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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Toeleveranciers staan in de rij voor goedkeuring installaties : mobiele zuiveringsoplossingen zijn in de maak
Ruijven, Jim van - \ 2017
greenhouse horticulture - water treatment - pesticides - clarifiers - purification plants
AQUAFARM van zuiveren naar oogsten
Verdonschot, P.F.M. - \ 2017
Aquafarm NL
afvalwater - waterzuivering - industriële grondstoffen - biobased economy - afvalwaterbehandeling - aquacultuur - biomassa productie - waste water - water treatment - feedstocks - waste water treatment - aquaculture - biomass production
Aquafarm ziet afvalwater als basis voor het produceren van hoogwaardige bouwstoffen, waarmee tegelijkertijd het water gezuiverd wordt.
Mobiele waterzuivering glastuinbouw
Ruijven, Jim van; Os, Erik van; Vermeulen, Peter - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1424) - 54 p.
kassen - glastuinbouw - afvalwaterbehandeling - afvalwater - waterverontreiniging - afvoer - zuiveren - waterzuivering - oppervlaktewater - oppervlaktewaterkwaliteit - gewasbescherming - pesticiden - substraten - cultuur zonder grond - mobiele uitrusting - greenhouses - greenhouse horticulture - waste water treatment - waste water - water pollution - discharge - purification - water treatment - surface water - surface water quality - plant protection - pesticides - substrates - soilless culture - mobile equipment
Application of a mobile unit for discharge water purification is one of four options to apply to the purification obligation per 1-1-2018. Depending on the amount of discharge, future water strategy and investment options, mobile purification can be an interesting option. The amount of discharge water varies with crop, irrigation strategy and quality of the irrigation water and is between 122 and 3.340 m3/ha/year for surveyed companies. About 65% of greenhouse companies discharges
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.

Groen proceswater: zuivering brouwerijprocesafvalwater met microalgen
Dijk, W. van; Weide, R.Y. van der; Kroon, A. - \ 2016
Lelystad : ACRRES - Wageningen UR (PPO 721) - 42 p.
brouwerij-industrie - brouwerijafvalwater - afvalwater - afvalwaterbehandeling - waterzuivering - algen - biomassa - biomassa productie - afvoerwater - flotatie - algenteelt - brewing industry - brewery effluent - waste water - waste water treatment - water treatment - algae - biomass - biomass production - effluents - flotation - algae culture
In 2012 is het project Groen Proceswater gestart. Hierin worden de mogelijkheden van zuivering van brouwerijprocesafvalwater met behulp van microalgen onderzocht. Dit is gedaan in een samenwerkingsverband van Heineken Nederland BV, Algae Food & Fuel en WUR-ACRRES. De resultaten behaald in 2012 en 2013 zijn beschreven in afzonderlijke rapporten. In dit rapport zijn de resultaten van 2014 en 2015 beschreven. In 2014 is onderzocht of een voorbehandeling van het proceswater via cavitatie-flotatie het zuiveringsresultaat kan verbeteren en in 2015 of de energie-input van de LEDbelichting kan worden verminderd door te flashen (afwisselende licht-donker periodes op microseconde tijdschaal). Verder is in 2015 en 2016 via een literatuurstudie gekeken naar de verwaarding van de geproduceerde algenbiomassa en zijn de conclusies van het gehele project samengevat.
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.
Anaerobic treatment of municipal wastewater in a UASB-Digester system : temperature effect on system performance, hydrolysis and methanogenesis
Zhang, Lei - \ 2016
University. Promotor(en): Grietje Zeeman; Huub Rijnaarts, co-promotor(en): Tim Hendrickx. - Wageningen : Wageningen University - ISBN 9789462579798 - 165
municipal wastewater - anaerobic digesters - hydrolysis - temperature - water treatment sludge - sludges - water treatment - sewage sludge - sewage - stedelijk afvalwater - anaërobe verteerders - hydrolyse - temperatuur - waterzuiveringsslib - slib - waterzuivering - rioolslib - rioolwater

