Solid wastes are any non-liquid wastes that arise from human and animal activities that are normally solid, comprising organic and inorganic waste materials such as product packaging, grass clippings, furniture, clothing, bottles, kitchen refuse, paper, appliances, paint cans, batteries, etc. produced in a society, which do not generally carry any economic benefits (Ramachandra, 2009, 2011; Getahun et al., 2012). Unplanned urban development coupled with rapid population growth and changes in the standard of living have led to the tremendous increase in the amounts of municipal solid waste (MSW) leading to mismanagement, which include mix of dry and wet wastes (due to insufficient segregation), dumping in drains and open spaces, disposal without treatment for energy or resource recovery. Municipal solid waste management (MSWM) is associated with the control of waste generation, its storage, collection, transfer and transport, processing and disposal in a manner that is in accordance with the best principles of public health, economics, engineering, conservation, aesthetics, public attitude and other environmental considerations. MSWM is considered a serious environmental challenge confronting local authorities (Ramachandra, 2011, 2012a) and current management approaches does not satisfy the objectives of sustainable development throughout the world (Thanh et al., 2011; Seo et al., 2004; Al-Khatib et al., 2010).
Major portion (70-75%) of MSW is organic (Ramachandra, 2009, 2011; Sathishkumar et al., 2001; Ramachandra et al., 2012b; Sharholy et al., 2007) and contribution of inorganic component is gradually changing and is likely to show further changes in the future. However, solid waste management (SWM) still has gaps due to lack of waste segregation at source level, treatment, re-use, recycling and appropriate disposal. Dumping of waste in open areas, roadside is also one of the common practices in developing countries. These approaches have led to public health risks, adverse environmental impacts, haphazard landfilling leads to depreciate the water quality and other socio-economic problems (Abushammala et al., 2009; Diaz et al., 1999; Chattopadhyay et al., 2007; Nickolas and Ulloa, 2007). The organic fraction of waste through treatment forms a secondary source of raw materials.
Treatment of organic fraction of waste alters its physical and chemical characteristics for energy and resource recovery. The important processing techniques include either composting (aerobic treatment) or biomethanation (anaerobic treatment). Composting through aerobic treatment produces stable product-compost which is used as manure or as soil conditioner. In metropolitan cities, compost plants are underutilised due to various reasons, most important reasons are unsegregated waste and production of poor quality of compost resulting in reduced demand from end users (Ramachandra, 2011). Vermi-composting is also practiced at few places. Biomethanation through microbial action under anaerobic conditions produces methane rich biogas. It is feasible when waste contains high moisture and high organic content. Uncontrolled and unscientific disposal of all the categories of waste including organic waste leads to the environmental problems such as contamination of land, water and soil environment due to leaching of nutrients, etc.
SWM to be effective requires separation of waste at source level with the implementation of 3Rs (reduce, reuse and recycling), treatment of organic fractions of wastes at local levels and disposal at sanitary landfills (Ramachandra, 2011; Tadesse et al., 2008). The indiscriminate dumping, inadequate treatment and poor recovery of organic fractions in urban areas have caused adverse effects on the local ecology, environment (such as air, water and land pollution) and human health (Sharholy et al., 2005; Rathi, 2006; Ray et al., 2005; Kansal et al., 1998; Jha et al., 2003, Gupta et al., 1998; Singh and Singh, 1998; Kansal, 2000). The sustained dumping of solid waste without treatment has overloaded the assimilative capacity of the surrounding environment, necessitates environment friendly treatment and management of solid waste.
Appropriate waste management policy needs to be based on the principle of sustainable development, which considers the society’s refuse as a potential resource. SWM facilities are crucial for environmental management and public health in urban regions. Techniques for solving regional waste problems inevitably have a large number of possible solutions due to variable population densities, incomes, multiple (actual and potential) locations for waste management infrastructure, protected landscape areas and high value ecological sites. Due to this, MSW management have received a great deal of attention as the country produces an estimated quantity of 50–600 million tonnes of urban solid waste annually. Environmentally sound waste management depends on various site-specific factors such as the characteristic of the waste, the efficiency of the waste collection and processing systems required by different waste management practices, availability of proximity of material for recovery from the waste stream, the emission standards to which waste management facilities are designed and operated, the cost effectiveness of the environmental obtained by different management practices and social performance of the community.
The waste generation quantum depends mainly on the consumption patterns, seasons, lifestyle and socio-economic factors. The per capita waste generation is expected to increase annually by 1.33% (Pappu et al., 2007; Shekdar, 1999; Bhide and Shekdar, 1998). Table 1 lists the quantity of waste generated in the metro cities of India, which highlight that the waste quantity generation is high in Chennai, Greater Bangalore and Greater Mumbai due to the standard of living and urbanisation. However, waste generated is comparatively low in the Pune and Lucknow (Ramachandra, 2009; Chanakya et al., 2007).

