COMPARISON OF THE FILTRATION CHARACTERISTICS BETWEEN ATTACHED AND SUSPENDED GROWTH

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COMPARISON OF THE FILTRATION CHARACTERISTICS BETWEEN ATTACHED AND SUSPENDED GROWTH MICROORGANISMS IN SUBMERGED MEMBRANE

BIOREACTOR

JUNGMIN LEE,WON-YOUNG AHN and CHUNG-HAK LEE*

School of Chemical Engineering,Seoul National University,Seoul 151-742,South Korea

(First received 27April 2000;accepted in revised form 16October 2000)

Abstract }An attached growth bioreactor was designed to minimize the e?ect of suspended microorgan-isms on membrane fouling in submerged membrane https://www.360docs.net/doc/e316905101.html,parison of mixed liquor from attached and suspended growth systems was made to elucidate major factors giving rise to di?erent ?ltration characteristics.Unexpectedly,the rate of membrane fouling of the attached growth system was about 7times higher than that of the suspended growth system despite similar characteristics of soluble fraction from the two reactors.Filtration performance proved to depend on the concentration of mixed liquor suspended solids (MLSS).Better ?ltration performance with suspended growth was explained by the formation of dynamic membranes with suspended solids.A series of analyses such as hydraulic resistance,speci?c cake resistance,scanning electron microscope,and atomic force microscope were carri-ed out to elucidate the di?erent ?ltration characteristics of the two systems.#2001Elsevier Science Ltd.All rights reserved

Keywords }submerged membrane bioreactor,suspended growth,attached growth,membrane fouling,dynamic membrane

INTRODUCTION

In wastewater treatment tighter controls on discharge limits have necessitated more elaborate and perhaps more expensive solutions than conventional biologi-cal treatment processes.One of the possible mod-i?cation of conventional biological treatment processes is the replacement of a secondary sedimen-tation tank by membrane units,which is called a membrane bioreactor (MBR).The use of MBRs in wastewater treatment is now emerging as an attrac-tive technology with considerable advantages over conventional treatment methods (Arnot and Zahir,1996;Chiemchaisri et al .,1993;Chiemchaisri and Yamamoto,1994).However,by their nature as ?lters,membranes are prone to fouling as a consequence of interactions between the membrane and the mixed liquor,which reduces the ?ltrate ?ux and increases the required membrane area (Bouh-abila et al .,1998),thereby deteriorating overall process performance.

Among theories proposed to explain ?ux behavior a resistance-in-series model,which is based on the

concept that the ?ux decline arises from a series of resistances,is generally used due to its ease of quantifying the degree of fouling.The cake resistance (R c ),one of the resistances cited in this model,has been reported as a main contributor to the total resistance (R t )in MBR processes (Chiemchaisri and Yamamoto,1994;Choo and Lee,1996a,b;Chang and Lee,1998;Kim et al .,1998;Chang et al .,1999;Lee,1999;Park et al .,1999).The cake layer could consist of a variety of components:microorganisms and various inorganic and organic substances includ-ing extracelluar polymeric substances (EPS).

A number of techniques have been explored in order to overcome membrane fouling due to the cake resistance (R c ).Those include backwashing,jet aeration,operation below critical ?ux,addition of coagulants,etc (Cote and Buisson,1997;Howell,1994;Ishida et al .,1993;Lee et al .,2000).Most of the studies have focused on minimizing the cake forma-tion on the membrane surface,but few authors have tried to remove one of the primary sources of cake layer,which are the microorganisms suspended in the bioreactor.In this study,an attached growth system was designed in order to reduce the e?ect of suspended solids on membrane fouling.Most of the microorganisms were ?xed on support media

with

*Author to whom all correspondence should be addressed.

Fax:+82-2-888-1604;e-mail:leech@snu.ac.kr

2435

only a negligible amount of microorganisms in the bulk.The ?ltration behavior and treated water quality were examined and compared with the suspended growth system and several analytical methods were applied to explain di?erent ?ltration characteristics of the two.

MATERIALS AND METHODS

Experimental setup

Figure 1shows a schematic diagram of the experimental setup for MBR.Two di?erent experimental settings were designed for attached and suspended microbial culture systems,respectively,in order to compare the ?ltration performance between them.Detailed operating conditions are shown in Table 1.A U-shaped hollow ?ber membrane module was immersed in the bioreactor having 5L of working volume.Hollow ?ber micro?lters used were made of polyethylene with apore size of 0.1m m (Mitsubishi Rayon Co.,Ltd.,Japan).Aeration was done through di?users at the bottom of the reactor to provide oxygen for biomass growth as well as shear to reduce cake formation at membrane surface.The bioreactors were put into a water bath to control the temperature at 258C.The membrane permeate was continuously removed by a peristaltic pump under a constant ?ux (25L/m 2/h),con-stantly monitoring the transmembrane pressure (TMP)build-up which indicates the extent of membrane fouling.The operation was stopped when the TMP reached 26kPa because it was di?cult to maintain the ?ux at constant level at TMP of over 26kPa.

The feeding ?ow rate of synthetic wastewater was 15L/d.The constant permeate ?ux was 25.0L/m 2/h,which is equal to the permeate ?ow rate of 40.4L/d with the membrane surface area of 0.0673m 2.Thus approximately 63%(25.4L/d)of the permeate was returned to the reactor in order to keep the reactor volume constant.It was necessary to operate the systems at a comparably higher permeate ?ux than usual to see the e?ect of each experimental parameter on the system performance in a limited time in the laboratory.However,the permeate recycle to the reactor does not seem to a?ect

the microbial conditions because the permeate originates from the reactor.

The membrane ?ux was calculated using an on-line computer connected to an electronic balance.All electric devices were connected to programmable logic controller (PLC,Master K10S,LG Industrial System,Korea)to automatically control the whole system.For attached growth (Fig.2(a)),looped cord media (BioMatrix Technol-ogies Inc.,USA)of which the total surface area was 4.37m 2was immersed into the reactor at least for a month with continuous feeding of the wastewater prior to the operation of micro?ltration.For suspended growth (Fig.2(b)),all the experimental setup and operating conditions are exactly same as those with attached growth except the elimination of the looped cord mediafrom the biorea ctor.

The stock of synthetic wastewater was stored in a refrigerator and diluted with tap water before feeding.The composition of synthetic wastewater fed to the reactor is shown in Table 2.The main sources of carbon and nitrogen were glucose and ammonium sulfate,respectively.The ratio of COD:N:P in the feed was maintained at 100:10:1with an in?uent COD concentration of 250mg/L.Sodium bicarbonate was added as a bu?er in order to control the pH of the mixed liquor in the range of 6.8–7.2.Analytical methods

Mixed liquor suspended solids (MLSS)was measured according to the analytical methods described in

the

Fig.1.Schematics of a submerged membrane bioreactor.