A novel treatment chain for low strength domestic sewage includes low temperature anaerobic treatment as the main process. It can improve the energy efficiency of sewage treatment compared with conventional aerobic sewage treatment. A combination of an Upflow Anaerobic Sludge Blanket reactor and a sludge digester, a UASB-digester system, was proven to be one of the successful anaerobic systems to challenge temperatures as low as 10°C and organic matter concentrations in the range of 382 and 1054 mg chemical oxygen demand (COD)/l. The UASB is operated at low sewage temperature (10°C) and high loading rate. The produced non-stabilised sludge in the UASB is recirculated over the mesophilic digester (35°C) to convert organic solids to methane gas and produce anaerobic biomass fed back into the UASB reactor, where it converts dissolved COD at the low temperature of the waste water.

The effect of sludge recirculation rate and sludge transfer point on the performance of a UASB-digester treating domestic sewage at 15 ˚C was studied in this research. The results show increased total COD removal efficiency when increasing the sludge recirculation rate from 1% to 2.6% of the influent flow rate. Methane gas production increases with the sludge recirculation rate, in the range of 1 to 12.5% of the influent flow rate. A higher sludge transfer point results in an increased suspended COD removal efficiency and a higher VSS concentration of the UASB sludge bed.

Co-digestion was applied for improving soluble COD removal efficiency of a UASB-digester system, operated at low temperatures and treating domestic sewage with a high dissolved/suspended COD ratio. Glucose was chosen as a model co-substrate and added to the sludge digester to produce additional methanogenic biomass, which was continuously recycled to inoculate the UASB reactor. Methane production in the UASB reactor almost doubles and soluble COD removal efficiency equals the biodegradability of the influent dissolved COD, due to a twofold increase in methanogenic capacity, when applying co-digestion 16% of influent organic loading rate. Therefore, co-digestion is a suitable approach to support a UASB-digester for treatment of low temperature domestic sewage.

A pilot scale UASB-digester (130 + 50 L) was studied to treat domestic wastewater at temperatures of 10-20°C at an HRT of 6 h in the UASB reactor and 15 h in the digester. The results show a stable COD removal efficiency of 60 ± 4.6% during the operation at 12.5 to 20°C. COD removal efficiency decreases to 51.5 ± 5.5% at 10°C. The decreased COD removal efficiency is attributed to an increased influent COD load, leading to insufficient methanogenic capacity of the UASB reactor at such low temperature. Suspended COD removal efficiency was 76.0 ± 9.1% at 10-20°C. The effluent COD concentration is 90 ± 23 mg/L at temperatures between 12.5 and 20°C, while soluble COD removal efficiency fluctuates due to variation in the influent COD concentration. 80% of the influent biodegradable COD is recovered as methane gas (including dissolved methane).

Low temperature (10-25°C) hydrolysis after applying a short pre-hydrolysis at 35°C was studied compared with those without the pre-hydrolysis. Batch experiments were executed using cellulose and tributyrin as model substrates for carbohydrates and lipids. Low temperature anaerobic hydrolysis rate constants increase by a factor 1.5 - 10 after applying a short anaerobic pre-hydrolysis at 35°C. The hydrolytic activity of the supernatant collected from the digestate after batch digestion of cellulose and tributyrin at 35°C was higher than that of the supernatants collected from the low temperature (≤ 25°C) digestates. The observed hydrolysis in the UASB of a UASB-digester system, treating domestic sewage at low temperatures (10-20°C) is in line with the elevated hydrolytic activity of mesophilic supernatant.

Effects of temperature and temperature shocks on specific methanogenic activity (SMA), and acetate affinity of the digester sludge were studied. Digester sludge from a UASB (12.5°C)-digester (35°C) system, was fed with acetate at constant temperatures of 10-35°C and at varying temperatures from 35°C to 25, to 15 to 10°C. The results show no lag phase in methane production rate when applying temperature shocks of 35°C to 25, 15, and 10°C. The temperature dependency of the SMA of the digester sludge after the temperature shocks was similar to the one at constant temperatures. Acetate affinity of the digester sludge was high at the applied temperatures (10-35°C). Latter is consistent with the finding of no VFA in the effluent of the UASB-digester, treating low strength, and low temperature (12.5°C) domestic wastewater.

