NO760354L

NO760354L -

Info

Publication number: NO760354L
Application number: NO760354A
Authority: NO
Inventors: H Nopper; H-H Maeurer
Original assignee: Becker & Van Huellen
Priority date: 1975-04-12
Filing date: 1976-02-03
Publication date: 1976-10-13
Also published as: IT1074571B; SE7512876L; FR2306825A1; FR2306825B3; FI753192A; DE2516121A1; DD123108A5

Description

Fremgangsmåte til fremstilling avMethod for the production of

fiberplater med våtmetoden.fiberboard with the wet method.

Oppfinnelsen vedrører fremstilling, av fiberplater med våtmetoden. The invention relates to the production of fiber boards using the wet method.

Ved våtmetoden blir de i en defibrator termisk og mekanisk oppberedede og deretter i en utskiller (f.eks. en syk-lon) fra dampen atskilte fibre, eksempelvis trefibre, påført en sikt i form av en vandig suspensjon med et faststoff-, d.v.s. fiberinnhold på 1 til 2 vektprosent for dannelse av en fiberflor etter en mekanisk awanning på sikten. Påføringen på sikten skjer som, regel gjennom innløpskåsser?hvor suspensjonen føres frem ved hjelp av pumper fra blandekar. In the wet method, the fibres, e.g. wood fibres, which are thermally and mechanically prepared in a defibrator and then separated from the steam in a separator (e.g. a cyclone), are applied to a sieve in the form of an aqueous suspension with a solid, i.e. fiber content of 1 to 2 percent by weight for the formation of a fiber pile after a mechanical dewatering on the sieve. The application to the sieve usually takes place through inlet hoppers, where the suspension is brought forward by means of pumps from mixing vessels.

Avvanningen på sikten skjer for det meste ved at vannet under påvirkning av tyngdekraften renner ut gjennom sikten. Deretter skjer en sugeavvanning, idet det under sikten tilveiebringes et undertrykk. Til slutt blir fiberfloren sam-menklemt før den egentlige pressing. På denne måten oppnås et faststoffinnhold på 30 til 40 vektprosent. Med en fremgangsmåte som ikke hører til teknikkens stand kan man sågar oppnå høyere verdier. Dewatering on the sieve mostly occurs by the water flowing out through the sieve under the influence of gravity. A suction dewatering then takes place, as a negative pressure is provided during the sieve. Finally, the fiber pile is clamped together before the actual pressing. In this way, a solids content of 30 to 40 percent by weight is achieved. With a method that does not belong to the state of the art, one can even achieve higher values.

Etter denne siktavvanning kjøres fiberfloren innAfter this screening dewatering, the fibrous pulp is driven in

i en presse hvor det, som følge av det ;red lukkingen av pressen oppstående pressetrykk, finner sted en ytterligere mekanisk presseavvanning. Man oppnår derved et faststoffinnhold på ca. 50 vektprosent og ved den nevnte fremgangsmåte kan man sågar oppnå minst 80 vektprosent i fiberfloren. in a press where, as a result of the press pressure arising after the closing of the press, a further mechanical press dewatering takes place. This results in a solids content of approx. 50 percent by weight and with the aforementioned method you can even achieve at least 80 percent by weight in the fiber pulp.

Det er klart at det ved fremstilling av fiberplater med våt&etoden kreves betydelige vannmengder.for å kunne bygge opp fiberfloren. Ved begynnelsen av den industrielle fremstilling var det vanlig bare å arbeide med friskvann og la dette gå ut som avløpsvann i urenset tilstand. På grunn av den stadig tiltagende friskvannsknapphet har man imidlertid mer. og. mer vært tvunget til å arbeide med begrensede friskvannmengder. Derved reduserte man riktignok avløpsvannmengden, men smuss-vannbelastningen var like stor, slik at man idag må regne med at det ved en produksjon av 1 tonn ferdige fiberplater forbru-kes mellom 10 til 50 m-^ friskvann og tilsvarende mengder av-r løpsvann. It is clear that when producing fiber boards with the wet method, significant amounts of water are required to build up the fiber layer. At the beginning of industrial production, it was common to only work with fresh water and let this go out as waste water in an impure state. Due to the ever-increasing scarcity of fresh water, however, there is more. and. more have been forced to work with limited quantities of fresh water. This reduced the amount of waste water, but the load of dirty water was just as great, so that today it can be assumed that in the production of 1 tonne of finished fiber boards, between 10 and 50 m-^ of fresh water and corresponding amounts of run-off water are consumed.