Table 1 Quantity of MSW generation rate in Metro cities

Quantification and assessment of characteristics of waste through door-to-door survey during two seasons (dry season and wet season) in the Can Tho city the capital of the Mekong Delta region (Thanh et al., 2010) show that an average household solid waste (HSW) generation is about 285.28 g/person/day (including 283.10 during dry season and 287.46g/person/day). Statistical analysis reveal that household quantity waste is positively correlated with the population density, urbanisation level and negatively correlated with household size. Total greenhouse gas (GHG) baseline emission by the HSW is estimated as 153.41 tons per day carbon dioxide equivalent, while compostable and recyclable accounted 80.02% and 11.73% respectively.
Ramachandra and Varghese (2003) explored the possibilities of achieving sustainable management of solid waste using Bangalore as a case study. The strategies include community participation, human resource development, legal mandates and adopting recent technologies like GIS-GPS and GIS System. Environmental audit of MSW management for Bangalore city was done by Ramachandra and Bachamanda (2007) by collecting the data from government agencies, field survey and interview with stakeholders.
Mismanagement of municipal solid waste is a vital source of anthropogenic GHG such as methane (CH₄), biogenic carbon dioxide (CO₂) and non-methane volatile organic compounds (NMVOCs), etc. (Ramachandra, 2009; Ramachandra et al., 2015; Thanh et al., 2010). Among these, Methane is considered as a potent
The organic components in the waste dumps and landfills generate about 60% methane (CH₄) and 40% CO₂ together with other trace gases during anaerobic decomposition (Hegde et al., 2003; Jha et al., 2008). This would vary depending on the waste composition, age, quantity, moisture content and ratio of hydrogen/oxygen availability at the time of decomposition (Jha et al., 2008). Evaluation of the quantitative and qualitative characteristics of MSW in Allahabad city (Sharholy et al., 2007) through door-to-door survey show the average generation rate varies from 0.37kg/capita/day to 0.44kg/capita/day and the total quantity of MSW is about 500 ton/day.
Quantum of MSW has increased from 650 tonnes per day – tpd (1988) to 1,450 tpd (2000) (Ramachandra et al., 2012) and 3,000–3,600 tpd (2016) due to the increase in population with the expansion of spatial extent. The daily collection is estimated at 3,000 tpd with a per capita generation from 0.16 kg/d (1988) to 0.58 kg/d (2009). Table 2 and Table 3 list composition during different time period and physical composition at different levels. Among which, residence (household waste) is the foremost contributor to the total waste stream with a high proportion of biodegradable waste, i.e., 72%.Presently, a quasi-centralised collection system is employed in Bangalore and the waste collection system from households (HH) closely follows the MSW (handling and management) MSW (H&M) rules 2000, employing door-to-door collection. In most of residential area the provision of dustbin is removed to avoid the multiple handling of waste (Chanakya et al., 2010; TIDE, 2000).The city has been facing severe shortage of landfills to dump garbage due to unplanned urbanisation. Bruhat Bangalore Mahanagara Palike (BBMP) is responsible for management of solid waste.

Table 2 Composition of MSW generation in Bangalore

Table 3 Physical composition of MSW in Bangalore

During the early stages, a large part of the organic fraction of city wastes were sent to a compost plant situated outside the city limits Karnataka Compost Development Corporation (KCDC). In 1988, the city was producing 650 tpd, among this about 100 tpd of market wastes were taken back for direct application on the land and another 150 tpd was handled by KCDC. A large segment of decomposable was ‘open dumped’ along the various arterial roads at outskirts of the city (Rajabapaiah, 1988). This trend of open dumping had continued beyond 2000. Today as the wastes generated has increased drastically; most wastes are being openly dumped at about 60 known dumping sites and many unrecorded sites. Composting accounts for 3.14%, but with increase in urban solid waste, the number of compost plants has not increased. Among these, more than 35 sites possess a mixture of domestic and industrial waste (Lakshmikantha, 2006). This highlights that the existing solid waste treatment methods in the city are neither efficiennor well-organised. Taking cognisance of the prevailing situation of wastemismanagement, The Government of India introduced statutory waste minimisation,treatment and environmentally sound management to address the earth’s dwindlingresources and the growing mountains of waste (MSWM, 2000; SWM, 2016).
Earlier studies concerning the MSW of Bangalore have mainly focused on various aspects of solid waste such as composition, generation and disposal. This includes various waste handling practices in Bangalore city (Sathishkumar et al., 2001), exploring options for handling wastes at decentralised levels (Ramachandra and Varghese 2003; Chanakya et al., 2009), comparative assessment of community bins and beneficial aspects of door to door collection systems, etc. These efforts have not captured the various factors that generate HSW, and its last stage of the life cycle. Further, the growing concern of GHG emissions necessitated the quantification of waste and GHG emissions with options to mitigate environmental implications. Estimation of the emission of methane from MSW disposal sites in India by using default, modified triangular methodology and by field investigation (Kumar et al., 2004b), show methane emission of 14.206 Gg, 7.667 Gg and 1.776 Gg respectively. The GHG emission from MSW management in Indian mega-cities, Chennai (Jha et al., 2008) based on IPPC tier I (default emission factors and other parameters as per IPCC guidelines) and tier II (applies country specific emission factors and other parameters) methods for estimating the CH₄ emission for the year 2000 from Kodungaiyur (KDG) and Perungudi (PGD) landfill sites, show CH₄ emission of 8.1 Gg (for KDG with the waste of 314 Gg) and 9.8 Gg (for PGD with the waste of 379 Gg) respectively. Emission fluxes were estimated by using Gas chromatography (GC-SRI, USA, Model 8610C) flame ionisation detector and with the knowledge of an area of landfills, CH₄annual emissions of 0.12 Gg y^-1, N₂O emission of 1 ty^-1 and 1.16 Gg y^-1 CO₂ emissions. In this regard, objectives of the current study are to
1. determine the composition of waste and the rate of generation of HSW
2. SWM being practised at household level
3. assess GHG emissions from the HSW
4. capture the role of various socio-economic factors that affect the generation, composition and management of solid waste.