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The increasing population over a period of sometime increased the generation of solid waste as well. The process of waste dumping in prehistoric times was very crude as it was disposed of on roads or on the exposed pits in the periphery of the cities. Solid wastes play a lead role in affecting the biotic as well as abiotic components of the surroun...
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Managing leachates from landfills in India is an important economic and environmental concern. Due to the exponential growth of population, industrialization and urbanization, several types of byproducts have been generated from day-to-day life. These byproducts are dumped in a haphazard or unempirical manner into the open space, which causes an alarming state of problem in developing country like India. In Indian context, in one of the major metro cities like New Delhi, the landfill techniques have been said to be a menace to the health of nearby residents. The present study has been undertaken to assess the environmental hazards that municipal solid waste landfill leachate poses to the groundwater. Three landfill sites, Bhalswa, Okhla, and Ghazipur of New Delhi, have been selected to determine the physicochemical properties, including significant metals of lowland leachate. Furthermore, the leachates from three different dumpyards have been compared with the permissible limits prescribed by Environmental Protection Agency, 1986. Thus, the present research findings focus for the Bhalswa landfill site leachate analysis, which indicates a high biochemical oxygen demand concentration of 3356 mg/L and chemical oxygen demand concentration of 5942 mg/L, respectively. However, the total dissolved solids, electrical conductivity, and ammonical nitrogen concentrations have been 12,384 mg/L, 32,600 µmho/cm, and 36.6 mg/L. It is observed that the Ghazipur landfill site was highly tainted as compared to Okhla and Bhalswa landfill sites. Further, quantitative analysis deduces the trend of heavy metals concentration of iron, nickel, zinc, arsenic, and chromium in the order of Bhalswa > Okhla > Ghazipur landfill sites. The toxicity hazard of dumpsites from Bhalswa, Ghazipur, and Okhla was also examined using the leachate pollution index, and the values were obtained such as 21.57, 26.61, and 20.28, respectively. Additionally, the present study reveals that the leachate percolating through all the landfill sites exceeds the permissible limits prescribed by Environmental Protection Agency, 1986, and thus, an immediate attention is required to circumvent its other adverse effect on the nearby area and groundwater reserves.
Dumpsites are reservoirs of persistent organic pollutants (POPs) and heavy metals (HMs), constituting environmental hazards to humanity. Autochthonous microorganisms in dumpsites exhibit various degrees of responses to contaminants. Unfortunately, there is a dearth of information on the types and concentration of pollutants and the array of microorganisms in these dumpsites which may play important roles in the metabolism of such pollutants or other community processes. Therefore, determining the microbial community structure in such contaminated sites across a municipality is essential for profiling the taxa that would serve as consensus degraders of the pollutants. In this study, soil samples from three dumpsites (Cele, CS; Solous, SS; and Computer Village, CVS) were characterized for geochemical properties using GC-MS, MP-AES, and other analytical protocols, while the dynamics of bacterial communities were evaluated based on their 16S rRNA gene barcodes. A significant difference in the bacterial communities was observed among the dumpsites in relation to the extent of pollution caused by POPs and HMs. CVS, with the highest HM contamination, was rich in Actinobacteria (41.7%) and Acidobacteria (10.2%), in contrast to CS and SS. Proteobacteria (34.1%) and Firmicutes (20%) were the dominant phyla in CS (highest POP contamination), while Bacteroidetes (45.5%) and Proteobacteria (39.9%) were dominant in SS soil. Bacillus was the dominant genus in the most polluted dumpsite. Canonical correspondence analysis revealed that polycyclic aromatic hydrocarbons (PAHs) and HMs shaped the structure of the bacterial operational taxonomic units (OTUs) in the most polluted dumpsite. Out of a total of 706 OTUs, 628 OTUs exhibited a significant correlation (>50%) with benzo(b)fluoranthene, azobenzene, dibenzofurans, pyrene, dibenzo(a,l)pyrene, Cu, and Zn. In particular, Proteobacteria (Achromobacter sp. and Serratia sp.), Bacteroidetes (Zhouia sp.), and Firmicutes (Bacillus sp.) were suggested to be pivotal to the ecophysiology of dumpsite soils contaminated with POPs and HMs. The results generally underscored the importance of metagenomic and physicochemical analyses of polluted systems in enabling correlations for useful prediction of drivers of such ecosystems. This will further improve our understanding of the metabolic potential and adaptation of organisms in such systems.
Agricultural residues are wastes generated whilst growing and processing these goods. The residues of agriculture are produced from numerous activities like cultivation, aquaculture, and livestock production. Wastes generated in the field or after processing in industries are multiphase and multicomponent. All three forms, liquid, solid, and gaseous wastes are generated by the agriculture sector which tends to pollute soil, water, and air. Waste causing environment degrading ability needs immediate attention. For ages, food and agro-wastes were either burnt or allowed to decompose in fields, but this can be possibly harmful to the environment. With the progress in technology, new approaches concerning their utilization, reuse, and processing need to be established to permit its sustainable utilization of residues and reduce pollution. Agricultural wastes are potential renewable energy resources. It is important to develop proper waste management strategies as it is the only best solution to have a healthy environment. In this paper, we discussed various strategies and technologies introduced to manage and utilize the waste that is generated in the agricultural field or after processing agriculture-based products. Appropriate management of waste is also beneficial in deriving out the essential useful product from the waste.KeywordsAgricultural wastesAgro-industry wastesBiofuelBiogasBioethanolIndustrial processing waste
