Note: Descriptions are shown in the official language in which they were submitted.
Back~round of the Invention
This disclosure pertains to organic waste processing.
More particularly, this disclosure pertains to a method and
apparatus for processing organic waste in an aqueous medium.
The disclosure also pertains to an apparatus for determining
the biochemical o~ygen d~mand (BOD) of an organ~c waste in
an aqueous ~edium.
A variety of methods for the dlsposal of organic
waste, either industrial or agricultural, are available.
Same of these methods, such as burial, land-fill, dumping at
sea, and the like, have a negative environmentaL imp~ct and
are not desirable. On the other hand, methods are available
for converting organic waste to a source of energy a~d/or a
~2
~ `' ~
~17166~
usable product and include, among others, biological aerobic
fermentation, biological anaerobic fermentation, thermophilic
aerobic digestion, destructive distillation (including
hydrocarbonization and pyrolysis), and incineration. W. J.
Jewell et al., "Methane Generation from Agricultural Wastes:
Review of Concept and Future Applications," Paper No. NA74-
107, presented at the 1974 Northeast Regional Meeting o, the
American Society o~ Agricultu~al Engineers, West Virginia
University, Morgantown, West Virginia, August 18-21, 1974.
Of this latte~r group, biological anaerobic fermentation
appears to be the most promising and has received consider-
able attention in recent yPars.
Current interest in biological anaerobic fermentation
appears to be due, at least in part, to the development of
the anaerobic filter. See, for example, J. C. Young et al.,
Jour. Water P _ . Control Fed., 41, R160 (1969); P. L.
McCarty, "Anaerobic Processes", a paper presented at the
Birmingham Short Course on Design Aspects of Biological
Treatment, International Association of Water Pollution
Research, Birmingham, England, September 18, 1974; and J. C.
Jennett et al., Jour. Water Poll. Control Fed., 47, 104
.
(1975). The anaerobic filter basically is a rock-filled bed
similar to an aerobic trickling filter. In the anaerobic
filter, howe~er, the waste is distributed across the bottom
of the filter. The flow of waste is upward through the bed
of rocks so that the bed is completely submerged. Anaerobic
microorganisms accumulate in the void spaces between the
rocks and provide a large, a~tive biological mass. The
effluent typically is essentially free of biological solids.
See J. C. Young et al., supra at R160.
7~8
The anaerobic filter, howe~er, is best suited for the
treatment of water-soluble organic waste. J. C. Young et
al., supra at R160 and R171. Furthermore, very long reten-
tion times of ~he waste in the filter are required in order
to achieve high reductions in the chemical oxygen demand
(COD) of the waste to be treated. That is, depending upon
the COD of the waste stream, reductions in such COD of from
36.7 percent to 93.4 percent required retention times of
from 4.5 hours to 72 hours. J. C. Young et al., supra at
R167. In addition, such results were achieved with optimized
synthetic wastes which were balanced in carbon, nitrogen,
and phosphorus content and which had carefully adjusted pH
values.
Accordingly, there remains a great need for a waste
processing method which can tolerate the presence of solids
in the waste stream and which can more rapidly process the
waste on an "as is" basis.
Sum~ary of the Invention
In accordance with the present invention, there is
provided a method for processing organic waste in an aqueous
medium which comprises serially passing an organic waste-
containing aqueous medium through a first immobilized microbe
reactor and a second immobilized microbe reactor, in which:
A. the first reactor is a~ aerobic reactor containing
a porous inorganic support which is suitable for the accumu-
lation of a biomass, and
B. the second reactor is an anaerobic reactor com-
prising a controlled-pore, hydrophobic inorganic membrane
which contains a porous inorganic support which is suitable
for the accumulation of a biomass.
Also in accordance with the present invention, there is
provided an apparatus for processing organic waste in an
aqueous medium which comprises a first immobilized microbe
reactor serially connected to a second immobilized microbe
reactor, in which:
A. the first reactor is an aerobic reactor containing
a porous inorganic support which is suitable for the accumu-
lation of a biomass, and
B. the second reactor is an anaerobic reactor com-
prising a controlled-pore, hydrophobic inorganic membrane
which contains a porous inorganic support which is suitable
for the accumulation of a biomass.
The present invention also provides an apparatus for
the determination of the biochemical oxygen demand of an
organic waste in an aqueous medium which comprises a sampling
and/or sensing means serially connected to an immobilized
microbe reactor which in turn is serially connected to a
sampling and/or sensing means, in which the reactor is an
aerobic reactor containing a porous inorganic support which
is suitable for the accumulation of a biomass.