The UASB-digester system to treat low strength, low temperature domestic sewage was provided with a proof-of-principle, and its essential underlying anaerobic processes were sufficiently elucidated to make the technology ready for further scaling up and demonstration in practice.

Slimmer omgaan met poep
Zeeman, Grietje - \ 2016
new sanitation - water treatment - waste water - urine - recovery - anaerobic treatment - separation
Betaalbaarheid zuivering lozingswater glastuinbouw : addendum bij LEI-rapport 2015-001 naar aanleiding van aangescherpte zuiveringseisen
Buurma, J.S. ; Meer, R.W. van der; Os, E.A. van; Ruijven, J.P.M. van; Veen, H.B. van der - \ 2016
Wageningen : LEI Wageningen UR (LEI nota 2016-026) - 19 p.
glastuinbouw - waterzuivering - investering - hergebruik van water - teeltsystemen - kostenanalyse - agrarische bedrijfsvoering - nederland - greenhouse horticulture - water treatment - investment - water reuse - cropping systems - cost analysis - farm management - netherlands
Op verzoek van LTO Glaskracht Nederland hebben LEI Wageningen UR en Wageningen UR Glastuinbouw de benodigde extra investeringen voor de zuivering van afvalwater in de glastuinbouw en de betaalbaarheid van die investeringen verder onderzocht. Dit verzoek kwam voort uit onderhandelingen met het ministerie van I&M over het tempo van de invoering van zuiveringseisen. In eerder onderzoek, gepubliceerd in LEI-rapport 2015-001, werd uitgegaan van 80% zuivering in 2016. In de lopende onderhandelingen wordt aangestuurd op 95% zuivering in 2018. Hierbij is discussie over de vraag of dit gemiddeld 95% over het mandje van stoffen in standaardwater moet zijn, of dat het 95% per stof moet zijn. Bij toepassing van zuivering met H2O2+UV vergt de eis van 95% zuivering een grotere zuiveringscapaciteit en grotere investeringen. In dit addendum wordt aangegeven hoe verhoging van de zuiveringseisen doorwerkt in verhoging van de benodigde zuiveringscapaciteit en de bijbehorende investeringsbedragen. Tegelijkertijd wordt aangegeven hoe de extra investeringen doorwerken in het beslag op bedrijfssaldo, inkomen uit bedrijf en vrije investeringsruimte.
'Standaard Water’ voor toetsing zuiveringstechnologie voor de glastuinbouw
Ruijven, Jim van; Blok, C. ; Beerling, E.A.M. ; Os, E.A. van - \ 2016
Wageningen UR - 3 p.
waterzuivering - pesticiden - glastuinbouw - waterverontreiniging - waterkwaliteit - water treatment - pesticides - greenhouse horticulture - water pollution - water quality
Het is noodzakelijk zuiveringstechnieken op een objectieve manier te toetsen op effectiviteit in de verwijdering van gewasbeschermingsmiddelen uit glastuinbouw lozingswater met water dat representatief is voor de glastuinbouw. Hiervoor is het in dit document beschreven ‘Standaard Water’ ontwikkeld. Dit water wordt gebruikt om op een gestandaardiseerde en reproduceerbare manier technologieën te beoordelen en heeft daarom een vastgestelde samenstelling. Het water dient als standaard voor lozingswater uit zowel substraat- als grondgebonden teelten en bevat nutriënten en sporenelementen, organische en minerale vervuiling en gewasbeschermingsmiddelen.
Klinkende munt slaan uit natuur vergt gerichte aanpak
Heide, C.M. van der; Borgstein, M.H. ; Hendriks, C.M.A. - \ 2016
Tijdschrift Milieu : Vereniging van milieuprofessionals 22 (2016)3. - p. 18 - 19.
natuurbeheer - ecosysteemdiensten - natuurgebieden - financieren - biomassa productie - recreatie - waterzuivering - noordwest-overijssel - nature management - ecosystem services - natural areas - financing - biomass production - recreation - water treatment
Met hun natuurterreinen hebben natuurorganisaties potentieel een groot kapitaal in eigendom. Via talloze ecosysteemdiensten kan de samenleving immers de vruchten van al dit natuurlijk kapitaal plukken, denk aan waterzuivering, koolstofopslag, beleving en biomassa. Ondanks hun waardevolle karakter zijn de meeste van die baten gratis, zonder dat daar inkomsten tegenover staan. Onderzoek in de Weerribben-Wieden maakt duidelijk dat een gerichte aanpak nodig is om klinkende munt te slaan uit natuurgebieden.
Overleving van pathogenen bij mestverwerking
Hoeksma, P. ; Rutjes, S. ; Aarnink, A.J.A. ; Blaak, H. ; Buisonjé, F.E. de - \ 2016
H2O online (2016)3 maart. - 9 p.
mestverwerking - pathogenen - omgekeerde osmose - mineralen - lozing - riolering - oppervlaktewater - waterzuivering - manure treatment - pathogens - reverse osmosis - minerals - disposal - sewerage - surface water - water treatment
In de producten van verschillende mestverwerkingsprocessen zijn de concentraties gemeten van een aantal pathogenen. De resultaten laten zien dat mechanische scheiding vrijwel geen effect heeft op het aantal pathogenen. Vergisting heeft weinig effect op virussen en grampositieve bacteriën, maar reduceert wel het aantal gramnegatieve bacteriën. Grampositieve bacteriën kunnen ook hittebehandeling tot 70°C overleven. Omgekeerde osmose, een membraantechniek die in een aantal mestverwerkingsinstallaties wordt toegepast, resulteert in een mineralenconcentraat dat als meststof wordt gebruikt en een effluent dat op het riool of oppervlaktewater wordt geloosd. Effluent na omgekeerde osmose is microbiologisch schoon, mits de integriteit van het RO-proces goed wordt bewaakt.
Eigen installatie, collectieve oplossingen of een mobiel systeem : naderende zuiveringsplicht dwingt telers tot keuzes
Beerling, Ellen - \ 2016
horticulture - greenhouse horticulture - water management - water treatment - agricultural research - standards - agricultural policy - residues - purification plants - cooperation - emission reduction

