CA2188234A1

CA2188234A1 - Bioreactor and method of measuring contaminants in an aqueous environment

Info

Publication number: CA2188234A1
Application number: CA 2188234
Authority: CA
Inventors: Louis A. Kaplan
Original assignee: Academy of Natural Sciences of Philadelphia
Current assignee: Academy of Natural Sciences of Philadelphia
Priority date: 1996-10-18
Filing date: 1996-10-18
Publication date: 1998-04-18

Abstract

A method and apparatus are provided for measuring the concentration of contaminants in an aqueous water system, wherein the contaminants are measured with the bioreactor containing a biofilm or microbial community which acts on the water to be analyzed to provide a measure of the amount of the dissolved organic carbon which is biodegradable. A bed for facilitating regulation of water flow through the bioreactor is provided, and an autosampling mechanism enables the measurement of total organiccarbon, inorganic carbon and oxygen ,between sample inflow and sample outflow atspecified time intervals.

Description

21882~ 1 BIO~EACTOR A~O METHOD OF MEASU~ING
CONTAMINANTS IN AN ~QUEOUS ENVIRONMENT

BACKGROUND OF ~VENTION
1. Field of Invenhor~
The present mvenuon relates to the field of water con~A~nin~ and tre~tmPnt meas~ menl~.

2. Bnef Descriptlon of the Prior Art Analyzing cont~min~ntc in a water ~upply can oflLen t~ke significant time to complete, and furthermore is oflen di~cult to carry out. Pre~ent techniques and apparatus generally require much time to obtain measurements or rea~ngs of water slJpply co"lal"in~.ls. Water utilities are confronted with the ta~k of ~ inil~ conl~inarl~ at reduced levels, while, at the sa~e time, controlling the levels of treatment compounds to maintain a safe concentration for consumption by users or ultimate discharge of the water into the ecosystem. Often strict go~ "~rll regulations must be met so as to have a minirrn- n a~ hle level of con~,unar~ts and maximum ~r~ept~hle levels of Ir~tnlenl chPmi~lc Coliform bacteria and other contamin~nt~ st be carefillly mor~tored andtreated. In addition to the tre~t."enl compounds themselves added to water, byproducts are o~en formed from the reaction of these comroun~c with the co.lt&r. ,~nants. Therefore, it is not possible to simply add a g~ven amount of treal"len~ r~l to a water supply, rather, the water must be mon~tored before, as well as af~er, and even during the l~ln~en~
process.
Thus the nee~ for accurate, timely analysis of cont~min~t~ ~ea~n~n~ rh~icals and byptoducts in a water system remains ilnportant to the ability to provide adequate reatn,ent and r"~n~e ~lent of a, water supply.
Dissolved organic matter is an ~mportant cu~nponent in a water system t~t must be carefillly monitored and controlled due to its relationship with the col~tn.~n~ The 218823~

greater the pr~,sellce of dissolved organic matter in a water systern the greater the potential for water cGr.~A~ c, such as, for e~mple, bacteria and other or~Pni~m~ to proliferate and fi~rther contribute to the degree of cQ~t~min~tion of a water suppb. The effect is more pronounc~d over time if bacteria and other organisms are allowed to build up.
Therefore, measurement of biodegradable organic matter in a water system provides infoll.lalion ~hich can be used to detPnnin~ the extent and succes~ of disinfectant or treatment to be ~dministere-d to a water supply.
Biodegrsdable orgar~ic carbon has been measured by a nu1nber of d;~ assays as a way of detennining the concentrations of biodegrad~ble dissolved or~anic matter present in the aqueous systenL The assays, however, are known to take sl~hst~nti~l t~me.
R~ hility and r~pidness of measurement are des~red when mor,.lo~ g the c4~lcent~ dtions of biodegradsble organic contnmi~nt~ at a water utility dunng the purification or disinfe~ting t~eat",ent process.

SUMMARY OF THE INVl~NTION
The present ~nvention provides a method and apparatus for measuring concentrations of cont~n1in~nt~ in aquatic systerns, such as, for elc~nlple, those present in water utility systems. Biodegradable dissolved or~anic matter is determ~ned by tbe present ~nveniton. ~method and appa~dtus are provided for measuring levels of orgar~ic carbon and inorganic carbon in a water ~ystem and utilizing a Jil~r~t;al analysis to detern~ine the level of biodegradable orgsn~c carbon cont~ined in a water system. The apparatus ofthe invention prov~de~ a bioreactor which is inocul~ted with microbes to forrn a biofilm which acts upon the biodegradable organic carbon present ill the water to be analyzed. The microbes generally con~r~ce the naturai flora and organisms indigenous to the water supply or ~ystem to be analyzed. The apparatus includes at least one chromalo~.~p~
colllmns which is packed with ~ material on which microbes can proliferate. Water flow is dire~led through the colunln with a p~mp. ll-e apparatus and method also f~cilitate 218823~

