GB2033406A

GB2033406A - Cellulosic Filter Aids

Info

Publication number: GB2033406A
Application number: GB7935507A
Authority: GB
Original assignee: Takeda Chemical Industries Ltd
Current assignee: Takeda Pharmaceutical Co Ltd
Priority date: 1978-10-13
Filing date: 1979-10-12
Publication date: 1980-05-21
Also published as: GB2033406B; JPS5554012A; FR2438492A1; DE2940390A1; JPS6147133B2; FR2438492B1

Abstract

Filter aids comprise (a) from 95 to 50 weight percent, on a dry basis, of a linter pulp having an alpha-cellulose content of at least 95 weight percent and a beating degree of from 20 to 70; and (b) from 5 to 50 weight percent, on a dry basis, of a wood pulp which preferably has a total cellulose content of at least 97 weight percent. They are useful for the clarification of alcoholic beverages, soft drinks, vinegars and fermentation broths.

Description

SPECIFICATION Filter Aid The present invention relates to a filter composition and to a method for clarifying fluids. More particularly, the present invention relates to a filtering method which involves the use of inter pulp and wood pulp in a predetermined ratio, and to a filter composition containing said two kinds of pulp in a predetermined ratio.

In chemical industries such as the food and pharmaceutical industries, naturally-occurring inorganic materials (e.g. asbestos, diatomaceous earth, acid clay, kaolin, colloidal clay soil and zeolite), naturally-occurring organic materials (e.g. anthracite, charcoal powder, wood pulp and sawdust) and artificial products (e.g. alumina gel, silica gel and other metal oxide gels) have heretofore been employed as filtration aids in various production processes.

In the sak6-brewing industry, which has to meet the demand for refined products having high clarity, such materials as asbestos, activated carbon, diatomaceous earth and wood pulp have so far been employed as filtration aids. Of these materials, asbestos is the most desirable filter material for the purpose of attaining a high degree of clarity, and it has therefore been employed most prevalently.

Characteristically, asbestos is made up of fine fibers having diameters of the order of one micron which are closely entangled, thereby yielding a filter layer which will remove fine solids and which offers little filtration resistance. Moreover, in preparing such a filter layer, this material is advantageous in that it can be easily loosened and dispersed. On the other hand, asbestos is disadvantageous in that it is difficult to peel off the filter cloth and it cannot be incinerated after use.

Recently, the use of asbestos has been restricted by various regulations because it allegedly has adverse effects upon human beings who are in or near establishments handling this particular material. In these circumstances the food, pharmaceutical and other chemical industries have been waiting for the advent of a new and useful filter aid that may take the place of asbestos.

Wood pulp, which has large individual fiber diameters, normally in the range of from about 5 to 40 microns, is deficient in its degree of entanglement with the result that when this pulp is used in combination with, for example, activated carbon, the carbon is liable to find its way into the filtrate.

Thus wood pulp is not as effective a filter aid as asbestos.

Diatomaceous earth is not as desirable as asbestos because the degree of clarity attainable therewith is not as good, and activated carbon must be used mostly in combination with other filter aids. In the above-circumstances, these filter aids cannot be and are not effective as asbestos.

Recently, linter pulp sheet has been developed, and it has attracted attention as a substitute for asbestos. It has even been adopted by some saké-brewers. Such linter pulp sheet has been manufactured by the steps of digesting and bleaching the linter pulp from cottonseeds to prepare a refined linter pulp, and then subjecting this material to beating, drying and sheet-formation.

However, because a web of linter pulp obtained in the above way may be broken up only with substantial difficulty, some sak#-brewers have had to install specialized disintegrating machinery therefor.

To break up the web of linter pulp, such a disintegrating machine is filled with water, and the linter pulp sheet is then immersed therein in order to disintegrate it with a high-speed rotary cutter. The free water is then removed and the disintegrated pulp is added to crude sake. The filter press or other pressure-type filter is subsequently precoated with the mixture and the clarifying-filtration process is then carried out. To use linter pulp sheets, it is therefore necessary to install specialized disintegrating machinery and apparently this has limited the wide-spread application of linter pulp sheets.

