Selection of Waste Disposal Sites Using DRASTIC and GIS: Case Study: Ghazvin...

Selection of Waste Disposal Sites Using DRASTIC and GIS: Case Study: Ghazvin Plain

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Ali Asghar Alesheikh
Associate Prof., GIS Dept.,
Faculty of Geodesy and Geomatics Eng.,
K.N.Toosi University of Technology,
Mirdamad Cross, Valiasr St.,
Tehran, Iran, 19967 15433
Tel: (9821) 8878 6212
Fax: (9821) 8878 6213
[email protected]

Mohsen Eslamizadeh
Ph.D. Student of Environmental Engineering
Graduate School of the Environment and Energy
Science and Research Campus
Islamic Azad University
Tehran, Iran,
[email protected]

Abstract
Urban population growths together with the development of new industries generate a huge amount of hazardous waste daily. Proper management of the waste is a challenging issue that must be addressed adequately. Land filling is one of the common methods used for waste disposal. Nowadays, the environmental impact of the disposal sites on human beings, wildlife, air and water quality, makes this issue a subject of many researches.

GIS (Geospatial Information System) is a computerized tool for solving geographic problems. It can then be used to optimize the selection process of landfill site. Through various functionalities, GIS is able to provide a better understanding of the effects of the sites on the environment.

The objectives of this paper are to identify and evaluate the major factors on landfill site selection, and to describe the methods for proper landfill location estimation. As a case study “Qazvin” city has been selected to evaluate the candidate locations. The data used include topographic maps, land use maps, geologic, surface hydrologic, underground water and meteorological data. The data are combined together using DRASTIC procedure on a commercial GIS software package to locate and visualize the selected site. The paper elaborates on the methodologies used, and the results are evaluated scientifically.

Introduction:
Landfill is an important component of any waste management system. Sustainable management of urban solid wastes may involve an integrated system of: (i) waste minimisation in the production process; (ii) reuse of products to extend their usefulness before entering to the waste stream; (iii) recovery of materials and energy from the waste (e.g. recycling, composting, heat from combustion); and (iv) depositing the remaining material in landfills (Leao et al., 2004).

Although waste volumes can be significantly reduced by diverting parts of the generated waste to recovery operations, landfills cannot be completely avoided. Since, there is always some waste the generation of which cannot be avoided or for which there is no technology available for processing and recovery. Landfill has been the most widely used method for urban solid waste disposal.

A successful landfill siting involves various techniques for Analyzing the basic suitability of all available land for sanitary landfills as an aid in the selection of a limited number of sites for more detailed evaluation (Lane and McDonald 1983).

Several researchers studied various aspects of waste management; the allocation of urban solid waste landfills (Themistoklis et al., 2005), hazardous solid waste centers (Canter, 1991), recycling operation facilities (Hokkanen and Salminen, 1997), are few works to name.

The present research work describes a DRASTIC methodology in a GIS environment to evaluate the suitability of the study region in order to site a landfill.

Study Area:
Qazvin watershed is about 9475 Km2 and extends from 48°44’to 50°51′ longitude and 35°24′ to 36°48′ latitude. This watershed is located at the north west of central plateau of Iran. Elevation of Qazvin city is 1298 m.

Population of Qazvin province was 1143200 in 2007. Nearly 59% of total population live in cities and 41% in villages. Mean annual daily temperature in the watershed varies between 5° at mountain area to 17.5° at southern part. 17 minor top branches form Shoor river.

There are 6 main faults in this area which are: Qazvin fault, Eipek fault, Eshtehard fault, Gheshlagh fault, Hasanabad fault and avaj fault.

Methodology Used Thematic maps and satellite images were collected and some paper maps were digitized to create a GIS database. In this research ESRI’s ArcView software were employed for performing GIS analysis. All data were converted to convenient format of ArcView. Then, data were projected to UTM map projection. Water level of groundwater is gathered from the test wells. Table 1 shows all the used parameters in this research.

ArcView software was employed to generate buffer zones based on table 1 to define the restricted areas. Figure 1 displays the study area with generated buffers. In this step, 24 locations were found for landfill site as primary candidates. In order to work in details, maps with 1/25000 scale were used to select highly suitable sites. This process resulted in 7 locations out of the 24. Figure 2 displays the locations of the 7 points..

Table 1: Site selection parameters and the relevant buffer zones

Row

Layer

Describe

Buffer

1

Village

1 to 5 family

2.5 km

2

5 to 40 family

3 km

3

40 to 1000 family

4 km

4

>1000 family

5 km

5

City

All

5 km

6

Road

Main road

120 m

7

Well

All

500 m

8

Spring

All

300 m

9

River

Main

200 m

10

Dam

All

1 km

11

Qanat

Main well

500 m

12

Path

300 m

13

Level of groundwater

 

>10 m

14

Protection area on environment

All

Not allowed

15

height

>3000 m

Not allowed

16

Rain

>1000 m

Not allowed

17

Forest

 

Not allowed

18

Slop

>10%

Not allowed

19

Fault

All

>150 m


Figure 1: Study area together with the generated buffers and 24 primary landfills


Figure 2: The position of the final selected sites

To identify the best site, DRASTIC method is chosen. In DRASTIC method there are 7 parameters to rank each site, namely: D: Depth to water table, R: Recharge, A: Aquifer Media, S: Soil Media, T: Topography, I: Impact of the unsaturated zone Media, C: Hydraulic conductivity of the Aquifer.

Every parameter in this method is assigned with a weight that is presented in table 2.

Table 2 : The weights of all DRASTIC input parameters

Weight Parameter
5 Depth to water table
4 Recharge
3 Aquifer Media
2 Soil Media
1 Topography
5 Impact of the unsaturated zone Media
3 Hydraulic conductivity of the Aquifer

Potential of pollution calculated based on the following formula:

DRDW + RRRW + ARAW + SRSW + TRTW + IRIW + CRCW = potential of pollution

The subscripts indicate the ranking as well as the weights of each parameter.

Based on this method the best location got 26 score and worst one got 226 score.

Conclusions:
The method described in this paper integrates the evaluation abilities of DRASTIC method and the analytical tools of GIS. The results can be useful for decision makers in Ghazvin city, too. Although, the final decision of where to site a landfill is as much a political decision as a scientific one, this research is for evaluating the basic suitability of all available locations for landfills as an aid in the selection of a limited number of sites for more detailed evaluation. It is important to emphasis that the actual availability of land for landfill could be significantly lower than the amount shown in the Table 1. A more thorough land analysis should consider other characteristics, such as more detailed analysis of current and future land uses, wind directions, price of the land, etc. It must be noted that the presented methodology is a tool to aid decision makers, it is not the decision itself.

References:

  • Hokkanen, J. and Salminen, P. (1997). Locating a waste treatment facility by multi-criteria analysis. Journal of Multi-Criteria Decision Analysis, 6: 175-184.
  • Lane, W. N. and McDonald, R. R. (1983). Land suitability analysis: landfill siting. Journal of Urban 346 Planning and Development, 109 (1): 50-61.
  • Leao, S., Bishop, I. and Evans, D. (2004). Spatial-Temporal model for demand and allocation of waste landfills in growing urban region. Computers, Environment and Urban Systems, 28: 353-385.
  • Themistoklis, D. K., Dimitrois, P. K. and Constantinos, P. H. (2005). Siting MSW landfills with a spatial multiple criteria analysis methodology. Waste management, 25: 818-832.