control and rP~ tion of the water passage through the column length. A bed is p~vided through which the water to be analyzed passes a~ it enters the column. A ~ bial i~oc~ .n i~ introduced to the bioreactor and resides on the packing material ~hithin the column. ~he bed provides aUI even flow of wa~er to the microbes within the column and facilitat~Q unifonn water recidçnce time as the water flows through the column.
The m~crobial Commll nity establish~s itself w~thin the co~umn, and there~r can be utilized to ~neasure biological activity with respect to water sa nples which ~o~ through the bioreactor. ~ sample of the inflow water is taken and a s~rlple of water is taken at the outflow. The biodegradable dissolved organic carbon (13DOC) present in the water~ample is acted upon by She microbe~ wherein thc biodegradable dissolvcd organ~c carbon conr~ntration is asc~ "ed by the dif~erence between the readings of DOC concentrations between the inflow and the outflow. The pre~ent in~ention provides a novel ~o~r~appara~us and snethod wherein con~nuous and ~ o~ readings of DOC concer.~rationsat the inflow and outflow po~nts ofthe bioreactor are obtained. The apparatus and method also pro~nde means for deae",uning inorganic carbon and organic carbon conc~n~lations~ and the concent, dtion of dissolved o~ygen in a water salnple.
It is an object ofthe present invention to provide a method and appsl~lus for deterrnini~g the cQ~ ~ion of biodegradable organic matter in a water system as a way to measure biodegradable dissol~ed organic matter in the water system.
It is another object of the pre~ent ~nvention to accomplish the above object with a bioreactor.
It i~ ~n object of the present ~n~ention to provide a novel bioreactor appa~tus which can meas~lre cQnce,l~rdions of materi~ ected by the rnicrobial community or biofilm present ~n the bioreactor.
It is another obje~t of the present invention to provide a bioreactor which can be used to prov~de accurat~ reading~ of biodegradable dissolved or~an~c carbon in an aquatic envirorunent, such as, for e- i ..ple, a ~rinkin~ water utility prucess~g plant.

218g23~

It is another object of the preseM invention to provide a novel method and apparatus for measuring Gu~ an aquatic en~uv~4~ , wh~re~ the nleasurelnent can be d~ ~ w~thin minutes of talcing a sanlple.
It is another ob~ect ofthe present invention to acc4,.~p!i~l. the above objects by providing water flow re~11~tine means for regulating the passage of water as it enters ~nd/or exits the bioreactor cQl~nQ
It is another object of the pre~ent ~n~ention to Impro~e the reliability and accuracy of measuring cQntarnin~nts ~n an aqueous enii~OMl~t with a b;ol~ea,~or by n~aint~inine a uniform flow of water to be analyzed as the water sample travels through the column of the reactor.
Another object of the present invention is to decrease the measurernent time of asc~ ~ing the concentration of cont~rnin~nt~ in an aqueous ~ o~u~ , narnely where the cont~rnin~llts coll~yr;s~ biode~dPhle dissolved organic maner BRIEF l)ESCRI~IION OF 1~ DRAWING PlGURES
Fig. 1 is a sc~ Pn~ c view of a bioreactor according to the present in~ention, with the bioreactor columns shown in secti~n~l view.
Fig. 2 is an alt~n~te embodiment of a bioreactor according to the present inYention with an ~vt~s~rnrline ~n~r.h~njs~
Fig 3 i~ an enlarged sectional view of the column bed of the apparatus of F;g. 1es~ ~d by the boK 3 of Fig. 1.
Fi~. 3a is a top cross-sectional view of the column of Pig. 3 taken along the line 3a--3a afFig. 3.
~ ig. 4 i~ a ri~ht side schematic view of the damper of the ~mho~liment shown in Fig.2.
Fig. 5 is a graph of streanl water BDOC concentration ~ s~ed as a fi~nction of time for the results of Table 1.

