Magnetic particles were synthesised for radionuclide removal from nuclear wastes by magnetic separation. Dendrimers with terminal amino groups attached to the particle surface were used to bind ...chelating groups for lanthanides and actinides. This led to a 50–400-fold increase of the distribution coefficients for europium and americium in comparison to the reference particles without the dendrimers. Back-extraction studies have demonstrated the possibility of multiple particle recycling.
ObjectivesHospital surveillance systems have been established to monitor occupational blood exposures. We compare short-term monitoring with long-term monitoring of data analysis over 11 years and 21 ...institutions to identify variations in the number of reported exposures.MethodsShort-term monitoring examines the current number of exposures compared to their average over previous years. Long-term monitoring detects trends over several years by various exposure characteristics (place, staff, procedure, etc) through estimating rates of change and using the best linear unbiased predictors (BLUPs) to prevent artefactual trends due to the many categories for each characteristic. Graphical representations of estimated rates help detect change and differences in rates of change.ResultsAnnual monitoring allowed detection of significant changes in the number of reported exposures. Long-term monitoring identified moderate trends over time. The BLUP corrected the estimate of each specific annual rate of change and allowed all other rates to reduce the random variability around the mean change for more specificity. League tables showed significant increases or decreases compared to no change. League tables for two-by-two comparisons allowed reliable comparisons between estimates of the rates of change, although with spurious ranking. Funnel plots enabled quick detection of changes in trends within specified confidence intervals. Long-term trends agreed with the dominant type of annual changes over the 11 years but were not as sensitive.ConclusionsThe two methods have different uses. Both are helpful for assessing short-term sudden and long-term minor changes in number of exposures, possibly reflecting the success or otherwise of introducing specific safety devices or guidelines.
This study assess the removal of fecal indicators (i.e., total coliforms, fecal coliforms, E. coli, fecal streptococci, and pathogens Salmonella sp. and helminth eggs) in a full-scale facultative and ...maturation pond system with primary screening and manual grit removal facility. The capacity of the plant is 6 ML/d. The results showed that the system was able to remove approximately 2.0 to 3.5 log units of fecal indicators and almost 100% of helminth eggs. Meanwhile, Salmonella was not eliminated significantly, as only 1.26 log units removal was found.Removal efficiency of fecal indicator bacteria was reported maximum during summers (3.4 to 4.0 log units) and minimum (1.9 to 2.0 log units) in winters.Further efforts were made to seek the correlation between key physicochemical wastewater quality parameters (biochemical oxygen demand, turbidity, and suspended solids) and indicator microorganisms (total coliforms, fecal coliforms, and fecal streptococci). Among all these parameters, suspended solids showed the highest correlation coefficient (r²) with total coliforms (0.79), fecal coliforms (0.78), and fecal streptococci (0.75). These correlations manifest that the improvement of microbiological quality of wastewater is strongly linked to the removal of suspended solids.
Nest architecture is a fundamental character shaping immune strategies of social insects. The arboreal ant
Temnothorax unifasciatus
nests in cavities such as oak galls where the entire colony lives ...in a unique small chamber. In these conditions, physiological and behavioural strategies likely prevail over compartmentalisation and are presumably tuned with colony size. We designed two experiments to study chemical and behavioural immune strategies against the entomopathogenic fungus
Metarhizium anisopliae
in colonies of different sizes. First, we compared spore germination and length of germinal tubes inside artificial nests, designed to impede the contact between the ants and the fungus, in colonies of different size. In the absence of direct contact,
Temnothorax unifasciatus
colonies inhibit fungal growth inside their nests, presumably through volatile compounds. The analysis revealed a positive correlation between fungistatic activity and colony size, indicating that workers of smaller colonies do not invest a higher per capita effort in producing such substances compared to larger colonies. Second, we performed a removal experiment of contaminated and non-contaminated items introduced inside the nests of colonies of different size. Small colonies challenged with contaminated fibres showed an increased removal of all the items (both contaminated and non-contaminated) compared to small colonies challenged with non-contaminated fibres only. Conversely, larger colonies moved items regardless of the presence of the spores inside the nest. Colony size qualitatively affected removal of waste items showing a pathogen elicited reaction in small colonies to optimise the reduced workforce, while the removal behaviour in larger colonies revealed to be expressed constitutively.