Table 1.Operating conditions of submerged membrane bioreactors

for both attached and suspended growth systems Constant ?ux (L/m 2/h)

25Maximum transmembrane pressure (kPa)26Temperature (8C)25Air ?ow rate (L/min) 2.5Working volume (L)5HRT (h)

8Feed concentration (mgCOD/L)

250Volumetric organic loading (kgCOD/m 3/day)0.75PH

7.0?0.2DO (mgO 2/L)

6.1?0.1

Jungmin Lee et al.

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Standard methods (APHA,1995).Mixed liquor pH was measured with a pH meter (Dong woo Medical System,Korea)and dissolved oxygen with a DO meter (58,YSI,USA).Chemical oxygen demand (COD)was determined by spectrophotometric method with DR 2000(Hach,USA)instrument and total organic carbon (TOC)by TOC analyzer DC-180(Rosemount,USA).Nitrate and ammo-nium concentrations were measured using ion selective electrodes and an autotitrator (Orion 940,USA).

To measure the amount of attached biomass on looped cord media,a sample of media was saturated with water at the start of the experiment,allowed to drip dry for 3min and dried at 1058C to measure the mass of the media.Every two days media samples were pulled from the reactor one by one to measure any change of the amount of biomass attached.

Protein and polysaccharide were analyzed by spectro-photometric methods;Dye-binding method was applied for protein analysis with Coomassie Brilliant Blue and BSA (bovine serum albumin)as a dye and a standard,respectively (Holme and Pect,1983).For quantitative analysis of polysaccharide,the phenol–sulfuric acid method was used with glucose as a standard (Dubois et al .,1956).The molecular weight distribution of soluble organics was measured with gel permeation chromatography (GPC,Waters,USA).Polyethyleneoxide (SE-150,Tosoh,Japan)was used as a standard.Refractive index detector (RID,Waters R401,USA)and Shodex-Ohpak KB 802,803columns were used.

The cake layers of mixed liquor in the attached and suspended growth systems were visualized by scanning electron microscope (SEM)(JSM-35,JEOL,Japan)and an atomic force microscope (AFM)(Dimension 3000,Digital Instruments).

Characterization of major components of soluble organics The oxidation states of organic molecules vary according to their chemical structures.Therefore,if the oxidation state of organic carbon is determined,rough estimation of the main substances in the sample solution could be made.If COD is expressed in mol O 2/L and TOC in mol C/L,the ‘‘average’’oxidation state of the organic carbon present can be obtained from equation (1)(Stumm and Morgan,1981).Oxidation state of organic carbon ?4eTOC àCOD T

TOC

e1T

In this context,soluble organics in the mixed liquor and on the membrane surface after ?ltration run were char-acterized by analyzing their oxidation states of organic carbons.Soluble organics in the mixed liquor was obtained with the centrifugation of the mixed liquor at 2000g for 10min and then second centrifugation of the supernatant at 10;000g for another 10min was given to completely remove microbial ?ocs and colloidal particles.The ?nal supernatant was analyzed for the characterization of soluble organics in the mixed liquor.To analyze the organic substances on the membrane surface after ?ltration run,the membranes were placed in phosphate bu?er solution and sonicated for 30min.The bu?er solution after sonication was centrifuged in the same way as described above.The ?nal supernatant containing organic solutes was analyzed in terms of COD and TOC to calculate the mean oxidation state of organic carbon using equation (1).

Batch stirred cell ?ltration

In order to examine the characteristics of the cake on the membrane surface,batch ?ltration experiments were per-formed in dead-end ?ltration mode using stirred cell unit (Amicon 8200,USA).Hydrophilic PVDF (polyvinylidene di?uoride)membrane with 0.22m m pore (GVWP,Millipore Corp.)was used.The membrane surface area was 30cm 2and the operating pressure ranged from 10to 110kPa.Speci?c cake resistances were measured under unstirred

conditions.

Fig.2.Submerged MBR:(a)attached growth (MLSS:100–2000mg/L,attached biomass:2000mg/L)and

(b)suspended growth (MLSS:3000mg/L)microorganisms.

Table https://www.360docs.net/doc/e316905101.html,position of synthetic wastewater

Composition Concentration (mg/L)

C 6H 12O 6

114C 5H 8NNaO 4H 2O 48.7(NH 4)2SO 4

56.7CH 3COONH 437.7NH 4Cl 5.67KH 2PO 4 5.00K 2HPO 4

7.00MgSO 4á7H 2O 9.02FeCl 3á6H 2O 0.21NaCl

6.77CaCl 2á2H 2O 0.60NaHCO 3

150

Permeability vs.growth pattern in submerged MBR 2437

The speci?c cake resistance was calculated using the slope of the plot of 1=J 2vs.t from equation (2)and the compressibility of the cake layer was determined using equation (3)(Chudacek and Fane,1984)

1J 2?R m m D P 2t

2m C b a

D P

t e2Ta ?a 0D P n

e3Twhere J is the permeate ?ux,R m is membrane resistance,m is the viscosity of permeate,D P is the operating pressure,C b is the MLSS concentration,a is the speci?c cake resistance,t is ?ltration time,a 0is the speci?c cake constant,and n is the compressibility of the cake layer.Resistance analysis

According to the resistance-in-series model the relation-ship between permeate ?ux and TMP can be given by (Choo and Lee,1996a)

J ?

D P t

e4TR t ?R m tR c tR f

e5T

where J is the permeate ?ux,D P is TMP,m is the viscosity of the permeate,and R t is total membrane resistance,R m is the intrinsic membrane resistance,R c is the cake resistance,and R f is the fouling resistance due to irreversible adsorption and pore plugging.

Flux and TMP data are used to calculate resistances by equation (4);?ltration of pure water with new membrane before operation gives R m and R t is calculated from the ?nal ?ux and TMP values at the end of the operation.R m tR f is measured after removing the cake layer by washing the membrane with tap water after the operation followed by ?ltration of pure water.From these values each of R t ;R m ;R c ,a nd R f can be obtained using equation (5).

RESULTS AND DISCUSSION

The performance of MBR processes were studied using submerged hollow ?ber membranes.Suction-type of micro?ltration of the mixed liquor for the attached growth (Fig.2(a))and suspended growth (Fig.2(b))systems were carried out,respectively,in order to compare each other in terms of ?ltration characteristics and quality of treated water.Attempts were then made to ?nd out factors a?ecting di?erent ?ltration characteristics between the two.Treatment e?ciency

The submerged MBR system was operated at HRT of 8h along with almost complete rejection of microorganisms for both systems.COD,NH 4–N,

and NO 3–N concentrations in the permeate were

monitored together with TMP variations during the system operation.In both systems,over 98%removal of COD and 95%removal of NH 4–N (Table 3)were achieved with the synthetic wastewater containing 250mgCOD/L and 20.2mgNH 4–N/L,showing that the treatment e?ciency was in excellent levels irrespective of growth conditions.Filtration characteristics

The increase rate of TMP is an important factor to evaluate the system performance in submerged MBR because it is directly related to the rate of membrane fouling.

