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.

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Anaerobic manganese- or iron-mediated pharmaceutical degradation in water
Liu, Wenbo - \ 2018
Wageningen University. Promotor(en): H.H.M. Rijnaarts, co-promotor(en): A.A.M. Langenhoff; N.B. Sutton. - Wageningen : Wageningen University - ISBN 9789463432214 - 235
drugs - biodegradation - anaerobic conditions - manganese oxides - iron oxides - removal - water pollution - geneesmiddelen - biodegradatie - anaërobe omstandigheden - mangaanoxiden - ijzeroxiden - verwijdering - waterverontreiniging

Pharmaceutical compounds, originating mainly from industrial production and public consumption, are detected at extremely low levels (ng·L-1 –µg·L-1) in groundwater, surface water, and wastewater. So far, the adverse effects of pharmaceuticals and their intermediates have been widely reported, and include toxicity to humans and ecosystem, and enhancement of antimicrobial resistance. These effects call for the elimination of pharmaceuticals from water. This can be done by both abiotic and biotic degradation in the presence of oxygen (aerobic conditions) or in the absence of oxygen (anaerobic conditions). The technologies under anaerobic conditions are generally more sustainable and attractive because they require less energy and produce less pollutants, such as greenhouse gas, compared to technologies under aerobic conditions. Anaerobic degradation with metal oxides such as manganese (Mn) or iron (Fe) oxides has clear advantages in both drinking water treatment and wastewater treatment. Therefore, anaerobic degradation of pharmaceuticals in water with Mn or Fe is promising to study and develop into applicable techniques. This thesis investigates the feasibility of anaerobic degradation of pharmaceuticals in Mn- and Fe-mediated systems via both abiotic removal processes and by biodegradation. In Chapter 1, the scientific and technological motivation of the thesis is proposed.

Applications and scientific developments of Mn- or Fe-based technologies to remove pharmaceuticals from water are reviewed and discussed in Chapter 2. Based on the removal mechanisms found in nature and technical systems, these Mn- or Fe-based technologies can be classified into 3 groups – physico-chemical removal, chemical removal, and biologically-related removal. A review of previous research indicates that pharmaceutical removal with Mn- or Fe-based technologies from water is efficient, and the removal efficiency varies whit the different technologies applied. Positive and negative aspects of these processes, such as (non-)specificity, treatment conditions, formation of and effects of intermediates and by-products, and effects of Mn or Fe compounds were evaluated. Based on that, new and promising Mn- or Fe-based technologies are proposed as future potential effective and sustainable pharmaceutical removal technologies. Among these proposed technologies, the dissimilatory Mn or Fe reduction is identified as a most attractive, sustainable, and low-cost technology because this novel technology requires neutral conditions and the bacteria involved are able to completely mineralize the pharmaceuticals.

The anaerobic biodegradation of pharmaceuticals coupled to dissimilatory Mn(IV) or Fe(III) reduction is tested with different types of Mn(IV) and Fe(III) (Chapter 3). With a mixture of adapted sediment to metoprolol and chemically synthesized Mn(IV), anaerobic biodegradation with amorphous, chemically synthesized Mn(IV) can effectively remove caffeine (26%) and naproxen (52%) after 42 days of incubation. Further experiments with Mn(IV) obtained from drinking water treatment plants show that this type of Mn(IV) can be used to remove metoprolol and propranolol, with respectively 96% and 31% after 72 days of incubation. The inoculum can also use Fe(III) as alternative electron acceptor to degrade metoprolol. Results show that metoprolol degradation with insoluble chemically synthesized Fe(III) and soluble Fe(III)-citrate reaches 57% and 52%, respectively. No significant removal is observed in all the abiotic controls, showing that the biodegradation is the main removal mechanism in pharmaceutical removal with Mn(IV) or Fe(III).

Abiotic removal of selected pharmaceuticals with MnO2 is compared under aerobic conditions and anaerobic conditions (Chapter 4). Results show that anaerobic conditions promote diclofenac removal, while it inhibits removal of metoprolol and propranolol. In demineralized water (demiwater), diclofenac removal under anaerobic conditions is 78%, and higher than the 59% found under aerobic conditions. In 50 mM phosphate buffer, and under aerobic conditions, the diclofenac removal achieves complete removal. Under anaerobic conditions the observed removal is similar as in demiwater. Preliminary investigation shows that diclofenac removal with MnO2 under anaerobic condition is better at acidic pH (pH 4 – 5) and the removal is higher when applying amorphous MnO2 compared to applying crystalline MnO2. The key factors determining the extent of pharmaceutical removal with MnO2 under anaerobic conditions are the following: the chemical structure and molecular properties of the pharmaceuticals, and the properties and activity of reactive sites on the MnO2 surface.

