Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Opname van struviet als categorie in het Uitvoeringsbesluit Meststoffenwet : advies
    Ehlert, P.A.I. ; Dijk, T.A. van; Oenema, O. - \ 2016
    Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 69) - 92
    magnesiumammoniumfosfaat - kunstmeststoffen - wetgeving - afvalwater - fosfaten - besmetters - afvalwaterbehandelingsinstallaties - magnesium ammonium phosphate - fertilizers - legislation - waste water - phosphates - contaminants - waste water treatment plants
    Only products, wastes and by-products designated by the Fertiliser Act can be freely traded as fertiliser in theNetherlands. Permitted fertilisers are listed in Regulation (EC) No 2003/2003 and wastes and by-products that canbe traded as fertiliser or as secondary raw material for fertiliser production are listed in Annex Aa of the implementingregulation of the Fertiliser Act. Wastes and by-products can be used as a fertiliser or a secondary raw materialif the criteria given in the Protocol for assessing the value and risks of waste used as fertiliser are met. Struvite is amagnesium ammonium phosphate (NH4MgPO4.6H2O) and is one of the forms in which phosphate can be recoveredfrom wastewater or process water. This origin means that struvite is classified as a waste, and as it is not listed inAnnex Aa the Fertiliser Act prohibits its use as a fertiliser. This publication reports on a study to formulate criteriafor lifting this waste status in accordance with the protocol. Depending on its quality, struvite acts as a fast-releaseor slow-release fertiliser. Due to the different techniques that are available for struvite formation, the differentwaste streams – municipal wastewater, effluent from manure processing, process water from the food manufacturingindustry – and different chemical polishing treatment processes, struvite can come in a range of qualities withdifferent concentrations of contaminants and may possibly contain pathogens. For the Ministry of Economic Affairs,the Scientific Committee on the Nutrient Management Policy has prepared an advice on including struvite in theFertiliser Act, with criteria. The study was based on literature research and consultation with stakeholders. Struviteis often co-precipitated with other phosphate minerals, such as phosphates of calcium, magnesium and iron, and anumber of these phosphates are present in struvite products. The advice covers this range of recovered phosphates
    Bio-filtration of helminth eggs and coliforms from municipal sewage for agricultural reuse in Peru
    Yaya Beas, R.E. - \ 2016
    Wageningen University. Promotor(en): Grietje Zeeman; Jules van Lier; Katarzyna Kujawa. - Wageningen : Wageningen University - ISBN 9789461734945 - 187
    waste water treatment - waste water treatment plants - anaerobic treatment - helminth ova - anaerobic conditions - filtration - public health - afvalwaterbehandeling - afvalwaterbehandelingsinstallaties - anaërobe behandeling - wormeneitjes - anaërobe omstandigheden - filtratie - volksgezondheid

    Where fresh water resources are scarce, treated wastewater becomes an attractive alternative for agricultural irrigation. However, the presence of large amounts of pathogens, even in treated wastewater, constraints its productive use, which is aggravated when sanitation and public health are poor. Among pathogenic indicators, helminth eggs are one of the most persistent microorganisms in treated effluents that may survive for several months in the irrigated fields. Application of upflow anaerobic sludge blanket (UASB) reactors could contribute to decrease the pathogenic content in wastewater due to physical and biological interactions with the anaerobic sludge bed, such as filtration and entrapment. In this thesis, the potential of the anaerobic sludge bed to particularly remove helminth eggs, was investigated in four phases. In the first phase, a temperature of 4° C was fixed in the UASB reactors in order to reduce the biological activity of the sludge. Hence, the anaerobic sludge filtration capacity at different upflow velocities was studied. This phase of the research was performed in two experiments. The first one using latex beads, simulating helminth eggs, and the second one using real helminth eggs, predominating in Peruvian wastewater. First experimental results show that increasing the upflow velocity led to a decrease in the removal efficiency of latex beads. At the lowest upflow velocity of 0.3 m·h−1, 100% removal of latex beads was reached. At an upflow velocity higher than 1 