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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Recycling nutrients contained in human excreta to agriculture : Pathways, processes, and products
Harder, Robin ; Wielemaker, Rosanne ; Larsen, Tove A. ; Zeeman, Grietje ; Öberg, Gunilla - \ 2019
Critical Reviews in Environmental Science and Technology (2019). - ISSN 1064-3389
blackwater - carbon - feces - fertilizer - nitrogen - organic matter - Phosphorus - potassium - recovery - resource-oriented sanitation - sewage - soil amendment - source-separation - urine - wastewater

The need for better nutrient management has spurred efforts towards more comprehensive recycling of nutrients contained in human excreta to agriculture. Research in this direction has intensified throughout the past years, continuously unfolding new knowledge and technologies. The present review aspires to provide a systematic synthesis of the field by providing an accessible overview of terminology, recovery pathways and treatment options, and products rendered by treatment. Our synthesis suggests that, rather than focusing on a specific recovery pathway or product and on a limited set of nutrients, there is scope for exploring how to maximize nutrient recovery by combining individual pathways and products and including a broader range of nutrients. To this end, finding ways to more effectively share and consolidate knowledge and information on recovery pathways and products would be beneficial. The present review aims to provide a template that aims to facilitate designing human excreta management for maximum nutrient recovery, and that can serve as foundation for organizing and categorizing information for more effective sharing and consolidation.

The Birth, Growth and Death of Intertidal Soft-Sediment Bivalve Beds : No Need for Large-Scale Restoration Programs in the Dutch Wadden Sea
Meer, Jaap van der; Dankers, Norbert ; Ens, Bruno J. ; Stralen, Marnix van; Troost, Karin ; Waser, Andreas M. - \ 2018
Ecosystems (2018). - ISSN 1432-9840
Crassostrea gigas - demography - Mytilus edulis - overfishing - proportional hazard - recovery - restoration - survival analysis

Recruitment and fate of all 1436 mussel and oyster beds of the Dutch Wadden Sea were studied for the period 1999–2013. Cox’s proportional hazard rate model with covariates such as orbital speed, exposure time and bed size and type showed that large, low-lying beds that experience a low orbital speed live longer. Yet the most striking result was that oyster and mixed beds have a much lower hazard rate than pure mussel beds. Simulation studies, using the observed recruitment series, which was very variable, and the estimated survival curves, showed large variability in total bed area, implying that the present area, though lower than before, does not point to a systematic deviation from the pre-1990 situation, that is, the situation before intensive fisheries on these intertidal beds and the disappearance of them around 1990. Claims that bivalve bed recovery is impossible without restoration efforts are premature and not supported by our analysis. On the contrary, the observed high survival rate of mixed and oyster beds and the expectation that such beds will predominate in the near future can easily result in larger future bed coverage than what has been measured before.

Re-using bauxite residues : benefits beyond (critical raw) material recovery
Ujaczki, Éva ; Feigl, Viktória ; Molnár, Mónika ; Cusack, Patricia ; Curtin, Teresa ; Courtney, Ronan ; O'Donoghue, Lisa ; Davris, Panagiotis ; Hugi, Christoph ; Evangelou, Michael W.H. ; Balomenos, Efthymios ; Lenz, Markus - \ 2018
Journal of Chemical Technology and Biotechnology 93 (2018)9. - ISSN 0268-2575 - p. 2498 - 2510.
hydrometallurgy - life-cycle assessment (LCA) - metals - recovery - sustainable processing - waste treatment and waste minimization

