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10 recommendations for stimulating bio-based builing materials
Mey, V. De; Verhoeven, J.T.W. ; Thoelen, P. ; Dam, J.E.G. van; Meyskens, S. ; Schik, W. - \ 2016
[Belgium] : Grow2Build - 17 p.
building materials - flax - hemp - biobased materials - biobased economy - stimulation - guidelines - northwestern europe - bouwmaterialen - vlas - hennep - materialen uit biologische grondstoffen - stimulatie - richtlijnen (guidelines) - noordwest-europa
The objective of the Northwest European project Grow2build is to support the supply chain of flax and hemp building materials from production of raw material to the production and implementation of end products. Up until now, 11 organisations from Belgium, France, the UK, Germany and the Netherlands have formed a consortium with a wealth of expertise in construction and bio-based building materials. The consortium aims to contribute to the integration of bio-based materials eg. hemp and flax in the construction industry and to improve the product value chain. This note “10 recommendations for stimulating biobased building materials (based on hemp and flax)” is one of the instruments to reach the aim.
Hemp for textiles : plant size matters
Westerhuis, W. - \ 2016
University. Promotor(en): Paul Struik, co-promotor(en): Tjeerd-Jan Stomph; Jan van Dam. - Wageningen : Wageningen University - ISBN 9789462577879 - 234 p.
cannabis sativa - fibre plants - textile fibres - textiles - photoperiod - hemp - plant fibres - plant density - harvesting date - sowing date - biobased materials - vezelgewassen - textielvezels - textiel - fotoperiode - hennep - plantenvezels - plantdichtheid - oogsttijdstip - zaaitijd - materialen uit biologische grondstoffen

Abstract

Key words: Cannabis sativa L., day length sensitivity, fibre hemp, genotype, harvest time, plant density, plant weight, primary fibres, secondary fibres, sowing date, textiles.

Westerhuis, W. (2016) Hemp for textiles: plant size matters, PhD thesis. Wageningen University, Wageningen, The Netherlands, 234 pp. With English and Dutch summaries.

Fibre hemp (Cannabis sativa L.) may be an alternative to cotton and synthetic fibres as a raw material for textile yarn production in the European Union. The agronomic options to manipulate plant development and crop growth with the aim to optimise hemp long fibre production were investigated. Field trials with factors sowing density, sowing date, harvest time and variety were conducted. Stems were traditionally processed by retting, drying, breaking, and scutching. Following standard protocols, almost 1500 hemp stem samples were analysed. Varieties differ widely in their fibre content, but this thesis shows that when variety and plant size are known, the amounts of fibres, wood, and retting losses are known. The dry weight of the stems at harvest, not the factors underlying this weight, are determinant. In retted stems the dry matter is split–up into fibres and wood in a fixed way. The options to manipulate this ratio by crop management, given variety, are very small and for practical reasons they can be neglected. In fibre hemp two bast fibre types occur. Primary or long fibres are valuable for yarn spinning. Secondary fibres are too short and their presence hampers the production of fine yarns. This thesis shows that the secondary fibre front height increases with plant weight. Although a causal relationship between secondary fibre formation and flowering does not exist, the secondary fibre front is found higher in flowering plants when compared to non–flowering plants of the same height. This is likely to be caused by the higher weight or momentum of flowering plants as compared with non–flowering plants of the same height. Consequently, a harvest before flowering is preferable. This was shown in a greenhouse experiment, in which the short–day response of hemp was used to create size ranges of flowering and non–flowering plants. To produce high–quality raw materials for textile production, short crops should be grown. The options to produce plants with the desired size are manifold. Since sowing density, sowing date, and harvest time do not have an additional effect on the primary fibre content besides the indirect effect through stem weight, any combination of these factors could be chosen to optimize plant size.

Hennep in Europa
Loo, E.N. van - \ 2014
Wageningen UR, Plant Breeding
vezelgewassen - hennep - agrarische geschiedenis - vezels - textiel - biobased economy - fibre plants - hemp - agricultural history - fibres - textiles
Samenvatting van de geschiedenis van de hennepteelt en de hedendaagse mogelijkheden van hennep.
