Vol. 4 No. 6 November
2012
DOI for issue:
10.7813/2075-4124.2012/4-6/A.40Baku, Azerbaijan| 287
INTERNATIONAL JOURNAL of ACADEMIC RESEARCH Vol. 4. No. 6. November, 2012
E. Setiawati, S. Notodarmodjo, P. Soewondo, Agus J. Effendi, Bambang W. Otok. Structural equation modeling and analytical hierarchy process for sustainable wastewater infrastructure of Jakarta. International Journal of Academic Research Part A; 2012; 4(6), 287-291. DOI: 10.7813/2075-4124.2012/4-6/A.40
STRUCTURAL EQUATION MODELING AND ANALYTICAL HIERARCHY PROCESS FOR SUSTAINABLE WASTEWATER
INFRASTRUCTURE OF JAKARTA
Endang Setiawati1, Suprihanto Notodarmodjo1, Prayatni Soewondo1, Agus Jatnika Effendi1, Bambang Widjanarko Otok2
1School of Environmental Engineering ITB, Bandung,
2Laboratory of Environmental and Health Statistic ITS, Surabaya (INDONESIA) E-mails: [email protected], [email protected], [email protected],
[email protected], [email protected]
ABSTRACT
This paper presented sustainable wastewater management system analysis using combination of Structural Equation Modeling (SEM) and Analytical Hierarchy Process (AHP) for the city of Jakarta, Indonesia. This research collected data samples from 270 respondents on SEM, and from 20 stakeholders and decision makers in waste- water system while using AHP. This stakeholders and decision makers were representing Jakarta Environmental Protection Agency, Ministry of Public Works-Cipta Karya, Jakarta Public Works Department, Jakarta Wastewater Company, and experts from environmental engineering consultants. The result of this research showed that infra- structure development strategy for sustainable wastewater system could be reached by using off-site system, or at least the synergy between on-site and off-site system.
Key words: AHP; SEM; sustainable; wastewater development 1. INTRODUCTION
Jakarta is the capital city of Indonesia with area of 65.000 Ha and population of 9.738.880. Like other metropolitan in developing countries [1], Jakarta is dealing with wastewater management problems. Jakarta’s city development along with population growth and urbanization and lack of city planning on wastewater infrastructure develops into surface water and groundwater pollution [2].
Jakarta currently has been served by sewerage system with grants from central government through Loan International Bank for Reconstruction and Development (IBRD). Those infrastructure and its facilities has been built in 1992-1996. With < 3% service coverage including Setiabudi and Tebet District, Master Plan of Wastewater and Drainage for Jakarta city has been done with JICA Assistance, and become the guideline for next development program (1991 - 2010). But, until 2011 there has been no significant development progress, and review master plan of waste water system (2012-2050) for Jakarta has been done also with JICA [1].
This study examined the indicators and variables which influenced the sustainability of provision of wastewater infrastructure and facility in theory, then compiled into theoretical model which will be proven by field data and become data-basis model. Those variables will analyzed by Structural Equation Modeling (SEM) [12, 13].
After that it will be analyzed using the sustainable hierarchical model that fits AHP basic [15]. Infrastructure strategy of wastewater system will be combined from the influence value of each variable on SEM and the priority of every criteria on AHP based on the opinion of the decision makers on local and central government.
2. METHODOLOGY
This research is first conducted by sampling 270 consumers of off-site system for the SEM method [10].
Another sampling is conducted to 20 decision makers in Jakarta wastewater system by filling AHP questionnaire [15]. Rating each sustainable criteria consistency ratio of samples, priority and best solution available for sustainability can be analyzed from hierarchy model and sampling result. Line coefficient is also analyzed from SEM [11, 14].
Model for sustainability on SEM can be seen as follow:
288 | PART A. NATURAL AND APPLIED SCIENCES
Fig. 1. Model for sustainability on SEM
Hierarchy model of sustainable wastewater system is built based on sustainable criteria such as Technology Selection [1, 2, 6, 7], Financial [4, 7, 8], Environmental [4, 5, 7, 8], Institution [6, 7, 9], and Socio-Cultural [3, 5, 7].
