select 525 respondents with different socio-economic characteristics as this attribute is reported to influence households’ solid waste disposal and separation behaviour (Alhassan et al., 2018). In the first stage, following the classification of residential and neighbourhood into low, middle and high income areas in Ghana (see Agyei-Mensah and Owusu, 2010), one community was randomly selected from each residential area (i.e. indigenous low-income area, migrant low-income area, middle –income area and high-income area), giving a total of four communities (see Table 1). After this, the probability proportion by size sampling was used to select 35 Enumeration Areas (EAs) from the lists of EAs provided by the Ghana Statistical Service (2012) and this consists of the second stage. Finally, households in the selected EAs were listed and using the list as a sample frame, 15 households were selected systematically with a random start and interval separately for each EA, giving a total of 525 households. Head of households or/and wife in the selected households’ were interviewed (see Table 1 for detailed sampling). Following Krej­ chie and Morgan (1970) sample selection formula, the minimum sample size of 384 was obtained by assuming a sampling error of 5 per cent; 95% confidence interval and a standard population proportion of 50 per cent. However, the sample size was increased to 525 households to allow for more general inferences about larger population (Cohen, 1992). Data was elicited from the respondents with the help of structured questionnaire (see appendix 1 for detailed questionnaire). Guided by previous studies and information elicited from key stakeholders and focus group discussions with community members the topics in the survey’s questionnaire were based on the households solid waste man­ agement behaviour (i.e disposal of solid waste and source separation), theory of planned behaviour construct, motivators and barriers to solid waste separation, demographic and socio-economic characteristics of the respondents.

participation in source separation of waste. Sama and Mbwange (2017) also found that the frequency of empting trash bins affect the choice of solid waste disposal options in Cameroon. In addition, Gebreeyosus and Berhanu (2019) and Rai et al. (2019) also noted that frequency of waste collection, mode of transportation and distance to waste collection center significantly influence households choice of solid waste disposal options. In recent times, the effect of socio-psychological factors especially attitude on waste management behaviour has gained attention. Attitude toward waste management behaviour is positive or negative mindset an individual has towards the practice. As a pro environmental behaviour, a positive attitude will promote proper waste management and vice versa (Alhassan et al., 2018). Empirical studies have confirmed this. Alhassan et al. (2017) reported that attitudes exert positive effect on willingness-to-pay for improved solid waste management services. Knussen et al. (2004) also found that in Glasgow, Scotland, attitude toward waste is a strong predictor of household intensions to participate in bring-recycling schemes. In their study Pakpour et al. (2014) confirmed positive attitude toward waste increases household waste recycling behaviour in Iran. Vassanadumrongdee and Kittipongvises (2018) reported that environmental attitudes increase WTP for waste management. A variable that seems to have potential influence on waste man­ agement especially source separation behaviour is monetary incentive. Monetary incentive for separating waste offers personal gains to the individuals and that may influence households to engage in such prac­ tices. They may see the monetary reward as an extra benefit of sepa­ rating solid waste. However, not much empirical studies have considered the effect of monetary incentive on source separation. For instance Dwivedy and Mittal (2013) in their study found that monetary benefits affect consumer’s willingness to participate in e-waste recycling program in India. Monella and Leyaro (2017) also found that monetary incentive influence households’ willingness to participate in wastes separation for reuse and recycle. The aforementioned analysis reveals that the results from the empirical studies are inconsistent a situation which could be as a result of the differences in the estimation techniques, differences in the char­ acteristics of the study area, and the various proxies for waste man­ agement behaviour. Moreover, comparatively fewer studies have examined the predictors of households’ source separation behaviour in Ghana. Also, it is seen that there is limited economteric study on waste disposal behaviour in Ghana. In addition, fewer studies (Dwivedy and Mittal, 2013; Monella and Leyaro, 2017) have examined the effect of monetary incentive on waste separation. Further, no empirical study exists on the effect solid waste separation may have on solid waste disposal behaviour. It is these gaps in the literature that the present study seeks to bridge. 3. Study area and methodology

3.2. Estimation method

3.1. Study area, data collection and sampling technique

Determinants of households’ source separation behaviour: Logit regression model. The main model for household waste separation behaviour can be expressed as;

The study design is a cross sectional survey and data was collected from February to July. The research was conducted in Accra, the most populated and wholly urbanized city in Ghana and often referred to as a ‘Millennium City’ (Ghana Statistical Service (GSS), 2014). It is the economic hub of Ghana and hosts a significant number of industries and companies and this has attracted people from other regions and different socio-economic background to migrant there in search for better employment opportunity (World Bank, 2014). The population of Accra as at 2010 was almost 4.3 million (Ghana Statistical Service (GSS), 2014). The consequential effects of rapid urbanization and increase population growth couple with a lot of economic activities in the city has led to continuous increase in waste generation and changing waste types. This has outstripped the capacity of local authorities to manage waste sustainably (Oteng-Ababio, 2013).