Inkomensvergelijking vezelgewassen versus graan
Wolf, P.L. de; Brink, L. van den; Spruijt, J. - \ 2012
Lelystad : Praktijkonderzoek Plant & Omgeving, Business Unit Akkerbouw, Groene Ruimte en Vollegrondsgroenten (PPO 518) - 13
vlas - inkomsten uit het landbouwbedrijf - bedrijfseconomie - rendement - vezelgewassen - hennep - akkerbouw - biobased economy - subsidies - markteconomie - flax - farm income - business economics - returns - fibre plants - hemp - arable farming - market economics
In 2012 is de verwerkingssteun voor o.a. vezelvlas en vezelhennep volledig ontkoppeld. Dat betekent dat deze steun wordt omgezet in een vaste inkomenstoeslag voor de teler, die daarvoor niet langer verplicht is om vlas of vezelhennep te telen. Daardoor dreigt de teelt van vlas en vezelhennep het af te leggen tegen financieel aantrekkelijkere teelten. In dit onderzoek worden de financiële aspecten voor agrarische ondernemers berekend, om het ministerie van EL&I te informeren bij beleidsvorming. Omdat de beide teelten regionaal geconcentreerd zijn, wordt de vergelijking gemaakt voor vlasteelt in Zuidwest Nederland en voor vezelhennep voor het Noordoostelijk zand- en dalgebied.
Oliehennep - Cannabis Sativa / Eiwit en oliepad
PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2012
hennep - cannabis sativa - olieleverende planten - planten met oliehoudende zaden - vezelgewassen - medicinale planten - voedergewassen - gewassen - akkerbouw - biobased economy - hemp - oil plants - oilseed plants - fibre plants - medicinal plants - fodder crops - crops - arable farming
Factsheet van het Eiwit en Oliepad met korte informatie over het gewas Oliehennep. Met het project Eiwit & Oliepad wil Innovatief Platteland samen met de gemeente Venray en andere partners het publiek de gelegenheid geven zich een beeld te vormen van de enorme multifunctionaliteit en de nog steeds verder te ontdekken mogelijkheden van in Europa te telen gewassen als grondstof voor de biobased economie
Effect van hennep op de populatiedichtheid van het wortellesieaaltje (Pratylenchus penetrans)
Wijnholds, K.H. - \ 2010
Kennisakker.nl 2010 (2010)4 maart.
hennep - pratylenchus penetrans - plantenplagen - populatiedynamica - plagenbestrijding - akkerbouw - vezelgewassen - waardplanten - hemp - plant pests - population dynamics - pest control - arable farming - fibre plants - host plants
In 2009 is in opdracht van Hempflax Agro BV en het Productschap Akkerbouw (PA) onderzoek gedaan naar het effect van hennep op de populatiedichtheid van Pratylenchus penetrans. De vraag hierbij was of de nu gebruikelijke, kortere teeltduur van dit gewas (zaai in mei en oogst in augustus in plaats van oogst in oktober) van invloed is op de vermeerdering van deze aaltjes. Op basis van deze éénjarige proef lijkt hennep ook bij kortere teeltduur een (heel) goede waardplant te zijn voor Pratylenchus penetrans. Hennep zelf lijkt niet gevoelig voor schade.
Effect van hennep op de populatiedichtheid van Pratylenchus penetrans
Wijnholds, K.H. ; Hoek, H. - \ 2010
Lelystad : PPO AGV - 15
cannabis sativa - hennep - pratylenchus penetrans - populatiedynamica - teeltsystemen - plagenbestrijding - nederland - akkerbouw - hemp - population dynamics - cropping systems - pest control - netherlands - arable farming
Resultaten van onderzoek met als vraagstelling in hoeverre bij een kortdurende teelt (mei – augustus) hennep een minder grote vermeerdering geeft van Pratylenchus penetrans dan op basis van oud onderzoek (bij een langdurende teelt) zou mogen worden verwacht. Op basis van dit éénjarige onderzoek lijkt hennep echter ook bij een vroeger oogsttijdstip een (zeer) goede waardplant te zijn voor Pratylenchus penetrans.
