Bestimmung geeigneter F�rderraten bei der Grundwasserprobennahme mithilfe von Partikel- und Radonmessungen

Dehnert, Jörg; Neitzel, Peter L.; Döring, Uwe; Lankau, Rosemarie; Schneider, Petra; Freyer, K.; Kuhn, Karin

doi:10.1007/s00767-003-0171-8

Cited by 2 publications

(6 citation statements)

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“…Furthermore, the action of pumping itself may alter water chemistry, for example, the reduction in pressure may cause the loss of CO 2 and so change the pH (Knehr et al, 1996). In contrast, Hahn and Matzke (2005), Dehnert et al (2003) and Schmidt (2005) found no or few significant differences between the deep bore water and the surrounding groundwater -either by packer sampler pumping, or by bailing the bore water. This is consistent with the results of the preliminary …”

Section: Representativity Of Samples -General Considerationsmentioning

confidence: 81%

Unbaited phreatic traps: A new method of sampling stygofauna

Hahn

2005

Limnologica

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1) A new method of sampling stygofauna is presented, along with some data derived from applications in the field. Numerous bores were sampled for fauna, water and bacteria, down to a depth of 7.50 m. Two or 3 unbaited traps were fixed to a central pole within the bore. The traps consist of an inert plastic chamber with holes in the upper parts and gaskets near the bottom and near the lid of each trap. The content of the traps was emptied monthly using a pump.(2) While the taxonomic composition of the trap samples seemed to be comparable to the surrounding groundwater, estimation of abundances in the traps might differ, with a potential over-estimation in the traps, in particular in sparsely populated aquifers. Detailed comparative studies on the performance of the method are, as yet, lacking.(3) Trap data of invertebrate communities reflect hydraulic changes, and highest abundances and taxa richness were found near the water table. They decreased rapidly with depth, implying that small-scale stratified sampling is possible.(4) The technique is cheap, reliable, simple and rapid to use, and allows simultaneous sampling of hydro-chemical, faunal and microbial samples. The method seems to be suitable for a wide range of sub-surface waters, where the water table is shallower than 8 m.

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Section: Representativity Of Samples -General Considerationsmentioning

confidence: 81%

Unbaited phreatic traps: A new method of sampling stygofauna

Hahn

2005

Limnologica

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“…Contrary to most values in literature, our results were obtained from flowing water: the greater the flow velocity, the greater the proportion of larger particles, and the lower the value of slope β. R3 R4 R5 R6 R7 R8 R9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Except for one site (Hofmann 1998), groundwater obtained from monitor wells with minimal disturbance during sampling contained more particles >2 µm than groundwater obtained from abstraction wells during operation: 2,500 to 10,000/ml (Dehnert 2003;Marre 2004) vs 2 to 120/ml. This contradicts our conclusion that the higher the flow velocity, the higher the concentration.…”

Section: Discussionmentioning

confidence: 99%

“…Hofmann (1998), Marre (2004) and Dehnert et al (2003) also measured particle concentrations in groundwater obtained from monitor wells. However their measurements were performed by batch particle counts instead of online counts (Hargesheimer and Lewis 1995).…”

Section: Comparison With Data From Monitor Wellsmentioning

confidence: 99%

“…(5) and β = 3.5 to particle concentrations with a diameter >2 µm yields values of several thousand particles/ ml for anaerobic ground waters. Dehnert et al (2003) abstracted groundwater from monitor wells with various discharge rates (0.2-1.2 m 3 /h). They measured the concentration of particles with a diameter >0.5 µm and arrived at particle concentrations between 0.25*10 6 and 2*10 6 / ml.…”

Section: Comparison With Data From Monitor Wellsmentioning

confidence: 99%

“…Groundwater contains solids and biomass (McDowell-Boyer et al 1986), which has been linked with transport of pollutants (McCarty and Zachara 1989) like pesticides and radio active elements, and of pathogenic bacteria and viruses (Schijven 2001;Foppen 2007). The concentration of solids in groundwater has most frequently been measured by filtering groundwater over membrane filters with successively smaller diameters (McCarthy and Degueldre 1993), yielding particle mass concentrations (mg/l), and much less frequently with particle counters (Hofmann 1998;Dehnert et al 2003;Marre 2004), yielding particle number concentrations (n/ml). These measurements were executed with the least possible disturbance during sampling.…”