Vanaf 1 januari 2018 moeten glastuinbouwbedrijven zuiveringstechnieken toepassen die restwater voor 95% kunnen zuiveren van gewasbeschermingsmiddelen. Telers hebben daarbij de mogelijkheid om een eigen installatie, een collectieve oplossingen of een mobiel systeem toe te passen dat het restwater op afroep komt zuiveren. Ellen Beerling en Daan van Empel belichten de staat van onderzoek en beleid.

Met goedgekeurde installatie kan teler voldoen aan wet op lozingen : markt voor zuiveringstechnieken is in beweging
Ruijven, Jim van - \ 2016
horticulture - greenhouse horticulture - water management - water treatment - measurement - purification plants - testing - drainage water - legislation - netherlands - agricultural research

Vanaf 1 januari 2018 moet elk glastuinbouwbedrijf een apparaat gebruiken dat 95% van de gewasbeschermingsmiddelen uit het lozingswater zuivert. Hoe gaat de overheid dat controleren? Dat gebeurt via de leverancier van de installatie. Als die aantoont dat zijn techniek dat voor elkaar krijgt, komt deze op een positieve lijst. Maakt de ondernemer op de juiste manier gebruik van zo’n goedgekeurde installatie, dan voldoet hij aan de wet.

Complementary surface charge for enhanced capacitive deionization
Gao, X. ; Porada, S. ; Omosebi, A. ; Liu, K.L. ; Biesheuvel, P.M. ; Landon, J. - \ 2016
Water Research 92 (2016). - ISSN 0043-1354 - p. 275 - 282.
Amphoteric Donnan model - Capacitive deionization - Enhanced salt removal - Extended working voltage window - electrodes - carbon - desalination - water treatment - ionization - elektrodes - koolstof - ontzilting - waterzuivering - ionisatie

Commercially available activated carbon cloth electrodes are treated using nitric acid and ethylenediamine solutions, resulting in chemical surface charge enhanced carbon electrodes for capacitive deionization (CDI) applications. Surface charge enhanced electrodes are then configured in a CDI cell to examine their salt removal at a fixed charging voltage and both reduced and opposite polarity discharge voltages, and subsequently compared to the salt removal of untreated electrodes. Substantially improved salt removal due to chemical surface charge and the use of a discharge voltage of opposite sign to the charging voltage is clearly demonstrated in these CDI cycling tests, an observation which for the first time validates both enhanced CDI and extended-voltage CDI effects predicted by the Donnan model [Biesheuvel et al., Colloids Interf. Sci. Comm., 10.1016/j.colcom.2015.12.001 (2016)]. Our experimental and theoretical results demonstrate that the use of carbon electrodes with optimized chemical surface charge can extend the CDI working voltage window through discharge voltages of opposite sign to the charging voltage, which can significantly enhance the salt adsorption capacity of CDI electrodes. Thus, in addition to carbon pore size distribution, chemical surface charge in carbon micropores is considered foundational for salt removal in CDI cells.

Geo-engineering experiments in two urban ponds to control eutrophication
Waaijen, G. ; Oosterhout, J.F.X. ; Douglas, G.C. ; Lurling, M.F.L.L.W. - \ 2016
Water Research 97 (2016). - ISSN 0043-1354 - p. 69 - 82.
lakes - restoration management - ecological restoration - eutrophication - field experimentation - dredging - bentonite - water quality - phytoplankton - water treatment - meren - herstelbeheer - ecologisch herstel - eutrofiëring - experimenteel veldonderzoek - baggeren - bentoniet - waterkwaliteit - fytoplankton - waterzuivering