y�i ¼ α þ xi β þ εi

[1]

where y*i is a respondent i’s utility of choosing an alternative and is a latent variable, β is a vector of coefficients of the explanatory variables (x), α is the intercept and εi is a random error term. The dependent variable, household source separation behaviour is binary in nature, taking a value 1 for adopting source waste separation or zero, for not adopting source waste separation. The binary outcome requires that a binary choice model is used. Drawing inspiration from the utility maximization theory (Ben-Akiva and Lerman, 1991) and previous 3

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Journal of Environmental Management 259 (2020) 110055

Table 1 Selected communities and sample allocation. Community

SES community

No. of households

Proportionate sample (%)

No. of selected EAs

Actual sample allocation to households

Airport residential area Dansoman Glefe Nima

High income Middle income Indigenous low income Migrant low income

1391 14,300 2368 19,196

4 38 6 52

2 11 4 18

30 165 60 270

37,255

100

35

525

Total

empirical studies as depicted in section 2, the explanatory variables in the current study are captured by household characteristics (age, gender, household size, income, education and occupation), attitude and monetary incentive. The rest are leaving in a compound house, reliance on private waste contractor and residential location all of which capture the prevailing situations that may facilitate or impede house­ holds waste separation behaviour in Ghana. Following Dwivedy and Mittal (2013), the logit regression model was used to estimate the factors that influence household source waste separation behaviour because it allows for the estimation of the proba­ bility that an event will occur or not, by predicting a binary outcome from a set of explanatory variables. The binary outcome can be repre­ sented by a dummy variable (yi) which is related to y*i as;

Table 2 Description of variable and descriptive statistics. Variables

Description

Measurement

Gender

Gender of household head Age of household head Income for household

1 if household head is 0.61 0.49 male, 0 otherwise Age of household head 42.99 10.33 (years) Monthly household 1446.00 1607.84 expenditure in Ghana cedis Years of formal 11.29 4.21 education Number of person living 4.33 1.94 in the household 1 if household head 0.66 0.37 worked in formal sector, 0 otherwise 1 if household receives 0.63 0.47 monetary incentive from source waste separation, 0 otherwise. 1 if household stays in a 0.74 0.44 compound house, 0 otherwise 1 if household head own 0.50 0.81 the house, 0 otherwise 1 if household used 0.16 0.37 house-to-house collection system, 0 otherwise 1 if household source 0.58 0.49 separate, 0 otherwise 1 if household stays in 0.11 0.32 indigenous low-income area, 0 otherwise 1 if household stays in 0.51 0.50 migrant low-income area, 0 otherwise 1 if household stays in 0.06 0.23 high income area, 0 otherwise Measurement House-to-house collection (HtH), informal waste collectors (INF), communal container collection (CCC) system and indiscriminate disposal method Measured as the average of the following five point Likert scale questions (with a reliability coefficient of 0.82): 1. In my opinion, source separation of solid waste is a good activity 2. I think that solid waste separation at home is interesting task 3. For me, solid waste separation at home is useful 4. Solid waste separation should be formalized in Ghana 5. Solid waste separation should be promoted in Ghana

Age Income Edu HHisze

Respondent level of education Household size

Occutype

Type of occupation

Monincen

Monetary incentive

Comphse

Leaving in a compound house

Tenancy

Tenancy type

where F is the cumulative distribution function (CDF) and the β parameter is estimated using the maximum likelihood procedure. In order to derive an explicit expression for these probabilities, an assumption is made about the distribution of the error terms. Assuming that each of the random terms is Type I Extreme Value distributed and the difference between random terms is logistically distributed, the probability of adopting source separation behaviour (Pi) is:

Private

Formal Private waste collector

WSB

Waste separation behaviour Indigenous lowincome area

h i Pi ¼ P yi ¼ 1 ¼

MLIA

Migrant lowincome area

HIA

High income area

Variables SWD

Description Solid waste disposal method

Attitude

Household attitude towards source separation

yi ¼ 1

if y�i > 0

[2]

yi ¼ 0

if y�i � 0

[3]

Using utility functions for two alternatives from Eq. (1) above, the probability of source separation behaviour is: P[yi ¼ 1] ¼ P(Ɛi > - xi β)

[4]

P[yi ¼ 1] ¼ -F(-xi β) ¼ F(xi β)

[5]

ðe xi β Þ ð1 þ exi β Þ

ILIA

[6]