m·h−1, the removal efficiency dropped under 90 %. The degree of stabilisation of the sludge nor the sludge bed volume did not have a significant effect. Second experiment's results show that with upflow velocities below 1.5 m·h−1 real helminth eggs removal is greater than 70 %. Simultaneously tested, total and faecal coliforms removal was less than 83 %. The most common helminth eggs species found in the studied wastewater were Ascaris lumbricoides, Trichuris spp. and Strongyloides spp. The second phase was performed using two lab-scale UASB reactors at average ambient temperatures between 16.7 °C and 28.5 °C in the city of Lima (Peru). Ascaris suum eggs originating from infected pigs were selected as model organisms, considering their similarity, in terms of size and morphology, with Ascaris lumbricoides, a human pathogen. The sludge filtration capacity was determined, applying upflow velocities between 0.09 and 0.68 m·h−1. Average helminth eggs removals varied between 26 and 93 %, depending on upflow velocity and sludge bed height. 93 % removal was achieved when applying an upflow velocity of 0.09 m·h−1 and a sludge bed height reaching 19-25 % of the total reactor height. The third phase was conducted to test the effect of lower operational temperatures in the UASB reactor on the pathogen removal from domestic wastewater. Thus, a lab scale UASB reactor in the city of Puno (Peru), treating wastewater with temperatures varying between 11.3 and 14.3 °C for a period of 22 weeks after the start-up of the reactor, was used. Upflow velocities varied between 0.12 and 0.41 m·h−1. Results confirmed outcomes of the first phase of this research concerning helminth eggs removal, and consequently show that the sludge bed filtration capacity varied between 89 and 95 %. Faecal coliform removal varied between 0.9 and 2.1 log10 and E. coli removal between 0.8 and 1.6 log10. In general, removal efficiencies regarding helminth eggs and faecal coliforms, are not sufficient to comply with reuse standards. Finally, the capacity of Down Flow Hanging Sponge (DHS) reactors for removing faecal coliforms from domestic UASB reactor effluent for agricultural reuse in developing countries was investigated. Applied reactors were the cube type DHS (G1) without recirculation, the cube type DHS (G1) with recirculation and the curtain type DHS (G2). Results reveal an average faecal coliform removal of 4.74, 3.42 and 1.25 log10 respectively. These results comply with categories A, B and C of WHO (1989) standards, correspondingly. Therefore, treatment trains consisting of UASB-DHS reactors can possibly be applied when agricultural reuse is contemplated.

    A Downflow Hanging Sponge (DHS) reactor for faecal coliform removal from an Upflow Anaerobic Sludge Bed (UASB) effluent
    Yaya Beas, R.E. ; Kujawa-Roeleveld, K. ; Lier, J.B. van; Zeeman, G. - \ 2015
    Water Science and Technology 72 (2015)11. - ISSN 0273-1223 - p. 2034 - 2044.
    faecal coliforms - biochemical oxygen demand - chemical oxygen demand - waste water - waste water treatment - anaerobic treatment - waste water treatment plants - fecale coliformen - biochemisch zuurstofverbruik - chemisch zuurstofverbruik - afvalwater - afvalwaterbehandeling - anaërobe behandeling - afvalwaterbehandelingsinstallaties
    This research was conducted to study the faecal coliforms removal capacity of Downflow Hanging Sponge (DHS) reactors as a post-treatment for an Upflow Anaerobic Sludge Blanket (UASB) reactor. Three long-term continuous lab-scale DHS reactors i.e. a reactor with cube type sponges without recirculation, a similar one with recirculation and a reactor with curtain type sponges. The porosities of the applied medium were 91%, 87% and 47% respectively. The organic loading rates were 0.86 kgCOD m-3 d-1, 0.53 kgCOD m-3 d-1 and 0.24 kgCOD m-3 d-1 correspondingly at hydraulic loading rates of 1.92 m3 m-2 d-1, 2.97 m3 m-2 d-1 and 1.32 m3 m-2 d-1, respectively. The corresponding averages for faecal coliform removal were 99.997%, 99.919% and 92.121% respectively. The WHO (1989) standards, in terms of faecal coliform content for unrestricted irrigation (Category A), was achieved with the effluent of the cube type DHS (G1) without recirculation. Restricted irrigation, category B and C is assigned to the effluent of the cube type with recirculation and the curtain type, respectively. Particularly for organic compounds, the effluent of evaluated DHS reactors complies with USEPA standards for irrigation of so called non-food crops like pasture for milking animals, fodder, fibre, and seed crops.
