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Size-segregated aerosol samplings were carried out during 2013-14 at Okhla landfills, Delhi, which is a municipal solid waste dumping station. Aerosol samples were collected on quartz filters using an Andersen impactor sampler having 9-stages with cut-off diameter >9.0, 9.0-5.8, 5.8-4.7, 4.7-3.3, 3.3-2.1, 2.1-1.1, 1.1-0.65, 0.65-0.43, <0.43 μm at flow rate 28.3 lpm. Additionally, a low-volume handy sampler was also used to measure total culturable microbial concentrations operates at flow rate of 2 lpm. The culturable total bacterial and fungal concentrations across the seasons ranged from 8.3×10 5 -1.8×10 7 cfu/m 3 and 1.2×10 3 -2.5×10 5 cfu/m 3 , respectively and also varied across the impactor stages. Major concentration peaks found during winter could be associated with high particulate matter concentration and favourable meteorological conditions in Delhi. On the other hand, comparatively lower concentrations were observed in summer. This is possibly because of microbial lethal effects of adverse meteorological conditions (high temperature and solar radiation) which are more prominent than that of release of microbial flux due to solar ground heating effect in summer. Size distribution analysis shows that bacteria were mostly abundant in fine particle sizes, i.e. <0.43-2.1 μm, but few peaks were also observed in size ranges between 5.8->9.0 μm. Fungal spores mostly peaked in coarse sizes (2.1-5.8 μm) and showed unimodal size distribution. Predominant identified bacterial strains were mostly belonged to Bacillus, Staphylococcus, Streptococcus, Klebseilla and Escherichia genera. Most of the identified fungal spores are known for adverse health effects causing numerous allergic and pathogenic inflammations. These results suggest that the open-solid waste dumping sites are a major source of bioaerosols, and residents living in the nearby areas of landfills are at high health risks. [ABSTRACT FROM AUTHOR]

Abstract: The paper deals with an economic manufacturing quantity (EMQ) model for the selling price and the time dependent demand pattern in an imperfect production process. Due to long-run, machine breakdown may occur, as a result, the system may shift to out-of-control state from in-control state and production systems begin to produce imperfect quality items. The production of imperfect items increases with time. All imperfect quality items are reworked at a fixed cost to restore these to its original quality. To reduce the production of the imperfect quality items, we consider reliability as a decision variable along with the development cost and the production cost as a function of reliability. The profit function is maximized by Euler–Lagrange formula. The numerical example, sensitively analysis, and graphical illustrations are given to illustrate the model. [Copyright &y& Elsevier]

[Display omitted] • Smoldering and ignition indicators were determined for open MSW landfill. • Elevated CO level showed presence of surface waste smoldering. • Elevated temperature level is major cause behind spontaneous landfill fire. The waste receiving capacity of most municipal solid waste (MSW) landfill sites in India is exhausted, resulting in the formation of larger waste heaps. In the majority of Indian cities, these old waste heaps are prone to frequent smoldering and ignition resulting into fires. In this study, the potential risk of spontaneous ignition of landfilled waste at landfill surface was analyzed based on the physico-chemical characteristics of waste, carbon monoxide (CO) levels, landfill surface temperature (LST). The leachate pollution index was also determined to analyze the leachate quality for three different seasons (monsoon, pre-monsoon and post-monsoon). The regression analysis was carried out to understand the thermal properties (smoldering temperature, smoldering time, ignition temperature etc.) of MSW. The results showed that old waste has a higher tendency to undergo ignition compared to fresh waste. It has also been observed that the lower MC of old waste samples in the range of 3.4% and 18.2% is the most likely cause of early smoldering (106.6–109.5 °C) and ignition (198.6–208.4 °C) of old waste. In pre-monsoon season, CO concentrations for sub-surface (10–30 cm depth) smoldering events (SSE) were observed to be between ∼ 150 to 200 ppm. This CO level substantially dropped to 10 ± 1 ppm in the post-monsoon season. The estimation of the leachate pollution index (LPI) showed an index score of 27.35, 30.47 and 10.71 for pre-monsoon, monsoon and post-monsoon seasons, respectively. The determination of CO levels, increased LST and physico-chemical properties of landfilled waste will greatly assist in the abatement of environmental pollution arising from landfill fires. [ABSTRACT FROM AUTHOR]