2188'~4 DET~ILED DESCRIPTION OF T~E PREFl~RRED EMBOD~IE~TS
Refe~ing to Fig. 1, 8 bioreactor 20 according to the present invention is shown comprising a w~ter ~nput line 21, a w~ter output line 22, means for moving the water through the reactor, which is shown wl~p"sin~ an in~ow pump 23, which preferably may comprise a pe~istaltic pump, and first and sesond columns 25 and 27, respc~ elr. A
sample source .~ ~o;, 24 is provided in which the water ~nput line 21 extends so that the in~ow pump 23 c~n draw a flow of water from the sa nple source 24 and move the water along thè input flow line 21 for delive~y to the first colurnn 25. The san~ple source, while shown, ~pr~ te~ as a rese~voir 24, is preferably provided as a direct line (not shown) ~om the water source to be analyzed, such as, for example, any ~rinL~ water sources, inr.ll-din~, without linlitation, reservoirs, streams, wells or springs. The direct line may include one or more filtration steps, as n~c~ssAry~ to remove debris, andJor other co~por~t~ from the ~Ivater source. Preferably filters used, while not shown, are c~n~rsed of m~tt n~l~ which do not ~nterfere w~th organ~c molecules and ,.,icrobes, and which permit microbes ~o pass through into the filtrate. Generally, large particles which might otherwise inte,~re with the coll-mn.c or water flow through the bioreactor 20 are desired to be removed.
The in~ow pump 23 directs the water through the t;rst column 25, out of the first column 25 through a transition line 26 and into a second column 27. The water inflow epr~s~nlod by arrow "a" may be diverted by an inflow valve 29 shown ~i~pose~ ~n line and downstream ~om the pump 23. The innow va~w 29 is located before the first column ~5 and can diven sarnple ~w to the sampling hlbe 30 in the direction of arrow "b". The ~rnrli~ tube 30 may be used for colle~ting spot sarnples or can be connected in-line for direct delivery of inflo~ sample to an analyzer, such as that sho~n in Fig. 2.
The first and sesond cQIIlmns 2s, 27 are provided with means for re~ ti~ and controlling the ~ow of water through a colun~n. Preferably7 a~ shown in Fig. 1, and in the 21g~2~ 1 enlarged view of Figs. 3 and 3a, is a be~ 32 conlprising a plurality of aperhJres 33 through which ~he ~ate~ elu~ g the first column 25, for eY~'e, is forced. The bed 32 is ~enerally compri ed of an end fittin~g 34a, d bed support 34b, and an o-ring or ga~ket member 34c, The bed support 34b i9 placed on the end of the end fitting 34a ~d is secured with the ga~ket 34c. The end fitting 34a is then placed onto the end of the column 25. An end cap 35 is placed over the end fitting 34a to secure the bed 32 in place on the end of the column 25. Suitable ~ttac,hment means is prov~ded for 8tt~cl,~ 1 of the bed 32 to the end ofthe column 25. ~s shown, the an~r,hmPnt means may, for exa~nple, comprise first t~reads ~Sa on the outer circurnference of the column and matingly associated second threa,ds 35a on the rim of the end cap 35. Preferably, the bed 32 compnse~ m~terials which do not inte~re~ ~ with the organic n~olecules and n~icroorgan~sm~
and which do not leach mol~ulPs into the system, PTF~ is an example of a compound that can be used to compnse the components ofthe bed 32, as can any other suitable inert rn~t~ , which will not react~ by adsorption, absorption, or othelwise, w~th the sample water, the ~ ~ei. or the cot~t~nu)~ t~ in the sample water, and which also will not leach material the.crrol... The bed 32 fn-;l;t~t~s even dispersion of the s~mple water through the colunm 25 represented by the arrows "cU, so that ~ater residence tinle and flow is genera~ly eq~lalized between v,auious ver~ical zones of travel through the column 25. Since the beds 32 can be the same for each column inflow and outflow, they are generally des~ t~ by the numeral 32. Similarly, water ~ow through se~ond column 27 is shown passing through the bed 32 in the direction of arrows "d". Optionally, while not shown, a ~va~er ja~P~e~ column can also be used as a way to maintain the te.,-~,.,. a~ure of the colunln.
The first and second column~ 25,27 are filled ~rith a pacl~ng matel~al, ~enera~ly 36, which preferably C0~ ~iiS a ~uitable base on which the n~crobes (not shown) ca,nproliferate to establish a biofilm or commllnity. The packing rnater~al 36 prefembly co1nprises a material which will not react with the water stream, the microbes, or any of the byproducts or ~~r~ being anatyzed. For example, the packing material 36may comprise a borosilicate glass. Preferably, an open-pored sintered glass matenal is used, and particularly preferably, open-pored sintered ~lass having a sphffe ~;Dm~trr of about 1 to 2 mrn, and a pore di~ t~ of ~om about 60 to 300 ~un, such as that comrnercially available m the indu~t~y.
The bioreactor 20 i~ prepared by assembling the compone~s shown in Fig. 1, and then packing the ~rst and second columns 2S,27 with the packing materiaI 36. The fi~t colurnn ~5 is filled about half-way wlth the source water, and the packing matenal 36 is added to fill a couple of c~ ~t;~PtP~s of vertical height of the f~rst column 25, and tapped to settle the packing material 36 w~thin the colum~L This step is rep~ated until the first column 25 is ful~y packed. The bed 32 is placed onto the top of the column 25 asdescribed above (Figs. 3 and 3a).
Source water is then punlped through the first column 25, through the connect;t-g tube 26 and then through the second column 27, until the second column 27 is about half fi~ll. The second colunm 2~ is packed in the sarne ~nanner as desc~ibed above in relation to the first column 25, and is then Glosed with a bed 32.
An output flow valve 3~ is provided on ~he OUtpLlt ~ow line 22 for diverting output flow from the second column 27 to a waste flow line 40 or to a s~nple output flow line 41. The sample output nOw line 41 m~y in ~rn be conne~ted to a sample analyzer for monitoring of the water outflow, such ~s that shown in Fig 2.
P~lably~ the first ~nd second colurnns 25,27 are co~l.~n~ed of a non reactive material, such ~s, for example, borosilicate gtass The flexl~le tub~ng util~zed to compnse the flow lines can comprise any suitable non-reactive composition, and pref~ bly a polytetr~uoroethylene material is used.
The bioreactor 20 must be inoculated with microbes in order to co....,.. ~lce operation. The micmbes utilized are tho~e indigenous to the water source to be measllred, such as for example a stream (not ~hown). The in~ow of source water 38 into the reactor wlllmn~ 25,27 introduces the uuwutJ~ a to the bioreact~r 20 where lhey ~eside on lhe surfiaces ofthe packing material 36. Generally, the source water 38 is pe~ll~d lo contintlouslS~ flo~r tilro~Jgh the bioreactor 20, at a predetermined rate, 90 ~at the microbial COIlu~ y or biofilm can be s.lct~in~d ur~thin the bioreactor 20. The bioreactor 20 must undergo a pe~-od of up to about four to 9Lx months, or som~times greater, for the rr~icrobial co.,...,~nilr to become established on the packing material 36 surfaces.
Establichrnrnt of the microbial community in the bioreactor 20 can be ascel la~ned by repeating a measurement of a w~ter sample cont~ining a known conce,~,dlion ofcontaminants until consict~nt re~ults are obtained. Generally, the biodegradable dissolved organic carbon expressed as a percent of dissolved organic carbon (DOC) which isovt;;d ~om the water inilow by the action of the microbes in the bioreactor 20 steadily increases from the in~tial inocul~tic)n of the bioreactor 20 w~th the water cont~ning the microbes until the biofilm ha~ been established, at which time the rate of DOC removal ~evels off. The biofilm est~htichm~m t~me depends on the type of Gon~,...,;.l,...l.. and ol~is-lL~ preser~ as well ~s other factûrs which might have an effect on the ~II.clobial metabolism rate. such as, for exunple, t~llly~ldlure and season of year.
Measurement ofthe ~OC conGe.~ a~ion can be pelrul"led by talcing a reading of the in~ow and the outflo~ and det~"",ling the difference in the concentration of DOC.
The microbe~ ~n the bioreactor 20 w~ll çon~lmP DOC Therefore, ~the total conc~ alion of orgar~ic calbon of the inflow is Icno~m, the difference ~n the organic carbon reading from the outflow provides a mea~ure of the conc~ ation of biodegradable di~olved organic carbon (BDOC). The measurement obt~ined i~ a net measllrement because the microbe~, while consuming organic molecules, excrete some organic motecllles, as well, such as for example~ wa~te products. Therefore, the measurement of BDOC which appears to be consumed actuaUy represents some organic ma~r which is co~s~1m~d by the n~icrobes and some organ~c matter ~hich t}le microbes have produced a~
byproducts of metabolism 2188~34 Once establic~P~ the bio~ or 20 can be utilized to ascertain the cor.r- ~1ra~ionof biode~radablc or~ar~iG n~atter presen~ in the water s~stem. The water sample 3 8, or stream, to be analyzed is pumped ~rough the column~ 2S,27 and sa~mples taken at the inflow and at the outflow to measllre the conce~ lions of c~.lt~u.lJ,Jants present in the fo~n of organic carbon molecules. Inor~anic carbon (IC) can also be det~ ;ned as a check on the m~crobe ac~ivity. The net change in organic carbon between the c~nLe~ a~ion ofthe in~ow versus the conCenll~LiOn of t}le outflow is re~les~,lta~ive of biodegrada~le dissolved orga~ic matter, which ha.~ been .~ ed (although a n~inor arnount of the organic carbon may actually have been a byproduct of microbial metaboli~n the reading obta~ned is generally accepted a9 an undere~ ,ate of BDOC cont~ n~t).
A preferred s~n~plin~ and mp~uring apparatus is shown in Fig. 2. A bio,t;a.,~or 100 w~th autos~npljng car~hiliti~s is shown ~n partial s~ rn~tic view. The ~ater supply source for sarnpling is generally represented by the rese~voir 101, but can cor~ e a direct line from a stre~m, well or other water supply to be analy~ed. An in~ow line 102 ex:tends ~om the sample reservoir 101 or stream to a sample in~ow pump 103 whichoperate~ to dra~ w~te~ from the sample source 101 and moves the water through the reactor ~rst and second colllmnc 105,106. The first and second columns 105,106 are preferably provided w~th the flow re~ tinn means described above in relation to Figs. 3 and 3a, and shown col~plising the bed 32 The flow regulation means fpril;t~/tp~ an even flow of sample water through the first and second columns 105,106 to prov~de unifonn r~ lPn~e t~me for sarnple contact with the biofilm established within the Srst and second colllmm 105,106. The bed 160 can be provided to be ofthe same conjtruction as the bed 32 described above and shown in Figs. 3 and 3a Sarnple water 9OWS into the first column 105, and then through a t~ansition tube109 connecting the c~ ns 105,106 and through the second Golumn out~ow tube 107.
The tran~Ttion tube 109 makes it possible for there to be an additional sanlpUng point between the cQll~mn~ 105,106. The second column outflow line 107 flows into an output 218~23 1 fiow diverter valve 108 which can be operated to diven the flow exihng the second column 106. As shown in Fig~ 2, three paths of travel are possl~le ~om the diverter valve 108. The output flow diverter valve 108 may be nlanually Op~l~t~ or cau~ be automatically operated in conjunction with a timer or other ".~rkqn~ or ele~,lror ~
means. A waste l~ne 111 is coMected to the output flow diverter valve 108 to provide a fiurther path of travel. A flow line 112 is also provided as a further path of travel for the s~mple flow com~ng out of the second colurnn 106, which flow line 112 leads to a TOC
analyzer 113. The third path oftravel ~hown from the diverter valve 1~8 co~ to an oxygen flow cell valve 114 which regulates passage through an oxygen flo~ cell 115.
The dissolved or~anic carbon ~DOC) conrentration of the water ~amples to be analyzed with the bioreactor 100, is ascertained with the use of a DOC analyzer 113. The analyzer 1 13 receives sample and through the use of W radiation and a Ghrr ~ AIoxidizing re~gent, such as, for e~t~mple~ orfi.~." persulfate, m easures the amount of formed carbon dioxide ,.,~ ,g ~om the oxidation ofthe carbon co~ ~ compounds present in the salr ple. S~ch analyzers are collu"er-iially a~ailable, such as, for eY~mrlP, a Sievers model 800 TOC analyzer. The concentration of the orgar~ic co~pounds presen~ in the water sa~nple is measured by the TOC analyzer 113.
Since the c~lcù~tion is deterrnined by taking the di~erenc~ betw~en the total car~on and the inol~,anic carbon to ascertain the total organic carbon, if high levels of inorganic carbon are pre~ent in the water samples, then the total organic carbonmeasurement is ovt;~ t~ An inorganic carbon (IC) removal mod~lle 116 is providedto remove the inorganic carbon from ~he ~ample. The removal module 116 may complise a vacu~n deg~ng module which has the capability of removing approx;nlstely 99% of the ~norgariic carbon in the sample. Unamended sample flow-s into the IC~ removal nlodule 116 and is de~sced and the sample is then sent to the TOC analyzer 113 where it is ~ci~ifi~d ~md analyzed for dissolved or~ar~ic carbon. The IC removal module 116 can be 218823ll co~ e~cially purchased as a Siever~ ICR Modu~e 800 (~or~anic C~rbon Removal Module).
~ r-~1ne~ are talcen oftotal orga~ic carbon (TOC) and inorgan~c carbon (IC) for each salnple. A tirner 117 i~ pro~ided to con~rol the ~ow p8th ofthe water sample to be analyzed by sele~ing b~,L~ , two ~ow paths. The timer 1 17 preferably compr~Aes a dig~tal two channel timer which can be set to regulate the f~ow ofthe sarnple to pass ~rough the IC removal module 116 for a reading of TOC or to bypass the re~ov~l module 116 for reading of IC. The ~r~ channel ofthe timer 117 changes between selection of flo~ from the inflow line 118 and ~ow through the out~ow line 1 l~ ofthe bioreactor 100 The second channel selects whether the TOC is measured with IC present or af~er IC removal has taken place. Thi~ perlnitss selec~ion b~ measurements ofTOC and IC, as well. The selection of ~nn~.lc iS time-based and can be pre~et. Aselection valve 120, which prefe,ably compnses an electrically controlled two-way position valve sw~tcher, cQnn~1s the TOC analyzer 113 with the IC removal module 116.
The selection valve 120 i5 switched to pern~t the ~ow of sample through the IC removal rnodule 116 for the TOC mea~urement. For the IC measurement, the remov~l module 116 is bypassed ~d the Inodule 116 is switched off. The pr~l~G~l ~d time of operation for TOC
and IC measurement is one hour. The timer 117 can therefore be see to ~Iten~te between un~nter~upted flow to the analyzer 113 and ~ow through the IC remo~al module 116, prior to the flow to the analyzer 113.
The ~econd channel regulates timed selection between sample in~ow and sample out~uw through an inflow/outflow va}ve 121. For eYYrnrle, the second cha~nel ofthe timer 117 can be set to change between inflow and outflow eYely two hours, so that for two hours the inflow is s~rnr'-~ and for the next ~o hours the outflow i5 S~ pl- I Other tinles can be used depen~ling on the TOC conc~"l,~tion, column size and the re~ n~e time reql~ired for the m~crobes in the bioreactor 100 to act on the biodegr~dable dissolved organic carbon.