Many urban ponds experience detrimental algal blooms as the result of eutrophication. During a two year field experiment, the efficacy of five in situ treatments to mitigate eutrophication effects in urban ponds was studied. The treatments targeted the sediment phosphorus release and were intended to switch the ponds from a turbid phytoplankton-dominated state to a clear-water state with a low phytoplankton biomass. Two eutrophic urban ponds were each divided into six compartments (300–400 m2; 210–700 m3). In each pond the following treatments were tested: dredging in combination with biomanipulation (involving fish biomass control and the introduction of macrophytes) with and without the addition of the flocculant polyaluminiumchloride, interception and reduction of sediment phosphorus release with lanthanum-modified bentonite (Phoslock®) in combination with biomanipulation with and without polyaluminiumchloride; biomanipulation alone; and a control. Trial results support the hypothesis that the combination of biomanipulation and measures targeting the sediment phosphorus release can be effective in reducing the phytoplankton biomass and establishing and maintaining a clear-water state, provided the external phosphorus loading is limited. During the experimental period dredging combined with biomanipulation showed mean chlorophyll-a concentrations of 5.3 and 6.2 μg L−1, compared to 268.9 and 52.4 μg L−1 in the control compartments. Lanthanum-modified bentonite can be an effective alternative to dredging and in combination with biomanipulation it showed mean chlorophyll-a concentrations of 5.9 and 7.6 μg L−1. Biomanipulation alone did not establish a clear-water state or only during a limited period. As the two experimental sites differed in their reaction to the treatments, it is important to choose the most promising treatment depending on site specific characteristics. In recovering the water quality status of urban ponds, continuing attention is required to the concurrent reduction of external phosphorus loading and to maintaining an appropriate fish community.
Resistance identification and rational process design in Capacitive Deionization
Dykstra, Jouke ; Zhao, R. ; Biesheuvel, P.M. ; Wal, A. van der - \ 2016
Water Research 88 (2016). - ISSN 0043-1354 - p. 358 - 370.
ionentransport - weerstand - waterzuivering - ontzilting - elektrodes - ionenuitwisseling - specifieke ionenelektrodes - ion transport - resistance - water treatment - desalination - electrodes - ion exchange - specific ion electrodes
Capacitive Deionization (CDI) is an electrochemical method for water desalination employing porous carbon electrodes. To enhance the performance of CDI, identification of electronic and ionic resistances in the CDI cell is important. In this work, we outline a method to identify these resistances. We illustrate our method by calculating the resistances in a CDI cell with membranes (MCDI) and by using this knowledge to improve the cell design. To identify the resistances, we derive a full-scale MCDI model. This model is validated against experimental data and used to calculate the ionic resistances across the MCDI cell. We present a novel way to measure the electronic resistances in a CDI cell, as well as the spacer channel thickness and porosity after assembly of the MCDI cell. We identify that for inflow salt concentrations of 20 mM the resistance is mainly located in the spacer channel and the external electrical circuit, not in the electrodes. Based on these findings, we show that the carbon electrode thickness can be increased without significantly increasing the energy consumption per mol salt removed, which has the advantage that the desalination time can be lengthened significantly.
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.

