Selection of an appropriate waste-to-energy conversion technology for Dhaka City, Bangladesh

Figures & data

Table 1. Description of sub-criteria.

Criteria	Sub-criteria	Description
Technology	Technological maturity	It means the development status of the technology i.e. whether the technology is in the research state or in commercial use state. More mature technology is preferred
	Reliability	It refers to success rate and the frequency of using the technology. More reliable technology is preferred
	Energy potential	Maximum possible generation of energy from waste is preferred
Environment	Land area requirement	Scarcity of land is one of the prime concerns. Minimum land requirement is preferred
	Air and water pollution	The selected WTE technology should provide minimum potential hazard to the environment. Minimum air and water pollution is preferred
	Requirement of waste separation	Separation of waste at source is one of the challenging tasks; hence, minimum requirement of waste separation is preferred
Financial	Plant establishment cost	Minimum plant establishment cost is preferred
	Operation and maintenance cost	Minimum operation and maintenance cost is preferred
	Revenue earn	Maximum possibility of revenue earn is preferred

Figure 1. Steps for applying AHP model.

Figure 2. Hierarchy structure of WTE technologies.

Table 2. Saaty’s discrete 9 value scale of relative importance.

Numerical value (i)	Definition
1	Equal importance
3	Moderate importance
5	Strong importance
7	Very strong importance
9	Absolute importance
2,4,6,8	Intermediate values between two adjoining judgements
1/i	Inverse importance

Table 3. A hypothetical comparison table.

	A1	A2	A3
A1	1	p	q
A2	1/p	1	r
A3	1/q	1/r	1

Table 4. The Random Consistency (RC) for various matrix size (n).

n	1	2	3	4	5	6	7	8	9
RC	0.00	0.00	0.58	0.90	1.12	1.24	1.32	1.41	1.45

Table 5. Relative weights of criteria and ranks of WTE alternatives.

		Weight of criteria		Ranks of WTE technologies
Attribute	Criteria	Level one	Level two	Anaerobic digestion (AD)	Pyrolysis	Plasma gasification (PG)
Technical aspect		0.52		0.25	0.26	0.49
	Technological maturity		0.17	0.77	0.13	0.10
	Reliability		0.55	0.16	0.28	0.56
	Energy potential		0.28	0.10	0.31	0.59
Environmental aspect		0.16		0.21	0.31	0.47
	Land area requirement		0.32	0.11	0.31	0.57
	Air and water pollution		0.17	0.57	0.28	0.15
	Requirement of waste separation		0.51	0.16	0.32	0.52
Financial aspect		0.32		0.45	0.24	0.34
	Plant establishment cost		0.54	0.73	0.19	0.12
	Operation and maintenance cost		0.17	0.15	0.28	0.57
	Revenue earn		0.29	0.10	0.30	0.6

Figure 3. (a) Rankings of WTE technologies using different criteria, (b) Overall ranking of WTE technologies.