    Microbial Removal of the Pharmaceutical Compounds Ibuprofen and Diclofenac from Wastewater
    Langenhoff, A.A.M. ; Inderfurth, N.S. ; Veuskens, T. ; Schraa, G. ; Blokland, M. ; Kujawa-Roeleveld, K. ; Rijnaarts, H.H.M. - \ 2013
    BioMed Research International 2013 (2013). - ISSN 2314-6133 - 9
    biodegradatie - geneesmiddelen - afvalwater - afvalwaterbehandeling - bioremediëring - afvalwaterbehandelingsinstallaties - verwijdering - oppervlaktewater - geneesmiddelenresiduen - biodegradation - drugs - waste water - waste water treatment - bioremediation - waste water treatment plants - removal - surface water - drug residues - personal care products - activated carbon - batch experiments - aquatic environment - metabolites - systems - sludge - acid - transformation
    Studies on the occurrence of pharmaceuticals show that the widely used pharmaceuticals ibuprofen and diclofenac are present in relevant concentrations in the environment. A pilot plant treating hospital wastewater with relevant concentrations of these pharmaceuticals was evaluated for its performance to reduce the concentration of the pharmaceuticals. Ibuprofen was completely removed, whereas diclofenac yielded a residual concentration, showing the necessity of posttreatment to remove diclofenac, for example, activated carbon. Successively, detailed laboratory experiments with activated sludge from the same wastewater treatment plant showed bioremediation potential in the treatment plant. The biological degradation pathway was studied and showed a mineralisation of ibuprofen and degradation of diclofenac. The present microbes were further studied in laboratory experiments, and DGGE analyses showed the enrichment and isolation of highly purified cultures that degraded either ibuprofen or diclofenac. This research illuminates the importance of the involved bacteria for the effectiveness of the removal of pharmaceuticals in a wastewater treatment plant. A complete removal of pharmaceuticals from wastewater will stimulate water reuse, addressing the worldwide increasing demand for clean and safe fresh water.
    On data requirements for calibration of integrated models for urban water systems
    Langeveld, J. ; Nopens, I. ; Schilperoort, R. ; Benedetti, L. ; Klein, J.J.M. de; Amerlinck, Y. ; Weijers, S. - \ 2013
    Water Science and Technology 68 (2013)3. - ISSN 0273-1223 - p. 728 - 736.
    afvalwaterbehandeling - afvalwaterbehandelingsinstallaties - riolering - watersystemen - stedelijke gebieden - monitoring - kalibratie - modellen - modelleren - oppervlaktewaterkwaliteit - noord-brabant - waste water treatment - waste water treatment plants - sewerage - water systems - urban areas - monitoring - calibration - models - modeling - surface water quality - noord-brabant - practical identifiability - simulation-models - optimization - uncertainty - quality
    Modeling of integrated urban water systems (IUWS) has seen a rapid development in recent years. Models and software are available that describe the process dynamics in sewers, wastewater treatment plants (WWTPs), receiving water systems as well as at the interfaces between the submodels. Successful applications of integrated modeling are, however, relatively scarce. One of the reasons for this is the lack of high-quality monitoring data with the required spatial and temporal resolution and accuracy to calibrate and validate the integrated models, even though the state of the art of monitoring itself is no longer the limiting factor. This paper discusses the efforts to be able to meet the data requirements associated with integrated modeling and describes the methods applied to validate the monitoring data and to use submodels as software sensor to provide the necessary input for other submodels
    A physiologically based kinetic model for bacterial sulfide oxidation
    Klok, J.B.M. ; Graaff, C.M. de; Bosch, P.L.F. van den; Boelee, N.C. ; Keesman, K.J. ; Janssen, A.J.H. - \ 2013
    Water Research 47 (2013)2. - ISSN 0043-1354 - p. 483 - 492.
