SUSTAINABILITY APPRAISAL OF WASTE MANAGEMENT IN NIGERIA: DEVELOPMENT AND EVALUATION OF AN INDEX BASED TOOL
ABSTRACT
Decision makers are continuously in search of a comprehensive yet simple means of assessing solid waste management to make effective and informed decisions. This is particular so for situations like Nigeria where streets are full of waste, many households have no waste collection services and a high rate of vehicle and equipment breakdown is recorded. Assessment is also crucial at a time when many waste management authorities are trying to embark on new revolutionary contracts with the private sector. Solid Waste Management assessment is a complex multi-dimensional process, involving multiple criteria and multiple actors and the many components that make up the system. Although various options such as incineration, gasification and composting are available as a solution for waste management, these options also add to the complexity of the situation in determining most preferred alternatives and decisions. In this study, an in-depth investigation of solid waste management in Nigeria is conducted by quantifying sustainable development to develop an assessment tool. Sustainable development with respect to solid waste management was broken down into its aspects and factors that influence those aspects in a hierarchy of three levels according to the procedure of analytic hierarchy process. Solid waste management practitioners across five locations representing Nigeria's multiple ethnic groups and diverse cultures and the climatic zones as well as four work sectors were surveyed. Data was obtained from a paired comparison based questionnaire survey using Analytic Hierarchy Process. A function was derived that illustrates the potential of SD as a tool for solid waste management assessment. General agreement across sectors was recorded but significant differences exist between regions. The regional difference highlighted indicates context as highly influential. Quick response and cooperation of participants suggests sympathy towards female researcher while slow contact establishment was recorded in Lagos despite an alliance with an indigene of the region. The function derived was adopted to evaluate the solid waste management strategy in Kaduna metropolis of Nigeria using a case study methodology. The accomplished assessment has shown that waste management strategies can be evaluated with the tool developed in this study. An index of 0.457 was established from the evaluation that employed the use of indicators, scoring and normalisation. High scores assigned to indicators will result in a high index, which suggests an effective strategy.
CONTENTS
TITLE PAGE i
DEDICATION ii
AKNOWLEDGEMENTS iii
DECLARATION iv
ABSTRACT v
CONTENTS vi
LIST OF FIGURES xiii
LIST OF PICTURES xiv
LIST OF TABLES xiv
OVERVIEW1
INTRODUCTION1
SOLID WASTE MANAGEMENT1
Solid waste management in Nigeria1
Legislation2
Solid waste generation and management elements2
Awareness and attitude3
Solid waste management assessment3
SOLID WASTE MANAGEMENT ASSESSMENT3
Sustainability assessment of solid waste3
RATIONALE AND AIMS OF STUDY4
METHODOLOGY5
Analytic Hierarch Process AHP5
RESULTS AND DISCUSSION OF LITERATURE AND QUESTIONNAIRE SURVEY6
CASE STUDY7
Case study methods7
SUSTAINABLE SOLID WASTE MANAGEMENT8
LITERATURE REVIEW9
INTRODUCTION9
SOLID WASTE MANAGEMENT9
Waste management hierarchy10
Integrated solid waste management11
Waste generation11
Responsibility of managing solid waste12
SOLID WASTE MANAGEMENT IN NIGERIA12
Nigeria12
Waste management legislation14
Federal government14
Local and state government15
CURRENT SITUATION16
Waste generation and composition16
Temporary Storage18
Collection and transportation18
Resource recovery and recycling21
Waste treatment and disposal21
Private sector participation22
Formal private sector22
2.2.6.2 Informal private sector 23
2.4.6.3 Informal sector entrepreneurs 24
Awareness and Attitude25
Awareness25
Attitude26
Cost, Funding and facilities26
Cost and Funding26