The MLSS concentration in the suspended growth reactor was 3000mg/L.On the other hand,the attached growth reactor contained only 100mg/L of MLSS while 2000mg/L of biomass were attached on the looped cord media.It was practically impossible to maintain MLSS concentration less than 100mg/L even in the attached growth reactor because release of microorganisms o?the cord media to the mixed liquor was inevitable.TMP was monitored under constant ?ux condition,and the operation was stopped when the TMP reached 26kPa.In case of suspended growth system the TMP increased to 26kPa after about 140h of operation,while it took only 20h for the attached growth system (Fig.3).In other words,the increase rate of the TMP for attached growth was surprisingly 7times higher than that for the suspended growth system.The attached growth system was originally designed to alleviate membrane fouling by removing the sources of

cake

Table 3.COD and ammonia removal e?ciency in attached and suspended growth MBR

COD (mg/L)

NH 4+–N (mg/L)

In?uent 250

20.2(TN 23.9)

Attached growth a

Suspended growth b

Attached growth a

Suspended growth b

Permeate 350.990.17%remov a

a MLSS:100mg/L,attached biomass:2000mg/L.b

MLSS:3000mg/L.

Jungmin Lee et al.

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layer,i.e.suspended solids and colloidal particles. However,contrary to expectations,membrane foul-ing proceeded much faster with the attached growth system than with the suspended growth although the latter had suspended solids30times higher than the former.

Other operating conditions being equal,the extent of fouling was believed to vary according to the mixed liquor composition in the bioreactor because membrane fouling should be the result of interaction between the mixed liquor and the membrane.The components of mixed liquor may be divided into two groups:(1)soluble fraction and(2)suspended solids including biomass and other colloids.Although the attached growth system was designed to minimize the e?ect of the latter,i.e.suspended solids,on mem-brane fouling,faster membrane fouling was observed with attached growth than that with suspended growth.In this context,soluble fraction,not sus-pended portion was thought to be more responsible for the membrane fouling in MBR.Consequently, comparison of soluble fraction of mixed liquor between the attached and suspended growth was made in order to explain such unexpected?ltration characteristics.

Comparison of soluble organic compounds in mixed liquor

A bioreactor like an activated sludge tank contains a variety of soluble organic compounds,such as residual in?uent substrate and soluble microbial products(SMP).The term SMP has been adopted to de?ne the pool of organic compounds that are released into bulk solution from substrate metabo-lism(usually with biomass growth)and biomass decay(Barker and Stuckey,1999).Soluble com-pounds have been also reported to have larger fouling ability than suspended solids due to their interaction with the membrane material(Bouhabila et al.,1998;Wisniewski and Grasmick,1998). Therefore,it might be suggested that the mixed liquors in the attached and suspended growth should contain di?erent soluble compounds from each other,which would lead to di?erent?ltration behavior.Several features such as(i)molecular weight distribution,(ii)organic contents,and(iii) oxidation state of organic carbons in the mixed liquor for both attached and suspended growth reactor were examined.

In order to compare the molecular weight(MW) distributions,mixed liquor from each reactor was pretreated with0.45m m?lter prior to GPC analysis. As shown in Fig.4,both solutions contained various compounds with awide distribution of MW from 0.1to400kDa;MW51kDa:20–25%,MW10–400kDa:40%.However,the attached and suspended growth bioreactors contained soluble organic com-pounds of quite similar MW distributions.TOC analysis was also adopted to characterize soluble organic contents.Two kinds of fractionation meth-ods for mixed liquors,?ltration and centrifugation, were employed to prepare analytical samples of soluble fractions because the de?nition of‘‘soluble’’compounds is still open to some debate.In the ?ltration method,a0.45m m?lter was used to separate soluble organic compounds from the mixed liquor.In the other method,mixed liquor was?rst separated by centrifugation at2000g for10min and the supernatant free of microbial?ocs was centri-fuged again at10;000g for10min to further remove residual colloids.The supernatant obtained from the ?nal step was used for TOC analysis.The TOC measurement showed that both attached and sus-pended growth reactors contained nearly the same amount of soluble organics regardless of the separa-tion methods(Fig.

5(a)).

Fig. 4.Molecular weight distribution of soluble organic compounds in mixed liquor for attached growth(MLSS: 100mg/L,attached biomass:2000mg/L)and suspended

growth(MLSS:3000

mg/L).

EPS are soluble organic macromolecules that are a major fraction of soluble microbial products due to metabolism and cell autolysis(Wingender et al., 1999).The quantitative analysis of EPS was per-formed because EPS have been reported not only as major sludge?oc components keeping the?oc together in a three-dimensional matrix,but also as key membrane foulants in MBR system(Nagaoka et al.,1996).In this study,protein and polysaccharide concentrations were measured as they are known to be the main constituents of EPS.Protein and polysaccharide contents of soluble EPS in suspended growth reactor were slightly larger than those in the attached growth reactor(Fig.5(b)).However,the di?erence in protein and polysaccharide quantity as well as their absolute concentrations(less than1.0 and 1.8mg/L each)was not so signi?cant that it could be concluded that both systems contained similar species and quantities of EPS though they were in di?erent growth conditions.

From the COD and TOC measurements the mean oxidation states of soluble organic carbons in attached and suspended growth reactors were calcu-lated based on equation(1)and summarized in Table 4.Based on the calculated mean oxidation states,main constituents of organic compounds were roughly estimated according to Stumm and Morgan (1981).The mean oxidation states of2–3of organics in the mixed liquor corresponds to organic acids, suggesting that the major components for both systems had carbons in the form of organic acids which might be metabolic by-products or end-products of biodegradation.By contrast,as the mean oxidation states(à0.8toà1.2)represents proteins and polysaccharides,they were presumed to be the major components of organic substances accumu-

lated on the membrane surface,possibly due to their hydrophobic interactions with the membrane. Anyway,as the mean oxidation states of organics for both systems appeared to be almost the same in the mixed liquors as well as on the membrane surface it could be concluded that quantitative and qualitative characteristics of the soluble organic fractions in the mixed liquors did not vary according to the growth conditions.In summary, based on the series of examinations described above,the di?erent?ltration performance between two systems could not be attributed to the organic fractions in the mixed liquors.Consequently,we returned to the starting point and paid deeper attention to the suspended fraction instead of the soluble one.

