INTRODUCTION

Heterogeneous mixture of substances, which does not have any further use to the society, is often referred to as waste.  Approximately, 3000-4000 t/d of municipal solid waste is generated in Bangalore metropolitan city of India and 55% of this waste is contributed by residential houses (Chanakya et al, 2009).  Analysis of total solid waste generated in the city shows that the municipal waste consist of high percentage of fermentables (>70%) and the balance being recyclables and inert materials (Chanakya and Sharatchandra, 2005).  In fermentable components, vegetable and fruit wastes are dominating and vary from 65 to 90% (Rajabapaiah, 1988; Ramachandra, 2006).  These fermentables are biodegradable and can be broken down into simpler compounds by aerobic and anaerobic microorganisms, leading to the formation of GHG (Green House Gases) emission.

Bangalore city employs a quasi-centralized collection system achieving 60% of collection efficiency (Ramachandra and Bachamanda, 2007) which is satisfactory and make the city clean. The waste collection system is in transition from community bin collection to door-to-door collection.  The primary collection system transfers the mixed or unsegregated waste from houses to transfer station using lightweight vehicles. At transfer station waste is quickly send to disposal site using heavy weight vehicles. There were seven authorized treatment and disposal sites (Mavallipura, near Doddaballapur, Cheemasandra, Mandur, Sheege Halli, Jannappanabande, Doadabidarahalli) for total collected city waste.  Mavallipura, near Doddaballapur and Mandur were receiving most of the waste generated from the city.  Mavallipura and near Doddaballapur have been completely closed in 2012 for further disposal, due to protests from the local people.  Currently, Mandur is the only active disposal site, which receives more than 600 t/d of garbage.  This limited availability of disposal and treatment sites have affected the collection and transportation of waste from transfer stations.  Consequently, odour problem, mosquito menace and increase of street dogs around the existing transfer stations.

Continuous accumulation of waste and reduction in number of disposal sites has increased the number of unauthorized waste disposal sites in and around the city. Inside city has small and temporary dumps, which can be eliminated with increase of collection efficiency. Large and permanent dumps on the outskirts of the city are posing a serious threat to the environment and are the concerns need to be addressed on priority.  A study conducted by Lakshmikantha, 2006 shows that there were 60 recorded open sites with many unrecorded sites. Among these, more than 35 sites possess a mixture of domestic and industrial waste.  With the close of major disposal and treatment site, there will be increase in number of open dumps.

Sometime wastes are dumped near the storm water drains or inside the drainage network.  These dumped wastes are gradually carried to locations of shallow and slow flow where they tend to accumulate until a storm event carries this large mass away.  Such large floating mass easily chokes the narrow path below road bridges and results in flooding (Shwetmala et al., 2009, Gupta and Nair, 2011; Gupta and Nair, 2010; Ramachandra and Mujumdar, 2006; ENVIS Report, 2005).  The objective of this paper is to assess the current situation of municipal solid waste management in Bangalore and its corresponding major environmental implications.