The present invention fur~her provides an apparatus ~or
the determination of the biochemical o~ygen demand of an
organic waste in an aqueous medium which comprises a sampling
and/or sensing means serially connected to a first immobilized
microbe reactor which is serially connected to a second
immobilized microbe reactor which is serially connected to a
sampling and/or sensing means~ in which:
A. the first reactor is an aerobic reactor containing
a porous inorganic support which is suitable for ~he accumu-
lation of a biomass, and
1 1 ~7 ~6 ~
B. the se~ond reactor is an anaerobic reactor com-
prising a controlled-pore, hydrophobic inorganic membrane
which contains a porous inorganic support which is suitable
for the accumulation of a biomass.
Brief Descri tion of the Drawin
P _ _ g
The drawing illustrates one embodiment of the present
invention as described by Examples 1 and 2, which embodlment
comprises treating sewage to give an effluent having a
significantly reduced oxygen demand and methane as a gaseous
product.
Detailed Descri tion of the Invention
As used herein, the term "biodegradable" means only
that at least some of the organic waste to be treated must
be capable of being degraded by microorganisms. As a
practical matter, at least about 50 percent by weight of the
organic waste usually will be biodegradable. It may be
necessary or desirable, however, to utilize in the process
of the present invention waste having substantially lower
levels of biodegradable organic matter.
Thus, the organic waste or the aqueous medium contain-
ing such waste can contain non-biodegradable organic matter
and inorganic materials, provided that the organic waste and
aqueous medium are essentially free of compounds having
significant toxicity toward the microbes present in either
reactor.
In general, the nature of the aqueous medium is not
critical. In msst instances, water will constitute at least
about 50 percent by weight of the medium. Preferably, water
-5-
668
will constitute from about 80 to about 98 percent by weight
of the aqueous medium.
Frequently, the waste stream to be treated by the
process of the present invention can be used without any
pretreatment. Occasionally, it may be desirable or neces-
sary to dilute the waste stream with water, to separate from
the waste stream excessive amounts of solids or excessively
coarse solids which might interfer with the pumping equipment
necessary to mQVe the aqueous medium through the processing
apparatus of the present invention, or to increase the pH of
the aqueous medium by, for example, the addition of an
inorganic or organic base, such as potassium carbonate,
sodium hydroxide, triethyLamine, or the like. Alternatively,
solid or essentially nonaqueous organic waste can be diluted
with wate~ as desired.
As already indicated, both the first and second reactor
of the method and processing apparatus of the present invention
contain a porous inorganic support which is suitable for the
accumulation of a biomass. In the case of the second reactor,
the inorganic support is contained within a controlled-pore,
hydrophobic inorganic membrane.
As a matter of convenience, the inorganic support in
the two reactors will be of the same type, although such is
not required. Preferably, the inorganic support in each
reactor is a porou~, high surface area inorganic support
which is suitable for the accumulation of a hi~h biomass
surface within a relatively small volume. More preferably,
at least 70 percent of the pores of the inorganic support
have diameters at Least as large as the smallest major
dimension, but less than about five times the largest major
dimension, of the microbes present in the reactor. Most
~L~17668
preferably, t~e a~e~age di~meter ~ the pores of the inorganic
support is in the range of from about 0.8 to about 220~.
As used herein, ~he expression "high surface area
inorganic ~upport" means an i~organic support having a
surface area greater than about 0.01 m2 per gram of support.
In general, surface area is determined by inert gas adsorption
or the B.E.T. method; see, e.g., S.J. Gregg and K.S.W. Sing,
"Adsorption, Surface Area, and Porosity", Academic Press,
Inc., New York, 1967. Pore diameters, on the other hand,
are most readily determined by mercury intrusion porosimetry;
see, e.g., N.M. Winslow and J.J. Shapiro, "An Instrument for -
the Measurement o Pore-Size Distribution by Mercury Penetra-
tion", ASTM Bulletin No. 236, Feb. 1959.
The inorganic support in general can be either siliceous
or nonsiliceous metal oxides and can be either amorphous or
crystalline. Examples of siliceous materials include, among
others, glass, silica, cordierite, wollastonite, bentonite,
and the like. Ex~mples of nonsiliceous metal oxides include,
among others, alumina, spinel, apatite, nickel oxide, titania,
and the like. The inorganic support also can be c~mposed of
a mixture of siliceous and nonsiliceous materials, such as
aLumina-cordierite. Cordierite materials such as the one
employed in the examples are preferred.
For ~ more complete description of the inorganic
support, see commonly-assigned u.S. Patent No. 4,153,51~,
filed September 14, 1977, in the names
of Ralph A. Messing and Robert A. Oppermann.
As already indicated, the inorganic support in each
reactor provides a locus for the accumulation of microbes.