Mixed liquor suspended solids

One of the clearest distinctions between attached and suspended growth systems should be the MLSS concentrations:the attached growth reactor con-tained only about100mgMLSS/L which corre-sponded to only 3.3%of the MLSS in the T

Jungmin Lee et al. 2440

suspended growth reactor(3000mgMLSS/L).It was presumed that such di?erence might have brought about di?erent?ltration performance.In this con-text,further micro?ltration experiments were carried out changing the MLSS concentrations in both attached and suspended growth systems in order to ?nd out the e?ect of MLSS concentration on micro?ltration characteristics.In all experiments, the attached growth reactor retained additional 2000mg/L of biomass attached on the looped cord mediaimmersed in the biorea ctor.The MLSS concentration for the attached growth changed from 100to2000mg/L,whereas it changed from2000to 5000mg/L for the suspended growth system.The change in MLSS concentration was achieved by adjusting the sludge retention time(SRT)in the reactor without additional biomass input.MLSS was increased with increase in SRT.When MLSS reached the intended concentration,additional2–3times the SRT were required to achieve stable sludge condition prior to the?ltration experiment.As shown in Fig.6, the rate of membrane permeability loss(e.g.,the rising rate of TMP)was retarded along with the increase in MLSS concentrations regardless of growth conditions, e.g.,the higher the MLSS concentration,the slower the rising rate of TMP. For example,in the suspended growth system it took 75h for TMP to reach26kPa at the MLSS of 2000mg/L,whereas it took260h at the MLSS of5000mg/L.It was particularly interesting, however,that at the same MLSS concentration of2000mg/L,the two systems gave rise to almost the same?ltration behavior;TMP reached26kPa after the almost same?ltration time for both systems (70and75h for attached and suspended growth system,respectively).From these experimental re-sults,MLSS was thought to have been mainly responsible for the unexpected better?ltration performance of the suspended growth system than that of the attached one.Formation of a dynamic membrane by mixed liquor suspended solids

Suspended solids could be an important factor a?ecting membrane permeability because the sus-pended solids,mainly microbial?ocs,in MBR could form a dynamic membrane on the surface of membrane.The conceptual illustration of dynamic membrane is shown in Fig.7.Small particles like soluble organics will deteriorate the permeability of membrane by directly adsorbing onto the surface or inside the membrane pores when arriving at the membrane without any interruption(Fig.7(a)). However,when large particles like microbial?ocs are present(Fig.7(b)),the deposit layer of micro-organisms will accumulate on the membrane surface which is known as a dynamically formed membrane (Shoji et al.,1990;Holdich and Boston,1990). Because low molecular weight substances or sub-micron colloidal particles could be rejected/sorbed and biodegraded by the dynamic membrane com-posed of living microorganisms(Yamagiwa et al., 1995),the dynamic membrane would provide small molecules with fewer chances of interaction with membranes and thereby alleviate the rate of mem-brane fouling.Also,the dynamic membrane may be removed from the membrane by the tangential air–liquid?ow to the membrane surface because aeration was provided continuously in MBR.Repeated processes of formation and removal of dynamic membranes may slow down the loss of membrane permeability.However,it may be worth noting that aeration in submerged MBR may have some negative e?ects on membrane permeability because soluble or submicron particles can directly adsorb inside and block the membrane pores if dynamic membrane is removed by the tangential air–liquid

?ow.

Fig.6.Filtration behaviors with varying MLSS concentra-

tion in attached and suspended growth

bioreactor.

Fig.7.Conceptual illustration of membrane fouling(a)

without and(b)with dynamic membrane.

Permeability vs.growth pattern in submerged MBR2441

To prove the existence of dynamic membrane,the SEM images of membrane surfaces were inves-tigated after ?ltration runs for attached and sus-pended growth systems.The membrane pores of a new membrane were clearly seen on the SEM image (Fig.8(a)).While the surface of the membrane used for the suspended growth (MLSS:3000mg/L)reactor was covered with the microbial ?ocs and EPS layers (Fig.8(b)),the membrane surface used for the attached growth (MLSS:100mg/L,attached biomass:2000mg/L)system was covered with some slime or gel layers (Fig.8(c)),but not so signi?cantly as that of the suspended system.AFM images provide some information on the roughness of the cake layer in each system.As shown in Fig.9,the cake layer in the suspended growth

was

Fig.9.AFM images of cake layer on membrane surfaces after ?ltration run:(a)used membrane for suspended growth (MLSS:3000mg/L)and (b)used membrane for attached growth (MLSS:100mg/L,

attached biomass:2000mg/L).a:root mean

square.

Fig.8.SEM images of cake layer on membrane surfaces after ?ltration run:(a)new membrane (?5,000),(b)used membrane for suspended growth (MLSS:3000mg/L,?5,000),and (c)used membrane for

attached growth (MLSS:100mg/L,attached biomass:2000mg/L,?5,500).

Jungmin Lee et al.

2442

recon?rmed to be rougher than that in the attached one as could be expected from the SEM images,comparing the standard deviation of the height of each cake layer.Resistance analysis

In this study,the attached growth system was originally designed in order to reduce the cake layer resistance (R c )which has been known as a major contributor to the total resistance (R t )(Chiemchaisri and Yamamoto,1994;Choo and Lee,1996a,b;Chang and Lee,1998;Kim et al .,1998;Chang et al .,1999;Lee,1999;Park et al .,1999).Resistance analysis was performed after ?ltration run in order to con?rm any changes in various resistances by introducing attached growth system (Table 5).R m ;R c ,a nd R f were measured right after the TMP reached 26kPa.It took 20h for attached (MLSS:100mg/L,attached biomass:2000mg/L)and 140h for suspended (MLSS:3000mg/L)growth to reach this TMP.In other words,the same total resistance was obtained about 7times faster with attached growth compared with suspended growth.Small decrement in R c was observed in attached growth system compared to suspended growth,but still R c held a large part of R t .However,decrease in R c was compensated with an increase in fouling resistance (R f ),which eventually led to severer loss of per-meability in the attached growth system.These results revealed that soluble or colloidal particles as well as microorganisms in the mixed liquor could accumulate and form a secondary dynamic mem-

brane on the surface of membrane,but without this the internal fouling would be severer.This is the reason why the R f value in the attached growth system is greater than that in the suspended one.Properties of cake layer on membrane surface Speci?c cake resistance is a parameter characteriz-ing the cake layer formed on the membrane surface during ?ltration.Unstirred cell ?ltration was carried out to determine the speci?c cake resistances of cake layers in both attached and suspended growth system.The speci?c cake resistance (a )and the compressibility (n )of the cake layers were analyzed by changing the operating pressure in the range of 14–109kPa and using equations (2)and (3).As shown in Fig.10,the speci?c cake resistances in the attached growth (MLSS:100mg/L,attached bio-mass:2000mg/L)was one order of magnitude higher than that of mixed liquor in the suspended growth (MLSS:3000mg/L)through all the pressures tested.The compressibility of mixed liquor for attached (MLSS:100mg/L,attached biomass:2000mg/L)and suspended (MLSS:3000mg/L)growth were 0.79and 1.08,respectively,indicating that the mixed liquor of suspended growth was more compressible than that of attached growth.As the cake layer in the suspended growth system contains more microorgan-isms,it may have higher compressibility.The low concentration of suspended microorganisms in the attached growth system could induce a lower compressibility of the cake layer.Also the AFM image of the cake layer of each system revealed