Technologies – Machinery, equipment and skilled labour27
Waste type and composition27
Road conditions27
Cost27
Availability of spare parts and technical skills27
Servicing requirements and haulage distances27
SUSTAINABILITY ASSESSMENT OF SOLID WASTE28
Environmental sustainability29
Air and water quality29
Resource Conservation30
Administrative sustainability30
Policy30
Management31
Responsibility issues32
Technical issues32
Social sustainability33
Health33
Social acceptability and Stakeholder involvement34
Social equity34
Service quality34
Economical and financial aspects35
Cost35
Employment35
SOLID WASTE MANAGEMENT ASSESSMENT36
Cost benefit analysis, CBA36
Life cycle assessment (LCA)37
Multi-criteria analysis38
RESEARCH RATIONAL39
SCOPE OF STUDY41
AIMS AND OBJECTIVES OF RESEARCH41
Aims41
Objectives41
INTRODUCTION41
RESEARCH STRATEGY42
PILOT SURVEY43
Participants of the Pilot Survey43
Postal questionnaire survey – Pilot44
THE STRUCTURED QUESTIONNAIRE SURVEY45
Sampling techniques and population46
Analytic Hierarchy Process (AHP)46
AHP – The procedure47
Hierarchical structure47
Pairwise comparisons48
Relative Weights – Eigen value method49
Aggregating Relative weights49
Expert choice software50
General application51
AHP application in solid waste management54
Participants54
QUESTIONNAIRE SURVEY56
Rationale for structured questionnaire survey56
Participants cooperation57
Questionnaire construction59
3.6.1 Questionnaire sequence 60
STUDY LOCATIONS60
Abuja61
Kaduna62
Lagos62
Maiduguri62
Port-Harcourt63
DATA PROCESSING AND ANALYSIS63
SUMMARY64
RESULTS AND DISCUSSION OF QUESTIONNAIRE AND LITERATURE SURVEY65
INTRODUCTION65
SUSTAINABLE DEVELOPMENT CONCEPT65
SUSTAINABILITY ASSESSMENT TOOL66
Sustainability assessment function67
SUSTAINABILITY ASSESSMENT ASPECTS68
Administrative aspect68
Environmental aspect69
Social aspect69
Economic aspect69
Aspects of sustainability assessment by sector70
Aspects of sustainability assessment by region71
FACTORS OF SUSTAINABILITY ASSESSMENT72
Environmental factors72
Environmental factors by sector73
Environmental factors by region73
Administrative factors74
Administrative factors by sector75
Administrative factors by region76
Social factors77
Social factors by sector78
4.5.3.1 Social factors by region 79
Economic factors79
Economic factors by sector80
4.5.4.1 Economic factors by sector 81
SUMMARY83
CASE STUDY83
INTRODUCTION83
SCOPE OF CASE STUDY83
Study area83
System boundary85
Temporary storage87
Collection88
Transportation89
Treatment and final disposal90
DATA INVENTORY92
Flow of waste92
5.3.1 Availability of Data 95
INDICATORS95
Developing the index96
5.4 METHODS 97
Environmental indicators97
Air Quality Indicator - Particulate matter98
Water Quality Indicator - Leachate98
Resource Consevation Indicator - Waste generation98
Administrative indicators99
Policy Indicator – Policy quality99
Management Indicator – Waste Collection100
Responsibility Issues Indicator – Information dissemenation101
Technologies Indicator – Breakdown of Conveyance fleet101
Social indicators102
Health Indicator - Exposure to waste102
Quaility of Service Indicator - Stakeholder satisfaction103
Stakeholders Participation Indicator - Stakeholders Awareness103
Social equity indicator – inter & Intra-generational equity104
Economic indicators104
Employment indicator – Job Creation104
Total cost – Cost recovery105
RESULTS AND DISCUSSION OF CASE STUDY ANALYSIS106
The environmental indicators106
Air quality106
Water quality107
Resource conservation107
The administrative indicators107
Policy indicators108
Management indicators108
Responsibility issues indicators108
Technologies Indicators109
The social indicators109
Health110
Quality of service110
5.5.3.3 Stakeholders’ involvement 111
5.6.3.4 Social Equity Indicators 111
The Economic indicators111
Employment Indicator - Job creation112
Total cost Indicator – Cost recovery112
Application to index113
CONCLUSION113
SUMMARY114
SUSTAINABILITY ASSESSMENT OF SOLID WASTE MANAGEMENT116
INTRODUCTION116
SOLID WASTE MANAGEMENT ASSESSMENT TOOL116