Linter pulp flakes were then developed, such flakes are obtainable by loosening up beaten fibre and then drying it into flakes. To use the flakes they are first soaked in water overnight and they are then manually loosened or mechanically disintegrated using a stirrer. Subsequently the free water is removed, if necessary, and the flakes are then used in the filtration of crude saké in the same manner as paper-type linter pulp.

Linter pulp flakes are superior to linter pulp sheet in that the former do not require the use of a specialized disintegrating machine. However, the flakes are disadvantageous in that the soaking process is time-consuming and manual labor is subsequently required for loosening up the fiber. The wet linter pulp obtainable from the above described beating process, which has not been dried and which contains some water, can be disintegrated rather easily, but because of possible contamination with germs, it presents storage problems and has not been commercially utilized.

We have conducted an extensive study to develop a filter aid which may be used in lieu of asbestos and it has now been found that a mixture of linter pulp and wood pulp in certain proportions exhibits a filtration performance far surpassing that of either pulp alone. The present invention has been conceived and developed on the basis of the above finding. Accordingly, the present invention provides a filter composition comprising from 95 to 50 weight percent (on a dry basis) of a linter pulp having an alpha-cellulose content of at least 95 weight percent, preferably, at least 98 weight percent, and a beating degree of from 20 to 70 and from 5 to 50 weight percent (on a dry basis) of a wood pulp having a total cellulose content of at least 97 weight percent.The present invention also provides a method for clarifying the fluid, which is characterized by employing from 95 to 50 weight percent (on a dry basis) of a linter pulp having an alpha-cellulose content of at least 95 weight percent and a beating degree of 20 to 70 in combination with 5 to 50 weight percent (on a dry basis of a wood pulp having a total cellulose content of at least 97 percent.

The linter pulp used in the present invention contains alpha-cellulose in a proportion of at least 95 weight percent, preferably at least 98 weight percent, and has a beating degree of from 20 to 70.

Such linter pulp is manufactured by subjecting cottonseed linter pulp to digesting, bleaching and beating processes until the final product has an alpha-cellulose content of at least 95 weight percent preferably at least 98 weight percent, and a beating degree of from 20 to 70. The fiber length of the linter pulp is preferably not greater than 1.5 mm and, for still better results, not greater than 1 mm.

The wood pulp can be produced in any manner known per se and may be a hardwood pulp, a softwood pulp or a mixture of such pulps. The total cellulose content of such wood pulp is preferably not less than 97%, the grain size thereof is desirably from about 15 to 35 microns in diameter and from about 50 to 700 microns in length.

The filter composition of the present invention is produced, for example, by blending linter pulp with wood pulp. The blending of the two pulps may be carried out in a dry condition or in a wet condition, although wet blending is preferred. Thus, in the wet blending method, a wet linter pulp beaten to a beating degree of from 20 to 70 (e.g. with a water content of about 70%) is kneaded with about 5 volumes of water and then wood pulp is added in a proportion of from slightly higher than 5 to 100 percent by weight based on the solid content of the linter pulp, followed by thorough kneading.

The blending can be preformed efficiently within the range of blending ratios specified herein. The blending and kneading operation can be performed in accordance with routine manufacturing practice, for example, by means of a stirrer or mixer.

The pulp blend is then processed into flakes. This operation may be performed by means of a loosening machine, a flaking machine or any other machine that may be found suitable for the purpose.

It should be noted, however, that crushing with a high-speed revolving crusher such as a hammer mill could cause entanglement of linter pulp fibers and a consequent entrapping of air which, in turn, would detract from water dispersibility and filtering performance, thus failing to accomplish the aims of this invention. Therefore, it is generally advisable to avoid crushing. The flakes obtained as above are layered in a thickness of about 1 cm or less and then dried to a water content of generally about 10% maximum. Any known drying procedure may be employed to dry the flakes, although drying with a hot blast or air is efficient.