Eq. (6), is estimated using the binary logit model (Greene, 2012). After obtaining the maximum likelihood estimates of the logit model, the marginal effect, which estimates how a marginal change in one in­ dependent variable changes the distribution of the dependent variable, holding all other variables constant is obtained. The empirical model for estimating household source separation behaviour is expressed as: WSBi ¼ α0 þ β1Gender þ β2Age þ β3Agesq þ β4HHsize þ β5Edu þ β6Income þ β7Monincen þ β8Attitude þ β9Occutype þ β10Comphse þ β11Private þ β12ILIA þ β13MLIA þ β14HIA þ Ɛi [7] The description and measurement of the variables in the above equation is presented in Table 2. Determinants of households’ choice of solid waste disposal method: Multinomial regression model. Households in the study area have to choose from four modes of solid waste disposal namely, house-to-house collection (HtH), informal waste collectors (INF), communal container collection (CCC) system and other illegal method such as indiscriminate disposal into drains, open space, water bodies, burning and burying (IND). Due to the multiple choices or outcome, the multinomial logit model (MNL) was used to examine the factors that influence households’ choice of a particular mode of solid waste disposal. The MNL was used over the probit or logit model because

Mean

Std. dev

it allows for estimation across more than two categories that are assumed to be mutually exclusive and it also corrects for endogeneity and interactions between different categories (Wooldridge, 2002). Following Greene (2012), the utility of i’s respondents for using solid waste disposal method j is;

4

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Journal of Environmental Management 259 (2020) 110055

[8]

Uij ¼ Vij þ Ɛij

Table 3 Type of solid waste source separated and motivators.

Where Uij represents respondents i’ s utility of choosing alternative j, Vij is the deterministic component of utility and εij is a stochastic element that represents unobservable influences on the respondent’s choice. If a particular respondent prefers option j in the choice set to any alternative option k, then the probability that the utility associated with option j exceeds that associated with the other options is; Pij ¼ P{Vij þ Ɛij > Vik þ Ɛij Δk ε C

[9]

where C is the set of all possible alternatives. Assuming that the error terms are independently Gumbel distributed the probability of choosing alternative j can therefore be expressed as; Pij ¼

exij β j Σ k¼i exik βk

[10]

Σ j¼1 Pj βjk Þ

Residential area in Accra metropolis Indigenous low-income area

Migrantlow income area

Middleincome area

Highincome area

Pure water sachet Plastic bottles, other plastics Food waste Metals Total

64.86

71.02

70.89

61.54

69.84

10.81

15.91

8.86

15.39

13.44

10.81 13.51 100

7.38 5.68 100

8.86 11.39 100

0.00 23.08 100

7.86 8.85 100

Residential area Indigenous low-income area

in Accra metropolis MigrantMiddlelow income income area area

Highincome area

Total

0.00

8.89

0.00

23.08

6.23

90.91

65.56

54.43

0.00

62.62

6.06 3.03

8.33 5.00

7.59 2.53

0.00 7.69

7.54 4.26

0.00

12.22

31.65

69.23

18.36

0.00 100

0.00 100

3.80 100

0.00 100

0.98 100

Factors that motivates household to source separate

Eq. (10), is known as the Multinomial logit model and this suggest the probability that respondent i will choose solid waste disposal method j among k alternatives (Greene, 2012), βj are the vector co­ efficients and xij denotes vector of independent variables which repre­ sents household characteristics (age, gender, household size, income, education, occupation and tenancy), attitude, staying in a compound house and waste separation behaviour. The last two captures the pre­ vailing situations that may affect the waste disposal method in Ghana. An important implication of this specification that follows from the independence of the error terms across the different options contained in the choice set is the property of the independence of irrelevant alter­ natives. This property requires that the probability of an option being chosen should be unaffected by the inclusion or omission of other al­ ternatives (Hausman and Mcfaden, 1984). In addition, the marginal effect of the model is estimated by taking the differential of Eq. (10) with respect to the independent variables holding other variables constant (Greene, 2012). The marginal effects equation is presented below: dPj ¼ Pj ðβjk dpk

Types of solid waste source separated

Commitment to clean environment sold for extra cash feed livestock Reuse empty bottles Given to waste collectors for free Burn the plastics Total

Total

financially from selling their waste to informal waste collectors and itinerant waste buyers, in the absence of formal channel. This study also asked respondents to state the type of waste they source separate and this is presented in Table 3. Based on the results, pure water sachets is the most separated waste (70%) in Accra metropolis, followed by plastic bottles, broken plastic chairs etc (13.44%), metals (8.85%), with food waste (7.86%) being the least separated waste. Regarding the various residential areas, in the indigenous lowincome area pure water sachet is the most separated waste (64.86%), followed by metals (13.51%). Similar pattern was observed in the middle- and high-income areas. The high demand for plastics by recy­ cling companies located in Accra motivate household to take up source separation as they earn money from the sales of these plastics. Also empty plastic bottles are reused for packaging local drinks; cooking oils and medicine whiles the metal cans are used by domestic charcoal seller to store charcoal. Similarly, Monella and Leyaro (2017) observed that plastic materials are the most recycled materials among households’ in Dar es Salaam. The zero (0) value for foodwaste in high-income area is expected. This is because most of the residents are the elite. Further, scavengers who usually go out sorting waste cannot gain access to such areas because the compound is walled and guided with security. Lastly, in Ghana only one vehicle come to collect waste and thus mixed sepa­ rated waste together, which discourage separation of waste at source. As presented in Table 3 the most important factor that motivates households’ to engage in source waste separation in Accra is monetary incentive (about 63%). Based on the residential areas, monetary incentive was the most important factor encouraging residents in the low-income areas (90.91%) to separate waste at source; in contrast, monetary incentive was the least motivational factor for residents in high-income area. This collaborates with other studies that have looked at similar issue such as by Monella and Leyaro (2017) and Mona (2010) who reported that monetary incentive encourage households to adopt source waste separation. Other reasons for households to separate waste are commitment to clean environment, the need to reuse empty bottles and the need to feed livestock.