Differences across regions117
THE SURVEY AND APPLICATION OF AHP118
Participation of waste management practitioners119
Questionnaire delivery119
Effects of gender and ethnicity of researcher120
APPLICATION OF SUSTAINABILITY ASSESSMENT TOOL – CASE STUDY120
Data source120
The indicators121
Scoring and normalisation of indicators121
APPLICATION OF THE SUSTAINABILITY ASSESSMENT TOOL121
SUMMARY122
CONCLUSION AND RECOMMENDATIONS AND FUTURE WORKS123
METHODOLOGY124
RESULTS AND DISCUSSION OF QUESTIONNAIRE AND LITERATURE SURVEY125
CASE STUDY- KADUNA CITY125
GENERAL DISCUSSION127
FUTURE WORKS127
Application of the sustainability assessment tool127
Re-administrating the survey128
Baseline data128
SUMMARY129
REFERENCE 130
APPENDICES 152
APPENDIX 1 - MAIN QUESTIONNAIRE SURVEY 153
APPENDIX 2 – PILOT QUESTIONNAIRE SURVEY 158
APPENDIX 3 – WASTE MANAGEMENT LAWS 162
LIST OF FIGURES
Figure 2.1 Waste management hierarchy 10
Figure 2.2 Africa – Nigeria 14
Figure 3.1 Hierarchical structure of waste management Sustainability Assessment 47
Figure 3.2 Example of pairwise comparison 49
Figure 3.3 Map of Nigeria showing survey locations 63
Figure 4.1 Hierarchical diagram of the aspects and factors 67
Figure 4.2 Aspects of sustainability assessment by sector 71
Figure 4.3 Aspects of sustainability assessment by region 72
Figure 4.5.1.1 Environmental factors by sector ………………………………………………………….….., 73
Figure 4.5.1.2 Environmental factors by region 74
Figure 4.5.2.1 Administrative factors by sector 76
Figure 4.5.2.2 Administrative factors by region 77
Figure 4.5.3.1 Social factors by sector 78
Figure 4.5.3.2 Social factors by region 79
Figure 4.5.4.1 Economic factors by sector 80
Figure 4.5.4.2 Economic factors by region 81
Figure 5.1 Map of Nigeria – Kaduna highlighted 84
Figure 5.2 Map of Kaduna 85
Figure 5.3 Waste management system boundary 86
Figure 5.4 Flow of waste 94
Figure 5.5 Sustainability assessment hierarchy model 95
LIST OF PICTURES
Picture 2.1 Temporary storage at roadside, Kaduna by-pass 13
Picture 2.2 Transport of waste with wheel barrow 19
Picture 2.3 Transport of waste with push cart and destroyed landscape 20
Picture 2.4 Transport of waste with truck from communal disposal site 20
Picture 5.1.1 Temporary storage - waste at communal disposal site 87
Picture 5.1.2 Temporary storage - waste at communal disposal site 88
Picture 5.1.3 Temporary storage within a household in Kaduna 88
Picture 5.1.4 Transporting waste to temporary storage with cart and wheel barrow 89
Picture 5.1.5 Transporting waste with fuel based vehicles 90
Picture 5.1.6 Open burning at communal disposal site 90
Picture 5.1.7 Open burning at final disposal site 91
Picture 5.1.8 Final disposal site at outskirts of Kaduna city, Airport Road 91
LIST OF TABLES
Table 2.1 waste composition of some Nigeria cities 17
Table 3.1 Studies employing AHP 53
Table 3.2 Survey locations and sectors 61
Table 4.1 Parameters Equation one 68
Table 5.1 Material flow 93
Table 5.2 Indicators 96
Table 5.3.1 Environmental indicators 106
Table 5.3.2 Administrative indicators 108
Table 5.3.3 Social indicators 110
Table 5.3.4 Economic indicators 111
CHAPTER ONE
INTRODUCTION
The main challenge of managing solid waste in generally in developed countries has shifted from ensuring minimum damage to public health and environment to the manner in which discarded resources are to be handled such that future generations are not deprived of its value (Chandak, 2010). Developing countries on the other hand are still battling with the protection of human health and well-being while attempting to conserve resources (Brunner and Fellner, 2007). However, many of the developed countries are still unable to decouple waste growth from economic growth with resulting economic and environmental burden driving the need to increase effective waste minimization and management (Fatta and Moll, 2003; Desmond, 2006). This applies to many member countries in the European Union (Fatta and Moll, 2003). The following sections give an overview of the chapters in the thesis.
