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Biomethanation potential for co-digestion of municipal solid waste and rice straw: A batch study
No full textRice straw (RS) contains a high amount of lignocellulosic materials which are difficult to degrade without
thermal pretreatment. In the present study, co-digestion of municipal solid waste (MSW) and RS was carried out
in three different ratios i.e., 1:1, 2:1, and 3:1 to get the maximum biomethanation potential and methane
generation rate constant (k). The biogas and methane (CH4) potential increased by 60% and 57%, respectively
for MSW and RS in the ratio 2:1 as compared to other combination. The values of k, biochemical methane
potential (μb) and sludge activity were measured as 0.1 d−1, 0.99 CH4-COD/CODfed and 0.50 g CH4-COD/g VSS,
respectively. The sludge activity was found to be 100% for 2:1 ratio. Co-digestion of RS with MSW can also
optimize the C/N ratio which is an essential parameter in the anaerobic digestion process
Geospatial assessment of tourism impact on land environment of Dehradun, Uttarakhand, India
No full textIndia’s tourism industry has emerged as a
leading industry with a potential to grow further in the
next few decades. Dehradun, one of the famous tourist
places in India located in the state of Uttarakhand,
attracts tourist from all over the country and abroad.
The surge in tourist number paved the way for new
infrastructure projects like roads, buildings, and hotels,
which in turn affects the topography of the mountainous
region. In this study, remote sensing and GIS techniques
have been used to assess the impact of tourism on the
land environment of Dehradun. Satellite images of the
years 1972, 2000, and 2016 were analyzed using objectbased
image analysis (OBIA) to derive land use and
land cover (LULC) and ASTER-DEM (Digital ElevationModel)
was used to determine the topography of the
study area. LULC classification includes built-up, vegetation,
forest, scrub, agriculture, plantation, and water
body. The slope of the region was categorized as gentle,
moderate, strong, extreme, steep, and very steep. To
assess the sprawl of built-up on high terrain land,
built-up class of LULC was overlaid on slope classes.
The overlay analysis reveals that due to increase in
tourism, the land use in terms of the built-up area has
been extended from gentle slope to very steep slope. The
haphazard construction on the extreme, steep, and very
steep slope is prone to landslide and other natural disasters.
For this, landslide susceptibility maps have also
been generated using multicriteria evaluation (MCE)
techniques to prevent haphazard construction and to
assist in further planning of Dehradun City. This study
suggests that a proper developmental plan of the city is
essential which follows the principles of optimumuse of
land and sustainable tourism
Challenges and opportunities associated with waste management in India
Full text linkIndia faces major environmental challenges associated with
waste generation and inadequate waste collection, transport,
treatment and disposal. Current systems in India cannot
cope with the volumes of waste generated by an increasing
urban population, and this impacts on the environment and
public health. The challenges and barriers are significant,
but so are the opportunities. This paper reports on an
international seminar on ‘Sustainable solid waste management
for cities: opportunities in South Asian Association for Regional
Cooperation (SAARC) countries’ organized by the Council
of Scientific and Industrial Research-National Environmental
Engineering Research Institute and the Royal Society. A priority
is to move from reliance on waste dumps that offer no
environmental protection, to waste management systems that
retain useful resources within the economy. Waste segregation
at source and use of specialized waste processing facilities
to separate recyclable materials has a key role. Disposal of
residual waste after extraction of material resources needs
engineered landfill sites and/or investment in waste-to-energy
facilities. The potential for energy generation from landfill via
methane extraction or thermal treatment is a major opportunity,
but a key barrier is the shortage of qualified engineers and
environmental professionals with the experience to deliver
improved waste management systems in India
Removal mechanisms of volatile organic compounds (VOCs) from effluent of common effluent treatment plant (CETP)
No full textThis study investigated the occurrence, removal and influence of plant-operating conditions on removal
mechanisms of 83 VOCs in different treatment units of a CETP in Mumbai, treating industrial waste on
primary and secondary level. A mass balance approach was used to predict VOC removal by volatilization,
stripping, weir drop, adsorption, and biodegradation. Results indicate that ~17% of VOCs were
removed by stripping in equalization tank and ~8% were removed by weir drop in primary clariflocculator