    afvalwaterbehandeling - biotechnologie - zwavelwaterstof - oxidatie - ontzwaveling - alkalibacillus haloalkaliphilus - microbiële fysiologie - afvalwaterbehandelingsinstallaties - waste water treatment - biotechnology - hydrogen sulfide - oxidation - desulfurization - alkalibacillus haloalkaliphilus - microbial physiology - waste water treatment plants - sulfur-oxidizing bacteria - biologically produced sulfur - dissolved sodium sulfide - parameter-estimation - hydrogen-sulfide - soda lakes - bioreactors - thiosulfate - mechanisms - pathways
    In the biotechnological process for hydrogen sulfide removal from gas streams, a variety of oxidation products can be formed. Under natron-alkaline conditions, sulfide is oxidized by haloalkaliphilic sulfide oxidizing bacteria via flavocytochrome c oxidoreductase. From previous studies, it was concluded that the oxidation-reduction state of cytochrome c is a direct measure for the bacterial end-product formation. Given this physiological feature, incorporation of the oxidation state of cytochrome c in a mathematical model for the bacterial oxidation kinetics will yield a physiologically based model structure. This paper presents a physiologically based model, describing the dynamic formation of the various end-products in the biodesulfurization process. It consists of three elements: 1) Michaelis–Menten kinetics combined with 2) a cytochrome c driven mechanism describing 3) the rate determining enzymes of the respiratory system of haloalkaliphilic sulfide oxidizing bacteria. The proposed model is successfully validated against independent data obtained from biological respiration tests and bench scale gas-lift reactor experiments. The results demonstrate that the model is a powerful tool to describe product formation for haloalkaliphilic biomass under dynamic conditions. The model predicts a maximum S0 formation of about 98 mol%. A future challenge is the optimization of this bioprocess by improving the dissolved oxygen control strategy and reactor design.
    Ammonium recovery and energy production from urine by a microbial fuel cell
    Kuntke, P. ; Smiech, K.M. ; Bruning, H. ; Zeeman, G. ; Saakes, M. ; Sleutels, T.H.J.A. ; Hamelers, H.V.M. ; Buisman, C.J.N. - \ 2012
    Water Research 46 (2012)8. - ISSN 0043-1354 - p. 2627 - 2636.
    afvalwaterbehandeling - urine - huishoudens - ammonium - denitrificatie - afvalwaterbehandelingsinstallaties - microbiële brandstofcellen - energieterugwinning - waste water treatment - urine - households - ammonium - denitrification - waste water treatment plants - microbial fuel cells - energy recovery - perfluorosulfonic membranes - bioelectrochemical systems - performance - transport - ph
    Nitrogen recovery through NH3 stripping is energy intensive and requires large amounts of chemicals. Therefore, a microbial fuel cell was developed to simultaneously produce energy and recover ammonium. The applied microbial fuel cell used a gas diffusion cathode. The ammonium transport to the cathode occurred due to migration of ammonium and diffusion of ammonia. In the cathode chamber ionic ammonium was converted to volatile ammonia due to the high pH. Ammonia was recovered from the liquid-gas boundary via volatilization and subsequent absorption into an acid solution. Ammonium recovery and simultaneous energy production from urine was proven possible by this novel approach.