Since the world economy has been confronted with an increasing risk of supply shortages of critical raw materials (CRMs), there has been a major interest in identifying alternative secondary sources of CRMs. Bauxite residues from alumina production are available at a multi-million tonnes scale worldwide. So far, attempts have been made to find alternative re-use applications for bauxite residues, for instance in cement / pig iron production. However, bauxite residues also constitute an untapped secondary source of CRMs. Depending on their geological origin and processing protocol, bauxite residues can contain considerable amounts of valuable elements. The obvious primary consideration for CRM recovery from such residues is the economic value of the materials contained. However, there are further benefits from re-use of bauxite residues in general, and from CRM recovery in particular. These go beyond monetary values (e.g. reduced investment / operational costs resulting from savings in disposal). For instance, benefits for the environment and health can be achieved by abatement of tailing storage as well as by reduction of emissions from conventional primary mining. Whereas certain tools (e.g. life-cycle analysis) can be used to quantify the latter, other benefits (in particular sustained social and technological development) are harder to quantify. This review evaluates strategies of bauxite residue re-use / recycling and identifies associated benefits beyond elemental recovery. Furthermore, methodologies to translate risks and benefits into quantifiable data are discussed. Ultimately, such quantitative data are a prerequisite for facilitating decision-making regarding bauxite residue re-use / recycling and a stepping stone towards developing a zero-waste alumina production process.

Evaluation of methodological aspects of digestibility measurements in ponies fed different haylage to concentrate ratios
Schaafstra, F.J.W.C. ; Doorn, D.A. van; Schonewille, J.T. ; Riet, M.M.J. van; Visser, P. ; Blok, M.C. ; Hendriks, W.H. - \ 2017
Animal 11 (2017)11. - ISSN 1751-7311 - p. 1922 - 1929.
dietary markers - digestibility - equines - recovery - total faeces collection

Methodological aspects of digestibility measurements were studied in four Welsh pony geldings consuming haylage-based diets with increasing proportions of a pelleted concentrate according to a 4×4 Latin square design experiment. Ponies were fed four experimental, iso-energetic (net energy (NE) basis) diets (i.e. 22 MJ NE/day) with increasing proportions of a pelleted concentrate (C) in relation to haylage (H). The absolute amounts of diet dry matter fed per day were 4.48 kg of H (100H), 3.36 and 0.73 kg of H and C (75H25C), 2.24 and 1.45 kg of H and C (50H50C) and 1.12 and 2.17 kg of H and C (25H75C). Diets were supplemented with minerals, vitamins and TiO2 (3.7 g Ti/day). Voluntary voided faeces were quantitatively collected daily during 10 consecutive days and analysed for moisture, ash, ADL, acid-insoluble ash (AIA) and Ti. A minimum faeces collection period of 6 consecutive days, along with a 14-day period to adapt the animals to the diets and become accustomed to the collection procedure, is recommended to obtain accurate estimations on dry matter digestibility and organic matter digestibility (OMD) in equids fed haylage-based diets supplemented with concentrate. In addition, the recovery of AIA, ADL and Ti was determined and evaluated. Mean faecal recovery over 10 consecutive days across diets for AIA, ADL and Ti was 124.9% (SEM 2.9), 108.7% (SEM 2.0) and 97.5% (SEM 0.9), respectively. Cumulative faecal recovery of AIA significantly differed between treatments, indicating that AIA is inadequate to estimate the OMD in equines. In addition, evaluation of the CV of mean cumulative faecal recoveries obtained by AIA, ADL and Ti showed greater variations in faecal excretion of AIA (9.1) and ADL (7.4) than Ti (3.7). The accuracy of prediction of OMD was higher with the use of Ti than ADL. The use of Ti is preferred as a marker in digestibility trials in equines fed haylage-based diets supplemented with increasing amounts of pelleted concentrate.