Det er også kjent at man kan arbeide i et helt lukket system, hvor siktavvannet og presseawannet benyttes om igjen som produksjonsvann for fiberflordannelsen etter en passende oppberedning. Ved denne kjente fremgangsmåte oppberedes avvannet under tilføring av antiseptiske produkter, pH-verdi-reguleringsmidler, såsom kalk eller nåtriumaluminat, klaringsmidler etc. Dessuten blir presseawannet også filtrert før denne behandl&ftgs: En ulempe ved denne fremgangsmåte er at man ikke It is also known that it is possible to work in a completely closed system, where the sieve water and press dewater are used again as production water for fiber pile formation after suitable preparation. In this known method, the dewater is prepared while adding antiseptic products, pH-value regulating agents, such as lime or sodium aluminate, clarifying agents, etc. In addition, the press dewater is also filtered before this treatment: A disadvantage of this method is that one does not

får en ekte oppberedning, og det betyr at produksjonsvannet til slutt tilsmusses opp til grensen for løsningsevnen, d.v.s. en smussbelastning på rundt 10$. Dette påvirker platekvalitet-en med hensyn til tykkelsessvelling, vannopptak, utseende o.s.v., slik at andelen av annen klasses plater stiger. Totalt sett, arbeider man altså ikke lenger med et kvalitetsriktig produksjonsvann, idet man belaster dette med så meget smuss og frem-medstoffer at man ikke lenger kan få en forstyrrelsesfri produksjon. Dessuten har denne fremgangsmåte den ulempe at den gets a real make-up, and that means that the production water is eventually polluted to the limit of its solubility, i.e. a dirt load of around 10$. This affects the board quality with regard to thickness swelling, water absorption, appearance, etc., so that the proportion of second-class boards rises. All in all, you no longer work with production water of the right quality, since you burden it with so much dirt and foreign substances that you can no longer get a disturbance-free production. Furthermore, this method has the disadvantage that it

høye smussbelastning blant annet også bevirker en tilsmussing av sikten og presseplatene, hvorved avvanningen blir dårligere og klebetilbøyeligheten forsterkes, slik at man blir nødt til high dirt loads, among other things, also cause soiling of the sieve and the press plates, whereby the dewatering becomes worse and the tendency to stick increases, so that you have to

å bruke voks som skillemiddel. Man får dessuten en uønsket temperaturøking av det omløpende produksjonsvann til 50 - 80°C. Ut ifra denne teknikkens stand tar man ifølge oppfinnelsen sikte på å behandle avvannet på en slik måte at det alltid kan benyttes om igjen med en lav restsmussbelastning - fortrinnsvis mindre eller lik 5-7 g/liter. to use wax as a separating agent. You also get an unwanted temperature increase of the circulating production water to 50 - 80°C. Based on the state of the art, according to the invention, the aim is to treat the waste water in such a way that it can always be reused with a low residual dirt load - preferably less than or equal to 5-7 g/litre.

For å oppnå dette, foreslås det derfor ifølge oppfinnelsen at oppberedningsprosessen minst innbefatter ett mekanisk oppberedningstrinn for vidtgående utskilling av uløste forurensninger og minst ett kjemisk og/eller plantebiologisk og/eller bakteriellbiologisk fremgangsmåtetrinn, i hvilket avvannet oppberedes til en restsmussbelastning som gjør at av vannet er meget godt egnet for fabrikasjonsprosessen, og at det ved prosessen betingede vanntap erstattes av friskvann. In order to achieve this, it is therefore proposed according to the invention that the preparation process includes at least one mechanical preparation step for extensive separation of undissolved pollutants and at least one chemical and/or plant biological and/or bacterial biological method step, in which the waste water is prepared to a residual dirt load which means that the water is very well suited for the manufacturing process, and that the water loss due to the process is replaced by fresh water.