[11]

The empirical model used to estimate the determinant of the choice of households’ solid waste disposal method is presented as; SWDi ¼ γ0 þ γ1Gender þ γ2Age þ γ3Agesq þ γ4HHsize þ γ5Edu þ γ6income þ γ7Occutype þ γ8Attitude þ γ9Tenancy þ γ10Cpmphse þ γ11WSB þ μi[12] Table 2, presents the variable description, measurement and the descriptive statistics of the sample households. The study sample households’ head are 61% male and the average age is about 43 years. On average household has a monthly expenditure (which is used as a proxy for household income) of about GH’ 1446.00 cedis. The household size is about 4 persons per household and about 16% of the sampled household work in the formal sector. Most of the sampled household stays in compound house (74%). About 63% of the respondents received money from the sale of separated waste. With an attitude score of 3.73, it suggests that the respondents agree that source waste separation is a good activity and thus have a positive attitude towards waste separation. The reliability coefficient of 0.82 which was measured using Cronbach’s α test suggest that the variable, attitude, is reliable. 4. Results and discussions 4.1. Household solid waste separation behaviour Table 3 presents the results for household solid waste separation behaviour in Accra Metropolis. The results reveal that majority of the respondents (58.10%) separate waste at source informally. It is also established that source separation behaviour is more prevalent in migrant-low income area (66.67%) and indigenous low-income area (55%). The fact that most of the respondents’ source separate waste is expected, as historically, waste generators in Ghana have benefited 5

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Journal of Environmental Management 259 (2020) 110055

The study also established that the four leading barriers to source waste separation (see Table 4) are lack of access to formal solid waste separation facilities (49.09%), inadequate storage container (14.55%), inadequate information on source separation (12.27%) and inadequate time to separate (10.91%). Consistent with the observation in Accra metropolis, lack of access to formal solid waste separation facilities was the most important factor which discourage residents in high-income (52.9%), migrant low-income area (54%), indigenous low-income area (36.67%) and middle-income area (47.67%) to adopt source waste separation. This was evident by the lack of formal solid waste separation facilities in the communities and the practice relating to mixed collec­ tion of solid waste by formal private waste contractors. So, it was not surprising when respondents cited lack of solid waste separation facil­ ities as a barrier to waste separation activities. Alhassan et al. (2018), Sidique et al. (2010) and Knussen et al. (2004) demonstrated that pro­ vision and availability of appropriate infrastructure is critical to encourage source separation and recycling behaviour as it reduces effort on waste management.

Table 5 Logit regression estimates for the determinants of households’ source separation behaviour.

4.2. Determinants of household solid waste separation behaviour Table 5 shows the coefficients and marginal effects of logit estima­ tions of the factors that influence households’ source separation behaviour in Accra. Based on the results (i.e marginal effect), gender, income, monetary incentives, attitude, house type, type of service pro­ vider and location variables (i.e indigenous low-income, migrant lowincome and high-income areas) significantly influence households’ de­ cision to engage in source waste separation. Consistent with expectation, male-headed household decreases the probability of source separation behaviour by 6.79% and is significant at 5% level. This suggests that male headed household is less likely to undertake source separation activity. This observation may be attributed to the fact that women in Ghana are traditionally responsible for domestic waste management and thus more likely to participate in waste separation activities. This con­ firms the findings of Ekere et al. (2009) and Banga (2013). Congruent with expectations, increases in household income de­ creases the probability of household source separation behaviour by 0.004% and is statistically significant at 5% level. This implies that affluence households are less likely to participate in solid waste sepa­ ration compared to poorer households and it confirmed our earlier findings. The reason for this observation is that the affluent is more

Indigenous low-income area

Migrantlow income area

Middleincome area

Highincome area

Total

Inadequate time to source separate Had not thought of sorting unsanitary to store separated waste inadequate storage container Lack of access to formal solid waste separation facilities Inadequate information on source separation

