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Polycyclic aromatic hydrocarbons over a tropical urban and a high altitude Himalayan Station in India: Temporal variation and source apportionment
No full textAbstract The temporal variations and major sources of polycyclic aromatic hydrocarbons (PAH) intrinsic to PM10 were investigated over a tropical urban atmosphere on the Indo-Gangetic Plain (IGP) and for the first time over a high altitude urban atmosphere at eastern Himalaya in India. Samples were collected over Kolkata, a megacity and Darjeeling, a high altitude (2200m asl) hill station in eastern India during the dry season (October 2015�May 2016). Fourteen PAHs were detected and quantified over Kolkata and Darjeeling during three consecutive seasons, viz., post-monsoon, winter and pre-monsoon. The total-PAHs concentrations were in the order of winter (78.08�146.71ngm�3)>post-monsoon (83.42�113.52ngm�3)>pre-monsoon (37.65�109.27ngm�3) at Kolkata, whereas post-monsoon (22.72�36.60ngm�3)>winter (8.52�28.43ngm�3)>pre-monsoon (5.45�13.34ngm�3) at Darjeeling. The observed seasonality of PAHs at Kolkata vis-a-vis Darjeeling has been explored in the light of anthropogenic activities, boundary layer dynamics and meteorological parameters such as temperature, relative humidity, wind speed and solar radiation. Negative correlation was observed between total-PAHs and temperature, wind speed and solar radiation over Kolkata and Darjeeling. The positive matrix factorization (PMF) model calculations suggested that coal (26), petrol (24) and diesel (17) combustion, commercial and household kitchens (18) and municipal solid waste incineration (15) are the possible contributors to the PM10 associated PAHs over Kolkata whereas diesel (37), commercial and household kitchens (23), coal (21) and petrol (20) are the possible PM10 associated PAH sources over Darjeeling
Managing future air quality in megacities: A case study for Delhi
No full textAbstract Megacities in Asia rank high in air pollution at the global scale. In many cities, ambient concentrations of fine particulate matter (PM2.5) have been exceeding both the WHO interim targets as well as respective national air quality standards. This paper presents a systems analytical perspective on management options that could efficiently improve air quality at the urban scale, having Delhi as a case study. We employ the newly developed GAINS-City policy analysis framework, consisting of a bottom up emission calculation combined with atmospheric chemistry-transport calculation, to derive innovative insights into the current sources of pollution and their impacts on ambient PM2.5, both from emissions of primary PM as well as precursors of secondary inorganic and organic aerosols. We outline the likely future development of these sources, quantify the related ambient PM2.5 concentrations and health impacts, and explore potential policy interventions that could effectively reduce environmental pollution and resulting health impacts in the coming years. The analysis demonstrates that effective improvement of Delhi's air quality requires collaboration with neighboring States and must involve sources that are less relevant in industrialized countries. At the same time, many of the policy interventions will have multiple co-benefits on development targets in Delhi and its neighboring States. Outcomes of this study, as well as the modelling tools used herein, are applicable to other urban areas and fast growing metropolitan zones in the emerging Asian regions
Membrane filtration immobilization technique—a simple and novel method for primary isolation and enrichment of bacteriophages
No full textTo develop a method for the isolation and enrichment of bacteriophages selectively against specific bacteria coupled with a membrane filtration technique.
Methods and Results: Rapid isolation and concentration of host-specific bacteriophages was achieved by exposure of the sample suspected to contain bacteriophages to a specific host immobilized on a 0�45 lm membrane in a membrane filtration unit. The principle behind this method is the exploitation
of host-specific interaction of bacteriophages with their host and maximizing this interaction using a classic membrane filtration method. This provides a chance for each bacteriophage in the sample to interact with the specific host on the membrane filter fitted with a vacuum pump. Specific bacteriophages of the host are retained on the membrane along with its host cells due to the effect of adsorption and these adsorbed bacteriophages (along with their hosts) on the filter disc are then amplified and enriched in regular nutritive broth tryptose soya broth by incubation. With the help of the plaque assay method, host-specific phages of various bacterial species were isolated, segregated and enriched.
Conclusions: The phage concentration method coupled with membrane filtration immobilization of host bacteria was able to isolate and enrich the host-specific bacteriophages by several fold using a lower quantity of an environmental water sample, or other phage suspensions. Enrichment of phages from single plaques was also achieved.