Table 5.E?ect of growth pattern on each resistance in the submerged MBR c

Attached growth a

Suspended growth b

1012/m

%1012/m %R m 0.49120.5012R c 2.9469 3.3980R f 0.81190.358R t

4.24

100

4.24

100

a MLSS:100mg/L,attached biomass:2000mg/L.b

MLSS:3000mg/L.c

R m ;R c ,a nd R f were measured right after the TMP reached 26kPa.It took 20h for attached and 140h for suspended growth to obtain the same total resistance of 4.24?1012

/m.

Fig.10.Speci?c cake resistances of mixed liquors for attached and suspended growth.

Permeability vs.growth pattern in submerged MBR 2443

rougher cake layer for the suspended growth system, which implicates loose packing of the particles and thus providing larger channels for the permeate?ow (Fig.9).These suggested that the mixed liquor of attached growth would have a higher fouling potential compared with that of suspended growth. However,when MLSS of2000mg/L existed in both attached and suspended growth reactors,little di?erence in both speci?c cake resistance and compressibility was observed demonstrating similar cake properties.It was a well expected result judging from the similar?ltration behavior at the same MLSS concentration(Fig.6).

CONCLUSIONS

In this study,two types of submerged MBR (attached and suspended growth systems)were compared with respect to various aspects in order to elucidate di?erent?ltration behavior from each other.The following conclusions could be drawn: (1)The loss of membrane permeability proceeded

more rapidly with the attached growth system than with the suspended one.

(2)Better?ltration performance with suspended

growth was attributed to the role of dynamic membrane formed on the membrane surface, which was con?rmed by SEM and AFM images.

This conclusion was drawn based on(i)the quantitatively and qualitatively similar proper-ties of soluble organic compounds in mixed liquors for both systems and(ii)the improve-ment of membrane permeability with increasing in MLSS concentrations regardless of growth conditions.

(3)Better?ltrability with the suspended growth

could also be due to the rougher cake layer having smaller speci?c cake resistance than that with the attached growth.

Acknowledgements}The authors would like to thank the Korean Ministry of Science&Technology for their?nancial support under Grant98-1-01-04-A-021.Mitsubishi Rayon Co.Ltd.,Japan,is acknowledged for providing the hollow ?ber membranes and BioMatrix Technologies Inc.,USA, for the looped cord media.

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Permeability vs.growth pattern in submerged MBR2445

The way常见用法

The way 的用法 Ⅰ常见用法： 1)the way+ that 2)the way + in which（最为正式的用法） 3)the way + 省略（最为自然的用法）举例：I like the way in which he talks. I like the way that he talks. I like the way he talks. Ⅱ习惯用法：在当代美国英语中，the way用作为副词的对格，“the way+ 从句”实际上相当于一个状语从句来修饰整个句子。 1)The way =as I am talking to you just the way I’d talk to my own child. He did not do it the way his friends did. Most fruits are naturally sweet and we can eat them just the way they are—all we have to do is to clean and peel them. 2）The way= according to the way/ judging from the way The way you answer the question, you are an excellent student. The way most people look at you, you’d think trash man is a monster. 3）The way =how/ how much No one can imagine the way he missed her. 4）The way =because

The way的用法及其含义(二)

The way的用法及其含义（二）二、the way在句中的语法作用 the way在句中可以作主语、宾语或表语： 1.作主语 The way you are doing it is completely crazy.你这个干法简直发疯。 The way she puts on that accent really irritates me. 她故意操那种口音的样子实在令我恼火。The way she behaved towards him was utterly ruthless. 她对待他真是无情至极。 Words are important, but the way a person stands, folds his or her arms or moves his or her hands can also give us information about his or her feelings. 言语固然重要,但人的站姿,抱臂的方式和手势也回告诉我们他(她)的情感。 2.作宾语 I hate the way she stared at me.我讨厌她盯我看的样子。 We like the way that her hair hangs down.我们喜欢她的头发笔直地垂下来。 You could tell she was foreign by the way she was dressed. 从她的穿著就可以看出她是外国人。 She could not hide her amusement at the way he was dancing. 她见他跳舞的姿势，忍俊不禁。 3.作表语 This is the way the accident happened.这就是事故如何发生的。 Believe it or not, that's the way it is. 信不信由你, 反正事情就是这样。 That's the way I look at it, too. 我也是这么想。 That was the way minority nationalities were treated in old China. 那就是少数民族在旧中

(完整版)the的用法

定冠词the的用法：定冠词the与指示代词this ,that同源,有“那(这)个”的意思,但较弱,可以和一个名词连用,来表示某个或某些特定的人或东西. (1)特指双方都明白的人或物 Take the medicine.把药吃了. (2)上文提到过的人或事 He bought a house.他买了幢房子. I've been to the house.我去过那幢房子. (3)指世界上独一无二的事物 the sun ,the sky ,the moon, the earth (4)单数名词连用表示一类事物 the dollar 美元 the fox 狐狸或与形容词或分词连用,表示一类人 the rich 富人 the living 生者 (5)用在序数词和形容词最高级,及形容词等前面 Where do you live?你住在哪? I live on the second floor.我住在二楼. That's the very thing I've been looking for.那正是我要找的东西. (6)与复数名词连用,指整个群体 They are the teachers of this school.(指全体教师) They are teachers of this school.(指部分教师) (7)表示所有,相当于物主代词,用在表示身体部位的名词前 She caught me by the arm.她抓住了我的手臂. (8)用在某些有普通名词构成的国家名称,机关团体,阶级等专有名词前 the People's Republic of China 中华人民共和国 the United States 美国 (9)用在表示乐器的名词前 She plays the piano.她会弹钢琴. (10)用在姓氏的复数名词之前,表示一家人 the Greens 格林一家人(或格林夫妇) (11)用在惯用语中 in the day, in the morning... the day before yesterday, the next morning... in the sky... in the dark... in the end... on the whole, by the way...

