2.1 The study area

Bangalore is the administrative, cultural, commercial, industrial and knowledge capital of the state of Karnataka, India currently with a population of about 7 million and area of 741 sq. km. and lies between the latitude 12°39’00” to 13°13’00” N and longitude 77°22’00” to 77°52’00” E (Figure 1). It is situated at an altitude of 920 metres above the sea level where as the winter temperature ranges from 12°C–25°C, while summer temperature ranges from 18°C–38°C. Mean annual precipitation is 880 mm. (Ramachandra and Kumar, 2010, 2008; Sudhira et al., 2007).
Bangalore city administrative jurisdiction was redefined in the year 2006 by merging the existing area of Bangalore city (221 sq. km) spatial limits with eight neighbouring urban local bodies (ULBs) and 111 Villages of Bangalore Urban District. The spatial extent of Bangalore now is 741 sq.kms with 198 administrative wards consisting of diverse economic and social back ground families (Ramachandra and Kumar, 2008, 2010; Sudhira et al., 2007). Bangalore city population has increased enormously from 65, 37, 124 (in 2001) to 95, 88, 910 (in 2011), accounting for 46.68 % growth in a decade (http://censuskarnataka.gov.in). Population density has increased from as 10,732 (in 2001) to 13,392 (in 2011) persons per sq. km. From 12st to 21st century the Bangalore grew rapidly due to intensified urbanisation coupled with improper planning and become one of the fastest growing cities in the world (Ramachandra et al., 2012).

Figure 1 Study area – greater Bangalore with the administrative wards (see online version for colours)

2.2 Methods

Assessment of the spatial patterns in GHG emissions due to solid waste generated in the municipality involved

1. Primary survey of sample household chosen randomly through the pre-tested and validated structured questionnaire
2. Compilation of ward-wise waste generation and composition data from the government agencies.

The survey at local levels (at ward levels – administrative units in a city to manage solid waste) helps to identify the problems and aid in evolving appropriate strategies for management of solid waste including the planning of household waste treatment options and its infrastructure.

2.3 Data collection

The structured questionnaire was designed to elicit information related to community attitude towards waste management behaviours and socio-economic factors. The questionnaire was pre-tested through a sample survey of about 60 households before taking up large scale survey. Multistage, stratified random survey of urban residences was conducted covering 1967 households during 2011–2012. These households represent heterogeneous population belonging to different income, education, and social aspects. Spatial distribution of 1967 households in eight zones (North, North East, East, South East, South, South West, West and North West) covering 138 wards is shown in Figure 2. The survey also considered parameters such as waste generation quantity, waste collection, time, frequency, number of persons involved in waste collection, collection is done, size of bin, distance of the bin from house, bin clearance time, transportation of waste, landfill site, distance of transportation of waste and socio-economic parameters such as income, household size, employment status, education level of the head of the family 1916 households responded to the quantity of solid waste generation per day.

Figure 2 Spatial distribution of residential houses in the surveyed area (see online version for colours)

2.4 Analysis method

Simple statistical analysis was done to assess the relationship between solid waste generation and socio-economic factors. Spatial distribution of houses and CO₂ equivalent emission from the wards of Bangalore were generated using GIS software MapInfo 7.5. In addition, the per capita generation rate was estimated using equation (1) and total quantity of waste is computed using equation (2) (Shwetmala et al., 2012; Ramachandra et al., 2015).

Generation rate (gram/capita/day) = Quantity of household waste (gram/day)/Population--------------------------(1) Total quantity of waste (gram/day) = Generation rate (gram/capita/day) * ward population--------------------------(2) Mismanagement of solid waste, which are rich in organic components emits GHG such as CO₂, Methane (CH₄). The overall carbon footprint is calculated in terms of CO₂ equivalent emissions. The GWPs for the relevant greenhouse gases used were: 1 (CO₂), 23 (CH₄), which are used to convert emission of different gases to carbon equivalents. CO₂equivalent emission from the solid waste is quantified through equation (3) (Ramachandra et al., 2015).
CO₂ equivalent emission= (W * EF_CO2 ) + (W * EF_CH4 * GWP_CH4 )-------------(3) Where, W is organic waste (gram/day); EF is the emission factor (0.016 Gg/Gg of waste for methane, which is equal to the EF obtained from MTM reported from landfills of Delhi (Kumar et al., 2004b) and lower than the value reported from Chennai landfill site (Jha et al., 2008) and 2.25 Gg/Gg of waste for carbon dioxide), GWPCH4 is GWP of 23 for CH₄.

 

 

 

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