Estimating the sustainability of towed fishing-gear impacts on seabed habitats: a simple quantitative risk assessment method applicable to data-limited fisheries
Pitcher, C.R. ; Ellis, Nick ; Jennings, Simon ; Hiddink, Jan G. ; Mazor, Tessa ; Kaiser, Michel J. ; Kangas, Mervi I. ; Mcconnaughey, Robert A. ; Parma, Ana M. ; Rijnsdorp, Adriaan D. ; Suuronen, Petri ; Collie, Jeremy S. ; Amoroso, Ricardo ; Hughes, Kathryn M. ; Hilborn, Ray ; Freckleton, Robert - \ 2017
Methods in Ecology and Evolution 8 (2017). - ISSN 2041-210X - p. 472 - 480.
benthic fauna - depletion - ecological risk assessment - ecoystem-based fishery management - effects of trawling - recovery - resilience - sensivity - trawl footprints - vulnerability indicators
1. Impacts of bottom fishing, particularly trawling and dredging, on seabed (benthic) habitats are commonly perceived to pose serious environmental risks. Quantitative ecological risk assessment can be used to evaluate actual risks and to help guide the choice of management measures needed to meet sustainability objectives. 2. We develop and apply a quantitative method for assessing the risks to benthic habitats by towed bottom-fishing gears. The meth od is based on a simple eq uation for relative benthic status (RBS), derived by solving the logistic population growth equation for the equilibrium state. Estimating RBS requires only maps of fishing intensity and habitat type – and parameters for impact and recovery rates, which may be taken from meta-analyses of multiple experimental studies of towed-gear impacts. The aggregate status of habitats in an assessed region is indicated by the distribution of RBS values for the region. The application of RBS is illustrated for a tropical shrimp-trawl fishery. 3. The status of trawled habitats and their RBS value depend on impact rate (depletion per trawl), recovery rate and exposure to tra wling. In the shrimp-trawl fishery region, gravel habitat was most sensitive, and though less exposed than sand or mudd y-sand, was most affected overall (regional RBS = 91% relative to un-trawled RBS = 100%). Muddy-sand was less sensitive, and though relatively most exposed, was less affected overall (RBS = 95%). Sand was most heavily trawled but least sensitive and least affected overall (RBS = 98%). Region-wide , >94% of habitat area had >80% RBS because most tra wling and impacts were confined to small areas. RBS was also applied to the region’s benthic invertebrate communities with similar results. 4. Conclu sions. Unlike qualitative or categorical trait-based risk assessments, the RBS method provides a quantitative estimate of status relative to an unimpacted baseline, with minimal requireme nts for input data. It could be applied to bottom-contact fish erie s world-wide, including situations where detailed data on characteristics of seabed habitats, or the abundance of seabed fauna are not available. The approach supports assessment against sustainability criteria and evaluation of alternative management strategies (e.g. closed areas, effort management, gear modifications).
Fosfaat vangen
Schoumans, Oscar - \ 2017
animal manures - phosphate - recovery - waste water treatment - projects - separation technology

Terwijl aan de ene kant fosfaatmijnen langzaam leegraken, lekt er aan de andere te veel fosfaat uit mest weg in de bodem en het water. Wetenschappers werken hard aan technieken om het mineraal terug te winnen en opnieuw te gebruiken.

De straat van de toekomst
Vreeburg, Jan - \ 2017
urban development - homes - cycling - water reuse - recovery - innovations - water treatment

2022 lijkt nog ver weg. Toch zijn Wageningse onderzoekers nu al bezig met de Floriade die dat jaar in Almere de poorten opent. Ze gaan daar de Straat van de Toekomst bouwen, die volledig is ingericht op hergebruik.

