Production of Drinking Water from Highly Contaminated Surface Waters: Removal of Organic,Inorganic, and Microbial Contaminants Applying Mobile Membrane Filtration Units     

Thomas Heberer  Dirk Feldmann  Kirsten Reddersen  Hans‐Juergen Altmann  Thomas Zimmermann 《洁净——土壤、空气、水》2002,30(1):24-33

In military out of area missions of the Bundeswehr, it can be necessary to produce drinking water even from highly polluted surface waters containing a variety of organic, inorganic, and microbiological contaminants. Thus, mobile drinking water purification systems must be able to remove such contaminants as far as possible to meet the requirements of the German and European drinking water regulation/directive. Presently, two novel drinking water purification units applying membrane filtration undergo intensive long‐term trials carried out by the Bundeswehr. If these trials positively proof the functionality of these units and their ability to remove all possible contaminants they shall substitute so far available devices which use large amounts of chemicals and charcoal filtration for water purification.In the course of a research project, the functionality of the new devices and their efficacy to remove high amounts of algae, microbes, and organic and inorganic pollutants are additionally tested in “worst‐case” field studies. In September 2000, the first mobile drinking water purification unit was tested at the Teltowkanal in Berlin, Germany.This canal was chosen because it carries high burdens of municipal sewage effluents. The results from the fatigue test confirmed the ability of the water purification unit to reduce the concentrations of all contaminants meeting the maximum tolerance levels set by the German/European drinking water regulation.The pre‐filtration device was very effective in removing algae and solid particles to protect the membranes from clogging and to enable an almost maintenance‐free operation. Residues of pharmaceuticals and some other organic contaminants have almost totally been removed from the surface water where they were detected at individual concentrations up to the μg/L‐level.  相似文献   

Red-Pelaged Harbour Seals, in Humboldt County, California: why some Seals Rust     

Dirk R Neumann  Wolfgang W Schmahl 《Marine pollution bulletin》1999,38(12):273-1183

In this paper we present data on the occurrence of red-pelaged harbour seals, Phoca vitulina, at a haul-out in Humboldt County, California. Density of red seals ranged from 4% to 17.5% (n=21) and was comparable to that reported for San Francisco Bay, being the highest documented worldwide. The red colouration is the result of natural inorganic iron oxide/hydroxide pigments (limonite), which are present in small patches on the beach sand of the seals haul-out at the mouth of the Mad River. Thorough analysis of the river water and ocean water excluded these as possible sources for the iron oxide/hydroxide pigments. We found that the manmade reinforcement of the river bank adjacent to the haul-out consisted of greenshist boulders with a very high iron content. Weathering of these rocks produces red iron oxide/hydroxide particles which are then redeposited by rain or river action in small patches across the haul-out. Seals receive their red colouration through direct physical contact with these patches. SEM examination showed that these particles can adhere lastingly to the seals’ hair. Other studies provide reason for concern that this situation may detrimentally impact the seals’ health.  相似文献   

Exhumation, strain localization, and emplacement of granitoids along the western part of the Central Bohemian shear zone (Bohemian Massif)   总被引：1，自引：1，他引：0  

Dirk Scheuvens  Gernold Zulauf 《International Journal of Earth Sciences》2000,89(3):617-630

Emplacement of granitoid magmas and simultaneous exhumation of deeply buried rocks has been investigated along the western part of the Central Bohemian shear zone (CBSZ, Bohemian Massif). Combined structural, petrological and geochronological data of the steeply dipping shear zone suggest complex uplift and exhumation of deeply buried, high-temperature Moldanubian rocks, resulting in the juxtaposition against the supracrustal Teplá-Barrandian unit. Uplift of Moldanubian rocks from depths of probably more than 30 km was initiated after crustal stacking in Upper Devonian times. Syntectonic Lower Carboniferous emplacement of the Klatovy pluton into the pre-existing shear zone led to melt-controlled strain softening and localization. However, the major part of the total displacement of the CBSZ was accommodated within a late- to post-intrusive high-temperature shear zone in the uprising Moldanubian unit and a post-intrusive unexposed fault zone in the Klatovy pluton, respectively. During uplift of the Moldanubian rocks, strain was strongly partitioned into melt-bearing zones (Klatovy pluton, migmatites of the Moldanubian unit) resulting in a repeated shift of deformation in space and time.  相似文献   

Sea-ice transport of riverine particles from the Laptev Sea to Fram Strait based on clay mineral studies   总被引：3，自引：0，他引：3  

Dirk Dethleff  Volker Rachold  Matthias Tintelnot  Martin Antonow 《International Journal of Earth Sciences》2000,89(3):496-502