“the way+从句”结构的意义及用法

“tｈｅwａｙ+从句”结构的意义及用法首先让我们来看下面这个句子: Ｒead the foｌloｗｉnｇpassagｅａnd talkａbout ｉt wi ｔh your classmaｔes．Try tｏｔeｌl whaｔyｏu thiｎk ｏf Tom aｎd ｏｆｔhe ｗay the chiｌｄrenｔrｅated ｈim. 在这个句子中，ｔhe waｙ是先行词,后面是省略了关系副词that或in whｉch的定语从句。下面我们将叙述“the ｗaｙ+从句”结构的用法。 1.tｈe wａy之后，引导定语从句的关系词是tｈat而不是hoｗ,因此，<<现代英语惯用法词典＞＞中所给出的下面两个句子是错误的：Ｔhｉs is ｔｈeｗayｈowｉtｈａppened. This is the way how he ａlwａｙs treats me. 2．在正式语体中,thaｔ可被in which所代替;在非正式语体中，ｔhat则往往省略。由此我们得到theｗay后接定语从句时的三种模式：1) tｈe ｗaｙ＋ｔhａt-从句２）the way +ｉn whiｃh－从句3) the ｗay +从句例如：Ｔｈe way(in whiｃh ，thａt) ｔhｅｓｅｃomｒade ｓloｏｋａｔｐrobｌems is wrong．这些同志看问题的方法

不对。Ｔｈｅｗａy(that ,ｉn ｗhiｃh)yoｕ’ｒe doinｇit is comple ｔeｌy crａzy.你这么个干法,简直发疯。 Wｅａdmiｒｅd him for thｅｗay ｉｎｗhｉch he fａｃeｓdiｆficultieｓ． Waｌlａｃe ａｎd Ｄarwiｎｇreed ｏn the way ｉｎwhi ｃh ｄｉfｆｅrｅnt forms ｏf life had ｂegｕn.华莱士和达尔文对不同类型的生物是如何起源的持相同的观点。 Thｉs is ｔｈe ｗaｙ（tｈａｔ) hｅdｉd it. I lｉkeｄｔhe waｙ(ｔhat) ｓｈeｏｒganized ｔhe ｍeetｉng． 3.theｗay(tｈat)有时可以与hｏw(作“如何”解）通用。例如： That’s tｈe ｗaｙ(tｈaｔ) shｅspoke. = Tｈat’s how shｅspoke.

Filtration

Filtration (过滤) The separation of solids form a suspension in a liquid by means of a poroous medium or screen which retains the soilds and allows the liquid to pass is termed filtration. 形成一个分离的固体悬浮在液体通过的多孔介质或屏幕的固体颗粒和保留允许液体通过被称为过滤。 In general,the pores of the medium will be larger than the particles which are to be removed,and the filter will work efficiently only after an initial deposit has been trapped in the medium.In the chemical laboratory, filtration is often carried out in a form of Buchner funnel ,and the liquid is sucked through the thin layer of particles using a source of vacuum:in even simpler eases the suspension is poured into a conical funnel fitted with a filter paper. 一般来说,孔隙介质的颗粒将大于中移走,并将与过滤能工作的很有效率只有经过一初始存款已陷于媒介。在化学实验室,进行过滤是经常在某种形式的Buchner漏斗,液体吸通过颗粒的薄层使用的一个来源:甚至在真空悬架系统是简单的简化了倒进一个锥形的漏斗配有一个滤纸。 In the industrial equivalent of such an operation, difficuities are involwed in the mechanical handling of much larger quantities of suspension and solids .A thicker layer of solids has to form and, in order to achieve a high rate of passage of liquid through the solids

way 用法

表示“方式”、“方法”，注意以下用法： 1.表示用某种方法或按某种方式，通常用介词in(此介词有时可省略)。如： Do it (in) your own way. 按你自己的方法做吧。 Please do not talk (in) that way. 请不要那样说。 2.表示做某事的方式或方法，其后可接不定式或of doing sth。如： It’s the best way of studying [to study] English. 这是学习英语的最好方法。 There are different ways to do [of doing] it. 做这事有不同的办法。 3.其后通常可直接跟一个定语从句(不用任何引导词)，也可跟由that 或in which 引导的定语从句，但是其后的从句不能由how 来引导。如：我不喜欢他说话的态度。正：I don’t like the way he spoke. 正：I don’t like the way that he spoke. 正：I don’t like the way in which he spoke. 误：I don’t like the way how he spoke. 4.注意以下各句the way 的用法： That’s the way (=how) he spoke. 那就是他说话的方式。 Nobody else loves you the way(=as) I do. 没有人像我这样爱你。 The way (=According as) you are studying now, you won’tmake much progress. 根据你现在学习情况来看，你不会有多大的进步。 2007年陕西省高考英语中有这样一道单项填空题： ——I think he is taking an active part insocial work. ——I agree with you_____. A、in a way B、on the way C、by the way D、in the way 此题答案选A。要想弄清为什么选A，而不选其他几项，则要弄清选项中含way的四个短语的不同意义和用法，下面我们就对此作一归纳和小结。一、in a way的用法表示：在一定程度上，从某方面说。如： In a way he was right.在某种程度上他是对的。注：in a way也可说成in one way。二、on the way的用法 1、表示：即将来(去)，就要来(去)。如： Spring is on the way.春天快到了。 I'd better be on my way soon.我最好还是快点儿走。 Radio forecasts said a sixth-grade wind was on the way.无线电预报说将有六级大风。 2、表示：在路上，在行进中。如： He stopped for breakfast on the way.他中途停下吃早点。 We had some good laughs on the way.我们在路上好好笑了一阵子。 3、表示：(婴儿)尚未出生。如： She has two children with another one on the way.她有两个孩子，现在还怀着一个。 She's got five children，and another one is on the way.她已经有5个孩子了，另一个又快生了。三、by the way的用法

The way的用法及其含义(一)

The way的用法及其含义（一）有这样一个句子：In 1770 the room was completed the way she wanted. 1770年，这间琥珀屋按照她的要求完成了。 the way在句中的语法作用是什么？其意义如何？在阅读时，学生经常会碰到一些含有the way 的句子，如：No one knows the way he invented the machine. He did not do the experiment the way his teacher told him.等等。他们对the way 的用法和含义比较模糊。在这几个句子中，the way之后的部分都是定语从句。第一句的意思是，“没人知道他是怎样发明这台机器的。”the way的意思相当于how；第二句的意思是，“他没有按照老师说的那样做实验。”the way 的意思相当于as。在In 1770 the room was completed the way she wanted.这句话中，the way也是as的含义。随着现代英语的发展，the way的用法已越来越普遍了。下面，我们从the way的语法作用和意义等方面做一考查和分析：一、the way作先行词，后接定语从句以下3种表达都是正确的。例如：“我喜欢她笑的样子。” 1. the way+ in which +从句 I like the way in which she smiles. 2. the way+ that +从句 I like the way that she smiles. 3. the way + 从句(省略了in which或that) I like the way she smiles. 又如：“火灾如何发生的，有好几种说法。” 1. There were several theories about the way in which the fire started. 2. There were several theories about the way that the fire started.