SOLID WASTE MANAGEMENT
This section is an overview of Chapter 2 where literature on solid waste management especially in Nigeria is reviewed. The section also includes the review of literature on the methods used in assessing solid waste management strategies. Waste management is regarded as a public service where efficient collection and safe disposal of wastes are essential to public health and environmental protection (Cointreau-Levine, 1994). It has evolved from the simple transportation of waste to landfills to complex systems, including waste prevention and waste recycling as well as several waste treatment and landfill technologies (Salhofer et al., 2007). While developed countries have achieved the first aim of waste management of providing protection to human beings and the environment and are battling resource conservation, the health and well-being of humans still suffer from inadequate waste management systems in developing countries and the first objective still remains a main priority (Brunner and Fellner, 2007).
SOLID WASTE MANAGEMENT IN NIGERIA
In Nigeria, there is a steady increase in waste quantity and variety due to population growth and industrialisation (Imam et al., 2007) while the basic solid waste management system based on collection, transportation and disposal remains highly inefficient and ineffective, especially in the
urban centres (Ayotamuno and Gobo, 2004). Nigeria is the most populous and the tenth largest country in Africa with a population of over a hundred and fifty million people across a landmass of 923,768 square kilometres (WDI, 2010).
Legislation
Nigeria operates a three tiers system of government made up of federal, state and local government with distinct functions accorded to each tier based on constitution (Afon, 2007). The milestone Federal legislation on environmental protection in Nigeria was the decree 58 of 1988, which established the Federal Environmental Protection Agency (FEPA) to control the growing problem of waste management and pollution in Nigeria (Walling et al., 2004; Imam et al., 2008). Solid waste management is constitutionally the responsibility of the local government but the state government steps in to complement their efforts especially in state capitals such as Kaduna, Lagos and Port-Harcourt (Afon, 2007). Despite their effort, the solid waste management scheme in Nigeria is characterized by a system fraught with lack of accountability and refuse filled spaces, drains and roads (Dauda and Osita, 2003; Walling et al., 2004).
Solid waste generation and management elements
The estimated waste generated per person in a day is 0.49 kg with households accounting for 90% of the urban waste (Solomon et al., 2009). It has a high organic content consistent with waste generated in developing countries such as Ghana, China and Jordan and Palestine (Qdais, 2007; Al Khatib et al., 2010; Zhang et al., 2010; Fobil et al., 2010). The composition of waste in Nigeria suggests a recyclable content of over forty percent with recycling rate estimated at 8-22%, carried out by the informal sector (Wilson et al., 2009). Other disposal options are open dumping, open burning and composting (Dauda and Osita, 2003; Imam et al., 2008; Ogwueleka, 2009).
The waste is temporarily stored within households or at communal disposal sites in various sizes of bins, bin bags, baskets, buckets and directly on the ground at communal sites (Abdullahi et al., 2008). Highly irregular collection of co-mingled waste is carried out by the state/local government directly, via contractors and/or informal waste managers (Sangodoyin, 1993; Agunwamba, 1998; Dauda and Osita 2003; Abdullahi et al., 2008; Imam et al., 2008). More than 50% of the population dispose waste at communal sites, which are basically open dumps (Dauda and Osita, 2003). Waste is typically transported by lorries, tippers, loaders, trucks, tractors, push carts and wheel barrows (Dauda and Osita, 2003; Afon, 2007; Imam et al., 2008). Collection and transportation accounts for between 70-80% of total waste management cost in Nigeria (UNDP, 1998) mainly funded by the
government. Irregular collection and transportation of waste is partly attributed to frequent breakdown of vehicles and inadequate facility and equipment (Dauda and Osita, 2003; Imam et al., 2008; Adewole, 2009).