    Autotrophic nitrogen removal from low strength waste water at low temperature
    Hendrickx, T.L.G. ; Wang, Y. ; Kampman, C. ; Zeeman, G. ; Temmink, B.G. ; Buisman, C.J.N. - \ 2012
    Water Research 46 (2012)7. - ISSN 0043-1354 - p. 2187 - 2193.
    afvalwaterbehandeling - afvalwaterbehandelingsinstallaties - stikstof - verwijdering - denitrificatie - temperatuur - anaërobe behandeling - ammonium - oxidatie - energiebesparing - stedelijk afvalwater - waste water treatment - waste water treatment plants - nitrogen - removal - denitrification - temperature - anaerobic treatment - ammonium - oxidation - energy saving - municipal wastewater - anaerobic ammonium oxidation - treat sewage - reactor - system
    Direct anaerobic treatment of municipal waste waters allows for energy recovery in the form of biogas. A further decrease in the energy requirement for waste water treatment can be achieved by removing the ammonium in the anaerobic effluent with an autotrophic process, such as anammox. Until now, anammox has mainly been used for treating warm (>30 °C) and concentrated (>500 mg N/L) waste streams. Application in the water line of municipal waste water treatment poses the challenges of a lower nitrogen concentration (
    Assessing sanitary mixtures in East African cities
    Letema, S.C. - \ 2012
    Wageningen University. Promotor(en): Jules van Lier, co-promotor(en): Bas van Vliet. - S.l. : s.n. - ISBN 9789461734136 - 167
    volksgezondheidsbevordering - sanitaire voorzieningen - oost-afrika - riolering - anaërobe afbraak - stedelijk afvalwater - afvalwaterbehandeling - afvalwaterbehandelingsinstallaties - sanitation - sanitary facilities - east africa - sewerage - anaerobic digestion - municipal wastewater - waste water treatment - waste water treatment plants

    The urbanisation of poverty and informality in East African cities poses a threat to environmental
    health, perpetuates social exclusion and inequalities, and creates service gaps (UN-Habitat, 2008).
    This makes conventional sanitation provision untenable citywide, giving rise to the emergence
    of sanitation mixtures. Sanitation mixtures have different scales, institutional arrangements, user
    groups, and rationalities for their establishment, location, and management. For assessing the
    performance of both the mixtures as a whole and the different sanitation approaches constituting
    these mixtures, novel approaches for analyses are required. This thesis, therefore, departs from
    the centralised-decentralised approaches to a modernised mixtures (MM) approach in seeking a
    more inclusive assessment of sanitary configurations taking into account public and environmental
    health, accessibility and flexibility of sanitation systems as sustainability criteria. To achieve this,
    the four objectives formulated for this thesis are to:
    1. Make an inventory of sanitary systems in Kampala and Kisumu.
    2. Assess and map sanitary systems along MM dimensions in Kampala and Kisumu.
    3. Assess sustainability of sanitary systems on defined MM criteria in Kampala and Kisumu.
    4. Enhance insights on the applicability of MM criteria as conceptual model, assessment and
    prescriptive tool for sanitary mixtures in East African cities.
    Case study cities were chosen from a typology of primary and secondary cities that have urban
    sewer systems since colonial times. The two cities were deemed to offer rich cases that would give
    a general outlook of other East Africa cities, thus can offer possibilities for generalization. The
    thesis utilised a multi-method and multi-level approach in data collection and analysis. A multicriteria
    analysis is used in sustainability performance assessment of sanitation systems based on
    defined MM criteria.
    Firstly, modernisation debates and resultant modernities in sanitation provision were reviewed
    in Chapter 2. The review shows that Western modernisation and resultant modernities and their
    structures of service provision have not resonated well in developing countries. Consequently,
    alternative theories that dispute a universal approach to modernity emerged to offer alternatives
    to modernisation. Alternative options are characterised by multiple rationalities, diversity and
    multiplicity. Modernities in terms of sanitation provision are further operationalized as competition
    between the proponents of centralised versus decentralised solutions. A third way of looking at
    sanitation modernisation that is more inclusive is advanced through the introduction of the MM
    approach.