way 的用法

way 的用法【语境展示】 1. Now I’ll show you how to do the experiment in a different way. 下面我来演示如何用一种不同的方法做这个实验。 2. The teacher had a strange way to make his classes lively and interesting. 这位老师有种奇怪的办法让他的课生动有趣。 3. Can you tell me the best way of working out this problem? 你能告诉我算出这道题的最好方法吗？ 4. I don’t know the way (that / in which) he helped her out. 我不知道他用什么方法帮助她摆脱困境的。 5. The way (that / which) he talked about to solve the problem was difficult to understand. 他所谈到的解决这个问题的方法难以理解。 6. I don’t like the way that / which is being widely used for saving water. 我不喜欢这种正在被广泛使用的节水方法。 7. They did not do it the way we do now. 他们以前的做法和我们现在不一样。【归纳总结】 ●way作“方法，方式”讲时，如表示“以……方式”，前面常加介词in。如例1； ●way作“方法，方式”讲时，其后可接不定式to do sth.，也可接of doing sth. 作定语，表示做某事的方法。如例2，例3；

the-way-的用法讲解学习

t h e-w a y-的用法

The way 的用法 "the way+从句"结构在英语教科书中出现的频率较高, the way 是先行词, 其后是定语从句.它有三种表达形式:1) the way+that 2)the way+ in which 3)the way + 从句(省略了that或in which),在通常情况下, 用in which 引导的定语从句最为正式,用that的次之,而省略了关系代词that 或 in which 的, 反而显得更自然,最为常用.如下面三句话所示,其意义相同. I like the way in which he talks. I like the way that he talks. I like the way he talks. 一.在当代美国英语中,the way用作为副词的对格,"the way+从句"实际上相当于一个状语从句来修饰全句. the way=as 1)I'm talking to you just the way I'd talk to a boy of my own. 我和你说话就象和自己孩子说话一样. 2)He did not do it the way his friend did. 他没有象他朋友那样去做此事. 3)Most fruits are naturally sweet and we can eat them just the way they are ----all we have to do is clean or peel them . 大部分水果天然甜润,可以直接食用,我们只需要把他们清洗一下或去皮.

way的用法总结大全

way的用法总结大全 way的用法你知道多少，今天给大家带来way的用法，希望能够帮助到大家，下面就和大家分享，来欣赏一下吧。 way的用法总结大全 way的意思 n. 道路,方法,方向,某方面 adv. 远远地，大大地 way用法 way可以用作名词 way的基本意思是“路,道,街,径”,一般用来指具体的“路,道路”,也可指通向某地的“方向”“路线”或做某事所采用的手段,即“方式,方法”。way还可指“习俗,作风”“距离”“附近,周围”“某方面”等。 way作“方法,方式,手段”解时,前面常加介词in。如果way前有this, that等限定词,介词可省略,但如果放在句首,介词则不可省略。

way作“方式,方法”解时,其后可接of v -ing或to- v 作定语,也可接定语从句,引导从句的关系代词或关系副词常可省略。 way用作名词的用法例句 I am on my way to the grocery store.我正在去杂货店的路上。 We lost the way in the dark.我们在黑夜中迷路了。 He asked me the way to London.他问我去伦敦的路。 way可以用作副词 way用作副词时意思是“远远地,大大地”,通常指在程度或距离上有一定的差距。 way back表示“很久以前”。 way用作副词的用法例句 It seems like Im always way too busy with work.我工作总是太忙了。 His ideas were way ahead of his time.他的思想远远超越了他那个时代。 She finished the race way ahead of the other runners.她第一个跑到终点,远远领先于其他选手。 way用法例句

the_way的用法大全教案资料

t h e_w a y的用法大全

The way 在the way+从句中, the way 是先行词, 其后是定语从句.它有三种表达形式:1) the way+that 2)the way+ in which 3)the way + 从句(省略了that或in which),在通常情况下, 用in which 引导的定语从句最为正式,用that的次之,而省略了关系代词that 或 in which 的, 反而显得更自然,最为常用.如下面三句话所示,其意义相同. I like the way in which he talks. I like the way that he talks. I like the way he talks. 如果怕弄混淆，下面的可以不看了另外，在当代美国英语中,the way用作为副词的对格,"the way+从句"实际上相当于一个状语从句来修饰全句. the way=as 1)I'm talking to you just the way I'd talk to a boy of my own. 我和你说话就象和自己孩子说话一样. 2)He did not do it the way his friend did. 他没有象他朋友那样去做此事. 3)Most fruits are naturally sweet and we can eat them just the way they are ----all we have to do is clean or peel them . 大部分水果天然甜润,可以直接食用,我们只需要把他们清洗一下或去皮. the way=according to the way/judging from the way 4)The way you answer the qquestions, you must be an excellent student. 从你回答就知道,你是一个优秀的学生. 5)The way most people look at you, you'd think a trashman was a monster. 从大多数人看你的目光中,你就知道垃圾工在他们眼里是怪物. the way=how/how much 6)I know where you are from by the way you pronounce my name. 从你叫我名字的音调中,我知道你哪里人. 7)No one can imaine the way he misses her. 人们很想想象他是多么想念她. the way=because 8) No wonder that girls looks down upon me, the way you encourage her. 难怪那姑娘看不起我, 原来是你怂恿的

the way 的用法

The way 的用法 "the way+从句"结构在英语教科书中出现的频率较高, the way 是先行词, 其后是定语从句.它有三种表达形式:1) the way+that 2)the way+ in which 3)the way + 从句(省略了that或in which),在通常情况下, 用in which 引导的定语从句最为正式,用that的次之,而省略了关系代词that 或in which 的, 反而显得更自然,最为常用.如下面三句话所示,其意义相同. I like the way in which he talks. I like the way that he talks. I like the way he talks. 一.在当代美国英语中,the way用作为副词的对格,"the way+从句"实际上相当于一个状语从句来修饰全句. the way=as 1)I'm talking to you just the way I'd talk to a boy of my own. 我和你说话就象和自己孩子说话一样. 2)He did not do it the way his friend did. 他没有象他朋友那样去做此事. 3)Most fruits are naturally sweet and we can eat them just the way they are ----all we have to do is clean or peel them . 大部分水果天然甜润,可以直接食用,我们只需要把他们清洗一下或去皮.

the way=according to the way/judging from the way 4)The way you answer the qquestions, you must be an excellent student. 从你回答就知道,你是一个优秀的学生. 5)The way most people look at you, you'd think a trashman was a monster. 从大多数人看你的目光中,你就知道垃圾工在他们眼里是怪物. the way=how/how much 6)I know where you are from by the way you pronounce my name. 从你叫我名字的音调中,我知道你哪里人. 7)No one can imaine the way he misses her. 人们很想想象他是多么想念她. the way=because 8) No wonder that girls looks down upon me, the way you encourage her. 难怪那姑娘看不起我, 原来是你怂恿的 the way =while/when(表示对比) 9)From that day on, they walked into the classroom carrying defeat on their shoulders the way other students carried textbooks under their arms. 从那天起,其他同学是夹着书本来上课,而他们却带着"失败"的思想负担来上课.