Denne fremgangsmåte kan gjennomføres som en såkalt hovedstrømprosess, hvor hele avvannsmengden underkastes en rensing, eller den kan hensiktsmessig gjennomføres i delstrøm, idet da det i delstrømmen rensede avvann blandes sammen.med urenset avvann igjen. This method can be carried out as a so-called main flow process, where the entire quantity of wastewater is subjected to a purification, or it can be suitably carried out in a sub-flow, as the wastewater cleaned in the sub-flow is mixed together with polluted wastewater again.

Det har vist seg at ved en rensing av avvannet i delstrøm til < 2 3 gA restsmussbelastning (løselige andel-,er) vil delstrømmengden ligge mellom 40 og 60$ av den totale strømmengde, fortrinnsvis under 50%. It has been shown that when cleaning the wastewater in a partial flow to < 2 3 gA residual dirt load (soluble fractions), the partial flow quantity will be between 40 and 60$ of the total flow quantity, preferably below 50%.

Ifølge oppfinnelsen foreslås det videre at de enkelte awannsstrømmer skal samles og blandes i en samlebeholder før videreføringen som produksjonsvann. På denne måten får man en best mulig homogenitet. According to the invention, it is further proposed that the individual waste water streams should be collected and mixed in a collection container before being passed on as production water. In this way, you get the best possible homogeneity.

Fordelaktig kan siktawannet bare delvis oppberedes sammen med presseawannet som delstrøm og etter oppberedningen igjen tilføres den ikke oppberedede hovedstrøm av siktawannet. Den delstrøm av avvannet som skal oppberedes kan hensiktsmessig utgjøre 40 til 60% av totalavvannsmengden, fortrinnsvis mindre enn 50%. Advantageously, the screening water can only be partially prepared together with the press water as a sub-stream and after the preparation, the unprepared main stream of the screening water is added again. The sub-flow of the wastewater to be treated can suitably amount to 40 to 60% of the total amount of wastewater, preferably less than 50%.

Den nye fremgangsmåte kan gjennomføres i forskjellige varianter. En meget effektiv løsning går ut på at avvannet som skal renses behandles bakteriellbiologisk i et basseng med raesofile og/eller termofile bakteriestammér som ikke trenger prosessfremmed foring og områdesnever pH-verdi-regulering. Slike bakteriestammér inneholdes eksempelvis i dyreavføring. Det på denne måten behandlede avvann sedimenteres deretter i et -fortrinnsvis traktformet avsetningsbasseng, idet overløpet anvendes igjen som produksjonsvann. Det sedimenterte slam trekkes ut og tilføres delvis til bassenget igjen som poding. Delvis fortykkes det ytterligere mekanisk i en slyngeskiller eller en filterbåndpresse. Filtratet anvendes som produksjonsvann og det gjenblivende restslam trekkes ut av produksjonsprosessen. The new method can be implemented in different variants. A very effective solution is for the wastewater to be treated to be treated bacterially in a pool with rheophilic and/or thermophilic bacterial strains that do not need process-related lining and narrow area pH-value regulation. Such bacterial strains are contained, for example, in animal faeces. The waste water treated in this way is then sedimented in a -preferably funnel-shaped settling basin, the overflow being used again as production water. The sedimented sludge is extracted and partly added to the pool again as inoculation. In part, it is further thickened mechanically in a loop separator or a filter belt press. The filtrate is used as production water and the residual sludge is extracted from the production process.

Rests-lammet er behandlet og tørket i en slik grad at det kan benyttes som gjødsel. The leftover lamb has been processed and dried to such an extent that it can be used as fertiliser.