Awareness and attitude
Generally poor attitude towards waste management is recorded in literature (Imam et al., 2008; Adewole 2009). The local and state government responsible for raising awareness on solid waste management issues often adopt seminars, conferences, workshops, training sessions as the most common techniques in creating awareness observed in the course of the survey in addition to environmental management topics included within junior secondary schools syllabus (Uhuo and Zavodska, 2010).
Solid waste management assessment
Solid waste management assessment is undertaken to measure performance of a scheme with the main aim of improving existing strategy and practices (Anschutz, 2004). The methodologies commonly used are generally based on three models – cost benefit analysis (CBA), life cycle assessment (LCA) and multi-criteria analysis (MCA) (Morrissey and Browne, 2004). All aspects of solid waste management are estimated in monetary terms in the case of CBA while LCA focuses on environmental impacts (Morrissey and Browne, 2004). MCA approaches are used to identify single most preferred options and/or to rank options in decision making while taking into account often conflicting criteria usually involving a wide range of multi-disciplinary stakeholders such as solid waste management (Mendoza et al., 1999; Qureshi and Harrison, 2001; Morrissey and Browne, 2004; Dodgson et al., 2009).
Sustainability assessment of solid waste
Modern waste management presents a high level of complexity that requires many aspects to be considered for suitable solution that encapsulates both the current state of the environment as well as its potential to provide support for future generations (Jha and Murthy, 2002). There is an apparent need to develop a comprehensive assessment method that enables identification of the present waste management status while giving stakeholders an insight into the problem and a platform for discourse.
Sustainable waste management emphasizes a shift from waste disposal to other waste management options that includes energy and material recovery, waste reduction and reuse in
addition to the aim of decoupling increase in waste generation from economic growth (Chung and Lo, 2003; Fatta and Moll, 2003; Desmond, 2006). There is an agreement across the environmental and waste management field on the basic principles and elements of the concept as well as many of the criteria used in characterising or measuring the system (Van de Klundert, 1996; Tammemagi, 1999; Chung and lo 2003; Lang et al., 2007).
To evaluate waste management systems sustainably, the issue of quantifying sustainable development arises, which requires transparent and reliable measurement that must generally be agreed upon by stakeholders (Jha and Murthy, 2002; Joseph, 2006; Lang et al., 2007). While the generic principles of sustainable development consist of social, environmental and economic aspects, the administrative aspect has been evaluated in many studies involving waste management (Van de Klundert, 1996; Van de Klundert and Anschutz, 2001; Chung and Lo, 2002 Hayward and Gaskin, 2005; Desmond, 2006).
The objectives for environmental sustainability are summarized as rational resource consumption and reduction of environmental pollution (Chung and Lo, 2003; Den Boer et al., 2007; Hung et al., 2007; Roussat et al., 2007; Imran et al., 2008). The administrative aspect encompasses policy, management, research and training, responsibility issues and technologies used to provide the waste management service (Van de Klundert and Anschutz, 2000; Walmsley et al., 2001). Social sustainability deals with ensuring human health and well-being in the present and future generations (Imran et al., 2008). Economically sustainable waste management takes into account all external costs into the total cost established for waste management (Imran et al., 2008).