10.00

4.60

13.95

29.41

10.91

6.67

6.90

11.63

11.76

9.09

13.33

3.45

2.33

0.00

4.09

23.33

13.79

15.12

0.00

14.55

36.67

54.02

47.67

52.94

49.09

10.00

17.24

9.30

5.88

12.27

Total

100

100

100

100

100

Coefficients

Std. error

Marginal effect

Std. error

Gender (Male dummy) Age Age square Income

0.6336** 0.0496 0.0006 0.0004**

0.311 0.1154 0.0013 0.0002

0.0679** 0.0053 6.19 e 05 4.08e-05**

Education Household size Monetary incentives Occupation type (Formal sector dummy) Attitude Compound house dummy Private waste collector Indigenous low-income area dummy Migrant low-income area dummy High-income area dummy Constant Observations LR chi2 (14) Log likelihood Pseudo R-square

0.0276 0.0424 2.1485*** 0.3823

0.0457 0.0730 0.3887 0.4097

0.0029 0.0046 0.2305*** 0.0410

0.0329 0.0124 0.0001 2.04e05 0.0049 0.0079 0.0393 0.0438

2.6110*** 1.5234*** 2.0229*** 1.8309***

0.2843 0.4819 0.4883 0.5229

0.2801*** 0.1634*** 0.2170*** 0.1964***

0.0212 0.0491 0.0511 0.0553

0.8448**

0.4188

0.0906***

0.0445

- 2.8041***

0.9735

- 0.3008***

0.1027

10.6882*** 525 175.31*** 179.9554 0.4959

2.7623

Notes: ***, ** and * shows significance at 1%, 5% and 10% respectively.

likely to have busy schedules and thus attach a higher opportunity cost to time spent separating solid waste, since it involves time and effort. Empirically, the finding from this study is consistent with Huhtala (2010) and Banga (2013) but contradicts that of Ekere et al. (2009) who reported a positive relationship between income and source separation of waste among Ugandans. The marginal effect of monetary incentive is positive and significant at 1% level. Specifically, receiving money in exchange for sorted solid waste increases the probability of household source separation behav­ iour by 23.05%. This confirms our previous finding that monetary in­ centives motivate household to source separate solid waste and is consistent with Dwivedy and Mittal (2013). Attitude has a positive relationship with source separation behaviour and is significant at 1% level. More specifically, having a positive attitude towards source waste separation increases the probability of household source separation by 28.01%. This confirms the notion that households with strong and positive views about solid waste source separation are more likely to undertake source separation activities. This supports the findings of Alhassan et al. (2018). The compound house dummy has a positive relationship with source separation behaviour and significant at 1% level. Specifically, living in a compound house increases the probability of household source separa­ tion behaviour by 16.34%. In Ghana, people who live in compound houses tend to share common facilities such as bathrooms, etc which allows for continuous interaction creating strong social cohesion. Consequently, their source separation behaviour becomes readily visible and motivates or keeps significant pressure on people to separate their waste. The estimated results also show that, engaging the services of formal private waste contractor decreases the probability of household source separation behaviour by 21.70% and is statistically significant at 1% level. In Ghana formal private wastes contractors are not mandated to collect sorted waste and the current practice relating to mixed collection of solid waste by them discourage their clients from undertaking source separation activities. In addition, staying in migrant and indigenous lowincome areas increases the probability of household source separation behaviour by 9.06 and 19.64% respectively and both are statistically significant at 1% level. In contrast, staying in high-income area

Table 4 Barriers to households’ source separation. Barriers to households’ source separation

Variables

6

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Journal of Environmental Management 259 (2020) 110055

of the determinants of households’ choice of solid waste disposal are presented in Table 7. The estimation is done with illegal disposal (i.e disposing of into drains, open space, water bodies, burning and burying) as the base category to determine the relative effect of each predictor on the choice of solid waste disposal. The empirical results reveal that the LR is statistically significant at 1% level, implying that the independent variables jointly determine the drivers of household choice of solid waste disposal. The results are discussed as follow:

decreases the probability of household source separation behaviour by 30.08% and is significant at 1% level. This suggests that households’ in low-income area are more likely to undertake source separation activ­ ities because of monetary incentives they received from informal waste collectors. In the case of resident in high income area, inadequate time serve as a barrier to source separation of waste. 4.3. Descriptive statistics of household choice of solid waste disposal in Accra Metropolis

4.4.1. House-to-house collection system As presented in Table 7, the factors which influence households’ decision to use HtH collection system are gender, age, age square, in­ come, household size, employed in the formal sector, compound house dummy, attitude and adoption of source separation of waste. Maleheaded households’ decreases the probability of using HtH collection system by 6.77% and is significant at 1% level. The implication is that male headed households’ are less likely to use the HtH collection system than illegal disposal option because women are traditionally responsible for managing waste at home and will therefore be willing to register with formal private contractor to collect waste from their house. Oten­ g-Ababio (2010) and Saphores et al. (2012) found female to be responsible for domestic waste management and more willing to pay for waste collection. Age has a non-linear relation with household decision to use HtH collection service as age and age square has a positive and negative relation with HtH collection system and both are statistically significant at 1% level. This suggests that the decision to use HtH collection system as opposed to illegal disposal option increases with age to a certain level, beyond which it reduces again. This is reasonable because at the early stage of life income increases gradually and peaks at point and declines at retirement. Therefore, younger people will be willing to pay to have his/her waste collected at a fee than older people. This finding