Det er imidlertid også mulig å underkaste restslammet en ytterligere bakteriell-biologisk stabilisering og først deretter foreta en ytterligere fortykning i en slynge skiller eller en filterbåndpresse. Dette restslam kan da anvendes som formiddel, mens filtratet kan benyttes som produksjonsvann. However, it is also possible to subject the residual sludge to further bacterial-biological stabilization and only then carry out a further thickening in a loop separator or a filter belt press. This residual sludge can then be used as a medium, while the filtrate can be used as production water.

En ytterligere differensiering av den bakteriell-biologiske fremgangsmåte består i at siktavvannet innmates i et første bio-basseng mens presseawannet innføres i et andre bio-basseng, idet det i det andre bio-basseng forbehandlede avvann overføres til det første bio-basseng, og det i det førs-te bio-basseng behandlede avvann tilføres fortykkeren, og det A further differentiation of the bacterial-biological method consists in the sieve water being fed into a first bio-basin, while the press waste water is introduced into a second bio-basin, the wastewater pre-treated in the second bio-basin being transferred to the first bio-basin, and the in the first bio-basin treated waste water is fed to the thickener, and that

for poding benyttede slam fra fortykkeren føres inn i det andre bio-basseng. Sludge from the thickener used for grafting is fed into the second bio-basin.

Det er kjent at ved den bakteriell-biologiske ned-bryting er de mesofile bakteriestammér virksomme optimalt opp til ca. 45°C, mens de termofile bakteriestammér er virksomme opp til ca. 75°C. Derfor foreslås det ifølge oppfinnelsen at defibrator-avdampvarmen benyttes for oppvarming av awannet It is known that during the bacterial-biological breakdown, the mesophilic bacterial strains are optimally active up to approx. 45°C, while the thermophilic bacterial strains are active up to approx. 75°C. Therefore, according to the invention, it is proposed that the defibrator evaporation heat be used for heating the waste water

henholdsvis produksjonsvannet, for derved å tilveiebringe optimale livsbetingelser for bakteriestammene. respectively the production water, thereby providing optimal living conditions for the bacterial strains.

Defibrator-avdampen kan kondenseres og blandes The defibrator vapor can be condensed and mixed

med produksjons- og/eller awannet.with production and/or wastewater.

Kondensasjonen kan eksempelvis skje ved at produksjonsvannet tilføres utskilleren i-en slik mengde at dampen kondenserer. En annen mulighet er at defibratoravdampen føres direkte eller etter en for-kondensasjon i én kondensator inn i et, fortrinnsvis det andre, for presseawannet beregnede bio-basseng. Condensation can take place, for example, by supplying the production water to the separator in such a quantity that the steam condenses. Another possibility is that the defibrator waste steam is fed directly or after pre-condensation in one condenser into a bio-pool, preferably the other, designed for the press water.

Ifølge oppfinnelsen kan fordelaktig frisk fiber-, stoffsuspensjon, fortrinnsvis 1,5% tykk, føres inn i det direkte foran fortykkeren anordnede bio-basseng. En slik ikke-prosessfremmed foring med cellulose betyr en betydelig øking av bakteriestammene.. Denne fremgangsmåte anbefales særlig véd manglende cellulose-innhold i awannet. Trefibre inneholder ca.- 50% cellulose. According to the invention, fresh fiber suspension, preferably 1.5% thick, can advantageously be introduced into the bio-pool arranged directly in front of the thickener. Such a non-process lining with cellulose means a significant increase in the bacterial strains. This method is particularly recommended due to the lack of cellulose content in the waste water. Wood fibers contain approximately 50% cellulose.

En annen prinsipiell variant av den nye fremgangsmåte består i at det siktawann som skal oppberedes skilles mekanisk i et - fortrinnsvis traktformet avsetningsbasseng, idet overløpet benyttes direkte som produksjonsvann og sedimentet sammen med det ennå urensede presseavvann avvannes i en slyngeskiller eller lignende, og det gjenblivende tykk stoff separat tilføres produksjonsprosessen, idet den atskilte væske, som inneholder det mekanisk rensede presseawann, oppberedes ved ozonisering og etter oppberedingen benyttes som produksjonsvann. Another principle variant of the new method is that the sieve water to be prepared is separated mechanically in a - preferably funnel-shaped settling basin, the overflow being used directly as production water and the sediment together with the still uncleaned press waste water being dewatered in a loop separator or similar, and the remaining thick substance is separately added to the production process, as the separated liquid, which contains the mechanically purified press water, is prepared by ozonation and after preparation is used as production water.