Fosfaat uit afvalwater vissen
Smet, Louis de - \ 2016
phosphate - waste water treatment - waste water - fertilizers - phosphorus fertilizers - waste utilization - biobased economy - recovery
Slimmer omgaan met poep
Zeeman, Grietje - \ 2016
new sanitation - water treatment - waste water - urine - recovery - anaerobic treatment - separation
Agrarisch Waterbeheer in de praktijk : Op zoek naar de gemene deler
Breman, B.C. ; Linderhof, V.G.M. - \ 2016
Het Waterschap 2016 (2016)6. - p. 7 - 9.
waterbeheer - waterschappen - duurzame energie - terugwinning - rioolwaterzuivering - zuiveringsinstallaties - landbouw - innovaties - klimaatadaptatie - stedelijke gebieden - water management - polder boards - sustainable energy - recovery - sewage treatment - purification plants - agriculture - innovations - climate adaptation - urban areas
In dit themanummer over Green Deals staan de volgende artikelen: 1) Green Deals: Code oranje, blauwe oplossing. 2) Op zoek naar de gemene deler: agrarisch waterbeheer in de praktijk. 3) Kraamkamer van innovatie. 4) Modern aanbesteden is kennis delen: marktvisie waterschappen. 5) De politicus Liesbeth van Tongeren: Niet langer in discussie met klimaatsceptici. 6) Er valt iets te kiezen: waterschappen integreren duurzame energieproductie succesvol in hun kerntaken. 7) Slimmer investeren: Strategisch asset management. 8) Creativiteit op het snijvlak van orde en chaos: Waterschap De Dommel flirt met paradoxen. 9) Open overheid, ook voor waterschappen. 10) Werken aan morgen is gisteren al begonnen: hoe ziet werken voor een waterschap er in 2026 uit?
Sanitation planning in developing countries : added value of resource recovery
Kerstens, S.M. - \ 2016
Wageningen University. Promotor(en): Grietje Zeeman, co-promotor(en): Ingo Leusbrock. - Wageningen : Wageningen University - ISBN 9789462576889 - 316 p.
sanitation - developing countries - recovery - urban planning - waste water treatment - waste treatment - waste management - environmental technology - volksgezondheidsbevordering - ontwikkelingslanden - terugwinning - stedelijke planning - afvalwaterbehandeling - afvalverwerking - afvalbeheer - milieutechnologie

Sanitation planning in developing countries: Added value of resource recovery

Worldwide 2.5 billion people lack access to sanitation. This impacts human live, the environment and represents a loss of valuable resources that can be regained from wastewater. This study shows that resource recovery can be a potential driver to accelerate sanitation. A new sanitation decision framework for policy makers was created and tested in Indonesia.

The variety of advantages and disadvantages of sanitation interventions complicates the sanitation planning process. Conventional sanitation systems consume energy, chemicals and land or produce a sludge that requires disposal, whereas a range of opportunities exists that enables valorization of resources from our “waste”. To support policy makers in planning sanitation that considers sustainability dimensions (social, environment and economy), a new sanitation framework was developed. This framework resolves trade-offs of sanitation alternatives across spatial and temporal scales in three steps. First, it identifies feasible wastewater and solid waste systems in relation to the type of residential area. Secondly, the anticipated population development, current access and formulated targets are an input to generate the number of required systems, their location and associated implementation costs. The required systems are visualized in geographical maps, while budgets are allocated to responsible implementing institutions. Thirdly, the potential demand from “back-end users” of sanitation products, such as agriculture for compost and phosphorus, aquaculture for produced duckweed and industries for recovered plastic and paper, to substitute conventionally produced materials is determined. These three steps are then combined to quantitatively evaluate the (1) environmental impact, (2) operational costs and benefits, and (3) the potential of selected sanitation alternatives to close material cycles. A case study of the Citarum River was performed in which (monetized) benefits such as health, welfare and revenues from the sale of recovered resources were compared with the costs of different (conventional and resource recovery) sanitation systems. The study showed that the economic Benefit to Cost Ratio (BCR) of resource recovery technologies is bigger than BCR of conventional (low cost) technologies, while improving the water quality. It thus shows that resource recovery is a potential driver to accelerate sanitation development. The framework was illustrated using Indonesia as an example, but its application can benefit the quality of millions of lives worldwide.