Applying MnO2 under anaerobic conditions to remove diclofenac from water is further investigated (Chapter 5). Results show that increasing the temperature from 10 to 30°C leads to an increase in the diclofenac removal, whereas further increase of temperature to 40°C results in a decrease in the removal. The latter effect is possibly due to Ostwald ripening and/or aging processes. Increasing the amount of MnO2 increases the diclofenac degradation, as this provides more reactive sites for diclofenac conversions. Further shifting the molar ratio of MnO2 and diclofenac from 2200:1 to 8900:1, however, does not further increase diclofenac removal, probably due to limited oxidation capacity of MnO2. The presence of metal ions strongly inhibits the diclofenac removal following the order of Mn2+> Ca2+ ≈ Mg2+ >Fe3+. The metal ions appear to adsorb onto the MnO2 surface and compete with diclofenac for reactive sites. Phosphate has a diverse effect on diclofenac degradation: low concentrations inhibit and high concentrations promote the removal. The humic acids significantly promotes diclofenac removal, probably caused by affecting MnO2 reactive surface sites.

To reuse the Mn or Fe during pharmaceutical removal under anaerobic conditions, biological production of Mn(IV) or Fe(III) is investigated under oxygen-limiting conditions, or with nitrate as electron acceptor (Chapter 6). Mn(IV) is successfully produced with Mn(II)-oxidizing bacteria under O2-limiting conditions, and the produced Mn(IV) is amorphous. Pharmaceutical removal with the Mn(II)-oxidizing bacteria is not observed. In abiotic pharmaceutical removal, using Mn(IV) from a drinking water production plant, is effective to remove metoprolol and propranolol. The successful production of Fe(III) is also observed under NO3--reducing conditions via biological processes. The biologically produced Fe(III) is also amorphous. There is no significant removal of pharmaceuticals coupled to the biological Fe(III) production. When comparing the biologically produced Fe(III) and other types of Fe(III), only Fe(III) from a drinking water production plant and one Fe(III)-based sorbent can remove propranolol.

Finally, the outcomes of this thesis are discussed and provide insights into the application of anaerobic degradation of pharmaceuticals with mediation of Mn and Fe oxides (Chapter 7). The removal mechanisms include adsorption, chemical oxidation, and biodegradation and are identified to contribute to the different removal processes. The anaerobic Mn(IV)- and Fe(III)-mediated pharmaceutical degradation processes are evaluated on the basis of removal performance, environmental and operational conditions, sustainability of the processes, as well as the Mn and Fe types involved. Results described in this thesis provide a proof of principal for anaerobic Mn(IV)- or Fe(III)-mediated degradation in removing pharmaceuticals from water. To translate the process into a pharmaceutical removal technology for water treatment, three steps are proposed including (1) exploring the limits of anaerobic Mn- or Fe-mediated pharmaceutical degradation processes; (2) simulating the process in practice with a controlled systems, and (3) translating the processes to a pilot-scale system before a full-scale application. In addition, research topics are identified that can help to meet these challenges in the future. In summary, anaerobic Mn(IV)- or Fe(III)-mediated systems can remove pharmaceuticals from water through both abiotic removal and biotic degradation. These are promising processes which can be developed into a robust, sustainable, affordable, and environmentally friendly technology to remove pharmaceuticals from water.

Evaluatie zuiveringstechniek voor verwijdering gewasbeschermingsmiddelen III
Ruijven, J.P.M. van; Beerling, E.A.M. ; Staaij, M. van der; Os, E.A. van - \ 2016
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1414) - 30
afvalwaterbehandeling - waterzuivering - afvalwater - waterverontreiniging - glastuinbouw - kassen - cultuur zonder grond - gewasbescherming - pesticiden - ozon - verwijdering - filtratie - technieken - waste water treatment - water treatment - waste water - water pollution - greenhouse horticulture - greenhouses - soilless culture - plant protection - pesticides - ozone - removal - filtration - techniques
Dutch greenhouse horticulture has to treat all discharged water from soilless cultivations for the removal of plant protection products, to meet the new Dutch Directive Hoofdlijnenakkoord (2015). Building on previous research, (1) the life span of activated carbon filters, (2) the effect of increasing concentrations of plant protection products on the removal efficacy of ozone and the removal efficacy of (3) multimedia filtration and (4) ultrasonic water treatment have been investigated. It turned out to be difficult to design an active carbon based water treatment system capable of durable treatment of greenhouse discharge water: organic and mineral material in the water blocked the pores, thereby clogging the filter system and causing leakage by pressure build-up. Activated carbon filtration (granular activated carbon, 48 min contact time, 50 μm prefiltration with sand filter) achieved a removal efficacy of >95% for up to 430 bed volumes treated. Combination with advanced oxidation improved the removal efficacy, but the removal time of the filter could not be determined due to leakage. The removal efficacy of ozone oxidation remained >98%, even at increased concentrations (factor 10 and 100) of plant protection products in the untreated water. The multimedia filter removed 75% of the plant protection products by adsorption, biological breakdown within the filter was not determined. Treatment of the water with ultrasonic waves hardly had any effect (maximum 30% efficacy) on the breakdown.
Fate of pharmaceuticals in full-scale source separated sanitation system
Butkovskyi, A. ; Hernandez Leal, L. ; Rijnaarts, H.H.M. ; Zeeman, G. - \ 2015
Water Research 85 (2015). - ISSN 0043-1354 - p. 384 - 392.