~1~823~1 In ~dditiQnl while the IC reading ~perates as a check on biofilm activi~, the ICreadings can be done less ~equently than the TOC ~7 ~ w~th the timer 117 ~-3ju~te~1 acco~ .gly.
As shown in Fig. 2, an oxygen monitofling s~stem, generally 130, is provided. The oxygen monitoring system 130 c~n be provided in line with the bioreactor flow paths to receive sunple inflow and sample outnow for analysis of oxygen content. The samp~e may flow through the analyzer in~ow line 118 wherein inflow sample is drawn through the in~ow/outflow valve 121 for ,.,~ .e..l with the TOC analyzer 113, as d above. Sample may also be moved through the colLlmn inflow line 132 w~th the inflo~
pump 103. Sample can be drawn through the col~mn inflow line 132 with the inflowpump 103 ~ndthenmo-~edthroug~thefir¢~column 105,tbroughtheco~ gtube 109 and through the second colurnn 106. The inflow pump 103 can be pre~et to a desired flow rat~ ~o provide adequ~te resi~pn~e time of the samp1e water in the columns 105,106 so that the microb~s can act on the n~ol~vl~s in the sample. In addition, wl~e not shown, an inflow se1e~tion valve may be provided to permit one or more of the analyzer inflow line 118 an~lor the oxygen analyzer flow line 133 to receive ~ flow at the sarne time, in addition to the ~ow to the colusnn lOS through the column inflovv line 132, which must be contin~10usl~ maintained, An o7ygen analyzer flow line 133 is co~ ed to a oxygenmonitor~n~ system ir~ow pump 134 which sends an inflow sample throu~h the o~cygen mon,l~ing system 130.
A putse damper 135 is provided to receive the flow ~om the o~ygen monitoring system in~o~N pump 134, ~hcre~lpon the flow is directed next through a tellip~lalul~
control means, shown in Fig. 2 co,n~ ;, g U~ ow water jacket 1 36 and an outflow~ater jacket 138. The oxygen monitonn~ system inClUtlp~ an inflow cell !37 and an outflo~ cell 115. Water in~ow san~ple enters the inflow cell 137 a~er passing through ~he water jacket 136 ~s shown in Fig. 2. An out~ow cell 1 15 receives sample outflow ~om the s~ond column 106 th~ough the o%~gen ~ow cell valve 114. The oxygen monito~ing 21882~