New wastewater treatment concepts towards energy saving and resource recovery
Khiewwijit, R. - \ 2016
Wageningen University. Promotor(en): Huub Rijnaarts, co-promotor(en): Karel Keesman; Hardy Temmink. - Wageningen : Wageningen University - ISBN 9789462576407 - 148 p.
waste water treatment - energy saving - recovery - municipal wastewater - nutrients - volatile fatty acids - afvalwaterbehandeling - energiebesparing - terugwinning - stedelijk afvalwater - voedingsstoffen - vluchtige vetzuren
At present, conventional activated sludge (CAS) systems are widely applied to treat municipal wastewater. The main advantages of CAS systems are that they are robust and generally produce an effluent quality that meets the discharge guidelines. However, CAS systems cannot be considered sustainable because they consume large amounts of energy (mainly for aeration and sludge treatment), have a high CO2 emission and do no recover a potential resource of water, energy and nutrients nitrogen (N) and phosphorus (P). Therefore, in this thesis new municipal wastewater treatment concepts that combine treatment with recovery of valuable resources and can save considerable amounts of energy were investigated by modelling and experiments.

Quantitative numerical results showed that the feasibility of two novel wastewater treatment configurations, including combined bioflocculation and anaerobic digestion but with different nutrient removal technologies, i.e. (cold) partial nitritation/Anammox or microalgae treatment, is location dependent. Using Dutch municipal wastewater and climate conditions, the configuration with cold partial nitritation/Anammox is the most promising wastewater treatment concept, because it can: 1) treat wastewater year round; 2) produce an effluent at a quality that meets the discharge guidelines; 3) reduce CO2 emission by 35% compared to the CAS system; 4) achieve a net energy yield up to 0.24 kWh per m3 of wastewater compared to a negative net energy yield of -0.08 kWh per m3 of wastewater for the CAS system; and 5) recover 80% of the sewage P. Additionally, the feasibility of the two configurations was investigated for 16 locations around the globe. The results quantitatively support the pre-assumption that the configuration with (cold) partial nitritation/Anammox is applicable in tropical regions and some locations in temperate regions. The configuration with microalgae treatment is only applicable the whole year round in tropical regions that are close to the equator line. The results also showed that the configuration employing microalgae treatment has an advantage over the configuration employing partial nitritation/Anammox with respect to consumption of aeration energy and recovery of nutrients, but not with respect to area requirements. For a tropical climate country like Thailand, the net energy yield of both configurations is at least a factor 10 higher than the CAS system, while CO2 emission is at least 22% lower.

In CAS systems energy recovery from wastewater is accomplished by anaerobic digestion of the organic solids in primary and secondary sludge into methane. However, volatile fatty acids (VFA), which are intermediate digestion products, may be preferred over methane, because VFA can be used as starting compounds for a wide range of higher value products. In this thesis the experimental results showed that a combined process with bioflocculation, using a high-loaded membrane bioreactor (HL-MBR) to concentrate sewage organic matter, and anaerobic fermentation, using a sequencing batch reactor to produce VFA is technologically feasible. An HL-MBR operated at a hydraulic retention time (HRT) of 1 hour and a sludge retention time (SRT) of 1 day resulted in very good performance, because as high as 75.5% of the sewage COD (chemical oxygen demand) was diverted to the concentrate and only 7.5% was mineralized into CO2. It was also found that 90% of the sewage NH4-N and PO4-P were conserved in the HL-MBR permeate, which can be reused as irrigation water as it is free from solids and pathogens.