These criteria then sorted based on priorities as follow:
Fig. 2. AHP sustainable hierarchy model
Availability of Spare Part Operational Easiness
Adaptability Investment Cost
O&M Cost Local Development Not Polluting Water Source
Efficiency of Raw Material Minimization of Wastewater
Regulation and Sanction for Wastewater Regulation and Sanction for
Environmental Protection Willingness to Pay
Local Capacity Society Acceptance Suitability of Local Culture
Technology Selection (TS)
Financial (F)
Environmental (L)
Institution (I)
Socio-Cultural (SC)
Sustainability (S)
Financial Benefit
Death Cause by Diarrhea Environmental
Quality System Endurance
Operational Easiness
Adaptability Availability of
Spare Part
Local Development Investment Cost
Not Polluting Water Source O&M Cost
Regulation and Sanction for Wastewater Efficiency of Raw
Material
Regulation and Sanction for Environmental
Protection Minimization of
Wastewater
Society Acceptance Willingness to Pay
Suitability of Local Culture Local Capacity
On-Site Off-Site
Combination Technology
Selection
Financial
Environmental
Institution
Socio-Cultural
System Endurance
Sustainability
Goal Criteria 1 Criteria 2 Alternative Solution
Baku, Azerbaijan| 289
INTERNATIONAL JOURNAL of ACADEMIC RESEARCH Vol. 4. No. 6. November, 2012
3. RESULTS AND DISCUSSION3.1. Infrastructure Development Strategy For Wastewater System Using Sem Method Result of sustainability model on SEM using AMOS 20 program can be seen as follow:
Table 1. Test result of sustainability model
Criteria Cut-off Value Calculation Result Remarks
Chi-Square Expected less 210.437 2 with df = 137 is 165.316 (Good Enough)
Significance Probability ≥ 0.05 0.000 Not Good
RMSEA ≤ 0.08 0.045 Good
GFI ≥ 0.90 0.927 Good
AGFI ≥ 0.90 0.899 Good
CMIN/DF ≤ 2.00 1.536 Good
TLI ≥ 0.95 0.987 Good
CFI ≥ 0.95 0.990 Good
Table 1 shows good result on 6 criteria, which means there is match between theories with the data.
Therefore it can be said that the model could be accepted with no modification are required.
Model of sustainability can interpret each and every line coefficient. Line coefficient is obtained as hypothesis in this research, which is presented in structural equation as follow:
= . + . + . + . + . (1)
Detail of the line coefficient test can be seen as follow:
Table 2. Result for line coefficient on the sustainability model
Variable Line Coefficient C.R. Prob. Remarks
Technology Selection (Ts) Sustainability (S) 0.156 2.505 0.012 Significant
Financial (F) Sustainability (S) 0.146 2.485 0.013 Significant
Environmental (E) Sustainability (S) 0.197 2.484 0.013 Significant
Institution (I) Sustainability (S) 0.203 2.460 0.014 Significant
Socio-Cultural (SC) Sustainability (S) 0.128 1.974 0.048 Significant
Based on table 2, the interpretation of each line coefficient can be described as follow:
For Technology Selection (TS), Financial (F), Environmental (E), Institution (I), and Socio-Cultural (SC) have positive and significant effect on Sustainability, it can be seen from the line coefficient value (0.128 – 0.203), the C.R. value (1.974 – 2.505), and the significances of probability (p) value (0.012 – 0.048) which are less than the determined significance level (α) of 0.05.
3.2. Infrastructure Development Strategy For Wastewater System Using Ahp Method
AHP modeling techniques consists of some steps involving building hierarchy model, rating model criteria, determining each matrix’s inconsistency ratio, paired comparison, and determining criteria priority and solution.
AHP sustainable hierarchical model criteria rating are conducted using pairwise comparison matrix. The value on pairwise comparison matrix comes from questionnaires sampled to decision makers in wastewater system. Saaty rating scale is used to rate sampled questionnaire result.
Due to the necessity of only one answer from each paired comparison matrix in AHP, then geometric average is taken from sampling answers
= ( ∙ ∙ … ∙ ) (2)
= Comparison value on questionnaire = , , … ,
= Number of samples
= Average value of comparison between criteria I and j with n samples
An example result of geometric average calculation of sustainable criteria in paired comparison matrix is shown as follow:
Table 3. Paired comparison matrix on sustainable criteria
Technological option
Finance/
Economy Environment Institution Social-Culture
Technological option 1 1.20 1.20 1.93 1.67
Finance/
Economy
1
1.20 1 1.35 1.97 1.46
Environment 1
1.20
1
1.35 1 2.12 1
1.04
Institution 1
1.93
1 1.97
1
2.12 1 1
1.03
Social-Culture 1
1.67
1
1.46 1.04 1.03 1
290 | PART A. NATURAL AND APPLIED SCIENCES
Consistency is a vital element in AHP method. Sampling result is valuable only if it’s value from inconsis- tency ratio (after converted into paired comparison matrix) is equal or lower than 0,1. Values with inconsistency ratio higher than 0,1 is deemed inconsistent and not used in further equation.