system inflow pump 134 supplies ~n oxygen inflow cell 137 with sample water. Theinflow cell 137 and the outflow cell 115 each contain aul ele~trode which is used to give rise to an eleollieal potential which is in turn is d~e~t~d by an ~mrlifier 149. The amplifier 149 can be any of those ~"u"~nc;all~ available for reading the potential from the flo~ cell electrodes, such as for example the Instec Dual Oxygen Electrode Amplifier ~odel 203. A
pulse damper 135 is pro~nded in the flow path before the inflow cell 137. The damper 135 f~cilitates an e~en resporlse by n~:ni ,;,;.~g strong flow ~ariations and variations ~n the measurement response.
Fig. 4 shows the damper unit 13~ in ~n enlarged view comprising conlpensation tub~ng 1~1 and a r~ t~r~ce unit 142 shown a~a the pump 134. The resistance ul~itpreferably comprises an adjustable cla~mp or other suit~ble narro~ng element which constricts ~Lhe flow through the line 143. The mater~al COllly~ ~g the damper co"~pone.,~s generally must not react .Yith the ~nolecules to be measured or affect the biofilm or leach ary material into the system.
The second electrode 115 is Gonne~;ted alternati~ely with the outflow through the outflow oxygen mo~ Jl;~ ~ line 145 or directly w~th the first ele~trode 137 of the inflow.
This arr~ng~ t provides for the calibration of both electrode~ 13~,115 at the same ti~ne.
The first electrode of the inflow cell 137 has an out]et line 147a through which the sample passes, which in turn is conn~ted to an i.~e~ ~ u~t valve 146 which can be set in one of two positions as shown, to d;~en3e the sample to a waste line 147b or to permit sarnple flow to the second electrode 115 through the transition line 147G. The oxygen flow cell ~ralve 114 located before the second electrode ofthe outflow cell 115 can be opela~ed to pern~it the sample flow ~om the in~ow cell 137 to enter the outflow cell 115.
The an~plifier 149 measures the response Prom the fir~ and second electrodes, 137 and 115, re,,~ ively. The elec~rodes 13~; 115 are in line oxygen electrodes auld are pro~ided to measure in re~l time with the ~ystem flow. Ihe re~ponse or signal detected by 2t88~3~