Slimme oplossing voor te weinig, te veel en te vuil water
Kwakernaak, C. ; Jansen, P.C. ; Kempen, M. ; Smolders, F. ; Rheenen, H. van - \ 2015
Water Matters : Kenniskatern voor Waterprofessionals - Dutch edition (2015)Oktober. - p. 30 - 33.
waterbeheer - waterkwaliteit - drinkwater - watervoorziening - klimaatverandering - watertekort - waterverzadiging - wateropslag - afvoer - hergebruik van water - biomassa productie - waterzuivering - water management - water quality - drinking water - water supply - climatic change - water deficit - waterlogging - water storage - discharge - water reuse - biomass production - water treatment
Water Matters is het kenniskatern van H2O. Het verschijnt twee keer per jaar, als bijlage bij Vakblad H2O. De uitgave van Water Matters (een initiatief van Koninklijk Nederlands Waternetwerk) wordt mogelijk gemaakt door: Alterra Wageningen UR, ARCADIS, KWR Watercycle Research Institute, Royal HaskoningDHV en de Stichting Toegepast Onderzoek Waterbeheer (STOWA).
Bioremediation of chlorinated ethenes in aquifer thermal energy storage
Ni, Z. - \ 2015
University. Promotor(en): Huub Rijnaarts, co-promotor(en): Tim Grotenhuis; P.F.M. van Gaans. - Wageningen : Wageningen University - ISBN 9789462575752 - 216
watervoerende lagen - thermische energie - verzwakking - grondwater - waterzuivering - duurzame energie - biogeochemie - aquifers - thermal energy - attenuation - groundwater - water treatment - sustainable energy - biogeochemistry

Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology

The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquifer thermal energy storage (ATES) appears attractive because such integration provides a promising solution for redevelopment of urban areas in terms of improving the local environmental quality as well as achieving sustainable energy supply. It will reduce the current negative interference between groundwater contaminants and ATES systems that arises from the rapid increase of ATES system numbers and generally long duration of contaminated groundwater treatments. However, currently the implementation of the combined system is at an initial stage, and still requires comprehensive study before advancing to mature application. Studies should specifically focus on understanding of the basic biogeochemical processes in aquifer systems under conditions of ATES and enhanced bioremediation and their mutual impacts when combined in ATES-ENA. To this end, the research as reported in this thesis employed laboratory experiments and modeling approaches focused on finding the essential process factors involved in the combined system, revealing possible drawbacks, and providing a better understanding to design alternative options on better operation of the combined system.