    In Chapter 3, the presence of urban sewer systems in Kampala and Kisumu cities is assessed. The
    results show that urban systems are of medium scale and serve about 10% of the city population.
    They are publicly owned and managed by public enterprises under new public management.
    Besides, they are conventionally designed, constructed and operated without the involvement
    of end-users. Treatment plants are either overloaded, underutilised or treatment stages are
    mismatched. Consequently, about 30-70% of the treatment stages are not operational. Effluent
    discharge standards and bio-solids reuse requirements are not met, and the adopted treatment
    technologies are inappropriate for the investigated conditions. Sewer networks are supported by
    pumping stations and siphons that are only partially operational due to high operational costs and
    mechanical failures. Public sewerage is further plagued by urban informality and multiplicity of
    city spatial structures. Planned city core, and to a limited extent peri-urban areas, are served by
    public sewers, while sewer trunk lines pass through informal slum settlements without connections.
    In Chapter 4, satellite systems are analysed and configurations mapped. Satellite systems are
    intermediate semi-collective decentralised sewerage and treatment systems developed parallel to
    urban and onsite systems. They are provided by multiple actors, serve planned middle and high
    income residential, industrial complexes, endowed public and private universities, and government
    facilities. In terms of scale, they are community, neighbourhood and small-urban sanitation
    solutions. Besides, satellite systems are private sewerage systems that utilise gravity sewers and
    localised mechanised or non-mechanised treatment. The flows are based on land use or facility
    specific and are treated close to the point of generation. They are based on conventional designs
    and construction protocols without end-user involvement.
    Onsite systems in Kampala and Kisumu cities are examined in Chapter 5. Planning forecast
    indicates that onsite systems will dominate sewer (urban and satellite) systems beyond the next
    two decades. They are small-scale, highly decentralised and use simple technologies. Pit latrines
    dominate septic tanks in number, with eco-san on pilot scales and bio-latrine being a new
    sanitation option. Faecal sludge collection, treatment and safe disposal is dismal. The private
    sector dominates over local authorities in provision of faecal sludge services, but public sewerage
    agencies receive and co-treat faecal sludge with sewage although sewage works are not designed to
    receive faecal sludge. They are regulated by the Ministry of Health, enforced by the city councils
    and are provided by multiple actors solely or in partnership. Onsite sanitation can be a transient
    or permanent solution depending on mass flows and spatial requirements. However, for better
    sanitation provision, a permanent solution, with room for amendments to anticipate changes in
    space and mass flow is imperative.
    In Chapter 6, sustainability performance of sanitation systems are assessed following the defined
    three MM criteria. The performance shows that there is no sanitation system that is completely
    outcompeted in performance, neither are there systems with a very good performance. Sanitation
    system choices, consequently, are made among imperfect options, which call for balancing the
    various elements of sanitation provision to suit different policy and local contexts. Varying the
    assigned relative weight of the various criteria used in the overall MCA assessment indicates
    that generally, any slight increase in weight has an impact on systems that already have a high
    performance whereas in the case of systems with low performance the change is dismal or even
    negative. Therefore, programmes for improvement of sanitation systems might be directed to
    improvement options where systems already have a relatively high performance. However, those
    with a low performance may need comprehensive or even system reconfigurations for significant
    impacts to be realised.
    In conclusion, sanitation mixtures are theorised as the co-existence of different phases of
    modernity in tandem with local context variables. Thus, there is no one-fit-all paradigmatic way
    to sanitation provision if the local contexts are apparently different even within the same city.