Ved denne variant, med ozonisering av awannet som skal oppberedes, blir awannet podet med en'ca. l,5%ig fiberstoffsuspensjon, hensiktsmessig før innføringen i avset-ningsbassenget og/eller før innføringen i slyngeskilleren. Forøvrig er det hensiktsmessig å avkjøle avvannet før ozoniseringen. In this variant, with ozonisation of the waste water to be prepared, the waste water is inoculated with approx. 1.5% fiber material suspension, suitably before introduction into the settling basin and/or before introduction into the loop separator. Otherwise, it is appropriate to cool the waste water before ozonation.

Isteden for ozoniseringen kan man benytte en plantebiologisk oppberedning av avvannet, idet dette hensiktsmessig føres over sivplantebed. Ved denne undervariant er en særlig kjøling ikke nødvendig, da kjølingen skjer automatisk ved fordunstingen på plantebedenes store overflate. Instead of ozonation, a plant-biological treatment of the wastewater can be used, as this is suitably carried over beds of reeds. With this sub-variant, special cooling is not necessary, as the cooling takes place automatically by evaporation on the large surface of the plant beds.

På tegningene er det ved hjelp åv strømningsskje-maer vist forskjellige varianter av den nye fremgangsmåte. In the drawings, different variants of the new method are shown using flow charts.

På tegningene viser i' AThe drawings show i' A

fig. 1 den bakteriell-biologiske rensing i en fig. 1 the bacterial-biological purification in a

hovedstrøm,mainstream,

fig. 2 viser den bakteriell-biologiske rensing i fig. 2 shows the bacterial-biological purification i

en delstrøm.,a substream.,

fig. 3 viser den kjemiske rensing i,en hoved-strøm, fig. 3 shows the chemical cleaning in a main stream,

fig. 4 viser den kjemiske rensing i en delstrøm, fig. 5 viser den plante-biologiske rensing i én hovedstrøm, og fig. 4 shows the chemical cleaning in a partial stream, fig. 5 shows the plant-biological purification in one main stream, and

fig. 6 viser den plante-biologiske rensing i en delstrøm. fig. 6 shows the plant-biological purification in a partial flow.

Som vanlig ved fremstilling av fiberplater med våtmetoden, blir i samtlige skjemaer 1 til 6 det oppdelte tre-virke omdannet til fiberstoff i en defibrator under tilsetning av damp, og går derfra til en utskiller hvor overskuddsdamp skilles ut. Deretter innføres fiberstoffet i det såkalte bøttesystem, hvor den ønskede fiberstoffkonsentrasjon på ca.. 1 til 2 vektprosent tilveiebringes under tilsetning av vann. For fiberflordannelse går så denne suspensjon over på langsikten hvor det skjer en tyngdekraftawanning, slik at en del av vannet dreneres bort. Den på denne måte forberedte fiberflor kjøres så inn i varmpressen og blir der først mekanisk og deretter i mindre grad termisk (fordampning) awannet og presset. Fra varmpressen uttas så den ferdigpressede fiberplate. As usual in the production of fiberboard with the wet method, in all schemes 1 to 6 the split wood is converted into fiber material in a defibrator with the addition of steam, and from there goes to a separator where excess steam is separated. The fiber material is then introduced into the so-called bucket system, where the desired fiber material concentration of approx. 1 to 2 percent by weight is provided while adding water. For the formation of fiber piles, this suspension is transferred to the long term, where gravity drainage occurs, so that part of the water is drained away. The fiber pile prepared in this way is then driven into the hot press where it is first mechanically and then to a lesser extent thermally (evaporation) dewatered and pressed. The pre-pressed fiber board is then removed from the hot press.

