Current solid waste management practices

1. Solid waste sources in campus: Major sources of organic wastes in the campus are residential area, cafeterias, mess, and hostels. Hostels and departments generate inorganic waste dominated by paper and plastic. This goes directly to the collection site apart from collection by an informal sector. The inorganic segregated wastes are given to an agency (ITC-BBMP). Cafeterias and mess has high percentage of food and vegetable waste (organic waste) which is given to piggeries through common collection bins. Waste from residential area contains organic waste along with inorganic waste and details have been given in Table 2. This suggests a need of waste management in residential area where organic fraction is more than other sources and there is scope for conversion of these waste through appropriate technologies to valuable resources.

Table 2: Source and major waste constituents

Solid waste generation rates and characteristics: MSW generally consist of organic waste and inorganic/ dry waste which mainly consist of paper, plastic, cloth, glass, metal and leather. The respective composition of campus MSW after implementation of DtD collection is shown in Table 1. The proportion of organic waste is much higher (82%) than other constituents of waste. Therefore, there is great potential of organic waste recovery from residential area of campus. The waste is suitable for feeding animals or it can also be used as feed materials in composting and biogas production. The quantity of paper, plastic, glass and metal is relatively small because most of these recyclable materials are collected before entering the MSWM system (Tai et al., 2011).

The total waste generated in the campus is 347.46 kg/day after implementation of DtD collection (in 2011). Table 1 infers that the generation rate is varying in all three collection sites of campus. The quantity of waste collected at site CS 1, CS 2 and CS 3 were 226.84 kg/day, 62.74 kg/day and 57.87 kg/day, respectively. It indicates that in residential area the largest generator of waste was near CS 1 followed by CS 2 and CS 3. This implies that the number of apartments near to CS 1 is higher than other two collection sites as well as residents near CS 1 produce more waste. Resources consumption and consequently waste generation at CS 1 are higher than both CS 2 and CS 3. Day wise results for CS 1, CS 2 and CS 3 collection sites are given in Fig 2. Total waste generation is high on Monday and Saturday which reflect higher consumption during weekends.

The comparable generation rates of waste for CS 1 and CS 3 at 0.128 kg/c/day and 0.106 kg/c/day, respectively, as opposed to 0.08 kg/c/day for CS 2 can be attributed to their standards of living as well as to daily food habit. The average per capita waste generation for Bangalore city was 0.35 kg/c/day at household level (Chanakya et al., 2009), which is higher than the present estimation, which is attributable to the current sampling location’s social and economic aspects.

2. Solid waste management with collection system:
The results suggest that significant progress has been made towards the key objective – increasing the efficiency of waste collection system. Changes in the collection practice, has seen the improvements in waste collections by three to fourfold as in CS 1. This large difference in total waste quantity collected shows the efficiency of DtD collection. Important features of both the collection system; DtD and community bin collection are discussed in Table 3. In community bin collection system, wastes generated in all residences were not reaching to the collection site. Community bins are located at the centre of locality which leads to waste littering in different unauthorized locations of campus. Change in collection process has also stopped littering of waste on road side, drainages and also around community bins (Fig 3). This has significantly reduced dog and monkey menace in the residential colony of the campus. Community bin collection system also requires maintenance of bins at regular intervals as broken bins leads to other complications. Source segregation helps to separate collection of recyclables, which fetches additional revenue. Also, daily disposal of waste has minimized odour problem in the locality.

Table 3: Comparative analysis of collection systems

Fig. 3. Bins near CS 1 (Collection Site 1) with different collection system

Waste composition has not changed much with the changes in the collection process as well as with time (Table 1). The largest quantity came from organic waste generated from leftovers of prepared food or from the waste generated during food preparation (Fig 2). This waste was generated throughout the day (breakfast, lunch, dinner) and is deposited mixed with all different type of waste in dustbins. After DtD collection, percentage of plastic has increased almost one and half time more than 2010. Reason could be that with this collection practice, usually waste is handed over by each residence in plastic pouches. Waste composition has also changed with time. Earlier studies (2000) shows that waste compositions - paper was 18% of total waste generated at that time (Sathiskumar et al., 2001) which has reduced to 5.7% and 4.9% in 2010 and 2011 respectively. This could be due to the paperless environment through automation in administration, etc. Also, increased use of internet has probably reduced the use of paper. In addition to this, frequent use of polybags has also reduced due to the active participation of environment conscious groups (mainly consisted of housewives) has motivated many to switch over paper as packaging materials in including grocery and vegetable vendors on the campus.