1,720,997 research outputs found
Contaminazione ambientale da trielina e percloroetilene: primi risultati delle indagini epidemiologiche
No full textVengono illustrati gfli effetti biologici di trielina e percloroetilene sugli indicatori biologici ematici di campioni della popolazione delle aree contaminat
L'inquinamento atmosferico da traffico motorizzato a Milano. Nota 1.Comportqamento dell'ossido di carbonio in alcuni nodi strqdali
No full textVerrrà inserito appena si riapriranno le bibiotech
[Studies of the behavior of nitrogen oxides in the air of the city of Milan]
No full textWILL BE ADDE
Direct quantification of bacterial biomass in influent, effluent and activated sludge of wastewater treatment plants by using flow cytometry
No full textA rapid multi-step procedure, potentially amenable to automation, was proposed for quantifying viable and active bacterial cells, estimating their biovolume using flow cytometry (FCM) and to calculate their biomass within the main stages of a wastewater treatment plant: raw wastewater, settled wastewater, activated sludge and effluent. Fluorescent staining of bacteria using SYBR-Green I + Propidium Iodide (to discriminate cell integrity or permeabilisation) and BCECF-AM (to identify enzymatic activity) was applied to count bacterial cells by FCM. A recently developed specific procedure was applied to convert Forward Angle Light Scatter measured by FCM into the corresponding bacterial biovolume. This conversion permits the calculation of the viable and active bacterial biomass in wastewater, activated sludge and effluent, expressed as Volatile Suspended Solids (VSS) or particulate Chemical Oxygen Demand (COD). Viable bacterial biomass represented only a small part of particulate COD in raw wastewater (4.8 ± 2.4%), settled wastewater (10.7 ± 3.1%), activated sludge (11.1 ± 2.1%) and effluent (3.2 ± 2.2%). Active bacterial biomass counted for a percentage of 30-47% of the viable bacterial biomass within the stages of the wastewater treatment plant. © 2010 Elsevier Ltd
Surrogate parameters for the rapid microbial monitoring in a civil protection module used for drinking water production
No full textRapid analyses based on flow cytometry (FCM) and quantitative PCR (qPCR) were proposed and applied in a full-scale mobile water treatment plant (flow rate of 4.4. L/s) utilized as a civil protection module for drinking water production for quasi real-time monitoring. The rapid methods applied here are two cultivation-independent techniques (FCM and qPCR). The microbiological quality of water was monitored on the basis of alternative microbial parameters, detecting cells with an intact and permeabilised membrane (in 20. min), cells with β-. d-galactosidase activity (in 40. min) and Escherichia coli (E. coli, in less than 3. h). These rapid techniques were compared with some conventional culturable bacteria groups (aerobic mesophilic bacteria, total coliforms and E. coli).Although intact bacteria were two orders of magnitude higher than culturable aerobic mesophilic bacteria (due to a large fraction of viable-but-not-culturable cells, but also chemolithotrophic bacteria), they both showed not significant reduction in cells after filtration, 2-3. log of removal after ozonation and a regrowth of about 1. log after granular activated carbon. Cells with β-. d-galactosidase activity (belonging to the group of total coliforms) were higher than culturable total coliforms, due to a large presence of active-but-not-culturable cells, especially in ozone treated water.E. coli quantified by qPCR decreased through filtration and they were under the quantification limit after ozonation, analogously to culturable E. coli. Despite a higher quantification limit for FCM and qPCR, they appear sufficiently accurate and suitable as surrogate microbial parameters, considering their rapidity (about an half hour with FCM). In the case of strong stress conditions such as ozonation, the surrogate microbial parameters, which include viable-but-not-culturable cells, might result more sensible in the evaluation of treatment efficiency
Effects of metalloid oxyanion tellurite on the growth characteristics of the phototrophic bacterium Rhodobacter capsulatus
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