Vlasteelt in Nederland in problemen door verandering EU-beleid
Bont, C.J.A.M. de; Jager, J.H. ; Janssens, S.R.M. - \ 2008
Agri-monitor 2008 (2008)oktober. - ISSN 1383-6455 - 2
akkerbouw - teelt - vlas - hennep - wereldmarkten - gemeenschappelijk landbouwbeleid - landbouwontwikkeling - nederland - zeeuws-vlaanderen - arable farming - cultivation - flax - hemp - world markets - cap - agricultural development - netherlands
Door veranderingen in het EU-beleid valt de teelt en verwerking van vlas in Nederland mogelijk weg en kan de ontwikkeling van de vezelhennepteelt moeilijkheden ondervinden. Het wegvallen van de vlasteelt en –verwerking zou ook verlies aan biodiversiteit, aan kenmerkende landschapsbeelden en cultureel erfgoed inhouden.
Annual fibre crop systems : EU ENFA project (SSPE-CT-2005-006581)
Lips, S.J.J. ; Dam, J.E.G. van; Elbersen, H.W. - \ 2008
Wageningen : Agrotechnology & Food Sciences Group
fibre plants - agro-industrial chains - natural fibres - flax - hemp - kenaf - european union - biobased materials - biobased economy - environmental impact - vezelgewassen - agro-industriële ketens - natuurlijke vezels - vlas - hennep - europese unie - materialen uit biologische grondstoffen - milieueffect
This report is the final report of WP26 on the annual fibre crops systems as studied in the EU ENFA project (SSPE-CT-2005-006581). The ENFA project aims to develop a dynamic agricultural and forest sector model for the integrated economic and environmental assessment of non-food alternatives in European agriculture and forestry. This report includes a description of fibre crop production chains of long and short fibres, as well as a market description of fibre crop products, with emphasis on flax, hemp and kenaf. Also environmental aspects of these chains and the regulations concerning fibre crops are addressed.
Vlas en vezelhennep en herziening van het EU-beleid
Bont, C.J.A.M. de; Jager, J.H. ; Janssens, S.R.M. - \ 2008
Den Haag : LEI Wageningen UR (Rapport / LEI : Werkveld 1, Internationaal beleid ) - ISBN 9789086152551 - 72
vlas - hennep - plantenvezels - landbouwproductie - gemeenschappelijk landbouwbeleid - subsidies - landbouwsector - agrarische economie - eu regelingen - nederland - biobased economy - flax - hemp - plant fibres - agricultural production - cap - agricultural sector - agricultural economics - eu regulations - netherlands
Vlas en vezelhennep en herziening van het EU-beleid geeft de mogelijke gevolgen aan van het ontkoppelen en opheffen van de Europese steun voor de betreffende sectoren in Nederland. Het rapport geeft een beeld van deze sectoren in Nederland en van de positie van Nederland in de EU op die terreinen. Geconcludeerd wordt dat ontkoppeling en het opheffen van de steun kan leiden tot het wegvallen of fors verminderen van de omvang van deze sectoren. 'Flax, hemp and the revision of EU policy' points out the possible consequences of decoupling and abolishing European support for the concerned sectors within the Netherlands. The report gives a picture of these sectors in the Netherlands and the position of the Netherlands within the EU in these fields. The conclusion can be drawn that the decoupling and abolition of the support could lead to the disappearance or considerable reduction of the size of these sectors.
Report of a Working Group on Fibre Crops (Flax and Hemp)
Bas, N. ; Pavelek, M. ; Maggioni, L. ; Lipman, E. - \ 2007
Rome, Italy : Bioversity International - 28
genenbanken - vezelgewassen - vlas - hennep - databanken - plantenverzamelingen - gene banks - fibre plants - flax - hemp - databases - plant collections
Members of the newly established ECPGR Working Group on Fibre Crops (Flax and Hemp), in the framework of Sugar, Starch and Fibre Crops Network, met for the first time at Wageningen, the Netherlands on 14–16 June 2006. Fifteen participants from the Czech Republic, Germany, Hungary, Italy, Latvia, Lithuania, the Netherlands, Poland, Portugal and Romania took part in the meeting to discuss flax and hemp national collection status reports as well as flax and hemp international databases development.