The blending ratio of linter pulp to wood pulp is such that from 95 to 50 weight percent (on a dry basis) of linter pulp is used in combination with from 5 to 50 weight percent (on a dry basis) of wood pulp. Preferably, the ratio is from about 90 to 70 weight percent on a dry basis or linter pulp to from about 10 to 30 weight percent on a dry basis of wood pulp. Compositions containing less than 5 weight percent wood pulp are not well dispersible and will not form a uniform filter layer.

The filter composition according to the present invention can be used in the same manner as asbestos and other known filter aids and in an amount comparable to the conventionally used amount of asbestos. In addition, using the filter composition of the present invention, it is not necessary to premix linter pulp with wood pulp and consequently the constituent pulps may be separately added to the fluid to be filtered at the time of filtering. In this case, too, the ratio of linter pulp to wood pulp may be similar to the ratio specified for the premixed composition.

The combined use of linter pulp and wood pulp according to the present invention ensures a filtering performance by far surpassing that obtainable by use of each constitutent pulp alone. Thus, linter pulp when alone cannot be disintegrated easily and, prior to use, requires prolonged soaking (e.g.

overnight) and considerably labor for subsequent fiber-loosening. In contrast, the composition according to the present invention need only be immersed in water or the fluid to be filtered for about 2 hours and does not require specialized disintegrating machinery for fiber-loosening but can be sufficiently loosened up by conventional procedures. Moreover, the loosened composition of the present invention is more readily dispersible in water than linter pulp flakes and also than wood pulp alone to make a uniform filter layer.

The composition of the present invention has a higher filtering power than linter pulp which means a shorter filtration time and moreover, the filtration surface thereof is so tough that the composition is free from carbon leakage trouble if activated carbon is used. The filtrate obtained using the composition of the present invention is sufficiently clear and, in the case of refined saké and other products, the results of organoleptic tests have been satisfactory. Furthermore, after filtering, the linter and wood pulps used in accordance with the composition of the present invention do not present disposal problems, for they may be incinerated easily and are available at low cost.

The present invention can be applied broadly to the filtration and clarification of liquids such as alcoholic beverages (e.g. sake, beer and wine), fruit juices, soft drinks, vinegars and various fermentation broths.

The following postulates may be offered with regard to the principle of the present invention. The hydrogen bonds in the fine linter pulp fibers are considered to impart tenacity to paper and therefore make the paper difficult to disintegrate in water. It would appear that as these hydrogen bonds are masked by inert wood pulp, the disintegration thereof into water is facilitated. It is thus suspected that as wood pulp is mixed with linter pulp, there results an increased tendency toward disintegration.

The following Examples further illustrate the present invention. The performance parameters indicated in this specification have the meanings defined below: o Dispersibility 0.3 g (on a dry basis) of the filter aid is suspended in about 100 ml of pure water in a 100 mlcalibrated cylinder. This suspension (100 ml) is well stirred and allowed to stand at room temperature.

The volume of the sediment formed in 5 minutes is obtained by reading the calibration to the order of ml. The value thus found is correlated with the uniformity of the filter layer.

o Disintegratability One gram (on a dry basis) of the filter aid is immersed in 20 ml of pure water at room temperature for one hour after which time it is disintegrated using a metal spatula. The ease of disintegration is evaluated according to the degree of disappearance of small lumps.

o Filtering Power One sheet of Toyo Filter Paper (No.131, diameter 70 mm Toyo Roshi K.K.) is set in position on a test pressure-filter (made of metal, filtration area 12.6 cm2, 40 mm in diameter, 300 mm long). A predetermined amount (200 g per m2 of filtration area) of the filter aid is suspended in 50 ml of a 25 weight percent aqueous solution of granular sugar and the suspension is gently added to a test filter.

The contents are washed with 50 ml of a 25 weight percent aqueous solution of granular sugar and pressurized air (160 mm Hg, constant) is introduced to obtain a precoating.