Chapter 2 assessed the limiting factor for reductive dechlorination of PCE in an Fe(III) reducing aquifer, being the typical type of subsurface in the Netherlands. A step-wise batch study was performed which consisted of redox conditioning by lactate and ascorbic acid, followed by reductive dechlorination in different scenarios. For the sediment material sampled from the Fe(III) reducing aquifer, conditioning of the redox potential could stimulate PCE dechlorination. It was concluded that 75 µmol electron equivalents per gram dry mass of aquifer material was the threshold to obtain a redox potential of -450 mV, which is theoretically suitable for PCE reductive dechlorination. However, dechlorinating bacteria required for fully reductive dechlorination are generally lacking in Fe(III) reducing aquifers. Without bioaugmentation of dechlorinating bacteria, PCE could only be reduced to TCE or cis-DCE. The step-wise approach and findings obtained from different scenarios tested in this study are relevant for improving the cost-effectiveness of the design and operation of in situ bioremediation. The redox potential of an aquifer can be used as a general indicator to evaluate the potential for CVOCs reductive dechlorination. For achieving specific goals of in situ bioremediation projects at different CVOCs contaminated sites with various environmental conditions, the balance between cost, benefit, and potential risks (e.g. bio‑chemical well clogging due to bacteria growth and precipitation of metal-oxides) should be estimated before the design and operation of the ATES-ENA systems. This chapter provides insights into the essential factors that determine the feasibility of ATES-ENA.

In Chapter 3, the two most important impacts of ATES on enhanced bioremediation of CVOCs were investigated using batch experiments. Besides, another type of underground thermal energy storage system, the borehole thermal energy storage (BTES) was also studied as a comparison to ATES. Here cis-DCE was targeted as it is commonly found to accumulate in the subsurface due to incomplete dechlorination. Compared to a natural situation (NS) with sufficient electron donor and bioaugmentation at a constant temperature of 10 ˚C, we assessed the effect of ATES by exchanging liquid between bottles kept at 25 and 5 ˚C, and the effect of BTES by alternating temperature between 25 and 5 ˚C periodically. Under ATES warm condition, cis-DCE was dechlorinated to ethene and at an increasing rate with each liquid exchange, despite no biodegradation being observed under ATES cold condition. The overall removal rate under alternating ATES conditions reached 1.83 μmol cis‑DCE/day, which was over 1.5 and 13 times faster than those in BTES and NS conditions. Most probably growth of biomass occurred under ATES warm condition, leading to an autocatalytic increase in conversion rates due to higher biomass concentration. Comparison between batches with or without Dehalococcoides inoculum revealed that their initial presence is a determining factor for the dechlorination process. Temperature then became the dominant factor when Dehalococcoides concentration was sufficient. The results also indicated that Dehalococcoides was preferentially attached to the soil matrix. This chapter highlights the importance of the dynamic temperature regimes in ATES on the bioremediation of CVOCs and recommends to implement biostimulation actions in the ATES warm well.

Further impacts of ATES related to change in redox condition on bioremediation of CVOCs, with focus on microbial responses of Dehalococcoides, were explored in Chapter 4. In this chapter, we adopted a recirculating column experiment with a flow rate of 10 mL/min (representing the flow velocity at a distance of 1.3 m from the center of a typical ATES well) to simulate the ATES system. To mimic potential periodic redox fluctuations that accompany ATES, serial additions of lactate and nitrate were performed. Firstly, also at the relatively high liquid velocity (compared to normal bioremediation conditions) complete reductive dechlorination from cis-DCE to ethene was achieved in the column system. However, dechlorination was immediately terminated by subsequent nitrate addition due to direct interruption of Dehalococcoides retention to the soil matrix. In our column system, which was much more homogeneous than subsurface in reality, repeated interruption of dechlorination via Dehalococcoides was extremely severe. Such repeated interruption by nitrate dosing eventually led to less easily reversible while requiring more efforts for recovering dechlorination. In addition, the hypothesis of the immobility of Dehalococcoides was further confirmed by the microbial analysis of microorganism in the liquid phase where only less than 0.1% of the Dehalococcoides inoculum could be found back. Although some field studies demonstrated easier regeneration of Dehalococcoides in the subsurface after suffering oxidant, results from this chapter emphasized the sensitive resilience of Dehalococcoides which needs careful consideration in biostimulated ATES condition, and a functional combined system requires dedicated ATES operation and monitoring on the aquifer geochemical conditions.