Significance and Impact of the Study: The isolation and detection of hostspecific bacteriophages from a low density bacteriophage water sample in a single step by the use of a simple and basic microbiological technique can be achieved. Enrichment of phages from low phage titre suspensions is also achieved very effectivel
Graphene-based materials supported advanced oxidation processes for water and wastewater treatment: a review
No full textAdvanced oxidation processes (AOPs) received much attention in the field of water and wastewater treatment due to its ability to mineralize persistent organic pollutants from water medium. The addition of graphene-based materials increased the efficiency of all AOPs significantly. The present review analyzes the performance of graphene-based materials that supported AOPs in detail. Recent developments in this field are highlighted. A special focus has been awarded for the performance enhancement mechanism of AOPs in the presence of graphene-based materials
Mechanical Atomatic Urinal Toilet Flusher
Full text linkThis invention relates to a system for facilitating an automatic urinal toilet flushing comprising: a pipe (P) having an intermediate enlarged in- ner diameter area, said pipe comprising: first portion P I having a first diameter d1; second portion P2 having a second diameter d2; a third portion P3 having a third diameter d3; wherein the first, the second and the third portions are se- quential and the diameter d2 is greater than diameter d1 and diameter d3; a tapered forth portion P4 connecting the first portion P I to the second portion P2; and a tapered fifth portion PS connecting the second portion P2 to the third portion P3; a valve mechanism located within the pipe (P), the said valve mechanism comprising an inlet dual valve (I), an outlet dual valve (2) and a connecting rod connecting the inlet dual valve (I) and outlet dual valve (2); and an actuating mechanism that gets automatically actuated and upon actu- ation, operates the valve mechanism to perform a flushing operation
Study of microbial community plasticity for anaerobic digestion of vegetable waste in Anaerobic Baffled Reactor
No full textAnaerobic baffled reactor (ABR) provides a selective environment for the microbial community and their
respective metabolic activities, which supports the physiochemical conditions required for an optimal
performance of reactor. Hydrolysis and methanogenesis are rate limiting steps of anaerobic digestion
which are very sensitive to changes in pH. Effluent recirculation provides buffering environment as well
as prevents loss of some methanogenic population. In the present study, we used four chambered (C-1, 2,
3, and 4) anaerobic baffled reactor treating vegetable waste under three operating conditions (OCs); no
effluent recirculation (OC I), 25% effluent recirculation (OC II), 100% effluent recirculation (OC III) and
studied changes in microbial diversity along with selected parameters. OC I showed dominance of
Bacteroidetes and Firmicutes in C-1 while remaining chambers were dominated by Proteobacteria,
Bacteroidetes, Thermotogae, Spirochaetes and Chloroflexi. This demonstrated that the hydrolytic and
fermentative taxa colonized chamber C-1 while syntrophic acetogenic population dominated the
remaining chambers. However, a drastic change was observed during OC III, advocated by an increase in
diverse population from Firmicutes and Actinobacteria in all chambers. Our results suggest plasticity in
microbial population, which could ensure a better reactor performance under different OCs in ABR for
methanogenesis
Arsenic removal by electrocoagulation process: Recent trends and removal mechanism
No full textcaused by the regular consumption of arsenic contaminated water, even at a lesser contaminated level.
The number of arsenicosis patients is increasing day-by-day. Decontamination of arsenic from the water
medium is the only one way to regulate this and the arsenic removal can be fulfilled by water treatment
methods based on separation techniques. Electrocoagulation (EC) process is a promising technology for
the effective removal of arsenic from aqueous solution. The present review article analyzes the performance of the EC process for arsenic removal. Electrocoagulation using various sacrificial metal anodes
such as aluminium, iron, magnesium, etc. is found to be very effective for arsenic decontamination. The
performances of each anode are described in detail. A special focus has been made on the mechanism
behind the arsenite and arsenate removal by EC process. Main trends in the disposal methods of sludge
containing arsenic are also included. Comparison of arsenic decontamination efficiencies of chemical
coagulation and EC is also reported
Experimental Study of CO2 Gasification of Biomethanation Waste
Full text linkGasification is one of prominent thermochemical processes generally used to convert organic feedstock to combustible syngas (CO and H2). An experimental study of biomass gasification using carbon dioxide as an gasifying medium was carried out in a fixed bed gasifier. The main aim of this study was to determine the effect of temperature on the output syngas. The present study reported the results for producing syngas with CO2 as gasification agent and biomass (rice husk and bio-methanation waste) as raw material. The gasification was performed at 700-900°C respectively and CO2 flow rate was maintained at 0.5 lpm. Maximum syngas
production found at high temperature (900°C). The syngas analysis showed higher hydrogen yield at higher temperatures
Arsenic removal by electrocoagulation process: Recent trends and removal mechanism
No full textArsenic contamination in drinking water is a major issue in the present world. Arsenicosis is the disease caused by the regular consumption of arsenic contaminated water, even at a lesser contaminated level. The number of arsenicosis patients is increasing day-by-day. Decontamination of arsenic from the water
medium is the only one way to regulate this and the arsenic removal can be fulfilled by water treatment
methods based on separation techniques. Electrocoagulation (EC) process is a promising technology for
the effective removal of arsenic from aqueous solution. The present review article analyzes the perfor-
mance of the EC process for arsenic removal. Electrocoagulation using various sacrificial metal anodes
such as aluminium, iron, magnesium, etc. is found to be very effective for arsenic decontamination. The
performances of each anode are described in detail. A special focus has been made on the mechanism
behind the arsenite and arsenate removal by EC process. Main trends in the disposal methods of sludge
containing arsenic are also included. Comparison of arsenic decontamination efficiencies of chemical
coagulation and EC is also reporte