During anaerobic fermentation of the HL-MBR concentrate at an SRT of 5 days, 35°C and without pH control, methane production was inhibited, but incomplete solids degradation mainly limited the VFA production as only 15% of the sewage COD was converted to VFA. Thus, the VFA yield needed to be increased. It was hypothesized that high pH (pH 8–10) fermentation combined with a long SRT, allowing for sufficient solubilization of solids and colloidal COD, can improve the VFA yield. In the current study, it was found that application of a pH shock of 9 in the first 3.5 hours of a sequencing batch cycle followed by a pH uncontrolled phase for 7 days gave the highest VFA yield of 440 mg VFA-COD/g VSS and this was equivalent to 26% of the sewage COD. This yield was much higher than at fermentation without pH control or at a constant pH between 8 and 10. The high yield in the pH 9 shock fermentation could be explained by: 1) a reduction of methanogenic activity; or 2) a high degree of solids degradation; or 3) an enhanced protein hydrolysis and fermentation. This study also demonstrated that the VFA yield can still be further optimized by fine-tuning pH levels and longer operation, possibly with fermentative microorganisms adapted to a high pH that are commonly found in nature. This would further increase VFA yield to 33% of the sewage COD.
Biorefinery : recovery of valuable biomolecules
Eppink, M.H.M. - \ 2015
Wageningen : Wageningen University - ISBN 9789462573789 - 28 p.
biorefinery - recovery - biomass - biofuels - separation technology - biomass conversion - biomass cascading - biobased economy - bioraffinage - terugwinning - biomassa - biobrandstoffen - scheidingstechnologie - biomassaconversie - biomassa cascadering
Inaugural speech Wageningen University, 23 April 2015
Products, by-products and recovered secondary materials from processed animal manure
Ehlert, P.A.I. ; Schoumans, O.F. - \ 2015
Wageningen : Alterra, Wageningen-UR (Alterra report 2668) - 29
animal manures - manure treatment - byproducts - fertilizers - nitrates - recovery - dierlijke meststoffen - mestverwerking - bijproducten - kunstmeststoffen - nitraten - terugwinning
Technieken om dierlijke mest en andere biomassa stromen te verwerken om de waardevolle componenten te benutten krijgen steeds meer de aandacht nu makkelijk winbare ertsen en energiebronnen van fossiele herkomst gelimiteerd raken en er meer en meer aandacht gegeven wordt aan terugdringen van uitstoot van CO2 van fossiele bronnen. Producten van dierlijke mest ressorteren onder diverse stelsels van regels van de Europese Unie. Deze stelsels zijn complex en bevorderen daardoor niet altijd een hergebruik. Dit rapport beschrijft kort welke technologieën er zijn om dierlijke mest te verwerken en welke producten daaruit resulteren. Vervolgens worden Europese wettelijke bepalingen beschreven die op deze producten van toepassing zijn. Deze bepalingen vragen aanpassing aan de nieuwe technologieën voor verwerking van dierlijke mest. Het rapport geeft daarvoor aanbevelingen.
Bio-induced solid selenium for recovery from water
Hageman, S.P.W. - \ 2015
Wageningen University. Promotor(en): Cees Buisman, co-promotor(en): Renata van der Weijden; Fons Stams. - Wageningen : Wageningen University - ISBN 9789462575103 - 156
selenium - waste water - waste water treatment - recovery - toxicity - bioreactors - afvalwater - afvalwaterbehandeling - terugwinning - toxiciteit - bioreactoren

Selenium in the form of selenate or selenite in wastewater needs to be removed due to its potential toxicity in the environment. Also, selenium is a valuable element that is used in several industries and current selenium resources are likely to be exhausted in less than 50 years. Waste streams containing selenium can therefore be used as a source of selenium. This requires conversion of the selenium in wastewater into a form that can be recovered. Biologically induced selenate reduction to recoverable selenium has the advantage that it uses the selective reduction capacities of biomass and a renewable electron donor.

To improve the recoverability of selenium the conversion of selenate to selenite was seen as an interesting opportunity. Selenite is more reactive than selenate and can be removed in a second step. As described in Chapter 2, it proved possible to convert selenate to mainly selenite at a low electron donor concentration.

Another method which is reviewed in this thesis is direct biological reduction of selenate to elemental selenium. After reduction the solids can be removed by a liquid solid separation process. Previously amorphous selenium particles were produced, which hampered recovery. In this research it is demonstrated that at a higher temperature, around 40 - 50°C, and at a higher pH, around pH 8 - 9, a more hexagonal selenium structure can be produced (Chapter 3). Crystalline acicular selenium particles of different sizes were thus obtained. This implies that selenium particles formation can be controlled and that selenium particles can grow. Large selenium particles make the separation process economic.