The way的用法及其含义(三)

The way的用法及其含义（三）三、the way的语义 1. the way=as（像） Please do it the way I’ve told you.请按照我告诉你的那样做。 I'm talking to you just the way I'd talk to a boy of my own.我和你说话就像和自己孩子说话一样。 Plant need water the way they need sun light. 植物需要水就像它们需要阳光一样。 2. the way=how（怎样，多么） No one can imagine the way he misses her.没人能够想象出他是多么想念她！ I want to find out the way a volcano has formed.我想弄清楚火山是怎样形成的。 He was filled with anger at the way he had been treated.他因遭受如此待遇而怒火满腔。That’s the way she speaks.她就是那样讲话的。 3. the way=according as （根据） The way you answer the questions, you must be an excellent student.从你回答问题来看，你一定是名优秀的学生。 The way most people look at you, you'd think a trash man was a monster.从大多数人看你的目光中,你就知道垃圾工在他们眼里是怪物。 The way I look at it, it’s not what you do that matters so much.依我看，重要的并不是你做什么。 I might have been his son the way he talked.根据他说话的样子，好像我是他的儿子一样。One would think these men owned the earth the way they behave.他们这样行动，人家竟会以为他们是地球的主人。

way的用法

一．Way：“方式”、“方法” 1.表示用某种方法或按某种方式 Do it (in) your own way. Please do not talk (in) that way. 2.表示做某事的方式或方法 It’s the best way of studying [to study] English.。 There are different ways to do [of doing] it. 3.其后通常可直接跟一个定语从句(不用任何引导词)，也可跟由that 或in which 引导的定语从句正：I don’t like the way he spoke. I don’t like the way that he spoke. I don’t like the way in which he spoke.误：I don’t like the way how he spoke. 4. the way 的从句 That’s the way (=how) he spoke. I know where you are from by the way you pronounce my name. That was the way minority nationalities were treated in old China. Nobody else loves you the way(=as) I do. He did not do it the way his friend did. 二．固定搭配 1. In a/one way：In a way he was right. 2. In the way /get in one’s way I'm afraid your car is in the way， If you are not going to help，at least don't get in the way. You'll have to move－you're in my way. 3. in no way Theory can in no way be separated from practice. 4. On the way (to……) Let’s wait a few moments. He is on the way Spring is on the way. Radio forecasts said a sixth-grade wind was on the way. She has two children with another one on the way. 5. By the way By the way，do you know where Mary lives? 6. By way of Learn English by way of watching US TV series. 8. under way 1. Elbow one’s way He elbowed his way to the front of the queue. 2. shoulder one’s way 3. feel one‘s way 摸索着向前走；We couldn’t see anything in the cave, so we had to feel our way out 4. fight/force one’s way 突破。。。而前进The surrounded soldiers fought their way out. 5.. push/thrust one‘s way（在人群中）挤出一条路He pushed his way through the crowd. 6. wind one’s way 蜿蜒前进 7. lead the way 带路，领路；示范 8. lose one‘s way 迷失方向 9. clear the way 排除障碍，开路迷路 10. make one’s way 前进，行进The team slowly made their way through the jungle.

the way的用法大全

在the way+从句中, the way 是先行词, 其后是定语从句.它有三种表达形式:1) the way+that 2)the way+ in which 3)the way + 从句(省略了that或in which),在通常情况下, 用in which 引导的定语从句最为正式,用that的次之,而省略了关系代词that 或in which 的, 反而显得更自然,最为常用.如下面三句话所示,其意义相同. I like the way in which he talks. I like the way that he talks. I like the way he talks. 如果怕弄混淆，下面的可以不看了另外，在当代美国英语中,the way用作为副词的对格,"the way+从句"实际上相当于一个状语从句来修饰全句. the way=as 1)I'm talking to you just the way I'd talk to a boy of my own. 我和你说话就象和自己孩子说话一样. 2)He did not do it the way his friend did. 他没有象他朋友那样去做此事. 3)Most fruits are naturally sweet and we can eat them just the way they are ----all we have to do is clean or peel them . 大部分水果天然甜润,可以直接食用,我们只需要把他们清洗一下或去皮. the way=according to the way/judging from the way 4)The way you answer the qquestions, you must be an excellent student. 从你回答就知道,你是一个优秀的学生. 5)The way most people look at you, you'd think a trashman was a monster. 从大多数人看你的目光中,你就知道垃圾工在他们眼里是怪物. the way=how/how much 6)I know where you are from by the way you pronounce my name. 从你叫我名字的音调中,我知道你哪里人. 7)No one can imaine the way he misses her. 人们很想想象他是多么想念她. the way=because 8) No wonder that girls looks down upon me, the way you encourage her. 难怪那姑娘看不起我, 原来是你怂恿的 the way =while/when(表示对比) 9)From that day on, they walked into the classroom carrying defeat on their shoulders the way other students carried textbooks under their arms.

“the-way+从句”结构的意义及用法知识讲解

“the way+从句”结构的意义及用法首先让我们来看下面这个句子： Read the following passage and talk about it with your classmates. Try to tell what you think of Tom and of the way the children treated him. 在这个句子中，the way是先行词，后面是省略了关系副词that 或in which的定语从句。下面我们将叙述“the way+从句”结构的用法。 1．the way之后，引导定语从句的关系词是that而不是how,因此，<<现代英语惯用法词典>>中所给出的下面两个句子是错误的：This is the way how it happened. This is the way how he always treats me. 2. 在正式语体中，that可被in which所代替；在非正式语体中，that则往往省略。由此我们得到the way后接定语从句时的三种模式：1) the way +that-从句2) the way +in which-从句3) the way +从句例如：The way(in which ,that) these comrades look at problems is wrong.这些同志看问题的方法不对。

The way(that ,in which)you’re doing it is completely crazy.你这么个干法，简直发疯。 We admired him for the way in which he faces difficulties. Wallace and Darwin greed on the way in which different forms of life had begun.华莱士和达尔文对不同类型的生物是如何起源的持相同的观点。 This is the way (that) he did it. I liked the way (that) she organized the meeting. 3.the way(that)有时可以与how(作“如何”解)通用。例如： That’s the way (that) she spoke. = That’s how she spoke. I should like to know the way/how you learned to master the fundamental technique within so short a time. 4．the way的其它用法：以上我们讲的都是用作先行词的the way，下面我们将叙述它的一些用法。

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