Table 6 presents the mode of solid waste disposal by residential area in Accra Metropolis. A chi-square test conducted between the mode of solid waste disposal and the residential locations, reveal that, there is positive relationship between the mode of solid waste disposal and residential locations and is statistically significant at 1%. This shows that households’ choice of solid waste disposal option is dependent on their socio-economic status and residential location. Based on the survey, House-to-House (HtH), Communal Container Collection (CCC) system, informal waste collectors and illegal disposal of waste are the mode of solid waste disposal method used by respondents in the study area. The HtH collection and CCC system is the official arrangement of solid waste disposal system provided by formal waste contractors. The HtH collec­ tion system is prevalent in high-income area where there are good road networks and less congestion. The CCC system, on the other hand, is prevalent in low to middle income residential areas with poor road network and highly congested. As shown in Table 6, in Accra metropolis, all the respondents (100%) from high-income area and about 26% of respondents in middle-income area used the HtH system. This is because the HtH collection system operates predominately in the high-income areas where the road net­ works are good. Interestingly, majority of the respondents (55.67%) in the middle-income area used the services of informal waste collector. Informal waste collectors are unregistered waste service providers who provide solid waste collection services to waste generators. According to the respondents the informal waste collectors provide reliable and affordable service compared to the formal waste contractors and this motivate them to use their service. While most (57.78%) of respondents from the migrant low-income area use the CCC system, none of the respondents in the indigenous low-income area use it. In contrast, most (98.33%) of the respondents in the indigenous low-income area dispose of solid waste illegally on open dump, open space and lagoon. This goes to suggest that none of the respondents used the official system of solid waste disposal. It is possible to attribute this observation to their attitude towards solid waste. As argued by Oteng-Ababio (2010) and Alhassan et al. (2017), most resi­ dents in low-income areas view waste as a useless material and still have the perception that solid waste management is the responsibility of local authourity as they have enjoyed fee-free solid waste collection services since immemorial.

Table 7 Multinomial regression estimates for household choice of solid waste disposal system. Variables

Gender Male dummy Age Age square Income Education Household size Occupation type Formal sector dummy Attitude

4.4. Determinants of households’ choice of solid waste disposal options The marginal effects from the multinomial logit regression estimates Table 6 Mode of household solid waste disposal by residential area in AMA (%).

Tenancy dummy

Classification

Informal waste collector

CCC

HtH

Illegal disposal

Total

Indigenous lowincome Migrant lowincome Middle-income High-income

1.67

0

0

98.33

100

38.89

57.78

3.33

0

100

55.76 0 37.71

0 0 29.71

26.67 100 16.37

17.58 0 20

100 100 100

Compound house dummy Source separation Observations LR chi2 (33) Log likelihood Pseudo R-square

House-to-house collection (HtH)

Informal waste collector (INF)

Communal Container collection (CCC)

Marginal effect

Marginal effect

Marginal effect

0.0677*** (0.0190) 0.02111** (0.0110) 0.0002** (0.0001) 0.0001*** (2.09e-05) 0.0019 (0.0040) 0.0126* (0.0078) 0.0934*** (0.0.0373)

0.0585 (0.0426) 0.0195 (0.0158) 0.0003* (0.0002) 6.92e-05 (5.9e-05) 0.0109* (0.0065) 0.0288** (0.0133) 0.1244** (0.0623)

0.09311** (0.0395) 0.0354** (0.0151) 0.0005*** (0.0002) 0.0002*** (6.5 e 05) 0.0032 (0.0061) 0.0254** (0.0119) 0.0922 (0.06226)

0.0437*** (0.0169) 0.0001 (0.0215) 0.0462*** (0.0185) 0.0928*** (0.0315) 525 380.82*** 502.2509 0.2749

0.0692** (0.0326) 0.0672 (0.0468) 0.0847 (0.0669) 0.1211** (0.0542)

0.0024 (0.0303) 0.0021 (0.0444) 0.0286 (0.0639) 0.0169 (0.0516)

Notes: ***, ** and * shows significance at 1%, 5% and 10% respectively. Illegal disposal (i.e disposing of indiscriminately into drains, open space, water bodies, burning and burying) is the reference group.