respectively. Biodegradation was the dominant mechanism in aeration tank and was relatively
poor for hydrophobic compounds which were more vulnerable to removal by stripping. Stripping
rates could be reduced by increasing the active biomass concentration and using fine pore diffusers to
reduce the air/effluent ratio. Decrease in Henry's constant and compound concentration can shift the
main removal mechanism from stripping to biodegradation. Results also show considerable agreement
between measured (71.2%) and predicted (67.1%) total removal, especially in aeration tanks. Equalization
tanks (actual, 20.5%, predicted, 16.9%), primary clari-flocculator (actual, 14.2%, predicted, 7.7%), and
secondary clarifier units (actual, 29.5%, predicted, 16.8%) showed fairly acceptable differences in
measured and predicted removal. The effect of other mechanisms on VOC removal need to be further
explored owing to their major contribution to VOC removal. This study is the first attempt in understanding
the mechanisms behind the removal of VOCs in each treatment unit, especially equalization
tanks and clarifier units, which have been severely underestimated till date
In-situ ammonia removal by methanogenic granular biomass
No full textMethanogenic grannules from sewage-fed 298-day old UASB reactor having high abundance of Nitrospira sp. were
evaluated for simultaneous methanogenesis and nitrification. Batch experiments were conducted under anaerobic and
oxygen limited condition using either 0.04% (v/v) methanol (C) or ammonium chloride (30-100 mg N/L) (N) or both (N+C).
Results showed that C-utilization preceded N-utilization in N+C sets indicating methanogenesis was independent of
ammonia removal. Ammonia removal with nitrate generation under oxygen-limited condition confirmed nitrification
potential of methanogenic grannule. However, under anaerobic conditions, decrease in ammonium nitrogen did not result
in stoichiometric increase in nitrite & nitrate concentrations. Further, hydrogenotrophic methanogens disappeared in N &
N+C sets. H2-mediated denitrification could possibly atrribute for disappearance of both nitrite or nitrate and
hydrogenotrophic methanogens. Increase in Methanosaetaceae compensated for methane production via acetoclastic
route. Thus, simultaneous nitrification & H2-mediated denitrification was confirmed as the plausible route for ammonia
removal in methanogenic granules under anaerobic condition. This finding of in-situ ammonia removal in methanogens
has opened new avenues for treating C/N wastewaters
Genome Annotation and Validation of Keratin-Hydrolyzing Proteolytic Enzymes from Serratia marcescens EGD-HP20
No full textStabilization and utilization of poultry waste demand efficient biodegradation either
by mixture of enzymes or by microbial system that can produce different types of proteinhydrolyzing
enzymes. For utilization of this keratinous biomass, in the present study, genome
was sequenced and annotated for a bacterium having multiple enzymatic options for hydrolysis
of different soluble and insoluble protein fractions of poultry waste. Among the soluble
protein substrates, optimum production of enzyme and soluble protein was observed in case of
casein, whereas among the insoluble protein substrates, maximum production of enzyme was
achieved when broken nails were used. Conditions for enhanced enzyme activity with
concurrent degradation of keratin-rich poultry feather waste to protein-rich hydrolysate were
optimized for different growth parameters. The bacterium grew well and highest protease
production occurred in 144 h at mesophilic temperature (30 °C) and alkaline condition (pH 8–
10) with enzyme activities of 134 and 168 U/mL, respectively
Stabilized landfill leachate treatment using heterogeneous Fenton and electro-Fenton processes
No full textIn the present study, stabilized landfill leachate treatment by heterogeneous Fenton and electro-Fenton
(EF) was carried out. Iron-manganese binary oxide loaded zeolite (IMZ) was used as a catalyst for
generating hydroxyl radicals in the acidic medium. Heterogeneous Fenton process was capable of
removing 88.6% COD from landfill leachate at the optimal conditions, while 87.5% COD removal was
observed at optimal EF treatment conditions. Biodegradability of landfill leachate was increased significantly
from 0.03 to 0.52 after Fenton treatment. The prepared heterogeneous catalyst was found
reusable with a reduction in COD removal rate. Even though, both the processes are efficient for leachate
treatment, the low catalyst dosage requirement in case of EF process justifies that it is more feasible than
Fenton process
Coarse particle (PM10–2.5) source profiles for emissions from domestic cooking and industrial process in Central India
No full textTo develop coarse particle (PM10–2.5, 2.5to10μm) chemical source profiles, real-world source sampling fromfour
domestic cooking and seven industrial processing facilities were carried out in “Raipur-Bhilai” of Central India.