Hennep voor textiel : de Agro-industriële productieketen
Dam, J.E.G. van; Heugten, W.G.N. van - \ 2006
textiel - hennep - vezels - kwaliteit - biobased economy - agro-industriële ketens - ketenmanagement - textiles - hemp - fibres - quality - agro-industrial chains - supply chain management
Poster met informatie over de productie van textiel uit hennepvezels.
Strooiseltest : koolzaadstro en dennenzaagsel voldoen goed
Hollander, C.J. - \ 2005
Veeteelt 22 (2005)18. - ISSN 0168-7565 - p. 79 - 79.
melkveehouderij - strooisel - zaagsel - hennep - krijtkalk - bedrijfsvergelijking in de landbouw - dairy farming - litter (plant) - sawdust - hemp - chalk - farm comparisons
Op het lagekostenbedrijf heeft men getest welke strooiselsoorten economisch aantrekkelijk zijn: dennenzaagsel, vlasstrooisel, geslibd krijt, koolzaadstro, eersteklas zaagsel, Allspan plus med-zaagsel, en hennep
Teelt van biomassa niet rendabel
Darwinkel, A. ; Borm, G.E.L. ; Zeeland, M.G. van; Floot, H.W.G. - \ 2001
PPO-bulletin akkerbouw 5 (2001)3. - ISSN 1385-5301 - p. 2 - 5.
miscanthus - hennep - industriële gewassen - brandstofgewassen - biomassa - biomassa productie - productiviteit - opbrengsten - gewasopbrengst - gewasproductie - veldgewassen - kosten-batenanalyse - rentabiliteit - economische evaluatie - economische haalbaarheid - chemische samenstelling - mineraalgehalte - voedingsstoffengehalte - voedingsstoffenbehoeften - mineralenopname - voedingsstoffenopname (planten) - plantenvoeding - stikstof - mestbehoeftebepaling - plantdichtheid - gewasdichtheid - gewaskwaliteit - bemesting - biobased economy - hemp - industrial crops - fuel crops - biomass - biomass production - productivity - yields - crop yield - crop production - field crops - cost benefit analysis - profitability - economic evaluation - economic viability - chemical composition - mineral content - nutrient content - nutrient requirements - mineral uptake - nutrient uptake - plant nutrition - nitrogen - fertilizer requirement determination - plant density - crop density - crop quality - fertilizer application
Op verschillende locaties in Nederland werd gedurende de jaren 1993-1999 onderzoek gedaan naar de geschiktheid van miscanthus en hennep als akkerbouwmatig geteeld energiegewas. De resultaten wat betreft gewasproductiviteit (biomassa-opbrengst) bij verschillende stikstofbemestingsniveaus en plantdichtheden, de minerale samenstelling en minerale behoeften van het gewas, gewasopkomst en gewasvestiging bij variërende plantleeftijd, poottijd en rhizoomgrootte (voor miscanthus), en voor beide gewassen de economische perspectieven. Ondanks goede opbrengsten kan het saldo niet tippen aan het gemiddelde van de gewassen in een normaal bouwplan; ook hier zijn weer subsidies nodig
Hennep als energiegewas: oogst- en bewaring
Kasper, G.J. - \ 1998
Landbouwmechanisatie 49 (1998)8. - ISSN 0023-7795 - p. 18 - 19.