Fig. 1 viser prosess-skjernaet for en bakteriell-biologisk rensing av avvannet i en hovedstrøm. Fig. 1 shows the process core for a bacterial-biological purification of the wastewater in a main stream.

Det fra langsikten kommende avvann tilføres et første bio-basseng som eventuelt - ved manglende cellulose-innhold i avvannet - kan podes med frisk fiberstoffsuspensjon fra bøttesystemet. Denne poding tjener som ekstra foring for de i bio-bassenget forhåndenværende bakteriestammér. Det første bio-basseng tilsettes dessuten awann som kommer fra pressen og allerede er forbehandlet i et andre bio-basseng. The wastewater coming from the long-term is supplied to a first bio-pool which, if there is no cellulose content in the wastewater, can be inoculated with fresh fiber suspension from the bucket system. This inoculation serves as additional lining for the bacterial strains present in the bio-pool. The first bio-basin is also supplemented with waste water that comes from the press and has already been pre-treated in a second bio-basin.

Det i det første bio-basseng forbehandlede avvann går så til en fortykker (avsetningsbasseng), hvis overløp som produksjonsvann tilføres en samlebeholder, og hvis restslam delvis tilføres det andre bio-basseng som podningsstoff. Det øvrige restslam går til en slyngeskiller eller en filterbåndpresse, idet filtratet går til samlebeholderen for produksjonsvannet. Det gjenblivende restslam kan benyttes som gjød-sel. The pre-treated wastewater in the first bio-basin then goes to a thickener (settling basin), whose overflow as production water is fed to a collecting tank, and whose residual sludge is partly fed to the second bio-basin as inoculant. The other residual sludge goes to a loop separator or a filter belt press, with the filtrate going to the collection container for the production water. The remaining sludge can be used as fertiliser.

Fra den nevnte samlebeholder for produksjonsvannet går dette videre til bøttesystemet og tilføres delvis., også utskilleren. From the aforementioned collection container for the production water, this goes on to the bucket system and is partially supplied, also to the separator.

Dersom restslammet ikke skal bearbeides til gjød-sel, men til et formiddel, blir restslammet, idet det kommer fra fortykkeren, ført til et stabiliseringsbasseng hvor det skjer en ytterligere bakteriell-biologisk stabilisering, og først deretter foretas den allerede nevnte skilling mellom produksjonsvann pg rest i en slyngeskiller eller en.filterbåndpresse. Den nevnte rest kan da benyttes som formiddel. If the residual sludge is not to be processed into fertiliser, but into a medium, the residual sludge, as it comes from the thickener, is taken to a stabilization basin where a further bacterial-biological stabilization takes place, and only then is the already mentioned separation between production water due to residual in a loop separator or a filter belt press. The aforementioned residue can then be used as a vehicle.

Avdampen i utskilleren utnyttes dessuten på den måten at den føres gjennom en kondensator, idet det konden-serte, ennå relativt varme vann føres til det andre bio-basseng. The steam in the separator is also used in such a way that it is passed through a condenser, with the condensed, still relatively warm water being sent to the second bio-basin.

Fig. 2 viser et prosess-skjerna for en bakteriell-biologisk rensing av avvannet i en delstrøm. Fig. 2 shows a process core for a bacterial-biological purification of the wastewater in a partial stream.

Det fra langsikten kommende avvann ledes delvis direkte til samlebeholderen, slik at bare en delstrøm, bestå- The wastewater coming from the long-term is partly led directly to the collection tank, so that only a partial flow,

ende av presseawannet og en del av siktavvannet, ledes til en første fortykker;; Overløpet fra denne fortykker går direkte til samlebeholderen, mens det avsatte slam tilføres en andre fortykker via et bio-basseng. Også dette overløp går til samlebeholderen. end of the press water and part of the sieve water, are led to a first thickener;; The overflow from this thickener goes directly to the collection container, while the deposited sludge is fed to a second thickener via a bio-basin. This overflow also goes to the collection container.

