Materials and Methods
Bangalore is situated between the latitudes 12°39’00’’ to 13°13’00’’ N and longitude 77°22’00’’
to 77°52’00’’ E with an area of 741 km2. The entire study area was divided into grids
of size 2.7 km×2.7 km. The city has therefore been segmented to a) core area, b) outer area and
c) peripheral areas. It has been found that the unauthorized dumping occurs both inside core
area as well as outside of the core area. Core area is the old city area with high population
density (>20,000/km2). The dump sites located within the core area of the city
have been reported to be small in size and often short lived (Chanakya et al., 2015). Whereas
dumps outside the core area are large and persistent having a long operation- al life and are
used as 'unauthorized' waste disposal sites. These large and long-lived dump sites cause
significant envi- ronmental concerns and therefore need to be studied. Thus, the results were
analyzed for two zones or areas namely, the core city area and outside the core city area (outer
area and peripheral area). The ratio of core city area and outside the core city area is 1:10.
Therefore, in order to estimate the quantity of wastes dumped, the composition of MSW at each
site and the area over which waste is spread, a study was conducted in 452 randomly located
large dump sites. These locations are spread across the city, 35 sites lying within the core
city area and 417 sites lying in the region outside the core city boundary up to a distance of
10 km from city boundary in a total area of 2,274 km2 (Figure 1). The dumpsite
locations were discovered, located using pre- calibrated hand-held Global Positioning System
(GPS) and photographed (Figure 2).
Occurrence of dump sites locations
The occurrence of open dumping locations in and around the city depends on population density,
distance from the
FIGURE 1
Bangalore: core area and outside core area (outer area and periphery) of the city
FIGURE 2
Dump sites located in core area and outside core area (outer area and periphery) of the city
centre of the city as well as approachable all-season road ac- cess emerging off these main exit
roads as these are key de- terminant for dump sites to originate (TIDE, 2000). Buffer lines of
100 m, 100-500 m, 500-1000 m, 1000-1500 m and
>1500 m were created around the major road networks of the city to determine the relation
between dump site occurrence and distance from the main road network. For each of the dump
sites, the distance from the Centre of the city was also determined using GIS. Ward wise
population data was used to arrive at population density with frequency of dump site locations.
Physical and chemical composition of MSW at unauthorized dump sites
Waste composition was determined at 28 randomly se- lected dump sites. At each dump, after
quartering a large quantity in a 1 m2 area, three samples of 1 kg each from dif-
ferent locations of the dump were collected. The number of samples for each site was decided
based on statistical analysis conducted for three sites bearing sample numbers 3, 6 and 9; all of which showed no significant
differences in composition (p>0.05). Each MSW samples were then segregated into or- ganic
fraction, plastics, construction debris, paper, cloth, glass, leather, metal, rubber, biomedical
waste, burnt waste and industrial waste. These components were physically seg- regated, weighed
separately using digital balance (DIGI, DS- 673) of 6 kg capacity and photographs were taken to
record composition estimates (Chanakya and Swamy, 2011). The most probable composition was also
estimated by scanning about 5-6 randomly chosen 1 m2 surface regions of the dump site
to identify the predominant waste type (Chanakya et al., 2015). It allowed three levels of
validation of data: physical estimate, visual field confirmation and photograph validation. The
waste samples were also collected for ultimate analysis using standard methods of APHA, 1975.
The samples were weighed and dried at 105°C in an oven until samples attained constant weight to
determine the moisture content and total solids (TS). Dried samples were powdered fine (<500
µm) using a laboratory grinder. The dried powder was then ignited at 550°C for 3 hours in a
muffle furnace to estimate the TS and VS ratio. The dried powdered samples of 1 gram were used
to analyze the carbon, hydrogen and nitrogen contents using CHN analyzer (LECO elemental
analyzer). Bulk densi- ty of wastes included construction debris, organic fraction, plastic, old
garbage (older dumps aged >6 months), other substances and recyclable rejects were measured.
The waste was filled in a bucket of volume 0.02 m3 and weighed in a calibrated spring
/electronic balance and waste category wise density was determined. Category-wise waste density
values were later used for converting waste volume into waste quan- tity. While it is
acknowledged that wastes will compact with time and when piled to greater depths, this estimate
gave the lower estimates for quantities of wastes found at each site. Previous work showed that
the open dumps rarely reached depths >1 m and therefore the effect of compaction has been
neglected for this study (Rajabapaiah, 1988; Chanakya et al., 2015).
Area of MSW spread at unauthorized dump sites
A total of 268 physically accessible dumps were selected to determine land area dedicated to dump
sites. At these sites, the length and breadth of these dumps were measured and most often
rectangular in shape as confirmed from satellite images. Spatial extent area of the dump site
was visually es- timated (VE), tracked with GPS and all observations were recorded on hard
copies (Baars and Dyson, 1981; Waite, 1994; Mumby et al., 1997; Palmer and Hoffman, 2001;
O’Donovan et al., 2002a; O’Donovan et al., 2002b; Tveit, 2009; Ode, 2010). Dump locations,
spatial extent with track and waypoints were overlaid on Google Earth imagery (GE) to verify and
compute spatial spread of such polygons. Spa- tial analysis was carried out with the help of
Mapinfo Profes- sional 7.5 SCP software. These waste dumps differed greatly in size and area.
Their assessment using GPS and GIS pro- vided area assessments of dumps with a higher
accuracy.
Quantification of wastes found at unauthorized dump sites
Quantification of waste at 268 dumps has been carried out through computing the volume of the
solid waste dump and later multiplying with measured waste densities of predomi- nant wastes
found in these open dumps. Volume of waste at dumps was confirmed using area and height. The
height of dumps was measured using reference height measurement method (Criminisi et al., 1999).
For reference height meas- urement, the known height of an adult volunteer observer was used as
a reference to measure the height of waste dumps (Figure 3). Dumps and reference adults were
positioned at the same focal plane of a camera to minimize any error in per- spective.
FIGURE 3
A reference height measurement used for height of dump site (a) The known height of an adult (hr)
is used as a reference to measure the height (h) of dump site. (b) The measured height of dump
site is 108 cm
FIGURE 4
Occurrence of dump sites inside and outside (outer area and periphery) the core city area