opslag - cannabis sativa - hennep - drogen - prijzen - prijsvorming - kosten - storage - hemp - drying - prices - price formation - costs
Gezien de korte oogstperiode moet hennep voor een aantal maanden worden opgeslagen. Onderzocht wordt het proces van veldroging en de kosten van droging tijdens bewaring
Alkaline hemp woody core pulping : impregnation characteristics, kinetic modelling and papermaking qualities
Groot, B. de - \ 1998
Agricultural University. Promotor(en): K. van 't Riet; J.E.G. van Dam. - S.l. : S.n. - ISBN 9789054858898 - 97
hennep - plantenvezels - papier - pulpbereiding - hemp - plant fibres - paper - pulping
<p>The aim of this thesis is to elucidate alkaline processing of hemp woody core, supporting the development and optimization of an efficient and non-polluting pulping process. This study has been a constituent of an integral programme to study fibre hemp.</p><p>It is known that the outer part of the fibre hemp stem can be used for textile and specialty paper purposes. The inner part consists of hemp woody core, which resembles hardwood and might be processed similarly for paper pulp. Literature data and prefeasibility studies show that alkaline processes can be used to produce hemp woody core pulp for papermaking.</p><p>Alkaline processes, based on sodium hydroxide (NaOH) are used for many wood and non-wood species. The most important process is the kraft process, but alternative NaOH based processes for pulp production have been investigated too. The currently developed alkaline process for high yield hardwood pulping may also be implemented for hemp woody core.</p><p>Pulp mixes for papermaking can vary, depending on the available fibre sources. The technological developments and the growing market outlet for hardwood fibres increase the possibilities to use hemp woody core for papermaking.</p><p>In chapter 2 swelling of hemp woody core chips after alkaline (peroxide) impregnation at 70 °C has been studied, as is practised in alkaline peroxide mechanical pulping (APMP) processes. Swelling of hemp woody core chips has been examined in relation to pulp yield and chemical composition of the chips after impregnation.</p><p>In contrast to wood chips, maximum swelling is attained at 70 °C without chemical treatment, possibly as the result of relatively high porosity of hemp woody core cell walls.</p><p>Alkaline swelling at 70 °C correlates with the xylan:lignin ratio. Swelling at ambient temperature shows some correlation with acidic group content.</p><p>Apparent pore size distributions have been examined, using 1H NMR spin-spin relaxation. Several apparent pore size distributions can be distinguished within each sample. Elevated temperature, NaOH and peroxide addition influence the apparent pore size distribution and the total pore volume in different ways.</p><p>Addition of peroxide results in remark-able increase of the apparent pore sizes. This emphasizes its importance, not only as bleaching chemical in the APMP process, but also promoting fibre flexibility.</p><p>Alkaline delignification of hemp woody core is studied in chapter 3. Shavings of hemp woody core were delignified isothermally at several temperatures with 1M NaOH in a flow-through reactor. From literature data and from experimental data reported in this chapter, it appears that the initial delignification stage is completed before customary reaction temperatures are reached. Consequently, modelling of alkaline delignification kinetics can be restricted to the bulk and residual delignification stages. This can be described with two simultaneous first order reactions: L/L0 = a2 exp (-k2t) + a3 exp (-k3t), with ki = Ai exp -Eai/(RT).</p><p>This equation has been solved integrally, calculating a2, a3, Ea2, Ea3, A2 and A3 for the best fit for the experimental data, resulting in an accurate description of the delignification reactions. This kinetic model has also been applied on literature data, supporting its validity for alkaline delignification kinetics in general.</p><p>This model is also used in chapter 4, to describe the kinetics of alkaline delignification in more detail, and to describe the degradation of xylan and cellulose. Shavings of hemp woody core were impregnated at room temperature with various NaOH concentra-tions (0.25-2.0M) and delignified isothermally at various reaction temperatures (150-180 °C) in a flow-through reactor.</p><p>Extraction and degradation of xylan from hemp woody core strongly depends on NaOH concentration. Consequently, to attain a certain lignin content, lower NaOH concentrations result in higher pulp yields. Extended pulping diminishes the differences in pulp yields, due to further xylan degradation.</p><p>The kinetics of lignin, xylan and cellulose degradation are modelled as a function of reaction time, temperature and NaOH concentration. The combined models resulted in a pulp yield model for hemp woody core, suitable for process optimization purposes. Degradation kinetics of perennial wood can be modelled similarly, which was illustrated using literature data on spruce and poplar.