The aim of this study was to identify pathways and processes of modern sediment transport from the Siberian hinterland to the Laptev Sea and further to the Arctic Ocean. Clay mineral analyses were performed on riverine suspended particulate material (SPM), surface sediments of the Laptev Sea shelf, and sea-ice sediments (SIS). Material collected during seven expeditions was included in this study. Clay mineral assemblages are used to decipher the distribution of riverine sediments on the shallow Laptev Sea shelf, the entrainment of fine particles into newly forming ice, and the transport of SIS from the Laptev Sea towards the ablation areas. A cluster analysis of our data set shows that the clay mineral assemblages of Laptev Sea shelf sediments and SIS are controlled mainly by the input of riverine SPM supplied by the Khatanga, Lena, and Yana Rivers. Whereas the western shelf clay-mineral province is characterized by enhanced smectite concentrations supplied by the Khatanga River, the eastern Laptev Sea is dominated by illite discharged through the Lena and Yana Rivers. The SIS smectite concentration serves as an indicator for sediment source areas on the circum-Arctic shelves. Subsequently, the Transpolar Drift can be distinguished into a Siberian Branch fed from the eastern Kara Sea and the western Laptev Sea, and a Polar Branch originating from the eastern Laptev Sea.  相似文献   

Wind tunnel and field calibration of five aeolian sand traps   总被引：4，自引：0，他引：4  

Dirk Goossens  Zvi Offer  Gary London 《Geomorphology》2000,35(3-4)

The efficiency of five aeolian sand samplers was tested via wind tunnel experiments and field measurements. The samplers were: the Big Spring Number Eight (BSNE) sampler, the Modified Wilson and Cooke (MWAC) sampler, the Suspended Sediment Trap (SUSTRA), the Pollet catcher (POLCA), and the saltiphone. In the wind tunnel, the samplers were calibrated against an isokinetic sampler (a modified Sartorius SM 16711 sampler with adjustable flow rate), and this for three sand types (median diameter: 132, 194 and 287 μm) and five wind speeds (ranging from 6.6 to 14.4 m s⁻¹). In the field, seven calibration tests of two weeks each were conducted. The absolute efficiencies of the BSNE, MWAC and POLCA are more or less comparable and vary between 70% and 120%, depending on sediment size and wind speed. For the SUSTRA, the efficiency is somewhat lower for fine sands and for wind speeds above 11 m s⁻¹. Finally, the saltiphone can accurately detect the periods of saltation transport, but in its current version, the instrument is not accurate when measuring the absolute saltation flux. The most recommendable sampler in the test is the MWAC, not only because of its high efficiency, but also because its efficiency is independent of wind speed.  相似文献   

Estimation of fisheries removals and primary economic impact of the small-scale and industrial marine fisheries in Colombia     

Jeffrey Wielgus  Dirk Zeller  Dalila Caicedo-Herrera  Rashid Sumaila 《Marine Policy》2010

Colombia has coasts on both the Atlantic and Pacific Oceans, but its marine fisheries are limited by the relatively small size of commercially important stocks. However, diverse fishery resources have traditionally been exploited by coastal communities, and industrial fisheries have grown in recent years with the intensification of tuna fishing in both oceans. The management of Colombia's fisheries has been hampered by frequent administrative changes, which has notably led to the disappearance of a part of the official landings data. We estimated total fisheries removals (reported plus discards and unreported catches) in the Colombian Atlantic and Pacific Oceans for the period 1950–2006. We used secondary sources of information to estimate missing data, and we estimated subsistence fishing and the unreported by-catches of the shrimp and tuna fisheries. We used available information on seafood prices to estimate the relative economic impact (gross revenues) of the small-scale and industrial sectors for the period 2000–2006. Our results suggest that for the period 1950–2006, the Colombian marine fisheries catches may have been almost twice the landings reported by FAO on behalf of the country (2.8 times higher in the Atlantic; 1.3 times higher in the Pacific). Although the total gross revenues of industrial fisheries were higher than those of the small-scale sector, the latter commanded higher gross revenues in the Atlantic in 2006.  相似文献   

Subdecadal‐scale vegetation responses to a previously unknown late‐Allerød climate fluctuation and Younger Dryas cooling at Lake Meerfelder Maar (Germany)          下载免费PDF全文

Stefan Engels  Achim Brauer  Nico Buddelmeijer  Celia Martín‐Puertas  Oliver Rach  Dirk Sachse  Bas van Geel 《第四纪科学杂志》2016,31(7):741-752

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Six circumpolar currents—on the forcing of the Antarctic Circumpolar Current by wind and mixing     

Dirk Olbers  Karsten Lettmann  Ralph Timmermann 《Ocean Dynamics》2007,57(1):12-31

The transport of the Antarctic Circumpolar Current (ACC) is influenced by a variety of processes and parameters. A proper implementation of basin geometry, ocean topography and baroclinicity is known to be a fundamental requisite for a realistic simulation of the circulation and transport. Other, more subtle parameters are those of eddy-induced transports and diapycnal mixing of thermohaline tracers or buoyancy, either treated by eddy resolution or by a proper parameterization. Quite a number of realistic numerical simulations of the circulation in the Southern Ocean have recently been published. Many concepts on relations of the ACC transport to model parameters and forcing function are in discussion, however, without much generality and little success. We present a series of numerical simulations of circumpolar flow with a simplified numerical model, ranging from flat-bottom wind-driven flow to baroclinic flow with realistic topography and wind and buoyancy forcing. Analysis of the balances of momentum, vorticity, and baroclinic potential energy enables us to develop a new transport theory, which combines the most important mechanisms driving the circulation of the ACC and determining its zonal transport. The theory is based on the importance of the bottom vertical velocity in generating vorticity and shaping the baroclinic potential energy of the ACC. It explains the breaking of the -constraint by baroclinicity and brings together in one equation the wind and buoyancy forcing of the current. The theory emphasizes the role of Ekman pumping and eddy diffusion of buoyancy to determine the transport. It also demonstrates that eddy viscosity effects are irrelevant in the barotropic vorticity balance and that friction arises via eddy diffusion of density. In this regime, the classical Stommel model of vorticity balance is revived where the bottom friction coefficient is replaced by (with the Gent–McWilliams coefficient and the baroclinic Rossby radius ) and a modified wind curl forcing appears.  相似文献   