the ~n~pl;f.. r 149 can be filrther integr~ted by a recording device (not shown) to c~ te a reading co.-~"o~-d-ng to the oxygen content of the san~plc.
It is ot~ten nf~55,;- y to calibrate the first and second electrodes 137, 115, wbich is done by bypassing the bioresctor columns 105,106 with the oxygen monitoring system calibration valve 148 set to close the in~ow line 133 snd draw calibration standard lS 1 ~om the c~libration flow line 150. Also, the oxygen flow cell valve 1 l~ i~ closed to prevent out~ow from entering the oxygen monitonng systenl 130. Pr~f~ f, the calibration ~ldar~ 151 comprises oxygen saturated water.
The measurement of TOC was obtained by t~king the data stored on the TOC
analyzer l 13 and processing it to obtain concentration values over time for the sample.
The activit~r and metabolism of the bacteria is observed over time, and the CQl~C~ ,lt~ ~tion of BDOC can be ascertained to evaluate the cont~min~nt le~el present in the water supply being analyzed.
The bio~eactor l00 i~ prepared for operation by iirst introd~ a flow of water ~om the source, such as for e~A~I pi~ a stre~m, which is to be analyzed. Cnn~litions for pr~para~ion and operation of the bioreactor l o0 require darknes~, so as to prevent light f~om activating any algae which m~ght be pre~ent in the water source or ~n the column.
Also, any ~ater to enter the bioreactor which cG."~ns disinfectant, such as chlorine or the like, must first be neutralized to prevent des~uction ofthe biofilm. The wate~ from the source i~ then pumped through the reactor cnl-l~nn~ Preferably, this is don~ ~t a flow rate of about 2 to 4 n~l/min. This can be done by ~tt~inE a direct supply line from the stream to the pump 103 or can b~ acl~ie~d by providing a li~e ~om ~ sample reselvoir 101 cot~t~uni~ the source water. The water must be ...~ t a col~tinuous rate of flow throulgh the reactor in order to allow the bacte~a and other org~J~ in the water to inh~bit the packirg m~te~ 110 of the Golumns 105,106. ~his generally takes ;rO~ 9~ y four to six months, a~er which tinle, the bioreactor 100 i~ ready for use.
The flow of source water must also be contuluously n~ d through the bioreactor 21&8~3'1 100 even when no ~ r~"~-lt~ arc to be taken, in order to enable the biofilm to a statc of e~uilibrium.
The ~U~ ."~nt of c~ all.;nal~ in a water supply is an ongoing task. The inocul~ted bioreactor lO0 is provided w~th a flow of s~rnple from the r~. ~ 101 or water source which was used to pro~ide the inoculum for the bioreac~or 100. For eY~mpl~ in insl~,ces where trea~ment chemical disinfectant has been added to the water ~upply, the biore~ctor 1û0 can be used to determine the BDOC level. The w~ter from the ILse vu,r 101 is made to flow through the bior~or 100 by the use ofthe pump 103.Preferred flow ratR of from about 2 to 4 ml/min. are generally u~ed for a bioreactor in which the colulnns 105,106 are about 2 to 3 cm in ~ t~r uld 40 to 70 cm in height.
Columns w~th di~e~ 1 size ~;m~n~lQns can also be ernployed, and other flow ra~es, both greater and slower can be used. Por exarnple, a single co~un~ c~n also be used. The aOw rate can be detennined by the volume of the column and can be regulsted w~th the pump to achieve uniform flow rates if di~ele.lt column ~izes and nun-be~ are used.
Water to be r"~-l~ed is pe~u~ ed to flow throllgh the bioreactor columns 105,106. The diverte~ valve 10~ is operated to perrnit sample out~ow ~om the secont column l06toentertheinffowJouttlowcontrolvalve 121. Thecontrolvalve 121 a~cepts the outflow ssmple and pem~ts the sample to fi~rther pass to the DOC analyzer 113, wl~er~.~yon the sample is Iun through a ~llhr.h~n~.l flow path which leads to the IC/DOC
valve 120. The IC/I)OC val~e 120 is operated ~th the timer 117 to control the flow to one of two pos~ble path~, one which IC removal takes place and another which IC is not removed. As noted above the timer 111 ha~ two channels and ~enerally the second channel re~ t~s the flow through the IC removal module 116 to either send the sa~ple to the IC removal module 116 for removal of IC or to bypass IC removal and pem~it the sarnple to fiow directly to the a~ zer 1 13. If the ~ample is directed through Ihe IC
removal path, the sample is then ~n~lyzed a~er the IC removal. Generally, the tinle~