</p><p>In chapter 5 strength and surface properties of test sheets, produced from alkaline hemp woody core pulp were examined. The development of bulk and tear with beating are similar as found for straw pulp; maximum tear strength is attained without beating. Burst and tensile strength, scattering and opacity develop similarly as for hardwood pulps, with less mechanical energy needed. Tear strength is not affected by pulp yield or composition, whereas lower tensile and burst strength are found with decreased yield and lower xylan content.</p><p>As the paper strength and surface properties of hemp woody core pulp are comparable with those for hardwood and straw pulps, it is conceivable that similar amounts of alkaline hemp woody core pulp can be used in pulp mixes for printing paper grades.</p><p>The polymerization degree (DP) of hemp woody core pulps has been related to the paper strength properties, and modelled as function of pulping conditions and time.</p><p>The influence of NaOH concentration on depolymerization and cellulose degradation is much stronger than reported in literature for other pulps. This may be related to the low density of hemp woody core, preventing diffusion effects. Finally, crystallinity has been examined and related to cellulose degradation of alkaline hemp woody core pulp.</p><p>In chapter 6 the results and conclusions are discussed. It is emphasised that hemp woody core has a lower density than hardwood or softwood. It is suggested that this is the cause for maximal swelling without NaOH addition, the found xylan and yield losses with NaOH impregnation, and the strong dependency of cellulose degradation and depolymerisation on NaOH concentration.</p><p>In general, it was confirmed that hemp woody core can be delignified similarly as hardwood. The modelling techniques used have been proved to be generally applicable on degradation and depolymerisation kinetics, not only for hemp woody core, but also for hardwood and softwood species. The paper characteristics are comparable both to hardwood and to straw pulp characteristics.</p>
Sequenced anaerobic - aerobic treatment of hemp pulping wastewaters
Kortekaas, S. - \ 1998
Agricultural University. Promotor(en): G. Lettinga; J.A. Field. - S.l. : S.n. - ISBN 9789054859505 - 145
industrieel afval - hennep - afvalwaterbehandeling - anaërobe behandeling - aërobe behandeling - industrial wastes - hemp - waste water treatment - anaerobic treatment - aerobic treatment
<p>Biological treatment is an indispensable instrument for water management of non-wood pulp mills, either as internal measure to enable progressive closure of water cycles, or as end of pipe treatment. In this thesis, the sequenced anaerobic-aerobic treatment of hemp ( <em>Cannabis sativa L.</em> ) pulping wastewaters is described, with a focus on the treatability of thermomechanical pulping (TMP) effluents and soda pulping black liquors. The research was performed within the framework of the Dutch Hemp Programme, which aimed to develop environmentally safe and economically feasible pulping processes as a measure to explore non-food markets for arable farming.</p><p>Pulp and paper industry wastewaters are highly heterogeneous, depending on the feedstock and the pulping processes utilized. Hemp TMP wastewaters were found to be non-toxic to methanogens and highly suitable for sequenced anaerobic-aerobic treatment, which enabled 63-66% COD removal at loading rates up to 27 g COD/ <em>l</em><SMALL>UASB<img src="/wda/abstracts/i2516.gif" VALIGN=middle width="6" height="6" ALT="dot" border="0"/></SMALL>d. Hemp black liquors on the other hand, were somewhat more problematic, due to the high methanogenic toxicity, causing 50% inhibition of acetoclastic methanogenic activity (50% IC) at concentrations ranging from 2-6 g COD/ <em>l</em> , which is 10 to 100 times lower than the black liquor concentrations in industry and comparable to the methanogenic inhibition of wood pulping wastewaters.</p><p>Apolar hemp extractives (resinous compounds) were observed to be the main source of inhibitory substances in hemp black liquors. Lignin derivatives on the other hand, were less important for methanogenic inhibition, since the main share of lignin in hemp black liquors was non-toxic. Despite the high methanogenic toxicity of hemp black liquors, anaerobic treatment was feasible, provided that adequate dilution was applied. Anaerobic treatment of diluted hemp stem wood black liquor (HSWBL) facilitated recovery of methane and high treatment efficiencies at high organic loading rates. Subsequent aerobic post-treatment provided almost complete removal of BOD, however COD-removal was limited due to the presence of recalcitrant lignin. Additionally, substantial detoxification was obtained after anaerobic-aerobic treatment. The major removal of inhibitory compounds was accomplished in the aerobic step.