0.3 g of activated carbon is then suspended in a 25 weight percent aqueous solution of granular sugar to prepare a test fluid. This test fluid is gently poured onto the precoating layer and filtered under air pressure (1 60 mm Hg, constant) at room temperature. The volumes of filtrate are read at intervals of one minute and plotted on section paper to obtain the filtering power (m3/m2 Hr).

o Toughness and Carbon Leakage After the above filtering power test, the filter paper carrying the cake is removed from the test pressure-filter and examined for any deposit of carbon particles (carbon leaks). If the precoating layer is not tough and coherent enough, it fails to withstand the flow of fluid so that carbon particles will penetrate the filter layer to reach the surface of the filter paper.

Exfolitation Resistance The ease of exfoliation of the precoating layer from the filter cloth or paper is tested.

0Filtrate Quality The filtrate is vacuum-filtered through a membrane filter (47 mm, TM-2, 0.47 FL in diameter, Saritorius GmbH, West Germany) and the visible foreign matter residues on the filter are counted.

o Filtrate Turbidity (Clarity) The turbidity of the filtrate is measured by means of an integral bulb HTR turbidimeter (Nippon Precision Optics K.K.). Any turbidity rating of > = 4 means that the filtrate is unsatisfactory in clarity.

On the other hand, when the filtrate is sake, its turbidity is measured by the analytical method specified by the National Bureau of Taxation, Japan, Any turbidity rating of equal to or more than 30 means that the filtrate is unsatisfactory in clarity.

0Crude Saké Filtration Test A polyvinylidene chloride filter cloth is set on a filter-press (50 cellsx90 cmx90 cm, filtration area about 70 m2). Then 7 kg, (1 00 g per m2 filtration area) of the filter aid is soaked in water for about 2 hours and disintegrated by kneading for about 20 minutes. This mixture is added to crude saké in 2 or more portions and fed to the filter-press under pump pressure to make a precoating layer. (In the case of linter pulp flakes which cannot be disintegrated after 2 hours' immersion, they are soaked overnight and then disintegrated). Then, a filtration trial is carried out using 70 m3 of crude saké including activated carbon.

Example 1 Thirty (30) kilograms of wet linter pulp (degree of beating, ca. 50: 70% water) from a beating process is well kneaded with 150 1 of water. This is then further well kneaded with 2.7 kg (30% based on the solid content of linter pulp) of hardwood pulp (50 mesh pass).

The kneaded mixture is mechanically loosened up into 2 to 5 mm flakes. The flakes are spread in a layer of < about 1 cm on the load tray of a hot-air circulating- dryer and are then dried under the influence of a hot current of air at 800C for about 3 hours, whereby the water content is reduced to < 10%. In this manner, 1 1.6 kg of a composition in flake form is obtained. (Sample Code RK 50-30).

The dispersibility of Sample RK 50-30 is 76 ml as shown in Table 1. This dispersibility is greater than the value of 60 ml for linter pulp flakes and far higher than the value of 11 ml for the 50-mesh grade hardwood pulp. The filtering power of this sample is 1.1 5 m3/m2 Hr which compares favorably with 0.95 m3/m2Hr for linter pulp flakes.

Sample RK 50-30 is also tough and the clarity of filtrate is satisfactory at O to 2.3. It is also superior to the control linter pulp flakes in exfoliation resistance and disintegratability.

Filtration data on Sample RK 50-30 as to crude saké are shown in Table 2. Thus, this composition gives a filtering power of 1.1 m3/m2.Hr, a filtrate turbidity of 5 to 20 and a satisfactory exfoliation resistance. The filtrate, i.e. refined sake, gives high sensory test scores. Thus, this composition is an excellent filter aid for the production of refined sake.