Anaerobic degradation - Black water - Grey water - Micropollutant removal - Pharmaceuticals - UASB reactor

Removal of 14 pharmaceuticals and 3 of their transformation products was studied in a full-scale source separated sanitation system with separate collection and treatment of black water and grey water. Black water is treated in an up-flow anaerobic sludge blanket (UASB) reactor followed by oxygen-limited autotrophic nitrification-denitrification in a rotating biological contactor and struvite precipitation. Grey water is treated in an aerobic activated sludge process. Concentration of 10 pharmaceuticals and 2 transformation products in black water ranged between low μg/l to low mg/l. Additionally, 5 pharmaceuticals were also present in grey water in low μg/l range. Pharmaceutical influent loads were distributed over two streams, i.e. diclofenac was present for 70% in grey water, while the other compounds were predominantly associated to black water. Removal in the UASB reactor fed with black water exceeded 70% for 9 pharmaceuticals out of the 12 detected, with only two pharmaceuticals removed by sorption to sludge. Ibuprofen and the transformation product of naproxen, desmethylnaproxen, were removed in the rotating biological contactor. In contrast, only paracetamol removal exceeded 90% in the grey water treatment system while removal of other 7 pharmaceuticals was below 40% or even negative. The efficiency of pharmaceutical removal in the source separated sanitation system was compared with removal in the conventional sewage treatment plants. Furthermore, effluent concentrations of black water and grey water treatment systems were compared with predicted no-effect concentrations to assess toxicity of the effluent. Concentrations of diclofenac, ibuprofen and oxazepam in both effluents were higher than predicted no-effect concentrations, indicating the necessity of post-treatment. Ciprofloxacin, metoprolol and propranolol were found in UASB sludge in μg/g range, while pharmaceutical concentrations in struvite did not exceed the detection limits.

Removal of micropollutants in source separated sanitation
Butkovskyi, A. - \ 2015
Wageningen University. Promotor(en): Huub Rijnaarts; Grietje Zeeman, co-promotor(en): L. Hernández Leal. - Wageningen : Wageningen University - ISBN 9789462574168 - 189
verontreinigende stoffen - verontreiniging - waterverontreiniging - afvalwater - stedelijk afvalwater - volksgezondheidsbevordering - waterzuivering - verwijdering - geneesmiddelen - farmaceutische producten - antibioticumresiduen - residuen - pollutants - pollution - water pollution - waste water - municipal wastewater - sanitation - water treatment - removal - drugs - pharmaceutical products - antibiotic residues - residues
Source separated sanitation is an innovative sanitation method designed for minimizing use of energy and clean drinking water, and maximizing reuse of water, organics and nutrients from waste water. This approach is based on separate collection and treatment of toilet wastewater (black water) and the rest of the domestic wastewater (grey water). Different characteristics of wastewater streams facilitate recovery of energy, nutrients and fresh water. To ensure agricultural or ecological reuse of liquid and solid products of source separated sanitation, the quality of these materials has to meet (future) standards, i.e. for micropollutant concentrations. Therefore the objectives of this thesis included assessment of micropollutant content of source separated sanitation products intended for resource recovery and examination of post-treatment technologies for micropollutant mitigation within source separated sanitation
Feasibility analysis of wastewater and solid waste systems for application in Indonesia
Kerstens, S.M. ; Leusbrock, I. ; Zeeman, G. - \ 2015
Science of the Total Environment 530-531 (2015). - ISSN 0048-9697 - p. 53 - 65.
sustainable sanitation - phosphorus recovery - municipal sludge - west java - nitrogen - removal - management - disposal - suitability - countries
Indonesia is one of many developing countries with a backlog in achieving targets for the implementation of wastewater and solid waste collection, treatment and recovery systems. Therefore a technical and financial feasibility analysis of these systems was performed using Indonesia as an example. COD, BOD, nitrogen, phosphorus and pathogen removal efficiencies, energy requirements, sludge production, land use and resource recovery potential (phosphorus, energy, duckweed, compost, water) for on-site, community based and off-site wastewater systems were determined. Solid waste systems (conventional, centralized and decentralized resource recovery) were analyzed according to land requirement, compost and energy production and recovery of plastic and paper. In the financial analysis, investments, operational costs & benefits and Total Lifecycle Costs (TLC) of all investigated options were compared. Technical performance and TLC were used to guide system selection for implementation in different residential settings. An analysis was undertaken to determine the effect of price variations of recoverable resources and land prices on TLC. A 10-fold increase in land prices for land intensivewastewater systems resulted in a 5 times higher TLC,whereas a 4-fold increase in the recovered resource selling price resulted in maximum 1.3 times higher TLC. For solid waste, these impacts were reversed — land price and resource selling price variations resulted in a maximumdifference in TLC of 1.8 and 4 respectively. Technical and financial performance analysis can support decision makers in system selection and anticipate the impact of price variations on long-termoperation. The technical analysiswas based on published results of international research and the approach can be applied for other tropical, developing countries. All costs were converted to per capita unit costs and can be updated to assess other countries' estimated costs and benefits. Consequently, the approach can be used to guide wastewater and solid waste system planning in developing countries.