    However, a shift of the centralised-decentralised dichotomy to modernised mixtures paradigm
    offers better impetus as it can utilise the advantages of both centralised and decentralised
    approaches without jeopardising existing provision pathways. The MM approach is helpful in assessing, mapping and describing sanitation systems in cities where sanitation mixtures are the
    norm rather than the exception.
    One way to modernise sanitation mixtures is by shifting the centralised-decentralised paradigm
    in order to modernise the mixed sanitation landscape. This is premised on the notion that such
    a shift will result in merging the strengths of centralised approach, e.g. economies of scale,
    efficiency, and convenience, with strengths of decentralised approach, e.g. accessibility, flexibility,
    participation, and reuse and recovery in development of intermediate systems configuration. This
    can be achieved through, among others, avoiding use of pumping stations, adoption of multiple
    service levels, involvement of private sector, servicing households at intermediate scale, and
    establishing sanitation suitability and management zones.
    The MM approach is also very helpful as a conceptual model for organising a research
    agenda which can be set along the four assessment dimensions of scale, management, flows
    and participation, as well as in searching for appropriate intervention measures along one or
    more of these dimensions. As an assessment and decision making tool, it is helpful in finding
    out which elements highlighted in the sustainability assessment need to be restructured and
    which need improvement in order to enhance their sustainability. However, translation of the
    proposed conceptual MM model into a mathematical model is a challenge yet to be explored.
    Considering its intrinsic dynamic character in dependence to varying spaces, flows, and scales
    along city development, a mathematical MM model would provide a regulatory design tool
    for city planners for adopting amendments to existing sanitation solutions. Obviously, up to
    date monitoring and inventory records are a pre-requisite for applying such a model, requiring
    institutional upgrading. Although the current results described in this thesis provide the basis
    for a more structured assessment and generalisation of sanitation mixtures, more research and
    contextualisation is needed in other regions, for further elaboration of MM model, and for the
    refinement of the assessment tool.

    Assessing sanitary mixtures in East African cities
    Letema, S.C. - \ 2012
    Wageningen : Wageningen Academic Publishers (Environmental policy series vol. 6) - ISBN 9789086867691 - 161
    volksgezondheidsbevordering - sanitaire voorzieningen - riolering - anaërobe afbraak - stedelijk afvalwater - afvalwaterbehandeling - afvalwaterbehandelingsinstallaties - oost-afrika - sanitation - sanitary facilities - sewerage - anaerobic digestion - municipal wastewater - waste water treatment - waste water treatment plants - east africa
    DIDSON observaties van gedrag van vis rond lozingspluimen
    Keeken, O.A. van; Burggraaf, D. ; Winter, H.V. ; Foekema, E.M. - \ 2011
    IJmuiden : IMARES (Rapport / IMARES Wageningen UR C079/11) - 31
    vissen - diergedrag - afvalwaterbehandelingsinstallaties - pompstations - rioolafvalwaterverwijdering - onderwaterakoestiek - nederland - vismigratie - fishes - animal behaviour - waste water treatment plants - pumping stations - sewage effluent disposal - underwater acoustics - netherlands - fish migration