Example 2 Thirty (30) kilograms (water content: 70%) of wet linter pulp from a beating process (beating degree: ca 50) is well kneaded with 1 50 1 of water and the mixture is then further well kneaded with 9 kg (100% based on the solid content of linter pulp) of 50 mesh grade hardwood pulp. The composition is loosened into 2 to 5 mm flakes by means of a flaking machine. The flakes are laid in a thickness of < about 1 cm on the load tray of a hot-air dryer and then dried under the influence of a hot current of air at 800C for about 4 hours, whereby 1 8 kg of flakes with a water content of < 10% are obtained.

(Sample Code RK 50-100).

As shown in Table 1, the RK 50-100 has a dispersibility of 60 ml, which is comparable to the value for linter pulp flakes. However, this sample has a superior filtering power, i.e. 1.33 rn#m2#Hr. The toughness of the filtration surface and the exfoliation resistance of this composition are both satisfactory, with the clarity of filtrate being 0 to 2.3. It is thus evident that the above composition is an excellent filter aid.

Filtration data on Sample RK 50-100 as to crude saké are given in Table 2. The sample gives a filtering power of 1.3 m3/m2#Hr, a filtrate (refined sake) turbidity of 5 to 20 and satisfactory exfoliation resistance and sensory test results. It is clear that the above composition is an excellent filter aid for the production of refined sake.

Example 3 Thirty (30) kilograms of wet linter pulp (water content: 70%) from a beating process (degree of beating: ca 50) is well kneaded with 1 50 1 of water and the mixture is then further kneaded thoroughly with 2.7 kg (30% based on the solids content of linter pulp) of 100-mesh grade hardwood pulp. The composition is loosened up with a flaking machine into flakes of from 2 to 5 mm in size. The flakes are laid in a thickness of < about 1 cm on the load tray of a hot-air dryer and then dried under the influence of a hot current of air at 800C for about 3 hours, whereby 11.7 kg of flakes with a water content of S 10% are obtained. (Sample Code RK 100-30).

As shown in Table 1, the dispersibility of Sample RK 100-30 is 75 ml, which compares favorably with 60 ml for linter pulp flakes. This particular composition has a filtering power of 1.21 m3/m2Hr and a filtrate clarity of O to 2.3 and is also satisfactory in toughness, exfoliation resistance and disintegratibility. It is thus evident that the above composition is an excellent filter aid.

Filtration data on Sample RK 100-30 as to crude saké are presented in Table 2. The sample gives a filtering power of 1.2 m3/m2#Hr, a filtrate (refined sake) turbidity of 5 to 20 and satisfactory exfoliation resistance and sensory test results. It is evident that the composition according to this Example is an excellent filter aid for the production of refined sake.

Example 4 Thirty (30) kilograms of wet linter pulp (water content: 70%) form a beating process (degree of beating: ca 50) is well kneaded with 1 50 1 of water and the mixture is then further well kneaded with 9 kg (100% based on the solids content of linter pulp) of 100-mesh grade hardwood pulp. The composition is loosened up with a flaking machine to prepare wet flakes of from 2 to 5 mm.

These flakes are laid in a thickness of < about 1 cm on the load tray of a hot-air dryer and then dried under the influence of a hot blast of air at 800C for about 4 hours, whereby 18 kg of flakes with a water content of ~10% were obtained. (Sample Code RK 100-100).

As shown in Table 1, the dispersibility of Sample RK 100-100 is 60 ml, which is equal to the value for linter pulp flakes.

The composition of this Example has a filtering power which is as high as 1.46 m3/m2 Hr and a filtrate clarity of O to 2.3, and is satisfactory in both toughness and exfoliation resistance. It is thus clear that this composition is a satisfactory filter aid. Filtration results with Sample RK 100-100 as to crude saké are given in Table 2. The composition shows a filtering power of 1.3 m3/m2.Hr. a filtrate (refined sake) turbidity of 5 to 20 and satisfactory exfoliation resistance and sensory test results. It is thus evident that the above composition is an excellent filter aid for the production of refined sake.