Enhanced charge efficiency and reduced energy use in capacitive deionization by increasing the discharge voltage
Kim, T. ; Dykstra, J.E. ; Porada, S. ; Wal, A. van der; Yoon, J. ; Biesheuvel, P.M. - \ 2015
Journal of Colloid and Interface Science 446 (2015). - ISSN 0021-9797 - p. 317 - 326.
activated carbon electrodes - desalination performance - water desalination - porous-electrodes - constant-current - adsorption rate - oxide - ions - electrosorption - removal
Capacitive deionization (CDI) is an electrochemical method for water desalination using porous carbon electrodes. A key parameter in CDI is the charge efficiency, ¿, which is the ratio of salt adsorption over charge in a CDI-cycle. Values for ¿ in CDI are typically around 0.5-0.8, significantly less than the theoretical maximum of unity, due to the fact that not only counterions are adsorbed into the pores of the carbon electrodes, but at the same time coions are released. To enhance ¿, ion-exchange membranes (IEMs) can be implemented. With membranes, ¿ can be close to unity because the membranes only allow passage for the counterions. Enhancing the value of ¿ is advantageous as this implies a lower electrical current and (at a fixed charging voltage) a reduced energy use. We demonstrate how, without the need to include IEMs, the charge efficiency can be increased to values close to the theoretical maximum of unity, by increasing the cell voltage during discharge, with only a small loss of salt adsorption capacity per cycle. In separate constant-current CDI experiments, where after some time the effluent salt concentration reaches a stable value, this value is reached earlier with increased discharge voltage. We compare the experimental results with predictions of porous electrode theory which includes an equilibrium Donnan electrical double layer model for salt adsorption in carbon micropores. Our results highlight the potential of modified operational schemes in CDI to increase charge efficiency and reduce energy use of water desalination
Biotechnologies for critical raw material recovery from primary and secondary sources: R&D priorities and future perspectives
Hennebel, T. ; Boon, N. ; Maes, S. ; Lenz, M. - \ 2015
New Biotechnology 32 (2015)1. - ISSN 1871-6784 - p. 121 - 127.
acid-mine drainage - heavy-metals - waste-water - selective precipitation - bacterial surfaces - nanoparticles - selenium - removal - copper - biosorption
Europe is confronted with an increasing supply risk of critical raw materials. These can be defined as materials of which the risks of supply shortage and their impacts on the economy are higher compared to most of other raw materials. Within the framework of the EU Innovation Partnership on raw materials Initiative, a list of 14 critical materials was defined, including some bulk metals, industrial minerals, the platinum group metals and rare earth elements. To tackle the supply risk challenge, innovation is required with respect to sustainable primary mining, substitution of critical metals, and urban mining. In these three categories, biometallurgy can play a crucial role. Indeed, microbe–metal interactions have been successfully applied on full scale to win materials from primary sources, but are not sufficiently explored for metal recovery or recycling. On the one hand, this article gives an overview of the microbial strategies that are currently applied on full scale for biomining; on the other hand it identifies technologies, currently developed in the laboratory, which have a perspective for large scale metal recovery and the needs and challenges on which bio-metallurgical research should focus to achieve this ambitious goal.
Quantification of individual polysulfides in lab-scale and full-scale desulfurisation bioreactors
Roman, P. ; Bijmans, M.F.M. ; Janssen, A.J.H. - \ 2014
Environmental Chemistry 11 (2014)6. - ISSN 1448-2517 - p. 702 - 708.
biologically produced sulfur - fed-batch bioreactor - equilibrium distribution - inorganic polysulfides - oxidizing bacteria - sulfide oxidation - aqueous-solutions - hydrogen-sulfide - sp nov. - removal
Environmental pollution caused by the combustion of fuel sources containing inorganic and organic sulfur compounds such as hydrogen sulfide (H2S) and thiols, is a global issue as it leads to SO2 emissions. To remove H2S from gas streams such as liquefied petroleum gas (LPG), biological processes can be applied. In these processes, polysulfide anions (S-x(2-)) play a significant role as they enhance the dissolution of H2S and act as intermediates in the biological oxidation of hydrogen sulfide ions to elemental sulfur. Despite their important role, the distribution of the various polysulfide species in full-scale biodesulfurisation systems has not yet been reported. With conventionally applied spectrophotometric analysis it is only possible to determine the total concentration of S-x(2-). Moreover, this method is very sensitive to matrix effects. In this paper, we apply a method that relies on the derivatisation of S-x(2-) to dimethyl polysulfanes. Owing to the instability of higher dimethyl polysulfanes (Me2S4 to Me2S8), standards are not commercially available and had to be prepared by us. We present a simplified quantification method for higher dimethyl polysulfanes by calculating high performance liquid chromatogaphy (HPLC) UV response factors based on the addition of internal standards. The method was subsequently used to assess the distribution of polysulfide anions in both a laboratory-scale and a full-scale biodesulfurisation unit. We found that the average chain length of polysulfides strongly depends on the process conditions and a maximum of 5.33 sulfur atoms per polysulfide molecule was measured. Results of this study are required by mechanistic and kinetic models that attempt to describe product selectivity of sulfide oxidising bioreactors.