Note: Chi-square (21) ¼ 709.059; Pr (¼ 0.000). 7

H. Alhassan et al.

Journal of Environmental Management 259 (2020) 110055

contradict that of Alhassan et al. (2017) and Adzawla et al. (2019). Income has a positive relation with household decision to use HtH and is significant at 1% level. An increase in income increases the probability of using HtH collection system by 0.01% than illegal waste disposal option. This suggests that the affluent is more likely to use the HtH collection system. This is attributed to the fact that the affluent has greater ability to pay for their waste to be collected at home. In addition, there are more likely to appreciate the environmental, economic and social benefit of proper disposal of solid waste. This supports the sub­ missions of Alhassan et al. (2017), Hagos et al. (2012), and Rahji and Oloruntoba (2009). The study also reveals that, the variable household size has a nega­ tive relationship with HtH and is statistically significant at 10% level. Specifically, an increase in household size decreases the probability of household using HtH system by 1.26% than illegal waste disposal op­ tion. This is reasonable because household size represent availability of family labour for waste disposal and thus the less likely to use the ser­ vices of formal waste collector to collect waste at a fee. It is observed that, working in the formal sector increases the prob­ ability of using HtH system by 9.34% than illegal waste disposal option. The result is statistically significant at 1% level. In Ghana, most workers in the formal sector earns monthly wage which tends to coincide with the monthly waste billing system used by the formal private contractor; making it more convenient (Oteng-Ababio, 2010). The results also demonstrate that staying in a compound house decreases the probability of using the HtH system by 4.62% than illegal waste disposal option. It is statistically significant at 1% level. The possible explanation can be that most compound houses in Ghana have inadequate space to keep extra waste bin provided by the formal private contractor. In addition, com­ pound houses in Ghana are more likely to be located in highly congested and poor road network residential areas where the HtH system is less likely to operate. The findings contradict the argument made by Adzawla et al. (2019) that staying in a compound house increases the likelihood of collecting domestic waste. Attitude toward source waste separation has a positive relation with the decision to use HtH collection system and is statistically significant at 1% level. More specifically, having a positive attitude increases the probability of using HtH collection system by 4.37% as opposed to using illegal waste disposal option. This is reasonable as those with positive attitude see the need for waste to be collected from their home by formal waste contractor at a fee. Alhassan et al. (2017) found a similar result. One of the key objectives of this current study was to examine the in­ fluence of household source separation behaviour on their waste disposal option. The study observed that that adoption of source waste separation decreases the probability of using HtH collection system by 9.28% and is significant at 1% level. This means that households that practice source waste separation are less likely to use the HtH collection system than illegal waste disposal option. In Accra, the formal private waste contractor who provides HtH collection service do not collect sorted waste separately and this discourage clients from separating waste at source and so this may be the reason for such an outcome.

5% level. Generally, larger households generate more waste and are endowed with labour which can be used to dispose of waste illegally or freely at open dump site rather than using informal waste collector which collect waste at a fee. It was observed that education has a positive relation with household decision to use the services of informal waste collectors and is statisti­ cally significant at 10% level. Specifically, a year increase in educational level increases the probability of using the services of informal waste collectors by 1.09% than to dispose of waste illegally. The fact that, the educated are more likely to use the service of informal waste collector can be attributed to the perceived high quality and reliable services offer by the informal waste contractor. However, working in the formal sector decreases the probability of using the services of informal waste col­ lector by 12.44% as opposed to illegal waste disposal option and is statistically significant at 5% level. The informal waste collectors oper­ ating in Ghana are not officially recognized by local authorities and their services are viewed as illegal and this may serve as disincentive for workers in the formal sector to use their services. It is also remarkable to observe that, attitude has a negative relation with household decision to use the services of informal waste collectors than illegal waste disposal option and is statistically significant at 5% level. Specifically, having positive attitude decreases the probability of using the services of informal waste collectors by 6.92%, which seems counterintuitive. The plausible explanation for this observation is that people have the perception that the informal waste collectors degrade the environment by disposing of waste illegally in open space and drains. The marginal effect of tenancy is negative and significant at 10% level. Thus, staying in your own house decreases the probability of using the services of informal waste collector by 9.27%, suggesting that house owners are less likely to use the services of informal waste collectors than use illegal waste disposal option. In Ghana, land lords are responsible for waste management and are mandated to register with the formal private contractor assigned to the community and thus less likely to use the service of informal waste collectors. In addition, household owners can also bury or burn their waste in their house rather than using the services of informal waste contractor. Another main objective of the study was to look at the effect of waste separation on waste disposal methods. As shown in Table 7, adoption of source waste separation increases the probability of using the services of informal waste collectors by 12.11% and is statistically significant at 5% level. Waste generators in Ghana have historically benefited financially from selling their waste to informal waste collectors; and this encour­ ages household using the services of informal waste collectors to sort waste at source. 4.4.3. Communal container collection system Gender, age, age square, income, and household size significantly affect household’s decision to use the CCC system. The marginal effect of gender is negative and significant at 5% level. Specifically, male-headed household decreases the probability of using the CCC system by 9.31% than using illegal waste disposal option. As argued previously, in Ghana women are traditionally responsible for waste disposal and thus, will be willing to carry waste and dump into the communal container at a fee. The results also establish that household decision to use CCC has positive and negative relationship with age (5% significant level) and age square (1% significant level) respectively, suggesting that the decision to use CCC system increases with age until certain level beyond which it de­ creases again. This contradicts Awunyo-Vitor et al. (2013) observation, who argued that the older people are more likely to use HtH collection options because they are more discipline and conscious of good sanita­ tion practices than the younger ones. Income has a negative relation with the decision to use the CCC system than illegal waste disposal option and is statistically significant at 1% level. An increase in income decreases the probability of using the CCC system by 0.02%. The implication is that the affluent is less likely to use the CCC system. Generally, the affluent are more likely to stay in a

