Biological Methods For Removal Research Articles

A critical overview on impact of different nano-catalytic assemblies for photodegradation of tetracycline

Abstract Recently, the removal of tetracycline, a toxic material, from aquatic medium has been a trending subject of research. Several different technologies including adsorption, biological removal method, solvent extraction, coagulation, chemical reduction, photocatalysis and ion exchange method for removal of tetracyclines from wastewater have been reported. However, photocatalysis of tetracyclines (TC) has gained huge interest because of more efficient mineralization of TC into CO2 and water. Several different nanomaterial based photocatalytic assemblies for the removal of tetracyclines have been widely reported for the removal of tetracyclines which have not been critically reviewed in the literature. This study provides an overview of recent progress of classification, synthesis, characterizations, mechanism of inorganic and metal organic framework nanocatalytic assemblies on photocatalysis of tetracyclines in aquatic medium. Additionally, kinetics and factors affecting the photocatalysis of tetracyclines have been discussed briefly. Future perspectives have also been presented for further advancement in this area.

Seabird bycatch in a sardine purse seine fishery

Abstract Limited understanding of seabird bycatch in purse seine fisheries has been highlighted as a key information gap in assessments of seabird bycatch in fisheries globally. This study documents the bycatch of breeding flesh-footed shearwaters (Ardenna carneipes) in a sardine purse seine fishery on the southern coast of Western Australia. Fishery-dependent bycatch records from 2009/2010 to 2017/2018 showed a strong peak in the mortality rate per fishing trip during March and April, closely associated with the final stage of chick rearing. Observers during those peak months in 2007, 2008, 2017, and 2018 recorded 171 mortalities during 222 trips at per trip rates (±95% confidence limits) ranging from 0.59 (0.25–1.17) in 2017 to 1.10 (0.56–1.96) in 2007. Zero mortalities were recorded on at least 70% of trips in any year, suggesting infrequent formation of net folds that can trap birds. Total annual mortalities estimated for 2016/2017 and 2017/2018 were 123 (52–251) and 172 (91–302), respectively. Although within a sustainable anthropogenic limit of 495 (369–660) estimated from conservative application of the potential biological removal method, the extent of other anthropogenic mortalities is unknown. Further research on the effect of distance of breeding colonies from fishing operations is required.

Tendencias de la bioenergía: del metagenoma de hábitats ricos en azufre a la purificación del biogás

Gran cantidad de residuos generados por la agroindustria son considerados tanto para la obtención de productos útiles de mayor valor agregado como para reducir el impacto ambiental. Existen alternativas para evaluar estos desechos siendo la producción de bioenergía una solución de gran precedente, desde la producción de biodiesel, bioetanol y biogás hasta aprovechar la biomasa. La producción de biogás por metanogénesis es una alternativa para la generación de biocombustibles y energía. Sin embargo, surge un problema que puede generar daños en la planta industrial durante la producción del biogás, cuando se inhibe su proceso fermentativo por la presencia tóxica del sulfuro de hidrógeno y se presenta un aumento en la emisión de SOx (en concentraciones de hasta 658 ppmv). Dentro de los métodos de remoción de este compuesto se encuentra el biológico, a través de microorganismos por oxidación. El objetivo de esta revisión es exponer las tendencias del uso de microorganismos oxidantes de azufre en biotecnología ambiental, particularmente el papel de éstos en la purificación del biogás.

Use of Biological Methods For Removal of H2S From Biogas In Wastewater Treatment Plants – A Review

Abstract Biogas is produced during anaerobic digestion of organic substances by a consortium of microorganisms. Biogas consists mainly of methane (CH4) and carbon dioxide (CO2). Other gases such as dinitrogen (N2), water vapour (H2O), ammonia (NH3), hydrogen sulfide (H2S) and other sulfur compounds could also be found therein. Biogas produced by waste biomass has been recognized as one of the most important alternative energy sources in the recent years. In order to be used as a source of energy to generate heat and electricity, biogas should be cleaned. H2S is a colourless, flammable, malodorous and toxic gas. The main issues due to the high concentrations of H2S in biogas are its corrosive action, which damages engines and the production of sulfur oxides (SOx) due to H2S combustion. The best ways to remove H2S from biogas are the biological methods with the use of biofilters, biotrickling filters, bioscrubbers and using of activated sludge.

Conservation Status of the Australian Humpback Dolphin (Sousa sahulensis) Using the IUCN Red List Criteria.

Australian humpback dolphins (Sousa sahulensis) were recently described as a new species endemic to northern Australia and potentially southern New Guinea. We assessed the species conservation status against IUCN Red List Criteria using available information on their biology, ecology and threatening processes. Knowledge of population sizes and trends across the species range is lacking. Recent genetic studies indicate Australian humpback dolphins live in small and relatively isolated populations with limited gene flow among them. The available abundance estimates range from 14 to 207 individuals and no population studied to date is estimated to contain more than 104 mature individuals. The Potential Biological Removal method indicates populations are vulnerable to even low rates of anthropogenic mortality. Habitat degradation and loss is ongoing and expected to increase across the species range in Australia, and a continuing decline in the number of mature individuals is anticipated. Considering the available evidence and following a precautionary approach, we considered this species as Vulnerable under IUCN criterion C2a(i) because the total number of mature individuals is plausibly fewer than 10,000, an inferred continuing decline due to cumulative impacts, and each of the populations studied to date is estimated to contain fewer than 1000 mature individuals. Ongoing research efforts and recently developed research strategies and priorities will provide valuable information towards the future conservation and management of Australian humpback dolphins.