Alternating electric field fluidized bed disinfection performance with different types of granular activated carbon
Racyte, J. ; Yntema, D.R. ; Kazlauskaite, L. ; DuBois, A. ; Bruning, H. ; Rijnaarts, H.H.M. - \ 2014
Separation and Purification Technology 132 (2014). - ISSN 1383-5866 - p. 70 - 76.
waste-water - 3-dimensional electrodes - bacteria - particles - adhesion - viability - removal - system - point - reuse
The removal of pathogens from effluents is important to promote the reuse of these water resources and safeguarding human health, especially in water scarce areas worldwide. Previously a proof-of-principle of a method for water disinfection consisting of fluidized bed electrodes (FBE) with RX3 EXTRA granular activated carbon (GAC) and a low strength alternating electric field (AC field) in radio frequency range (80–200 kHz) was published. In the study presented here we investigated the mechanistic role of 10 different types of GAC in radio frequency FBE disinfection with Escherichiacoli YMc10 as the model microorganism. The disinfection performances with only GAC, and GAC combined with an AC field were quantified. Seven GACs showed poor to intermediate and three GACs (Norit RB3 (2.7 Log CFU E. coli decrease), Sorbonorit 3 (2.8 Log CFU E. coli decrease) and RX3 EXTRA (3.4 Log CFU E. coli decrease)) showed substantial disinfection in FBE. The results suggest a relation between the pHpzc of the GAC and the disinfection performance. Disinfection performance increased with bigger particle size and decreasing conductivity of tested GACs. We conclude that these physico-chemical and physical properties of GAC are important factors controlling the disinfection performance of these type FBE systems.
Geoengineering in lakes: welcome attraction or fatal distraction?
Mackay, E. ; Maberly, S.C. ; Pan, G. ; Reitzel, K. ; Lurling, M.F.L.L.W. - \ 2014
Inland Waters : Journal of the International Society of Limnology 4 (2014). - ISSN 2044-2041 - p. 349 - 356.
modified bentonite clay - phosphate adsorption - phosphorus release - shallow lakes - water-quality - sediment - nutrient - aluminum - removal - phoslock(r)
The use of geoengineering techniques for phosphorus management offers the promise of greater and quicker chemical and ecological recovery. It can be attractive when used with other restoration measures but should not be considered a panacea. The range of materials being proposed for use as well as the in-lake processes targeted for manipulation continues to grow. With increasing political imperatives to meet regulatory goals for water quality, we recommend a coordinated approach to the scientific understanding, costs, and integration of geoengineering with other approaches to lake management.
Biofilm growth of Chlorella sorokiniana in a rotating biological contactor based photobioreactor
Blanken, W.M. ; Janssen, M.G.J. ; Cuaresma, M. ; Libor, Z. ; Bhaiji, T. ; Wijffels, R.H. - \ 2014
Biotechnology and Bioengineering 111 (2014)12. - ISSN 0006-3592 - p. 2436 - 2445.
microalgae - cultivation - system - water - biofuels - removal - model
Microalgae biofilms could be used as a production platform for microalgae biomass. In this study, a photobioreactor design based on a rotating biological contactor (RBC) was used as a production platform for microalgae biomass cultivated in biofilm. In the photobioreactor, referred to as Algadisk, microalgae grow in biofilm on vertical rotating disks partially submerged in a growth medium. The objective is to evaluate the potential of the Algadisk photobioreactor with respect to the effects of disk roughness, disk rotation speed and CO2 concentration. These objectives where evaluated in relationship to productivity, photosynthetic efficiency, and long-term cultivation stability in a lab-scale Algadisk system. Although the lab-scale Algadisk system is used, operation parameters evaluated are relevant for scale-up. Chlorella Sorokiniana was used as model microalgae. In the lab-scale Algadisk reactor, productivity of 20.1¿±¿0.7¿g per m2 disk surface per day and a biomass yield on light of 0.9¿±¿0.04¿g dry weight biomass per mol photons were obtained. Different disk rotation speeds did demonstrate minimal effects on biofilm growth and on the diffusion of substrate into the biofilm. CO2 limitation, however, drastically reduced productivity to 2–4¿g per m2 disk surface per day. Productivity could be maintained over a period of 21 weeks without re-inoculation of the Algadisk. Productivity decreased under extreme conditions such as pH 9–10, temperature above 40°C, and with low CO2 concentrations. Maximal productivity, however, was promptly recovered when optimal cultivation conditions were reinstated. These results exhibit an apparent opportunity to employ the Algadisk photobioreactor at large scale for microalgae biomass production if diffusion does not limit the CO2 supply. Biotechnol. Bioeng. 2014;111: 2436–2445. © 2014 Wiley Periodicals, Inc.
Negative density dependence of seed dispersal and seedling recruitment in a Neotropical palm
Jansen, P.A. ; Visser, M.D. ; Joseph Wright, S. ; Rutten, G. ; Muller-Landau, H.C. - \ 2014
Ecology Letters 17 (2014)9. - ISSN 1461-023X - p. 1111 - 1120.
scatter-hoarding rodent - tropical tree - spatial-patterns - plant diversity - forest - competition - removal - consequences - mechanisms - herbivores
Negative density dependence (NDD) of recruitment is pervasive in tropical tree species. We tested the hypotheses that seed dispersal is NDD, due to intraspecific competition for dispersers, and that this contributes to NDD of recruitment. We compared dispersal in the palm Attalea butyracea across a wide range of population density on Barro Colorado Island in Panama and assessed its consequences for seed distributions. We found that frugivore visitation, seed removal and dispersal distance all declined with population density of A. butyracea, demonstrating NDD of seed dispersal due to competition for dispersers. Furthermore, as population density increased, the distances of seeds from the nearest adult decreased, conspecific seed crowding increased and seedling recruitment success decreased, all patterns expected under poorer dispersal. Unexpectedly, however, our analyses showed that NDD of dispersal did not contribute substantially to these changes in the quality of the seed distribution; patterns with population density were dominated by effects due solely to increasing adult and seed density.