4.4.2. Informal waste collector The results also reveal that age square, education, household size, employed in the formal sector, attitude and source separation of waste influences household’s decision to use the services of informal waste collectors noted in the local parlance as “Kaya Bola”. Age square has a positive relation with household decision to use the service of informal waste collector and is statistically significant at 10% level. This suggests that the decision to use the service of informal waste collector increases with age. This is attributed to the fact that older persons are more likely to be land-lord/lady and thus will like to increase their property value by engaging the service of informal waste collector to collect waste at source for a fee. An increase in household size decreases the probability of household using the services of informal waste collectors by 2.88% as opposed to illegal waste disposal option, and is statistically significant at 8

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Journal of Environmental Management 259 (2020) 110055

well-planned and good road network residential area where CCC system does not exist. Furthermore, the affluent are more likely to have space in their homes to bury or burn the waste they generate. This result is consistent with that of Oteng-Ababio (2013), but contradicts that of Tadesse et al. (2007) who reported that households with higher incomes dispose of waste in communal waste containers. Household size is found to increase the probability of using the CCC system (5% significant level) by 2.54% than illegal waste disposal option. A larger household size means the availability of labour used to dispose of waste into the central container which is located at a distance from the house. This finding contradict the observation by Adzawla et al. (2019) who reported that larger household decreases the probability of using open and public waste disposal.

Funding We profoundly thank Deutscher Akademischer Austauschdienst (DAAD) and Association of African Universities (AAU) in providing funding for the research. Availability of data and materials The dataset used in this paper is available and accessible upon request from the corresponding author. Declaration of competing interest The authors declare that they have no competing interests.

5. Conclusion and policy implication

Appendix A. Supplementary data

This study examined the determinants of households’ source waste separation behaviour and solid waste disposal options in Accra metropolis referred as ‘Millennium city’ in Ghana. The logit and multi­ nomial logit regression models were used to analyse the factors that influence households’ source waste separation behaviour and solid waste disposal options respectively. The logit regression estimates show that the determinants of households’ source separation behaviour are gender, income, monetary incentives, attitude, compound house dummy, type of service provider and location variables (i.e indigenous low-income, migrant low-income and high-income areas). A further analysis established that, the most and least separated solid waste is water sachets and food waste respectively. Also, the most important factor that motivates and discourages households’ source separation activities is monetary incentive and the lack of access to formal solid waste separation facility respectively. The multinomial logit estimates reveal that gender, age, age square, income, household size, employed in the formal sector, compound house dummy, attitude and adoption of source separation of solid waste pre­ dict household decision to use house-to-house collection system, while age square, education, household size, employed in the formal sector, attitude and source separation of solid waste drive households’ decision to use the services of informal waste collectors. Also, gender, age, age square, income, and household size influence household’s decision to use the CCC system. Based on the above findings the paper makes a number of policy recommendations. First, the results show that households’ attitude to­ wards source waste separation influence source separation behaviour and choice of solid waste disposal options, suggesting that Accra Metropolitan Assembly should intensify solid waste separation and proper waste disposal education as an effective way to encourage source separation and proper waste disposal. This may enhance positive atti­ tudes towards proper solid waste management. Also, households’ re­ ported that lack of formal solid waste separation facilities is the biggest obstacle to source separation behaviour. Thus, the government should institute and implement Waste Minimization policy which promote the 3Rs (i.e reduce, reuse and recycle) and makes waste separation mandatory. In addition, Accra Metropolitan Assembly which is the implementation agency should provide and make waste separation fa­ cilities accessible and convenient since this may promote source sepa­ ration behaviour. Considering monetary incentives as one of the factors that motivate source separation behaviour, it will be helpful if local authourities provide correct monetary incentives to encourage source separation activities. Furthermore the results revealed that adoption of source separation decreases the probability of using house-to-house collection option but increases the likelihood of using the services of informal waste contractor. Thus, the Accra Metropolitan Assembly should find innovative ways of integrating the informal waste contractor into the formal system, since they tend to fill the gap created by the formal waste contractor.

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