2i8823'~

chaMel re~1lati~g the IC module flow is switched on an hourly bas~s to pro~ide an hour of IC removed sample analysis and ~ hour of IC present sample anal~rsi~.
The above d~,libc~ ~mrling procedure with respect to the IC remo~val described in col-n~ion u~th sa,mple outflow is also done w~th respe~ to the inflo~ sample. In that case inflow sarnple from the DOC in~ow l~ne 118 is ~noved to the in~ow/o~lt~ow ~alve 121 with tlle use ofthe pump 1~2. The inflow undergoes the same 5~...p1ing proced~res as de~ d above in rela~ion to the outflo~N s~mrling ulalysis and the IC renlovalmodule. 116. The inflow sample is ~neasured by the l)OC analyzer 113 to pro~ide readings of carbon co~,cPnll ~lion for sample in~ow with and without removal of ir~orga~, carbon.
EX~LE 1 The following data was generated with water from White C~ay Creek located in southeastern Pennsylvarua. The flow rate was main~ain~d at 4 ml/nlin. The columns used were t~o borosilicate glass tubes each having an internal ~i~et~r of 2.S cn~ and a length of 60 cm, sold under the narne Chromaflex~9 by Kontes. The packing m~tPn~l co~ ,lised open pored sintered gla~s of 1-2mm sphere di~m~ r, 60-300~n pore d;D~n~ter, n~)~ifie~ which is sold under the name SiranT~ by Schott. PTFE ~bing used to connect the pump~, vaives and colllTnn~ in the arra~ ,mPnt de-~til,ed above and shown m Fig. 2. The bioreactor was ~noculated by pumping water from the White Clay Creekthrough a filter ~y~tem ~ncl~lding a first 2S llm filter in line with a second 0.3 ~m filter, and then through the cnll-mn~ This was done in the absence of light ~nd for a period of fo~;r months ~fter which time the bioreactor was cQloni7Pd When the reactor wa~ inoculated and the bio~lm fonned, a ~ample of the White Clay Creek water wa~ drawn ~nto thebioreactor witS tSe in~ow p~lmp and pumped through the co~ n~ at a rate of 4ml/n~n.
The readings were taken and recorded in Table I below, and the total orgaluc carbon (TOC) in mgCIl, ascertained by taking the differenGe bet~een (i) the avera~e of the hrst six values of TOCin and (ii) the average of the next 5iX TOCo~lt values to obtain the first poi~ "A~ on G~aph 1 ~Fig.5). Suhsequ~ readings ~ the same manner, ~d ~ Table 1, produced poin~ "B",~C", and "D~. The r~ C leplt3~n ~nple ~om u~ch ~e IC
re~oved by the IC ranov~ module.
TA~B~E I
Data Used to C~cula~ Stre~n water BDOC Concentra~on TCKC (mgC~L) D~te Time In Out 5~0/96 18:3S 2.725 18:41 2.706 18:47 2.665 18:53 2 673 18:59 2.671 19:05 2.679 20:2g 1.869 1.g58 20:41 1.859 20:47 1.864 20:53 1.865 20:59 1.854 22:29 2.608 2~:35 2.622 22:41 2.631 22;47 2.630 22:53 2630 22:59 2.622 5/31l96 00:38 1.858 00:44 1.8~3 00:50 1.847 00:56 1.850 01 :02 1.853 02:32 2.594 02:38 2.608 02:44 2 612 02:50 2.625 02:56 2 613 03 02 2.621 04:33 1.859 04:39 1 856 2188231-l TOC(lngC/L) Date Time In Out 04;45 1.860 04:51 1.861 04;57 1.910 05:03 ~.588 06:33 2 600 06:39 ~ ~06 06:51 2.613 06:57 2.6lS
07:03 2.623 0~:21 1.862 ~8:2~ 1.8S3 08:33 1.852 While not shown, alternately, several TOCin readings with IC present (t~t ~s, water ~om the in~ow) can be taken at six minute intervals over the course of an hour and an average value of ~g CA can be obtained for ICin. Du ing the next hour, several TOCout readings with the IC present (that i~ er from the outilow) can be taken in about 9L~ minute intelvals and an average v~lue of ~g C/l c~n be obtained for ICout.
As pointed out abo~e, the IC conee~ ion can be used as a checlc on the biological activity of the biofilm.

Dissolved oxygen can al~o be measured by the bioreactor appara~. The oxygen monitoring sy~tem des~ d above was utilized by ~rst cali~r~lg the electrodes by bypassing the reactor, closing offvalve 148, and usin~ ~2 saturated w~ter lSl from the calibration line lS0. For optimal result~, a call~ration check was pe,ru~ ed on the electrodes a~er each reading. The electrode used was a Clark-~tyle polarographicelectrode (~glAgCl). The ~ow rate, temperature, and pressure are kept const~)t, then more accurate re6ults can be ob~ . The values of dissolved oxygen c~ncP ~ ions are i~dicated in mm Hg and the following formula is used to convest the result to ~

218g23~

X- p9?(mmHg~ ~ 1 778103 inmg~
5.996 105 T(~C)~2.011 107 The amrlifi~r takes the reading fronl the electrode and provides a measurelnent of the oxygen level in the sample. A valve is provided and is switched to permit in~ow and outaow readings to be made.
Other nlodificatinn~ con~nctent with the scope ofthe i.-~,G.ltion desc,;bed herein may also be made. For f ~ le, w~ile not shown, it is understood that filtcrs may be used to remove lar~e particles of debn~ from the water flow to the Golumns. The filtration may be done in line before the entry to the column or analyzers or c~n be done in the line feeding the stre~rn water to the reactor. In ~ddition while ~wo col~mn~ are shown, the apparatus may colllr~e ~d~itional columns, as well, or a single colurnn may be used. The valYes can be manually or ele~llonically ope~ated and can also be controlled with a timer.

Claims

1. An apparatus for determining the concentration of biodegradable organic matter in an aqueous environment comprising:
a) pump means for moving water from a source along a path of travel, b) at least one column having an inlet opening and an outlet opening and a space therein to permit the passage of water flow through said space;
c) regulating means for facilitating regulating the water flow through the column;
d) an outflow line extending from said outlet opening of the column;
e) packing material provided within the column space; and f) a biofilm within said column.