U–Pb LA-SF-ICP-MS zircon geochronology of the Serbo-Macedonian Massif, Greece: palaeotectonic constraints for Gondwana-derived terranes in the Eastern Mediterranean     

Guido Meinhold  Dimitrios Kostopoulos  Dirk Frei  Felix Himmerkus  Thomas Reischmann 《International Journal of Earth Sciences》2010,99(4):813-832

The Pirgadikia Terrane in northern Greece forms tectonic inliers within the Vardar suture zone bordering the Serbo-Macedonian Massif to the southwest. It comprises Cadomian basement rocks of volcanic-arc origin and very mature quartz-rich metasedimentary rocks. U–Pb laser ablation sector-field inductively-coupled plasma mass spectrometry analyses of detrital zircons from the latter reveal a marked input from a Cadomian–Pan-African source with minor contribution from Mesoproterozoic, Palaeoproterozoic and Archaean sources. The metasedimentary rocks are correlated with Ordovician overlap sequences at the northern margin of Gondwana on the basis of their maturity and zircon age spectra. The Pirgadikia Terrane can be best interpreted as a peri-Gondwana terrane of Avalonian origin, which was situated close to the Cadomian terranes in the Late Neoproterozoic–Early Palaeozoic, very much like the Istanbul Terrane. The second unit investigated is the Vertiskos Terrane, which constitutes the major part of the Serbo-Macedonian Massif in Greece. It comprises predominantly igneous rocks of Silurian age and minor metasedimentary rocks of unknown age and provenance. U–Pb analyses of detrital zircons from a garnetiferous mica schist of the Vertiskos Terrane indicate derivation from 550 to 1,150 Ma-old source rocks with a major Cadomian peak. This, combined with minor input of >1,950 Ma-old zircons and the absence of ages between ca. 1.2 and 1.7 Ga suggests a NW Africa source. The protolith age of the garnetiferous mica schist is presumably Early Ordovician. One sample of garnet-bearing biotite gneiss, interpreted as meta-igneous rock, comprises predominantly subhedral zircons of igneous origin with late Middle Ordovician to Silurian ages. We suggest that the rock association of the Vertiskos Terrane is part of an ancient active-margin succession of the Hun superterrane, comparable to successions of the Austro- and Intra-Alpine Terranes. The new data of this study provide evidence of occurrences of Avalonia- and Armorica-derived terranes in the Eastern Mediterranean and moreover help to clarify palaeogeographic reconstructions for the peri-Gondwana realm in the Early Palaeozoic.  相似文献   

Emulating AOGCM results using simple climate models     

Dirk Olivié  Nicola Stuber 《Climate Dynamics》2010,35(7-8):1257-1287

Three simple climate models (SCMs) are calibrated using simulations from atmosphere ocean general circulation models (AOGCMs). In addition to using two conventional SCMs, results from a third simpler model developed specifically for this study are obtained. An easy to implement and comprehensive iterative procedure is applied that optimises the SCM emulation of global-mean surface temperature and total ocean heat content, and, if available in the SCM, of surface temperature over land, over the ocean and in both hemispheres, and of the global-mean ocean temperature profile. The method gives best-fit estimates as well as uncertainty intervals for the different SCM parameters. For the calibration, AOGCM simulations with two different types of forcing scenarios are used: pulse forcing simulations performed with 2 AOGCMs and gradually changing forcing simulations from 15 AOGCMs obtained within the framework of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. The method is found to work well. For all possible combinations of SCMs and AOGCMs the emulation of AOGCM results could be improved. The obtained SCM parameters depend both on the AOGCM data and the type of forcing scenario. SCMs with a poor representation of the atmosphere thermal inertia are better able to emulate AOGCM results from gradually changing forcing than from pulse forcing simulations. Correct simultaneous emulation of both atmospheric temperatures and the ocean temperature profile by the SCMs strongly depends on the representation of the temperature gradient between the atmosphere and the mixed layer. Introducing climate sensitivities that are dependent on the forcing mechanism in the SCMs allows the emulation of AOGCM responses to carbon dioxide and solar insolation forcings equally well. Also, some SCM parameters are found to be very insensitive to the fitting, and the reduction of their uncertainty through the fitting procedure is only marginal, while other parameters change considerably. The very simple SCM is found to reproduce the AOGCM results as well as the other two comparably more sophisticated SCMs.  相似文献