RATIONALE AND AIMS OF STUDY
Solid waste management in Nigeria has received considerable attention mostly in the areas of waste quantity and quality (Sridhar et al., 1985; Adedibu 1988; Afon 2007; Afon and Okewole, 2007; Sha’Ato et al., 2007); a few on regulations and governance (Adedibu 1986; Oyelola and Babade 2008; Kalu et al., 2009; Nzeadibe 2010) and especially on the status of the existing strategy (Agunwamba, 1998; Dauda and Osita, 2003, Izugbara and Umoh, 2004; Ayotamuno and Gobo, 2004; Ajibade, 2007; Ajani 2008; Babayemi and Dauda, 2010); state of the environment
(Akeredolu 1988; Olukesusi, 1988; Bammeke and Sridhar, 1989; Baumbach, 1995; Aluko et al., 2003; Olaniyan 2007; Anake 2009) and fewer regarding perception and awareness (Babayemi and Dauda, 2010; Longe et al., 2009). While work on systematic assessment of current strategy is non- existent, Abdullahi et al. (2008) proposed an appropriate management strategy that included all stakeholder categories operating in the existing scheme including the highly controversial informal
sector. Where waste management is assessed, the approach employed is usually not based on any particular methodology and is strictly qualitative (Agunwamba, 1998; Longe and Williams 2008; Imam et al., 2008; Adewole, 2009).
Although most management of waste strategies including that of Nigeria ascribe to sustainability, assessing progress towards this goal commonly carried out by use of indicators varies widely with no consistent tool or framework for application (Desmond, 2006). Some assessment tools have been proposed in Europe and Asia that have incorporated the desired social and administrative aspects while integrating various stakeholder groups and levels (Desmond, 2006) with some having a bias towards a particular issue (Van de Klundert and Anschutz, 2000) and therefore not considering the system holistically.
The main aim of this study is to quantify sustainable development with regards to solid waste management in an attempt to develop an assessment tool. The aims include establishing the current situation of waste management in Nigeria by generating an index to demonstrate the sustainability of an existing waste management scheme in a particular city and thereby appraising the applicability of the sustainability assessment model established. The objectives identified in achieving these aims are discussed in section 3.1.2.
METHODOLOGY
The strategy adopted to achieve the aims of this study detailed in Chapter three is outlined in this section. It primarily involved a structured questionnaire survey administered to solid waste management practitioners across Nigeria over a period of eleven months. The main aim of the survey was to corroborate the suitability of the concept and its broken down aspects and factors for evaluating solid waste management schemes and to illustrate the varying significances of the aspects and factors. Relevant literature on waste management was reviewed to appraise assessment methods and the current state of solid waste management particularly in Nigeria, which identified sustainable development SD as a suitable concept to build the assessment tool. The structured questionnaire survey adopted analytic hierarchy process (AHP) as the research instrument to collect data from waste management practitioners.
Analytic hierarchy process, AHP
Analytic Hierarchy Process, AHP was employed in this research to determine the preferences of practitioners on the issue of sustainable waste management. The AHP is a theory of measurement, originally devised by Saaty (1980) through pairwise comparisons and relies on the judgements of
practitioners or stakeholders to derive priority scales for factors of an issue or system (Saaty, 2008). As a multi-criteria technique, it has a practical nature that takes into account the complexity of different aspects and interests that are often conflicting due to diversity of its stakeholders within the waste management system (Zahedi, 1986; Leung, 1998). The priority scales measure elements in relative terms. The comparisons are made using a scale of absolute judgements that represent how much one element dominates another with respect to a given attribute. AHP is further discussed in section 3.3.2.
Data was analyzed using AHP technique with Expert Choice software and non-parametric statistical analysis – Kruskal Wallis using Minitab 15. The survey data was processed to identify significance of aspects and factors by individual stakeholders while descriptive statistics was used to establish the overall significances. The Kruskal Wallis analysis was applied to test for differences between the significances selected across sectors and locations for the aspects and factors.
Taking time and resources into account, five locations were deemed appropriate to represent the geographic locations in Nigeria. Diversity of opinion and approach among practitioners is further achieved by the four groups of practitioners identified – Central government; local/state government; private and academic sector. Section 3.3.8 presents a detailed discussion of the participant categories.