Different compositions of pharmaceuticals in Dutch and Belgian rivers explained by consumption patterns and treatment efficiency
Laak, T.L. ter; Kooij, P.J.F. ; Tolkamp, H. ; Hofman, J. - \ 2014
Environmental Science and Pollution Research 21 (2014)22. - ISSN 0944-1344 - p. 12843 - 12855.
waste-water treatment - personal care products - treatment plants - environmental concentrations - transformation products - aquatic environment - risk-assessment - drinking-water - removal - fate
In the current study, 43 pharmaceuticals and 18 transformation products were studied in the river Meuse at the Belgian-Dutch border and four tributaries of the river Meuse in the southern part of the Netherlands. The tributaries originate from Belgian, Dutch and mixed Dutch and Belgian catchments. In total, 23 pharmaceuticals and 13 transformation products were observed in samples of river water collected from these rivers. Observed summed concentrations of pharmaceuticals and transformation products in river water ranged from 3.5 to 37.8 µg/L. Metformin and its transformation product guanylurea contributed with 53 to 80 % to this concentration, illustrating its importance on a mass basis. Data on the flow rate of different rivers and demographics of the catchments enabled us to calculate daily per capita loads of pharmaceuticals and transformation products. These loads were linked to sales data of pharmaceuticals in the catchment. Simple mass balance modelling accounting for human excretion and removal by sewage treatment plants revealed that sales could predict actual loads within a factor of 3 for most pharmaceuticals. Rivers that originated from Belgian and mixed Dutch and Belgian catchments revealed significantly higher per capita loads of pharmaceuticals (16.0¿±¿2.3 and 15.7¿±¿2.1 mg/inhabitant/day, respectively) than the Dutch catchment (8.7¿±¿1.8 mg/inhabitant/day). Furthermore, the guanylurea/metformin ratio was significantly lower in waters originating from Belgium (and France) than in those from the Netherlands, illustrating that sewage treatment in the Belgian catchment is less efficient in transforming metformin into guanylurea. In summary, the current study shows that consumption-based modelling is suitable to predict environmental loads and concentrations. Furthermore, different consumption patterns and wastewater treatment efficiency are clearly reflected in the occurrence and loads of pharmaceuticals in regional rivers.
Electrochemical conversion of micropollutants in gray water
Butkovskyi, A. ; Jeremiasse, A.W. ; Hernandez Leal, L. ; Zande, T. van der; Rijnaarts, H. ; Zeeman, G. - \ 2014
Environmental Science and Technology 48 (2014)3. - ISSN 0013-936X - p. 1893 - 1901.
waste-water - bisphenol-a - anodic-oxidation - organic pollutants - treatment systems - by-products - degradation - electrodes - removal - disinfection
Electrochemical conversion of micropollutants in real gray water effluent was studied for the first time. Six compounds that are frequently found in personal care and household products, namely methylparaben, propylparaben, bisphenol A, triclosan, galaxolide, and 4- methylbenzilidene camphor (4-MBC), were analyzed in the effluent of the aerobic gray water treatment system in full operation. The effluent was used for lab-scale experiments with an electrochemical cell operated in batch mode. Three different anodes and five different cathodes have been tested. Among the anodes, Ru/Ir mixed metal oxide showed the best performance. Ag and Pt cathodes worked slightly better than Ti and mixed metal oxide cathodes. The compounds that contain a phenolic ring (parabens, bisphenol A, and triclosan) were completely transformed on this anode at a specific electric charge Q = 0.03 Ah/L. The compounds, which contain a benzene ring and multiple side methyl methyl groups (galaxolide, 4-MBC) required high energy input (Q = 0.6 Ah/L) for transformation. Concentrations of adsorbable organohalogens (AOX) in the gray water effluent increased significantly upon treatment for all electrode combinations tested. Oxidation of gray water on mixed metal oxide anodes could not be recommended as a post-treatment step for gray water treatment according to the results of this study. Possible solutions to overcome disadvantages revealed within this study are proposed.
Tracking C and N dynamics and stabilization in soil amended with wheat residue and its correponding bioethanol by-product: a 13C/15C study
Cayuela, M.L. ; Kuikman, P.J. ; Bakker, R.R.C. ; Groenigen, J.W. van - \ 2014
Global change biology Bioenergy 6 (2014)5. - ISSN 1757-1693 - p. 499 - 508.