</p><p>The effective reduction of methanogenic toxicity during sequenced anaerobic-aerobic treatment of hemp black liquors was used as a detoxification strategy denominated upfront dilution, recirculating the aerobic effluent to dilute the incoming influent to sub-toxic concentrations. The feasibility of the upfront dilution method was demonstrated in an experiment, in which direct anaerobic treatment and sequenced anaerobic-aerobic treatment with upfront dilution were compared. Direct anaerobic treatment of 12 g COD/ <em>l</em> HSWBL led to almost complete inhibition of the methanogenic activity within 14 days. While recirculation of 75% of the aerobic post-treatment effluent for upfront dilution of the toxic HSWBL, enabled anaerobic treatment at loading rates up to 21.5 g COD/ <em>l</em><SMALL>UASB<img src="/wda/abstracts/i2516.gif" VALIGN=middle width="6" height="6" ALT="dot" border="0"/></SMALL>d without noticeable inhibition of methanogenesis. Extensive detoxification was confirmed during anaerobic-aerobic treatment of 20 g COD/ <em>l</em> HSWBL recirculating 86% of the aerobic effluent. COD and BOD removal was 47% and 68%, respectively, after anaerobic treatment; and 74% and 97%, respectively, after anaerobic-aerobic treatment at an overall loading rate of 3.6 g COD/ <em>l<img src="/wda/abstracts/i2516.gif" VALIGN=middle width="6" height="6" ALT="dot" border="0"/></em> d, while 30-35% of the incoming COD was recovered as methane.</p><p>Lignin removal during anaerobic-aerobic treatment of hemp pulping wastewaters was remarkably high and ranged up to 44%, of which globally half was obtained anaerobically. Studies on hemp TMP wastewater revealed that lignin removal during anaerobic treatment corresponded to the lowest molecular weight derivatives, indicating that biodegradation was the major removal mechanism. Subsequently, aerobic post-treatment of hemp pulping wastewaters caused extensive polymerization of lignin to molecular weights in excess of 34 kD, which was associated with strong increases in wastewater color. Autoxidative polymerization of polyphenols formed out of lignin by anaerobic bioconversion is proposed as a mechanism for the observed increase in lignin molecular weight and color. Apart from the highly stable high molecular weight lignin-derived humic COD, biologically treated pulping effluents are relatively clean, which offers benefits for lignin removal during tertiary treatment, such as reduced fouling of ultrafiltration membranes and improved precipitation with divalent salts.</p><p>Comparison of anaerobic-aerobic treatment and aerobic treatment shows that treatment efficiencies and detoxification were similar. The anaerobic-aerobic treatment system however, provided 50% lower surplus sludge production, production of methane as an energy source (0.16 m <sup>3</SUP>/kg COD <sub>removed</sub> ), less nutrient dosage and substantial reductions in aeration costs.</p><p>The results of this research demonstrate that sequenced anaerobic-aerobic treatment is a suitable technology for the treatment of hemp pulping wastewaters. Upfront dilution effectively reduced inhibition of methanogenesis by extractive compounds during anaerobic treatment, whereas the observed increase in lignin molecular weight after biological treatment offers benefits for lignin removal during optional tertiary treatment.</p>
Descriptors for flax (Linum spp.) : developed for the cooperation with Dutch private breeding companies
Soest, L.J.M. van - \ 1996
Wageningen : CPRO-DLO - 6
cannabis sativa - vlas - genenbanken - genetische bronnen - germplasm - hennep - linum usitatissimum - genetische bronnen van plantensoorten - hulpbronnenbehoud - flax - gene banks - genetic resources - hemp - plant genetic resources - resource conservation
Oogst en conserveringstechniek van vezelhennep = Techniques for harvesting and storage of fibre hennep
Maeyer, E.A.A. de; Huisman, W. - \ 1995
Wageningen : IMAG-DLO (Rapport / Dienst Landbouwkundig Onderzoek, Instituut voor Milieu- en Agritechniek 94-27) - ISBN 9789054060956 - 138
cannabis sativa - hennep - oogsten - verwerking - opslag - hemp - harvesting - processing - storage
Gebruik van groeiregulatoren in vezelhennep
Geel, W.C.A. van; Werf, H.M.G. van de - \ 1994
In: Jaarboek 1993-1996 : verslagen van afgesloten onderzoeksprojecten op de regionale onderzoekcentra en het PAGV. Akkerbouw Lelystad : Proefstation voor de Akkerbouw en de Groenteteelt in de Vollegrond [etc.] (Publikatie / Proefstation voor de Akkerbouw en de Groenteteelt in de Vollegrond, Regionale Onderzoekcentra No. 70a-81A) - p. 129 - 133.
cannabis sativa - hennep - plantengroeiregulatoren - hemp - plant growth regulators
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