    Binnen het project 'een pluim voor vismigratie’ zijn twee technieken toegepast om het gedrag van vis rond lozingspunten te onderzoeken: telemetrisch en akoestisch. Bij het telemetrisch onderzoek worden (lokaal) gevangen vissen van kleine zenders voorzien en teruggeplaatst in het water. Elke zender zend met regelmaat een uniek signaal uit dat door strategisch onder water opgestelde ontvangers kan worden opgevangen. Wanneer een signaal door meerdere ontvangers wordt opgevangen kan door middel van een kruispeiling de positie van de vis worden bepaald. Het voordeel van deze methode is dat individuele vissen voor een langere periode over een groot gebied kunnen worden gevolgd. Nadelen zijn: dat de te volgen vis vooraf een (beperkte) operatie moet ondergaan; dat het aantal individuele vissen dat kan worden gevolgd beperkt is; en dat te kleine vis niet met een zender kan worden uitgerust. Bovendien zijn de materiaalkosten (m.n. de zenders) van dit type onderzoek erg hoog en is de uitwerking van de data specialistisch en tijdrovend. Voor de akoestische methode wordt gebruikgemaakt van een akoestische camera, waarmee ook in troebel water en ’s nachts onder water opnames gemaakt kunnen worden. De kwaliteit van de beelden is dusdanig dat soorten doorgaans kunnen worden onderscheiden en ook een schatting van de lengte van de vis mogelijk is. Op deze wijze kan een goede indruk worden verkregen van het gedrag van de lokale visgemeenschap, zonder dat de vis daadwerkelijk ‘gehanteerd’ hoeft te worden. Ook kleine vis(soorten) zijn met deze techniek zichtbaar. Na aanschaf van de camera zijn de kosten van het onderzoek beperkt. Het gezichtsveld van de akoestische camera is echter beperkt waardoor het niet mogelijk is individuele vissen gedurende een langere periode te volgen. Dit rapport presenteert de resultaten van het akoestisch onderzoek van visgedrag bij een aantal lozingspluimen (bij drie rioolzuiveringsinstallaties en een poldergemaal) met een akoestische camera (de DIDSON) opgenomen zijn. Het doel van de DIDSON metingen was te onderzoeken of vissen in of nabij een lozingspluim afwijkend/vermijdend gedrag vertonen. In de bijlagen van dit rapport zijn de waarnemingen in tabelvorm opgenomen. Tevens zijn ter illustratie enkele opvallende beelden weergegeven, zoals deze met de DIDSON zijn gemaakt.
    Inventarisatie van lozingspluimen als potientiele migratie-barriere
    Foekema, E.M. ; Rippen, A.D. ; Slijkerman, D.M.E. - \ 2011
    Den Helder : IMARES (Rapport / IMARES Wageningen UR C078/11) - 28
    vissen - waterkwaliteit - rioolafvalwaterverwijdering - afvalwaterbehandelingsinstallaties - koelwater - zout water - vismigratie - fishes - water quality - sewage effluent disposal - waste water treatment plants - cooling water - saline water - fish migration
    Dat niet-fysieke barrières, zoals een plaatselijke verandering in waterkwaliteit of lozingen van verontreinigende stoffen, een potentiële belemmering voor trekkende vis kan vormen wordt vaak geopperd, maar hier zijn echter zeer weinig studies naar uitgevoerd. De meeste studies hebben betrekking op zuurstofarme zones in stroomgebieden of pluimen uit waterkrachtcentrales met oververzadiging aan zuurstof. In veel laboratoriumexperimenten is vastgesteld dat vissen vele chemische en fysische componenten kunnen waarnemen en hierop reageren, maar dergelijk ontwijkgedrag is in de vrije natuur slechts zeer zelden bestudeerd. In hoeverre lozingspluimen vismigratie belemmeren door ontwijkgedrag is momenteel derhalve nog vrijwel onbekend. Het is echter aannemelijk dat (migrerende) vissen in het veld ook reageren op de lozing van water dat qua karakteristiek afwijkt van de omgeving. De confrontatie met dergelijke lozingspluimen zal dan aanleiding kunnen geven tot een aarzeling, zoekgedrag langs gradiënten, of zelfs tot de keuze kunnen leiden om niet door de pluim heen te zwemmen. Afhankelijk van de reactie van de vis en de lokale situatie zal een lozingspluim dan een belemmering of zelfs een barrière voor migrerende vis kunnen vormen. Dit zal vooral het geval zijn wanneer de lozingspluim gedurende een lange periode de totale breedte van de waterweg overbrugd. De waarschijnlijkheid dat dit in de Nederlandse situatie gebeurt is onderzocht voor drie typen lozingen te weten: lozing van koelwater, lozing van zout (kwel)water, lozing van effluent uit een rioolwaterzuiveringsinstallatie (rwzi).
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