The major concern on possible negative impact of enhanced bioremediation on ATES is biological clogging attributed to biomass growth. As chemical clogging due to Fe(III) precipitates is a common problem in the functioning of ATES, the clogging issues (both biological and chemical) should be addressed before practical application. The potential clogging issues in the combined system were then researched in Chapter 5 using the same recirculating column system as in the previous chapter. For this purpose, two flow rates, 10 and 50 mL/min, were implemented. In the two columns, enhanced biological activity and chemically promoted Fe-oxide precipitation were studied by addition of lactate and nitrate respectively. Pressure drop (∆P) between the influent and effluent of the columns was monitored to indicate clogging of the system. The results showed no increase in ∆P during the period of enhanced biological activity, with large amount of lactate and active inoculum being added, even when the concentration of total bacteria in the liquid phase increased by four orders of magnitude. Nitrate addition, however, caused significant increase of ∆P. Remarkably, in the column with higher flow rate (50 mL/min), an unforeseen blow-up occurred at the end of experiment, as the buildup of pressure in the system was higher than the strength of the glass column. However, in the column with flow rate of 10 mL/min, high pressure buildup caused by nitrate addition could be alleviated by lactate addition. Such finding indicates that the risk of biological clogging related to biostimulation is relatively small, because by maintaining a low redox condition biostimulation itself may counter chemical clogging in ATES. Nevertheless, acknowledging that a column system cannot fully mimic real ATES conditions, additional tests are necessary to further investigate the clogging issues in the combined system.

In Chapter 6, we performed a simulation of ATES-ENA with a reactive transport model, using ATES as the engineering tool for lactate injection in a hypothetical TCE contaminated aquifer which is assumed to be homogeneous. Many relevant processes in the combined system were simulated, such as TCE, cis-DCE and VC dechlorination, sulphate and Fe(III) reduction, organic acid fermentation and oxidation and growth of different biomass. In total 15 scenarios are considered in the model, including variations in lactate dosage (three concentration levels: 3.8, 1.9 and 0.38 mmol/L), temperature (three pairs for the ATES cold/warm well: 5/15 ˚C, 10/10 ˚C, 5/25 ˚C), biomass mobility (purely mobile or immobile), and pH limitation on Fe(III) reduction (absence and presence of such an effect). In the five years’ simulation by the model, complete dechlorination to ethene was achieved within 1 year, in the influence zone of the ATES wells, for the reference scenario with 3.8 mmol/L lactate, 5/15 ˚C ATES well temperatures and mobile biomass. Scenarios with lower dosage of lactate gave results with less dechlorination progress. Growth of biomass, especially iron reducer and lactate fermenter, was significant also in the first year (for both mobile and immobile biomass scenarios). Biomass also spread throughout the influence volume of ATES for both warm and cold wells. However, scenarios with different well-temperature pairs did not noteworthy differ in dechlorination progress. This could probably be due to biomass concentration being the limiting factor in this model setup, while temperature was not. Such situation was quite different than that in Chapter 3, of which experiment with bioaugmentation in the beginning. Besides, the model here could not include the important autocatalytic process (Chapter 3) which generated much faster dechlorination than just could be realized by only temperature increase in this chapter. In general, the modeling in this chapter suggests that applying ATES as engineering tool for biostimulation (substrate injection and bioaugmentation) can be a cost-effective approach to support the combined system.

Eventually in Chapter 7, overall discussions upon results gained from previous chapters were integrated and the research questions as presented in the introduction are reiterated. In addition, recommendation upon future study, and wider implications with future perspective for practical application are also discussed. We concluded that redox condition is the most essential factor in the ATES-ENA system. The mutual impacts of ATES and ENA were revealed to be quite positive. Elevated temperature in the ATES warm well synergizing with groundwater transport can provide “1 + 1 > 2” effect. Besides, ENA can probably reduce risk of chemical clogging in ATES, instead of causing biological clogging. The further investigation was recommended to perform with larger scale pilot tests. Finally, a brief review of possible applications was given for two countries, the Netherlands and China, which both have dense groundwater and subsurface contaminations around urban areas. The ATES technology is much more mature in the Netherlands, whereas in China, the advantage is the more flexible usage of subsurface. For both countries, ATES-ENA can provide cost‑effective outcomes on both energy production and groundwater management.

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