RESULTS AND DISCUSSION OF LITERATURE AND QUESTIONNAIRE SURVEY
The result and discussion of Chapter four presents the findings generated from the structured questionnaire and literature survey administered to eighty-seven solid waste management practitioners. Sustainable development is proposed from the literature survey as a concept to base the appraisal of solid waste management schemes and practices. The subsequent breakdown of the concept into measurable units is also suggested from review of literature. The result of the structured questionnaire survey designed to quantify sustainability as a means of assessing solid waste management is shown. The findings include corroborating sustainability development (SD) as an appropriate concept for building solid waste management assessment tool and its breakdown. The data collected from practitioners was analyzed to show the overall significance apportioned to each aspect and factor that was employed to derive a sustainability function to appraise waste management strategies. In addition, the weightings assigned by the five regions and four sectors are presented and significant statistical differences found mainly across the regions has been illustrated.
CASE STUDY
In Chapter five, the solid waste management scheme in Kaduna metropolis was appraised using the assessment tool developed in a case study analysis to evaluate the applicability of the tool. Kaduna, the capital of Kaduna state, is one of the largest cities in northern Nigeria ranked as the fourth most populous city with a population of 1,563,300 (Sanusi, 2010). It is one of the most important political, industrial and economic centres in Nigeria (Ojo, 1995; Okunola et al., 2007). It has been selected amongst the cities for establishing integrated solid waste management instituted by federal government (Hussain, 2008; Olaniyan et al., 2009).
The system boundary is defined by household and commercial waste from Kaduna metropolis over a period of one year. The solid waste management processes assessed included temporary storage, collection, transport, treatment and final disposal (den Boer, den Boer & Jager, 2007; Bjorklund et al., Cleary 2009). The data inventory analysis involved data collection and calculation procedures to quantify relevant inputs and outputs of the solid waste management scheme in Kaduna city where 0.5 kg per capita daily waste generation, was adopted (Dauda and Osita, 2003; Nabegu, 2010). Due to scarcity of reliable data, representative data from other waste management strategies similar to that of Kaduna metropolis are employed. Indicators were specified, scored, normalised and aggregated to generate an index. The indicators are derivatives of the factors specified in the solid waste management assessment tool. The data used was relatively available and practical to measure and record.
Case study methodology
The sustainability function (Equation one) of Section 4.3.1 was used to establish the index for Kaduna metropolis by applying data gathered from literature. Two indicators were specified for each factor and assigned a maximum score of 100 points each to maintain uniformity across assessment factors while ensuring all aspects are appraised. Maximum scores specified for particular indicators are generally based on studies carried out by international bodies mainly United Nations Environmental Program scoreboard specified for ASEAN region (UNEP, 2005). The scores determined for each indicator were inserted into the SI function and aggregated to derive the sustainability index for the case study. Generally, a normative orientation is adopted for awarding the scores with a defined threshold specified similar to the study of Lang et al. (2007) The environmental indicators employed include particulate matter, methane (CH4) emission, leachate quality, disposal rate, waste generation and material recovery. The administrative
indicators encompass quality of policy and its applicability under policy factor; created waste management agencies and their level of functionality within their jurisdiction under management factor; acceptance and awareness in the responsibility issue category and the resilience and maintainability of technologies used within the system. Social indicators assessed include health, satisfaction of users regarding the strategy in place, consistency of service, awareness and participation of all stakeholders and fairness of the strategy within this generation and between generations. The economic indicators are based on the wages available for waste management jobs and the total costs of waste management compared to what is generally charged by service providers.
SUSTAINABLE SOLID WASTE MANAGEMENT
Chapter six focuses on the solid waste management assessment tool developed and its applicability. The results obtained from the attempt at quantifying sustainable development with regards solid waste management using a questionnaire survey has established an equation based on four evaluative aspects and thirteen factors. Amongst the four aspects, administrative aspect was found to be the most significant aspect despite its absence as a generic principle of sustainable development in the past (McDougall et al., 2001; Chung and Lo, 2003).
The chapter also includes the differences in Importance recorded across the various sectors and regions although an overall function was determined. This is in addition to willingness of waste management practitioners to take part in the survey, the differences associated with mode of questionnaire delivery and effects of gender and ethnicity of researcher. The applicability of the assessment tool with regards to other situations or regions is also examined in addition to the Kaduna management strategy evaluated.
The next chapter, Chapter two, will cover the review of pertinent waste management literature with particular emphasis on Nigeria and the assessment methods applied to management strategies.
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