organic-matter - macroaggregate dynamics - carbon sequestration - microbial biomass - removal - network - quality - impact - inputs
Removing agricultural cellulosic residues from fields for the production of ‘second generation biofuels'has the potential to profoundly alter C and N cycling in soil, increasing the risk of soil organic matter depletion and favoring soil–atmosphere gaseous exchanges. However, these negative impacts could potentially be offset by amending the soil with the solid by-product which is generated during bioethanol production. In a 100 days laboratory study, we investigated the fate of C and N after soil amendment with doubly labeled (13C, 15N) wheat residue (WR) and the corresponding bioethanol by-product (i.e. nonfermentable wheat residue NFWR) with and without extra N addition. Substituting WR with the corresponding amount of recovered bioethanol by-product partially compensated the C losses of full crop residue removal. When the equivalent amount of C was added as WR and NFWR, NFWR-derived C was found in significantly higher proportion in macroaggregates in soil (17.0 vs. 8.9%) after 100 days. Addition of both WR and NFWR reduced soil organic C (SOC) mineralization, i.e. it caused a negative priming effect in soil. However, this pattern was reversed when extra N was added. Both WR and NFWR increased the proportion of soil water-stable macroaggregates from 16% (in control) to 20–24% (in the different treatments). The results suggest that the more recalcitrant compounds derived from bioethanol production may stabilize more strongly and persist within the protected fractions of SOM pools. Our study demonstrates that NFWR, compared with WR application, neither increased N2O emissions nor had a negative impact on aggregate formation in the midterm. This demonstrates that NFWR has potential for replenishing SOC stocks
The impact of the Nitrates Directive on nitrogen emissions from agriculture in the EU-27 during 2000–2008
Velthof, G.L. ; Lesschen, J.P. ; Webb, J. ; Pietrzak, S. ; Miatkowski, Z. ; Pinto, M. ; Kros, J. ; Oenema, O. - \ 2014
Science of the Total Environment 468-469 (2014)2014. - ISSN 0048-9697 - p. 1225 - 1233.
integrated assessment - oxide emissions - pig slurry - soils - phosphorus - separation - efficiency - removal - losses - europe
A series of environmental policies have been implemented in the European Union (EU) to decrease nitrogen (N) emissions from agriculture. The Nitrates Directive (ND) is one of the main policies; it aims to reduce nitrate leaching from agriculture through a number of measures. A study was carried out to quantify the effects of the ND in the EU-27 on the leaching and runoff of nitrate (NO3-) to groundwater and surface waters, and on the emissions of ammonia (NH3), nitrous oxide (N2O), nitrogen oxides (NOx) and dinitrogen (N2) to the atmosphere. We formulated a scenario with and a scenario without implementation of the ND. The model MITERRA-Europe was used to calculate N emissions on a regional level in the EU-27 for the period 2000–2008. The calculated total N loss from agriculture in the EU-27 was 13 Mton N in 2008, with 53% as N2, 22% as NO3, 21% as NH3, 3% as N2O, and 1% as NOx. The N emissions and leaching in the EU-27 slightly decreased in the period 2000–2008. Total emissions in the EU in 2008 were smaller with implementation of the ND than without the ND, by 3% for NH3, 6% for N2O, 9% for NOx, and 16% for N leaching and runoff in 2008. However, regional differences were large. The lower emissions with ND were mainly due to the lower N inputs by fertilizers and manures. In conclusion, implementation of the ND decreased both N leaching losses to ground and surface waters, and gaseous emissions to the atmosphere. It is expected that the ND will result in a further decrease in N emissions in EU-27 in the near future, because the implementation of the measures for the ND is expected to become more strict.
The effect of harvesting on biomass production and nutrient removal in phototrophic biofilm reactors for effluent polishing
Boelee, N.C. ; Janssen, M. ; Temmink, H. ; Taparaviciute, L. ; Khiewwijit, R. ; Janoska, A. ; Buisman, C.J.N. ; Wijffels, R.H. - \ 2014
Journal of Applied Phycology 26 (2014)3. - ISSN 0921-8971 - p. 1439 - 1452.
afvalwaterbehandeling - biofilms - dikte - dichtheid - algen - biologische waterzuiveringsinstallaties - fototropie - stikstof - fosfor - verwijdering - biobased economy - waste water treatment - biofilms - thickness - density - algae - biological water treatment plants - phototropism - nitrogen - phosphorus - removal - biobased economy - waste-water treatment - photosynthetic efficiency - chlorella-sorokiniana - microalgal biofilms - phosphorus removal - mass-transport - fresh-water - light - growth
An increasing number of wastewater treatment plants require post-treatment to remove residual nitrogen and phosphorus. This study investigated various harvesting regimes that would achieve consistent low effluent concentrations of nitrogen and phosphorus in a phototrophic biofilm reactor. Experiments were performed in a vertical biofilm reactor under continuous artificial lighting and employing artificial wastewater. Under similar conditions, experiments were performed in near-horizontal flow lanes with biofilms of variable thickness. It was possible to maintain low nitrogen and phosphorus concentrations in the effluent of the vertical biofilm reactor by regularly harvesting half of the biofilm. The average areal biomass production rate achieved a 7 g dry weight m-2 day-1 for all different harvesting frequencies tested (every 2, 4, or 7 days), corresponding to the different biofilm thicknesses. Apparently, the biomass productivity is similar for a wide range of biofilm thicknesses. The biofilm could not be maintained for more than 2 weeks as, after this period, it spontaneously detached from the carrier material. Contrary to the expectations, the biomass production doubled when the biofilm thickness was increased from 130 µm to 2 mm. This increased production was explained by the lower density and looser structure of the 2 mm biofilm. It was concluded that, concerning biomass production and labor requirement, the optimum harvesting frequency is once per week.
Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage
Xiao, H.W. ; Zhang, S.L. ; Zhai, J. ; He, Q. ; Mels, A.R. ; Ning, K.J. ; Liu, J. - \ 2013
Water Science and Technology 67 (2013)10. - ISSN 0273-1223 - p. 2257 - 2264.
afvalwaterbehandeling - helofytenfilters - zware metalen - verontreinigde sedimenten - plantenweefsels - waste water treatment - artificial wetlands - heavy metals - contaminated sediments - plant tissues - waste-water treatment - acid-mine drainage - heavy-metals - removal - performance - experience - decades - china
This study was conducted to investigate the retention and distribution of Cu, Pb, Cr, and Zn in a hybrid constructed wetland (CW) that consists of both vertical baffled flow wetlands (VBFWs) and horizontal subsurface flow wetlands (HSSFs) with unique flow regimes and oxygen distribution. The heavy metal concentrations in water, sediments, and plant tissues in the hybrid CW were analysed. The removal of heavy metals from the water stream in the monitoring period was not statistically significant. Metal concentrations in the sediments generally decreased along the wastewater treatment process. The reductive anaerobic condition in the VBFW may promote the sulphate reduction and form highly insoluble Cu, Pb, and Zn sulphides, resulting in the higher concentration of the bivalent cations in the VBFW sediments than the corresponding values in the HSSF; however, the aerobic and anoxic environments in the HSSF enhanced the removal of Cr with the co-precipitation of iron and manganese oxides, and their hydroxides. Metal concentrations in plant tissues were not significantly influenced by the concentrations in sediments, while roots contained statistically higher metal concentrations than stems and leaves. The sediments stored 94.01, 86.31, 95.85, and 89.51% of the total Cu, Pb, Cr, and Zn retained in the hybrid CW system, respectively, while only small fractions (
Electrochemical phosphate recovery from nanofiltration concentrates
Kappel, C. ; Yasadi, K. ; Temmink, B.G. ; Metz, S.J. ; Kemperman, A.J.B. ; Nijmeijer, K. ; Zwijnenburg, A. ; Witkamp, G.J. ; Rijnaarts, H. - \ 2013
Separation and Purification Technology 120 (2013). - ISSN 1383-5866 - p. 437 - 444.
amorphous calcium-phosphate - municipal waste-water - aqueous-solution - precipitation - hydroxyapatite - magnesium - struvite - removal - substitution - experiences
The high total phosphorus content of raw domestic wastewater with its significant eutrophication potential offers an excellent possibility for phosphate recovery. Continuous recirculation of NF concentrate to an MBR and simultaneous phosphate recovery from the NF concentrate can be applied to produce reusable water, recovering phosphates, while at the same time decreasing the scaling potential of the recirculated NF concentrate, prolonging the retention times of slowly biodegradable soluble compounds (e.g. micropollutants) and recirculating multivalent cations to promote the bio-flocculation. Here we introduce an electrochemical system to recover phosphates. An electrochemical cell was divided into an anode and a cathode compartment separated by a cation exchange membrane. Precipitation of phosphates from nanofiltration concentrate was induced by locally increasing the pH at the cathode surface by water electrolysis and thereby creating supersaturated conditions at the cathode. 70–95% recovery of total phosphate was achieved at a pH of 8–10 near the cathode. Ion analysis, XRD and ATR-FTIR spectra indicated that the precipitate consisted of amorphous calcium phosphate (ACP) and minor proportions of amorphous calcium carbonate (ACC). The amount of ACC was dependent on the pH. Calcium phosphate scaling at the cathode surface did not occur due to H2-gas formation preventing nucleation and growth at the cathode.
A metal ion charged mixed matrix membrane for selective adsorption of hemoglobin
Tetala, K.K.R. ; Skrzypek, K. ; Levisson, M. ; Stamatialis, D.F. - \ 2013
Separation and Purification Technology 115 (2013). - ISSN 1383-5866 - p. 20 - 26.
sickle-cell-disease - exchange chromatography - protein adsorption - bovine hemoglobin - human blood - separation - depletion - purification - adsorbers - removal
In this work, we developed a mixed matrix membrane by incorporating 20–40 µm size iminodiacetic acid modified immobeads within porous Ethylene vinyl alcohol (EVAL) polymer matrix. The MMM were charged with copper ions for selective adsorption of bovine hemoglobin in presence of bovine serum albumin. EVAL membrane without immobead and immobead alone showed low non-specific adsorption towards bovine hemoglobin and bovine serum albumin. Use of buffers with pH ¿6.8 i.e. pI of bovine hemoglobin resulted in high bovine hemoglobin adsorption. The developed mixed matrix membrane has a maximum static adsorption capacity of 219.5 mg bovine hemoglobin per g bead and the adsorption isotherm curve is of a Langmuir type. Under similar flow rates, the mixed matrix membrane showed significant low pressure drop compared to a packed bed column containing equal amount of beads. Maximum and faster (6 h) adsorption of bovine hemoglobin can be achieved through dynamic mode only using mixed matrix membrane and not by packed bed column and static mode of mixed matrix membrane. The mixed matrix membrane has three times selective adsorption of bovine hemoglobin than bovine serum albumin, from a binary mixture containing equivalent amounts of both proteins
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