Example 5 Thirty (30) kilograms of wet linter pulp (water content: 70%) from a beating process (degree of beating: ca 50) is well kneaded with 1 50 1 of water and the mixture is then further kneaded with 2.7 kg (30% based on the solid content of linter pulp) of softwood pulp (average grain size: 100,u long). The composition is loosened up with a flaking machine to prepare wet flakes having a size of from 2 to 5 mm. The flakes are laid in a thickness of < about 1 cm on the load tray of a hot-air dryer and then dried under the influence of a hot blast or air at 800C for about 3 hours. By the above procedure there is obtained 11.7 kg of flakes with a water content of ~ 10% (Sample Code RS 100-30).

As shown in Table 1, Sample RS 100-30 has a dispersibility of 78 ml, a filtering power of 1.1 m3/m2,Hr and a filtrate clarity of O to 2.3. This composition is also satisfactory in toughness, exfoliation resistance and disintegratability.

Example 6 Thirty (30) kg of wet linter pulp (water content: 70%) from a beating process (degree of beating: ca 30) is well kneaded with 1 50 1 of water and the mixture is then further kneaded with 2.7 kg (30% based on the solid content of linter pulp) of 50-mesh grade hardwood pulp. This composition is loosened up with a flaking machine to prepare wet flakes having a size of from 2 to 5 mm. The flakes are laid in a thickness of < about 1 cm on the load tray of a hot-air dryer and dried under the influence of a hot current of air at 800C for about 3 hours. By the above procedure there is obtained 11.6 kg of flakes with a water content of < 10%. (Sample Code RK 50-30 A).As shown Table 1, the above sample gives a dispersibility of 74 ml and a filtering power of 2.4 m3/m2#Hr, which are both highly satisfactory.

The composition is also excellent with regard to toughness of the filtration surface and gives a high filtrate clarity of O to 2.3. The composition is also superior to control linter pulp flakes in exfoliation resistance and disintegratability.

Filtration trails with the above composition for the clarification of crude saké show that, as presented in Table 2, the composition is satisfactory in filtering power (1.3 m3/m2.Hr), filtrate turbidity (0--20), disintegratability, exfoliation resistance and sensory evaluation. It is thus evident that this composition is an excellent filter aid for the production of refined sake.

Example 7 Thirty (30) kilograms of wet linter pulp (water content: 70%) from a beating process is well kneaded with 1 50 1 of water and the mixture is then further kneaded thoroughly with 2.7 kg (30% based on the solid content of linter pulp) of 50-mesh grade hardwood pulp. The composition is loosened up with a flaking machine to prepare wet flakes having a size of from 2 to 5 mm. The flakes are laid in a thickness of I about 1 cm on the load tray of a hot-air dryer and then dried under the influence of a hot current of air at 800C for about 3 hours. By the above procedure there is obtained 11.6 kg of dry flakes with a water content of 6109/0. (Sample Code RK 50-30B).

As shown in Table 1, this composition is superior to control linter pulp flakes, giving a dispersibility of 80 ml and a filtering power of 2.0 m3/m2#Hr, a tough filtration surface, a filtrate clarity of O to 2.0, and satisfactory exfoliation resistance and disintegratability. The results of filtration trials with this composition for the clarification of crude saké are presented in Table 2. Thus, this composition has satisfactory filtering power (1.0 m3/m2.Hr), filtrate (refined sake') turbidity (0 to 12), disintegratibility, exfoliation resistance and sensory evaluation. It is evident that the above composition is an excellent filter aid for the production of refined sake.