2. The apparatus of claim 1, wherein said regulating means comprises a bed having a plurality of apertures therein.

3. The apparatus of claim 2, wherein a bed is provided at each column end proximate said column inflow opening and said column outflow opening.

4. The apparatus of claim 1, wherein said biofilm comprises microbes indigenous to said aqueous environment to be analyzed.

5. The apparatus of claim 1, wherein said packing material comprises borosilicate glass.

6. The apparatus of claim 1, wherein said packing material comprises sintered borosilicate glass beads.

7. The apparatus of claim 1, wherein said column includes temperature regulating means.

8. The apparatus of claim 7, wherein said temperature regulating means comprises a water jacket.

9. The apparatus of claim 2, wherein said bed includes an end fitting provided on an end of each column, a bed support retained on said end fitting by a gasket, and an end cap having attachment means for attaching said end cap to said cloumn end

10. The apparatus of claim 9, wherein said attachment means comprises first threads disposed on the outer peripherial surfaces of each cloumn end, and second mating threads provided on the end up.

11. An apparatus for determining the concentration of contaminants in an aqueous environment comprising:
a) pump means for moving water from a source along a path of travel;
b) a first column having an inlet opening and an outlet opening and a space therein to permit the passage of water flow through said space;
c) a second column having an inlet opening and an outlet opening and a space therein to permit the passage of water flow there through;
d) connecting means for connecting the outlet opening from the first column to the inflow opening of the second column:
e) regulating means for facilitating regulating the water flow through a column;
f) an outflow line extending from said outlet opening of said second column;
g) packing material provided within the column space of each said column;
h) a biofilm within said column.

12. The apparatus of claim 11, wherein said regulating means comprises a bed having a plurality of apertures therein.

13. An apparatus for determining the concentration of contaminants in an aqueous environment comprising:
a) a bioreactor comprising at least one column with a path of travel being defined through said column, wherein said column has a microbial communty present therein;

b) wherein said path of travel includes an inflow path of travel through which water flow travels to a column, and an outflow path of travel through which a water flow travels from a column;
c) inflow sampling means for obtaining a sample from the inflow path of travel;
d) outflow sampling means for obtaining a sample from the outflow path of travel;
e) control means for alternately sampling between inflow and outflow;
f) measuring means for determining the concentration of organic compounds for each outflow sample and for each inflow sample.

14. The apparatus of claim 13, wherein said control means includes regulatable valve means having electronically controlled means for changing between inflow and outflow sampling,

15. The apparatus of claim 14, wherein said control means includes a time regulated switch having two channels, wherein the first channel controls the changing between the inflow and outflow sampling and wherein the second channel regulatesbetween inorganic carbon measurement and total organic carbon measurement.

16. The apparatus of claim 15, wherein said measuring means includes oxidizing means for oxidizing the organic compounds present in the water sample, and detecting means for determining the amount of carbon dioxide produced from an oxidized sample.

17. The apparatus of claim 14, including an oxygen monitoring means.

18. The apparatus of claim 13, including oxygen monitoring means connected to said inflow line and to said outflow line, and regulating means for alternately selecting flow through said oxygen monitoring means to comprise flow from one of the inflow line and the outflow line.

19. The apparatus of claim 18, wherein said oxygen monitoring means comprises an inflow cell and an outflow cell wherein each of the inflow cell and the outflow cell contain an electrode.

20. The apparatus of claim 13, wherein said at least one column comprises a plurality of columns arranged in series and connected to one another by connecting means.

21. A method for determining the concentration of biodegradable dissolved organic carbon contaminants in a water system, comprising the steps of:
a) providing a flow path for water to be analyzed, said flow path including an inflow path and an outflow path;
b) establishing a biofilm along a zone of said flow path, said zone being provided between said inflow path and said outflow path.;
c) providing along said flow path flow regulation means for regulating the flow of water to the zone containing the biofilm;
d) flowing said water through said first flow regulation means, e) flowing said water through the zone of the flow path at which said biofilm iscontained;
f) flowing water out from the zone of the flow path at which said biofilm is contained and through a second flow regulation means;
g) measuring with measuring means the concentration of dissolved organic carbon of the flow water (DOCin) prior to the flow water entering the zone containing the biofilm;
h) measuring with measuring means the concentration of dissolved organic carbon of the flow water (DOCout) after the flow water has passed through the zone containing the biofilm;
i) subtracting the OCout reading from the OCin reading to obtain a measurement of biodegradable dissolved organic carbon concentration of the water sample.

22. The method of claim 21, wherein the flow of water through the zone containing the biofilm is moved through the zone at a flow rate which enables the biofilm act upon the components in the water stream.

23. The method of claim 22, wherein the flow rate is from about 2 to 4 ml/min.

24. The method of claim 21, wherein step g) includes obtaining inflow sample from the inflow path.

25. The method of claim 21, wherein step h) includes obtaining an outflow sample from the outflow path.

26. The method of claim 24, further including the steps of delivering said inflow sample to an analyzer, and measuring the dissolved organic carbon content of the sample.

27. The method of claim 21, wherein step d) includes the step of flowing the water sample through a bed and facilitating an even flow of water sample through the column.

28. The method of claim 21, further including the step of regulating with timer means the selection of sample inflow and sample outflow to be measured by the measuring means, and alternately measuring DOCin and DOCout concentrations of a water sample.

29. The method of claim 21, further including the step of flowing sample through an inorganic carbon removal module prior to measuring DOCin and DOCout

30. The method of claim 21, further including the step of flowing sample through an oxygen analyzer nodule to determine the amount of oxygen in the watersample.