Anvendelsen av restslammet i denne fortykker skjer på samme måte som ved prosessen i fig." 1. Det samme gjelder også for oppvarmingen av bio-bassenget ved hjelp av avvanne fra utskilleren. The use of the residual sludge in this thickener takes place in the same way as in the process in fig. 1. The same also applies to the heating of the bio-basin using waste water from the separator.

Fig. 3 viser prosess-skjemaet for en kjemisk Fig. 3 shows the process diagram for a chemical

rensing i en hovedstrøm.purification in a main stream.

Det fra langsikten kommende avvann tilføres en fortykker. Presseawannet går sammen med avsetningsslammet fra denne fostykker og en fiberstoffsuspensjonspoding til en slyngeskiller eller lignende. Podingen med fiberstoffsuspensjon tjener i dette tilfelle til å binde også fine bestand-deler i awannet på en adsorbtiv måte, slik at også disse be-standdeler slår seg ned i slyngeskilleren og ikke videretrans-porteres sammen med væsken. The wastewater coming from the long-term is fed into a thickener. The press waste water goes together with the settling sludge from this foot piece and a fiber material suspension inoculation to a loop separator or the like. In this case, the inoculation with fiber material suspension serves to bind also fine constituents in the waste water in an adsorptive manner, so that these constituents also settle in the loop separator and are not further transported along with the liquid.

Faststoffet fra slyngeskilleren føres, så tilbake til bøttesystemet, mens væsken sammen med overløpet fra fortykkeren går gjennom en kjøleinnretning og en ozoniserings-innretning og til samlebeholderen for produksjonsvannet. The solid from the loop separator is then fed back to the bucket system, while the liquid together with the overflow from the thickener goes through a cooling device and an ozonization device and to the collection container for the production water.

Fig. 4 viser prosess-skjemaet for en kjemisk rensing i en delstrøm. Fig. 4 shows the process diagram for a chemical cleaning in a partial flow.

Denne fremgangsmåte atskiller seg fra fremgangsmåten i fig. 3 bare ved at en del av det fra langsikten kommende avvann overføres direkte til samlebeholderen for produksjonsvannet. This method differs from the method in fig. 3 only in that part of the waste water coming from the long-term is transferred directly to the collection container for the production water.

Fig. 5 viser prosess-skjemaet for en plante-biologisk rensing i en hovedstrøm. Fig. 5 shows the process diagram for a plant-biological treatment in a main stream.

Denne fremgangsmåte svarer i det vesentlige til fremgangsmåten i fig. 3, frem til slyngeskilleren. Deretter går væsken fra slyngeskilleren sammen med" overløp fra fortykkeren gjennom en mellombeholder, over plantebed med sivplant-er og så til samlebeholderen for produksjonsvannet. This method essentially corresponds to the method in fig. 3, up to the coil separator. The liquid from the loop separator then goes together with the "overflow from the thickener" through an intermediate container, over plant beds with reed plants and then to the collection container for the production water.

Fig. 6 viser prosess-skjemaet for en plantebiologisk rensing i en delstrøm, og denne fremgangsmåte atskiller seg fra den i fig. 5 ved at en del av det fra langsikten kom mende avvann går direkte til samlebeholderen. Fig. 6 shows the process diagram for a plant biological purification in a partial flow, and this method differs from that in fig. 5 in that part of the wastewater coming from the long-term site goes directly to the collection container.

Claims

1. Method for the production of fiber boards using the wet method, where the sieve water and the press water in a closed circuit

run after corresponding preparation is used again as production water for fiber pile formation, characterized in that the preparation process includes at least a mechanical preparation step for extensive separation of undissolved pollutants and at least one chemical and/or plant-biological and/or bacterial-biological process step, in which the wastewater to be purified is prepared before it is reused, to a residual dirt load that is well suited for the manufacturing process, and in that only the process-related water loss is replaced with fresh water.