Table 1 Filtration Performance Test Dispersi- Filtering Sample bility Disinte- power Exfoliation Turbidity code (mi) gratability lm3/m2Hrl Toughness resistance (clarity Linter pulp 60 Poor 0.95 Good Poor O to 2.3 (flakes) Wood pulp 11 RK50-30 76 Good 1.15 Good Good O to 2.3 RK50-100 60 Good 1.33 Good Good O to 2.3 RK100-30 75 Good 1.21 Good Good Otto2.3 RK-100-100 60 Good 1.46 Good Good O to 2.3 R5100-30 78 Good 1.1 Good Good Otto2.3 RK50-30A 74 Good 2.4 Good Good O to 2.3 RK50-30B 80 Good 2.0 Good Good O to 2.0 Table 2 Filtration Trials with Crude Saké Filtering Sample power Turbidity Exfoliation Code m3/m2#Hr {clarity) resistance Linter pulp 1.0 5 to 20 Poor (flakes) RK50-30 1.1 5 to 20 Good RK50-100 1.3 5 to 20 Good RK100-30 1.2 5 to 20 Good RK100-100 1.3 5 to 20 Good RK50-30A 1.3 0 to 20 Good RK50-30B 1.0 0two12 Good Turbidity: as measured by the analytical method specified by the National Bureau of Taxation, Japan.

Example 8 A 200-mesh screen-netting of stainless steel is set in a position on a metallic test pressure-filter with a filtration area of 12.6 cm2 (40 mm in diameterx300 mm long) and the flakes produced according to the method of Example 1 (Sample Code RK 50-30 are used [0.378 g (300 g per m2 filtration area) ] to precoat the pressure-filter in conventional manner. To 300 ml of a fermentation broth of Acetobacter aceti (lFO-3283*) is added 0.7 g of the above filter aid flakes (about 0.2% based on the broth) as a body aid and this mixture is put in the test pressure-filter. The broth is filtered under air pressure (160 mmHg, constant) and a filtration rate of 0.04 ma/m2.Hr, whereby a clear solution is obtained. The above result indicates that the composition according to the present invention is an excellent filter aid which is fully able to replace diatomaceous earth.

Claims

1. A filter composition which comprises:~ (a) from 95 to 50 weight percent, on a dry basis, of a linter pulp having an alpha-cellulose content of at least 95 weight percent and a beating degree of from 20 to 70; and (b) from 5 to 50 weight percent, on a dry basis, of a wood pulp.

2. A filter composition which comprises:- (a) from 95 to 50 weight percent, on a dry basis, of a linter pulp having an alpha-cellulose content of at least 95 weight percent and a beating degree of from 20 to 70; and (b) from 5 to 50 weight percent, on a dry basis, of a wood pulp having a total cellulose content of at least 97 weight percent.

3. A filter composition as claimed in claim 1 or claim 2 wherein the linter pulp has an alphacellulose content of at least 98 weight percent.

4. A composition as claimed in any of claims 1 to 3 wherein the linter pulp is present in an amount of from 90 to 70 weight percent (on a dry basis) and the wood pulp is present in an amount of from 10 to 30 weight percent (on a dry basis).

5. A composition as claimed in any of Claims 1 to 4 wherein the linter pulp has a fiber length of not greater than 1.5 mm.

6. A composition as claimed in claim 5 wherein the linter pulp has a fiber length of not greater than 1 mm.

7. A composition is claimed in any of claims 1 to 6 wherein the wood pulp has a grain size of from 15 to 35 microns in diameter and from 50 to 700 microns in length.

8. A composition as claimed in claim 1 or claim 2 substantially as herein described with reference to the Examples.

9. A method of clarifying and/or filtering a fluid which comprises passing said fluid through a filter composition as claimed in any of claims 1 to 8.

10. A method as claimed in claim 9 substantially as herein described with reference to the Examples.

11. A fluid whenever clarified and/or filtered by a method as claimed in claim 9 or claim 10.

12. A method as claimed in claim 9 wherein the fluid is sake, beer, wine or vinegar.

13. A method as claimed in claim 12 substantially as herein described with reference to Examples 1 to 7.

*The number preceeded by the symbol IFO- is the accession number of this organisum at the Institute For Fermentation, Osaka, Japan (IFO).

14. Sake, beer, wine, or vinegar whenever clarified and/or filtered by a method as claimed in claim 12 or claim 13.

1 5. The use of a composition as claimed in any of claims 1 to 8 for the filtration and clarification of a fluid. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~