Section: Introductionmentioning

confidence: 99%

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Cause and Prevention of Clogging of Wells Abstracting Groundwater from Unconsolidated Aquifers

Beek¹

2011

Water Intell Online

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Cover: Air lifting at the beginning (front cover) and end (back cover) of the rehabilitation of a clogged well near El Toad, Kom Hamada (Beheira Water And Drainage Company, Damanhour, Egypt) van Beek, Cornelius G.E.M. Cause and prevention of clogging of wells abstracting groundwater from unconsolidated aquifers. Oorzaak en preventie van verstopping van putten, die grondwater onttrekken uit niet verkitte watervoerende pakketten This thesis was started by the author after his retirement from KWR Watercycle Research Institute (formerly Kiwa Water Research). The data used in this thesis were mainly collected during his service in the Joint Research Programme of the water sector (BTO) by KWR Watercycle Research Institute and the participating water companies, and contract research for individual water companies. The SEM/EDS data were provided by ASPEX Corporation, Delmont, PA, USA. KWR BTO 2010.041 ISBN 978-90-74741-93-4 VRIJE UNIVERSITEIT Cause and prevention of clogging of wells abstracting groundwater from unconsolidated aquifers ACADEMISCH PROEFSCHRIFT ter verkrijging van de graad Doctor aan de Vrije Universiteit Amsterdam, op gezag van de rector magnificus prof.dr. L.M. Bouter, in het openbaar te verdedigen ten overstaan van de promotiecommissie van de faculteit der Aard-en Levenswetenschappen op donderdag 2 december 2010 om 13.45 uur in de aula van de universiteit, De Boelelaan 1105 door Cornelius Gerardus Engelinus Maria van Beek geboren te Tilburg promotor: prof.dr. P.J. Stuyfzand Summary R1 R2 R3 R4 R5 R6 R7 R8 neerslagen ondiep grondwater, dat zuurstof bevat, en dieper grondwater, dat ijzer(II) bevat. Bij de vorming van ijzer(III)hydroxide neerslagen kunnen drie oxidatie processen actief zijn: homogene, heterogene en biologische oxidatie. Bij homogene oxidatie worden ijzer(II) en zuurstof gemengd, en slaan ijzer(III)hydroxiden neer.Onder neutrale omstandigheden is dit een traag proces, en de snelheid neemt toe bij toenemende pH en toenemende ijzer(II)-en zuurstofconcentratie. Zodra enig ijzer(III) hydroxide neerslag aanwezig is, zal heterogene oxidatie optreden, gekenmerkt door adsorptie van opgelost ijzer(II) door deze neerslagen en daaropvolgende oxidatie van geadsorbeerd ijzer(II). In dit twee traps proces is de adsorptie eigenlijk snelheidbepalend. Onder neutrale omstandigheden is adsorptie snel, en de snelheid neemt toe met toenemende pH, en met toenemende ijzer(II) en ijzer(III)hydroxide concentratie, of beter ijzer(III)hydroxide oppervlakte. Overal waar omstandigheden ook maar enigszins acceptabel zijn, zullen bacteriën die aan deze omstandigheden zijn aangepast, aanwezig zijn. Bijgevolg, in watervoerende pakketten die zowel zuurstof als ijzer(II) bevatten, zullen IJzerOxiderende Bacteriën (IOB) aanwezig zijn, die vroeger of later zullen worden aangetrokken door de onttrekkingsput. Zodra IOB aanwezig zijn, zal biologische oxidatie optreden, gekenmerkt door adsorptie van opgelost ijzer(II) door de celwanden van IOB en door "Extracellular Polymeric Substance" (EPS) en daaropvolgende oxidatie van geadso...

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Bestimmung geeigneter F�rderraten bei der Grundwasserprobennahme mithilfe von Partikel- und Radonmessungen

Cited by 2 publications

References 14 publications

Unbaited phreatic traps: A new method of sampling stygofauna

Unbaited phreatic traps: A new method of sampling stygofauna

Cause and Prevention of Clogging of Wells Abstracting Groundwater from Unconsolidated Aquifers

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