2. Method according to claim 1, characterized in that the preparation is carried out as a partial stream purification, with the wastewater purified in the partial stream being mixed again with the untreated wastewater. 3« Method according to claim 2, character 3 is based on the fact that in the case of purification of the wastewater in partial flow to a residual dirt load (soluble fractions) of less than or equal to 2-3 gA, the partial flow amount is between 4-0 and 60% of the entire flow amount, preferably below 50%. 4 "Procedure according to claim 2 or 3" characterized in that the individual streams of waste water are collected and mixed in a collection container before they are carried on as production water. 5 "Procedure according to claim 4" characterized in that the sifting water is only partially prepared together with the press water as a sub-stream and after the preparation, the unprepared main stream of sifting runoff is added again. 6. Method according to claim 5, characterized in that the partial flow of the wastewater to be prepared constitutes approximately 40 to 60% of the total amount of wastewater, preferably less than 50%. 7* Method according to one or more of claims 1 to 6, characterized in that the unwatered as must be cleaned and treated in a bio-pool in a bacterial-biological way with mesophilic or thermophilic bacterial strains such as; does not need process-related lining bg narrow area pH-value regulation^ e.g. strains of bacteria contained in animal faeces, and that the treated wastewater is sedimented in a pre-, . step by step funnel-shaped sedimentation basin, the overflow being used again as production water and the sedimented sludge is extracted and partly returned for inoculation in the bio-basin and partly thickened mechanically in a loop separator or a filter belt press, as the filtrate is also used as production water and the remaining amount of residual sludge is drawn out of the production process. 8. Method according to claim 7, characterized in that the residual sludge is used as fertiliser. 9- Method according to claim 7"characterized j' ..;iv, e d • that the residual sludge is subjected to further bacterial-biological stabilization and then thickened in a loop separator or a filter belt press, the residual sludge being used as a medium and the filtrate being used as production water. 10. Method according to one or more of claims 7 to 9"characterized in that the sieve water is fed to a first bio-basin and the press waste water is fed to a second bio-basin, with the second bio-basin being pretreated .led wastewater is transferred to the first bio-basin and the wastewater treated in the first bio-basin is fed to the thickener, and that the sludge used for grafting from the thickener is fed into the second bio-basin. li". - ':• Method according to one or more of claims 7" to 10, characterized in that the defibrator evaporation heat is used for heating the waste water respectively the production water, thereby providing optimal living conditions for the bacterial strains*, 12. Method according to claim 11, kar a:..k t e r i-sJe r:t' in that the defibrator exhaust is condensed and mixed with the production water and/or the dewater. 13» Method according to claim 12, c a r a c t i - s e r t v e d : that the production water is supplied to the separator in such a quantity that the steam condenses. 14* Method according to one or more of claims 11 to 13, characterized in that the defibrator exhaust is supplied to at least one bio-pool directly or after condensation in a condenser. 15. Method according to claim 14, k a r. [ a c t e r i - s ert by feeding the defibrator steam into the second bio-basin designed for the press water. 16. Method according to one or more of claims 7 to 15, characterized in that a temperature between 40 and 45°C prevails at least in the bib basin. 17. Method according to one or more of the claims. 7 to l6, characterized in that at least in the bio-basin connected directly in front of the thickener, fresh fiber material suspension is introduced as inoculum. 18. Method according to one or more of claims 1 to 6, characterized in that the sifting water prepared as a bowl is separated mechanically in a preferably funnel-shaped sedimentation basin, the overflow being used directly as production water, and the sediment is dewatered together with the still uncleaned press water in a sling separator or similar in and ... the remaining solids are supplied separately to the production process, while the separated liquid, which contains the mechanically cleaned press water, is further prepared by ozonation and. after preparation is used as production water.. 19.. • Method according to claim l8tcharacterized by that. The waste water to be prepared is inoculated with an approx. 1.5% fibrous material suspension before the introduction into the settling basin and/or before the introduction into the loop separator 20. Method according to claim 18 or 19, k a r-at-le, t-e r i-s ert in that the wastewater is cooled before the ozonation. 21.. Modification of the method according to claims l8 to 20 t - characterized by the fact that instead of ozone, a plant biological preparation of is carried out. unwatered. 1 22. Method according to claim 21, characterized in that the waste water for plant-biological purification is passed over beds of reeds.