Using a newly developed culture technology known as the Semi-Intensive Floating Tank System (SIFTS), rainbow trout (
Oncorhynchus mykiss), mulloway (
Argyrosomus japonicus) and barramundi (
Lates ...calcarifer) were produced in a 0.13
ha static, inland saline water body over a period of 292 days, yielding the equivalent of 26
tonnes/(ha
year). Rainbow trout were grown with an FCR of 0.97 from 83 to 697
g over 111 days (specific growth rate (SGR), 1.91%/day) between June and September, when average daily water temperatures ranged from 12.3 to 18.2
°C. Over the same time period, mulloway grew only from 100 to 116
g, however, once temperatures increased to approximately 21
°C in October, food intake increased and mulloway grew to an average size of 384
g over 174 days with an SGR and FCR of 0.68%/day and 1.39, respectively. Barramundi stocked in November with an average weight of 40
g increased to 435
g in 138 days (SGR 1.73%/day) with an FCR of 0.90. The SIFTS significantly reduced nutrient input into the pond by removing settleable wastes as a thick sludge with a dry matter content of 5–10%. The total quantity of dry waste removed over the culture period was 527
kg (5
tonnes/(ha
year)), which was calculated to contain 15
kg of nitrogen (144
kg/(ha
year)) and 16
kg of phosphorus (153
kg/(ha
year)). The release of soluble nutrients into the pond resulted in blooms of macro- and micro-algae which caused large and potentially lethal diurnal fluctuations in dissolved oxygen within the pond, however, comparatively stable levels of dissolved oxygen were maintained within each SIFT
1
1
The acronym SIFTS describes the Semi-Intensive Floating Tank System which is comprised of a number of Semi-Intensive Floating Tanks (SIFTs).
through the use of air lift pumps.
Spent pot liner (SPL), a hazardous solid waste produced at cell houses of aluminum smelters, is a potential source of fluoride pollution. Leachates collected from SPL disposal sites were found to ...contain fluoride at considerable concentration levels (up to 575 mg/L). This paper reports a study of selective fluoride removal following laboratory-prepared, ion-exchange treatment. Spent pot liner leachates were pretreated with lime to bring the fluoride level down to approximately 10 mg/L for economic and effective working of the ion exchanger. The detailed ion-exchange treatment study for removal of fluoride was carried out on synthetic SPL leachates and the optimum treatment thus developed was applied on natural SPL leachates. Bench-scale studies were carried out at various flow rates and pHs and in the presence of other ions commonly available in the SPL leachates. The prepared exchanger reduced the level of fluoride from approximately 10 mg/L to less than 1 mg/L. Results indicate that the extraction was 100% up to 6-mL/min flow rate through the ion exchanger and it works efficiently in the pH range of 7 to 10. There is no effect of the other ions present in leachates on removal of fluoride. The exchanger has good capacity to exchange and can be recharged by eluting fluoride sorbed on the exchanger using two molar hydrochloric acid.
A prototype radial/vertical clarifier with 60° cone bottom was built and evaluated for application in recirculating aquaculture. Samples were analyzed for particle size distribution using a laser ...diffraction particle analyzer (Mastersizer S, Malvern Instruments Ltd., Worcestershire, UK) and total suspended solids (TSS) to determine the effectiveness of the clarifier. Surface area calculated mean influent and effluent particle diameters were 81.12
±
1.57
μm and 54.48
±
0.79
μm, respectively—a 33% reduction in mean particle size. Mean particle size within the system was 73.19
±
1.37
μm. Mean influent and effluent particle diameters, based upon volume, were 340.62
±
3.59
μm and 176.07
±
2.37
μm, respectively, with a resulting overall particle size reduction of 48%. Average TSS was relatively low at all sampling points, 11.4
mg/L, 2.1
mg/L and 2.6
mg/L for influent, effluent and system sampling points, respectively, with a resulting average removal rate of 82%. The authors believe the suitability of radial/vertical flow clarifiers as a water efficient, low cost alternative solids collection device for recirculating aquaculture was demonstrated.
media pulse: Books MINER, GARY; Parsons, Simon A.; Jefferson, Bruce ...
Journal - American Water Works Association,
01/2007, Letnik:
99, Številka:
1
Journal Article