To grow larger selenium particles, a long-term experiment was performed at 50°C (Chapter 4). The reduction rate was poor, but selenium acicular particles were produced. These particles were also detected as clusters. These clusters open up new recovery opportunities. With Eerbeek sludge the optimal conditions for selenate conversion are around pH=7 and 30°C. To enlarge the selenium particles it is strongly recommended to use a different sludge since the optimal conditions with Eerbeek sludge do not match the conditions needed for acicular particle formation.

When selenate is converted to selenite, the selenite can be precipitated by sulphide to form selenium sulphide. Emmtec sludge was used to reduce the sulphur compounds to sulphide, leaving selenium as the sole remaining element. This process was performed at T=30°C and a pH between 6 and 7. The selenium thus recovered had a crystalline hexagonal structure (revealed by x-ray diffraction) and the particles were as large as 125µm3.

Future research on the two routes that are explored in this thesis can give insights into selenium reduction mechanisms and the formation of large selenium particles. The recoverability of biological selenium particles has also been improved (as discussed in this thesis). In conclusion, this thesis has resulted in a new, bio-selective, renewable selenium recovery method via selenium sulphide.

Mest vol verwaarden? Wat kan raffinage betekenen?
Starmans, D.A.J. ; Buisonjé, F.E. de; Dijk, W. van; Haan, J.J. de; Timmerman, M. ; Visser, C.L.M. de - \ 2015
Lelystad : WUR/ACRRES (Rappot / PPO-AGV 658) - 41
mestverwerking - samenstelling - bioraffinage - economische haalbaarheid - haalbaarheidsstudies - terugwinning - materialen uit biologische grondstoffen - manure treatment - composition - biorefinery - economic viability - feasibility studies - recovery - biobased materials
Het doel van deze studie was te inventariseren welke waardevolle stoffen uit mest gewonnen kunnen worden en wat de potentie is in technologie en markt om deze te verwaarden. De inhoud van mest kan onderverdeeld worden in de volgende hoofdcategorieën: organische stof, mineralen, zware metalen, aminozuren, vluchtige vetzuren, antibiotica, hormonen. Via literatuuronderzoek is de samenstelling van elke categorie uiteen gesplitst in de verschillende stoffen met daarbij het gemiddelde gehalte van de betreffende stof in mest. Voor elke stof is de range in marktprijs nagegaan en aan de hand van het gehalte en marktprijs is de intrinsieke waarde van elke stof in de mest bepaald. Per hoofdcategorie van stoffen valt aan de hand van de waarde van de componenten te voorspellen of het mogelijk is om een sluitende business case te maken.
Evaluating Aquatic invertebrate vulnerability to insecticides based on intrinsic sensitivuty, biological traits, and toxic mode of action
Rico, A. ; Brink, P.J. van den - \ 2015
Environmental Toxicology and Chemistry 34 (2015)8. - ISSN 0730-7268 - p. 1907 - 1917.
ecological risk-assessment - fresh-water arthropods - species sensitivity - community structure - lambda-cyhalothrin - short-term - responses - microcosms - recovery - stream
In the present study, the authors evaluated the vulnerability of aquatic invertebrates to insecticides based on their intrinsic sensitivity and their population-level recovery potential. The relative sensitivity of invertebrates to 5 different classes of insecticides was calculated at the genus, family, and order levels using the acute toxicity data available in the US Environmental Protection Agency ECOTOX database. Biological trait information was linked to the calculated relative sensitivity to evaluate correlations between traits and sensitivity and to calculate a vulnerability index, which combines intrinsic sensitivity and traits describing the recovery potential of populations partially exposed to insecticides (e.g., voltinism, flying strength, occurrence in drift). The analysis shows that the relative sensitivity of arthropods depends on the insecticide mode of action. Traits such as degree of sclerotization, size, and respiration type showed good correlation to sensitivity and can be used to make predictions for invertebrate taxa without a priori sensitivity knowledge. The vulnerability analysis revealed that some of the Ephemeroptera, Plecoptera, and Trichoptera taxa were vulnerable to all insecticide classes and indicated that particular gastropod and bivalve species were potentially vulnerable. Microcrustaceans (e.g., daphnids, copepods) showed low potential vulnerability, particularly in lentic ecosystems. The methods described in the present study can be used for the selection of focal species to be included as part of ecological scenarios and higher tier risk assessments.