Collected samples were analysed for 32 chemical species including 21 elements (Al, As, Ca, Cd, Co, Cr, Cu, Fe,
Hg, K, Mg, Mn, Mo, Na, Ni, Pb, S, Sb, Se, V, and Zn) by atomic absorption spectrophotometry (AAS), 8 water-soluble
ions (Na+, K+, Mg2+, Ca2+, Cl−, F−, NO3
−, and SO4 2−) by ion chromatography, ammonium (NH4
+) by spectrophotometry,
and carbonaceous fractions (OC and EC) by thermal/optical transmittance. The carbonaceous
fractions were most abundant fraction in household fuel and municipal solid waste combustion emissions
while elemental speciesweremore abundant in industrial emissions.Most of the elemental specieswere enriched
in PM2.5 (b2.5 μm) size fraction as compared to the PM10–2.5 fraction. Abundant Ca (13–28%) was found in steelrollingmill
(SRM)and cement production industry (CPI) emissions, with abundant Fe (14–32%) in ferro-manganese
(FEMNI), steel production industry (SPI), and electric-arc welding emissions. High coefficients of divergence (COD)
values (0.46 to 0.88) among the profiles indicate their differences. These region-specific source profiles aremore relevant
to source apportionment studies in India than profiles measured elsewhere
Managing future air quality in megacities: Co-benefit assessment for Delhi
No full textUrbanization, population and economic growth in Indian megacities like Delhi have resulted in an increase in
energy and transportation demand leading to severe air pollution and related health impacts, as well as to the
rapid growth in the greenhouse gas emissions. In this study, an integrated assessment of air quality and climate
policies for Indian cities – with a particular focus on National Capital Territory of Delhi, has been carried out. We
have developed emission inventory of air pollutants and greenhouse gases for the base year (2010) and evaluated
the impact of current policies on emission projections by 2030 in the business-as-usual scenario. Emissions
of coarse and fine particulate matter are projected to be 51% and 15% higher in 2030 as compared to present. As
the current legislations do not indicate progress towards the achievement of the Indian National Ambient Air
Quality Standards in Delhi, we explored the effectiveness of additional emission control strategies with either
advanced end-of-pipe emission controls or low carbon policies. Relative to the baseline scenario, the set of
alternative policy strategies would reduce emissions rapidly in 2030. The results revealed that air quality policies
under various scenarios could also have co-benefits of reducing carbon emissions. At the same time, the results
suggest that low carbon policies would be more efficient to cut emissions as compared to advanced end-of-pipe
emission control policies. However, their implementation could be limited by the availability of clean fuels. In
the climate policy scenario, carbon emission in 2030 is estimated to decrease by 19% relative to baseline.
Additional controls combined with low carbon policies like controlling non-industrial emissions create an opportunity
to further enhance the scope for co-benefits and to attain the air quality standards in Delhi
Growth associated degradation of aliphatic-aromatic copolyesters by Cryptococcus sp. MTCC 5455
No full textThe degradation of aliphatic-aromatic copolyesters, poly[(butylene succinate/terephthalate/isophthalate)-
co-(lactate)] (PBSTIL) and poly(butylene adipate co-terephthalate) (PBAT) under mesophilic
conditions was investigated using the yeast, Cryptococcus sp. MTCC 5455. Complete degradation of
PBSTIL and PBAT films was observed at 25 �C within 96 and 216 h, respectively. Lipase was produced
during the course of degradation and the encoding gene was expressed in Escherichia coli BL21 (DE3). The
production of lipase was enhanced by cumulative induction with 0.1mM IPTG and 1.5mM lactose for
24 h at 25 �C, which resulted in a maximum lipase activity of 27.75 ± 1.0 U/mL. Spectral studies of the
degraded polymeric films confirmed the hydrolysis of ester bonds by the lipase. Scanning electron microscopy
revealed the formation of cracks and holes on the surface of the polymeric films during
degradation. The results indicated the feasibility of the process towards degradation of polymeric waste
at ambient temperatures within a short period of time