Inconsistency ratio equation is conducted using Expert Choice 11 program. The example of inconsistency ratio of sustainable criteria equation using Expert Choice 11 program is shown as follow:
Fig.3. Inconsistency ratio of sustainable variable equation result output
The final result of AHP method is determination of global criteria (the most important criteria) to achieve sustainable wastewater system. The most important criteria on sustainable wastewater system is visible in priority rating shown on Expert Choice 11 output as follow:
Fig. 4. Sustainable Criteria Priority Output
Sustainable wastewater system priority can also be determined using Expert Choice 11 program. The result is shown as follow:
Fig. 5. Sustainable wastewater system priority output
3.3. Infrastructure Development Strategy for Wastewater System Using Combination of SEM and AHP Method
SEM approach shows that Technology Selection (0.156), Financial (0.146), Environmental (0.197), Institution (0.203), and Socio-Cultural (0.128) have positive and significant effect on Sustainability. And from AHP we knows that the rate on each criteria, Technology Selection (0.261), Financial (0.243), Environmental (0.204), Institution (0.127), and Socio-Cultural (0.165). The combination between SEM and AHP are simply the multiplication between line coefficients on SEM with criteria rate on AHP, the result will shows as follow:
Table 4. Priority of strategy using combination of SEM and AHP
Variable Line Coefficient Criteria Rate Combination of SEM and AHP
Percentage of Combination
Technology Selection 0.156 0.261 0.040716 24.9358 %
Environmental 0.197 0.204 0.040188 24.6125 %
Financial 0.146 0.243 0.035478 21.7279 %
Institution 0.203 0.127 0.025781 15.7892 %
Socio-Cultural 0.128 0.165 0.021120 12.9346 %
Combination approach on SEM and AHP prioritize the Technology Selection on 24.9358 % then Environmental factor with 24.6125 %. The best solution for infrastructure development strategy for sustainable wastewater system can be reach by using off-site system, or at least the synergy between on-site and off-site system.
4. CONCLUSION
Result with SEM approach shows that Sustainability affected by institution with line coefficient value of 0.203, Environment with 0.197, Technology Selection with 0.156, Financial with 0.146, and Socio-Cultural with 0.128. While the AHP approach shows the criteria rate on each variable are Technology Selection (0.261),
Baku, Azerbaijan| 291
INTERNATIONAL JOURNAL of ACADEMIC RESEARCH Vol. 4. No. 6. November, 2012
Financial (0.243), Environmental (0.204), Socio-Cultural (0.165), and Institution (0.127). The infrastructure development strategy for sustainable wastewater system using combination approach of SEM and AHP prioritize on variable technology selection and environmental. And the most important criteria to get sustainable wastewater system are technology selection and financial. Meanwhile the best solution for infrastructure development strategy for sustainable wastewater system can be reached by using off-site system, or combination between on-site and off-site system.
REFERENCES
1. Setiawati E., Suprihanto N., dan Bambang, W.O., The Strategy for Infrastructure Development of Sustainable Wastewater System by SEM Method (Case Study of Setiabudi and Tebet District in South Jakarta), The 3rd International Conference on Sustainable Future for Human Security, 2012.
2. Nyachhyon, Bardan Lal., Service Enhancement and Development of Sanitary Sewerage System In Urban And Semi-Urban Setting In Nepal, Economy Policy Network, Singha Durbar, Kathmandu, Nepal, 2006.
3. Flores A., Buckley C., Fenner R., Selecting Wastewater System for Sustainability in Developing Countries, United Kingdom, 2008
4. Carvalho De. Scpe et al., Application of a Sustainability Index for Integrated Urban Water Management In Southern Africa Cities: Case Study Comparison – Maputo And Hermanus. Water Institute of Southern Africa (WISA) Biennial Conference, Sun City, South Africa, 2008.
5. Balkema et al., Indicators For The Sustainability Assessment Of Wastewater Treatment System, Urban Water 4 (2002), 153-161, 2002.
6. Balkema A., Weijers S.R. and Lambart F.J.D., On Methodologies For Comparison Of Wastewater Treatment Systems with Respect to Sustainability, Proc. WIMEC Congress on Options For Closed Water Water Systems, March 11-13, Wageningen, The Netherland, 1998.
7. Werner, Melanie., Water and Wastewater Systems Sustainability In Remote Australia, Master of Engineering Thesis, School of Civil, Mining and Environmental Engineering-Faculty of Engineering, University of Wollongong, 2009.
8. Mukherjee N., And van Wijk C., Sustainability Planning and Monitoring in Community Water Supply and Sanitation: A Guide on the Methodology for Participatory Assessment (MPA) for Community- Driven Development Programs, Washington D.C., The World Bank Water and Sanitaton Program.
Accessed24/6/05, available from: http://www.wsp.org/pdfs/mpa%202030.pdf, 2003.
9. Bradley B.R., Daiger G.T., Rubin R. And Tchobanoglous G., Evaluation of Onsite Wastewater Treatment Technologies Using Sustainable Development Criteria, Clean Technologies and Environmental Policy 4: 87-99, 2002. http://dx.doi.org/10.1007/s10098-001-0130-y.
10. Levy P.S. and Stanley L., Sampling of Populations: Methods and Applications, Third Edition, John Wiley and Sons. Inc., New York, 1999.
11. Lee S.Y., Structural Aquation Modeling: A Bayesian Approach, John Wiley and Son, West Sussex, England, 2007.
12. Lee S.Y., dan Xin Y.S., “On Bayesian estimation and model comparison of an integrated structural equation model”, Journal of Computational Statistics and Data Analysis, Department of Statistics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, 2008.
13. Mulaik S.A, Linear Causal Modeling With Structural Equation, Chapman and Hall, USA, 2009.
http://dx.doi.org/10.1201/9781439800393.
14. Brown T. A., Confirmatory Factory Analysis for Applied Research, The Guilford Press, New York, 2006.
15. Saaty T.L., The Analytical Hierarchy Process, McGraw Hill International, 1980.