Impulsive sounds change European seabass swimming patterns: influence of pulse repetition interval
Neo, Y.Y. ; Ufkes, E. ; Kastelein, R.A. ; Winter, H.V. ; Cate, C. ten; Slabbekoorn, H. - \ 2015
Marine Pollution Bulletin 97 (2015)1-2. - ISSN 0025-326X - p. 111 - 117.
startle-response - trawling vessel - fish - habituation - behavior - noise - variability - avoidance - zebrafish - recovery
Seismic shootings and offshore pile-driving are regularly performed, emitting significant amounts of noise that may negatively affect fish behaviour. The pulse repetition interval (PRI) of these impulsive sounds may vary considerably and influence the behavioural impact and recovery. Here, we tested the effect of four PRIs (0.5–4.0 s) on European seabass swimming patterns in an outdoor basin. At the onset of the sound exposures, the fish swam faster and dived deeper in tighter shoals. PRI affected the immediate and delayed behavioural changes but not the recovery time. Our study highlights that (1) the behavioural changes of captive European seabass were consistent with previous indoor and outdoor studies; (2) PRI could influence behavioural impact differentially, which may have management implications; (3) some acoustic metrics, e.g. SELcum, may have limited predictive power to assess the strength of behavioural impacts of noise. Noise impact assessments need to consider the contribution of sound temporal structure.
Ion adsorption-induced wetting transition in oil-water-mineral systems
Mugele, F. ; Bera, B. ; Cavalli, A. ; Siretanu, I. ; Maestro, A. ; Duits, M. ; Cohen Stuart, M.A. ; Ende, D. van den - \ 2015
Scientific Reports 5 (2015). - ISSN 2045-2322 - 8 p.
hydration forces - surfaces - recovery - wettability - interfaces - membranes - charge - layer
The relative wettability of oil and water on solid surfaces is generally governed by a complex competition of molecular interaction forces acting in such three-phase systems. Herein, we experimentally demonstrate how the adsorption of in nature abundant divalent Ca2+ cations to solid-liquid interfaces induces a macroscopic wetting transition from finite contact angles (˜10°) with to near-zero contact angles without divalent cations. We developed a quantitative model based on DLVO theory to demonstrate that this transition, which is observed on model clay surfaces, mica, but not on silica surfaces nor for monovalent K+ and Na+ cations is driven by charge reversal of the solid-liquid interface. Small amounts of a polar hydrocarbon, stearic acid, added to the ambient decane synergistically enhance the effect and lead to water contact angles up to 70° in the presence of Ca2+. Our results imply that it is the removal of divalent cations that makes reservoir rocks more hydrophilic, suggesting a generalizable strategy to control wettability and an explanation for the success of so-called low salinity water flooding, a recent enhanced oil recovery technology.
A process synthesis approach for isolation of isoflavones from okara
Jankowiak, L. ; Mendez Sevillano, D. ; Boom, R.M. ; Ottens, M. ; Zondervan, E. ; Goot, A.J. van der - \ 2015
Industrial & Engineering Chemistry Research 54 (2015)2. - ISSN 0888-5885 - p. 691 - 699.
driven process synthesis - antioxidant activity - food - adsorption - extraction - separation - products - recovery - integration - components
Owing to the complexity of food matrices, process synthesis methodologies have not been as widely applied in the food industry as in the chemical industry. Here, we describe the application of a process synthesis methodology to design a system to separate valuable components from a byproduct of the soymilk production. The method yielded a number of potential processing pathways and relevant mechanistic questions, which required experimental input. The combination of considering the overall system on the level of general transformations, heuristics, and additional insights through experiments resulted in a simplified conceptual process design for the separation of isoflavones from okara with a globally more sustainable choice. The holistic approach within process design as an implication of the methodology is discussed.
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