Bioremoval of an azo textile dye, Reactive Red 198, byRhizopus oryzae

Among all environmental contaminants, industrial dye is one of the major pollutants of soil, water, and air. There are different chemical, physical, and biological methods for removal of all types of synthetic media from the environment. One common method is to utilize microorganisms like yeast, fungi, or bacteria. In this study, we identified a soil-derived microorganism and evaluated its efficacy for removal of industrial dye from wastewater. First, a strain of fungus isolated from various samples of soil was defined via colonial identification and DNA sequencing. Second, the bioremoval activity of the defined fungus (Rhizopus oryzae) in treating the water-soluble monoazo dye, Reactive Red 198, in synthetic media was evaluated using high-performance liquid chromatography. The effects of varying factors in processing, including dye concentration, fungal volume, time, and pH were determined. Under optimal conditions, a dye removal rate of 96% was obtained.

Estimates of population size of white‐chinned petrels and grey petrels at Kerguelen Islands and sensitivity to fisheries

AbstractWhite‐chinned petrels Procellaria aequinoctialis and grey petrels Procellaria cinerea are among the most frequently killed seabird species by accidental bycatch, and both species have received strong conservation concern. Data on population size are required to evaluate the impact of bycatch and to establish management plans. We estimated the population size of both species at Kerguelen, Southern Indian Ocean, from 2004 to 2006 by explicitly taking into account detection probability of burrows using distance sampling and burrow occupancy. A total of 31 line‐transects were distributed across the eastern part of Kerguelen, representing a total length of 566 km. Detectability was low (from 0.19 to 0.54 for white‐chinned petrels, 0.58 for grey petrels). Burrow densities varied from 1.37±0.67 to 25.77±5.23 burrows ha−1 for white‐chinned petrels and was 2.78±0.79 burrows ha−1 for grey petrels. For white‐chinned petrels, these densities were extrapolated to the entire surface area of vegetation and there were 234 000 (186 000–297 000) active burrows on Kerguelen. For grey petrels, the number of active burrows for the eastern part of Kerguelen was 3400 (1900–5600). Based on these estimates, the potential biological removal method suggests that the additional mortality on birds caused by the fisheries operating around Kerguelen can be considered a serious threat for the species at least at the regional scale of the Southern Indian Ocean, especially for grey petrels.

Biological and chemical removal of Cr(VI) from waste water: Cost and benefit analysis

The objective of the present study is cost and benefit analysis of biological and chemical removal of hexavalent chromium [Cr(VI)] ions. Cost and benefit analysis were done with refer to two separate studies on removal of Cr(VI), one of heavy metals with a crucial role concerning increase in environmental pollution and disturbance of ecological balance, through biological adsorption and chemical ion-exchange. Methods of biological and chemical removal were compared with regard to their cost and percentage in chrome removal. According to the result of the comparison, cost per unit in chemical removal was calculated €0.24 and the ratio of chrome removal was 99.68%, whereas those of biological removal were €0.14 and 59.3%. Therefore, it was seen that cost per unit in chemical removal and chrome removal ratio were higher than those of biological removal method. In the current study where chrome removal is seen as immeasurable benefit in terms of human health and the environment, percentages of chrome removal were taken as measurable benefit and cost per unit of the chemicals as measurable cost.

Degradation of microcystins using immobilized microorganism isolated in an eutrophic lake

The final purpose of our series of studies is to establish a biological removal method of cyanobacteria and their toxic products using immobilized microorganisms that can lyse cyanobacteria and decompose microcystins. To establish the biological removal method in non-point areas and water purification plants, as the first step, we explored bacteria active against the cyanobacterial hepatotoxin microcystin in the present study. Eleven active bacteria were isolated from samples taken from Lakes Tsukui and Sagami, Japan. Among 3 strains (B-9 to B-11) with degradative activity, strain B-9 exhibited the strongest activity. The 16S rDNA sequence of the strain B-9 showed the highest similarity to that of Sphingomonas sp. Y2 (AB084247, 99% similarity). Microcystins-RR and -LR were completely degraded by strain B-9 (SC16) within 1 d, which led to an immobilized microorganism with a polyester resin. The degradation of microcystin-RR in a bioreactor using the immobilized strain B-9 was observed and microcystin-RR (>90%) was completely degraded after 24 h. Microcystin-RR was added to the lake water at regular intervals and the degradation after 24 h was observed in the bioreactor over a 72-d period. An over 80% removal efficiency continued for 2 months, showing that the life of the immobilized B-9 in terms of activity was at least 2 months under the optimized conditions. From these results, this immobilized B-9 is feasible for the practical treatment of microcystins in non-point areas and water purification plants.

Aerial surveys and the potential biological removal technique indicate that the Torres Strait dugong fishery is unsustainable

AbstractThe globally significant dugong population of Torres Strait supports an important indigenous fishery for meat and oil. The fishery is protected by the Torres Strait Treaty between Australia and Papua New Guinea. A time series of aerial survey estimates from 1987–2001 confirms that there is considerable temporal variability in the size of the dugong population in the region and adds to a growing body of evidence from other aerial surveys and satellite tracking that dugongs undertake large‐scale movements associated with temporal and spatial changes in the distribution of their seagrass food. The magnitude of these effects on both the size of the population and the catch cannot be disaggregated from the effects of population depletion from over‐harvesting. The Potential Biological Removal method was used in conjunction with the aerial survey data to estimate sustainable anthropogenic mortality from all causes for a range of empirically‐derived estimates of dugong life‐history parameters. These estimates of a sustainable harvest are so far below the current harvest that it must be unsustainable. Governments should heed the Islanders' requests for assistance in implementing co‐management of the fishery as a matter of urgency.