The porous nature of the support not only permits the
accumulation of a relatively high biomass per unit volume of
11~6~
reactor but also aids in the reten~ion of ~he biomass
within each reactor.
As used herein, the term "microbe" tand derivations
thereof) is meant to include any microorganism which degrades
organic materials, e.g., utilizes organic materials as
nutrients. This te~minology, then, also includes micro-
organi~ms which utilize as nutrients one or more metabolites
of one or more other microorganisms. Thus, the term "microbe",
by way of illustration only, includes al~ae, bacteria,
molds, and yeasts. The preferred microbes are bacteria,
molds, and yeasts, with bacteria being most preferred.
In general, the nature of the microbes present in each
reactor is not critical. It is only necessary that the
biomass in each reactor be selected to achieve the desired
results. Thus, such biomass can consist of a single microbe
species or several species, which species can be known or
unknown (unidentified). Furthermore, the biomass in each
reactor need not be strictly aerobic or strictly anaerobic,
provided that the primary functions of the two reactors are
consistent with their designations as aerobic and anaerobic
reactors, respectively. The term "primary function" as used
herein means that at least 50 percent of the biomass in each
reactor functions in accordance with the reactor designation.
Stated diferently, the demarcation line or zone
between an aerobic function and an anaerobic function is not
critical and need not always lie between the two reactors.
In practice, such demarcation line or zone can vary from the
midpoint of the first reactor to the midpoint of the second
reactor and to some extent can be controlled by regulating
the amount of oxygen dissolved in the waste stream.
1~76~ !3
Examples of microbes which can be employed in the
aerobic reactor include, among others, strict aerobic bacteria
such as Pseudomonas fluorescens, ~cinetobacter calcoaceticus,
and the like; facultati~e anaerobic bacteria such a~ ~scherichia
coli, Bacillus subtilis, Streptococcus faecalis, Staphylococcus
aureus, Salmonella typhimurium, Klebsiella pneumoniae,
Enterobacter cloacae, Proteus w lgaris, and the like; molds
such as Trichoderma viride, Aspir~illus ni~er, and the like;
and yeasts such as Saccharomyces cerevisiae, Saccharomyces
ellipsoideus, and the like.
Examples of microbes which can be utilized in the
anaerobic reactor include, among others, facultative anaerobic
bacteria such as those listed above; anaerobic bacteria such
as Clostridium butyricum, Bac~eroides frazilis, Fusobacte ium
necrophorum, Leptotrichia buccalis, Veillonella par w la,
Methanobacterium formicicum, Methanococcus mazei, Methano~arcina
barkeri, Peptococcus anaerobius, Sarcina ventriculi, and the
like; and yeasts such as Saccharomyces cerevisiae, Saccharomyces
ellipsoideus, and the like.
As already pointed outJ the microbes employed in each
reactor are selected on the basis of the results desired.
If a particular product is not required, the choice of
microbes can be made on the basis of waste conversion effi-
ciency, operating parameters ~uch as temperature, flow rate,
and the like, microbe availability, microbe stability, or
the like. If, on the other hand, a particular product is
desired, the micro~es typically are selected to maximize
production of that product. By way of îllustration only,
the table below indicates some suitable ccmbinations of
microbes which will yield the indicated product.
_9_
~1~766~3
~I c c c c c c c c c c ~ 3 C
D~ ] ~ ~
C
O ol ~i ?~
o s S a) S~ Ei t~ ~1 E3 ¦
~ = o 0 'C ~ Y C~ ~ ~
-10~
~1~7~i8
~ o ~l
~ ~ ~o o
O O ~ 'd
h ~ ::3
o
S~ ~ ~ ~ .
t~ rl h
~: O U
t~ ~ ~ ::1
.,, :L u~ .n
.~ ~ .~ .~
~ ,1 ,J ~
¢ u ~ h
~q ~ Ul
O O
C~ C.) C:
O a
~ ~ ~ ~
p! .~ ~a 01
.,1 ~ ~
S~ ~ ~ ~
¢ ~ ~
Q .,1 c~
U~ 5~ U~
E~
~L11761~8
In general, the microbes are introduced into each
reactor in accordance with conventional procedures. For
example, the reactor can be seeded with the desired microbes,
typically by circulating through the reactor an aqueous
microbial suspension. Alternatively, the microbes can be
added to the waste stream at any desired point. In cases
where the waste stream already contains the appropriate
types of microbes, the passage of such waste through the two
reactors wilL in due course establish the requisite microbe
colonies in each reactor.
The second reactor also contains a controlled-pore,
hydrophobic inorganic membrane. As used herein, the term
"membrane" refers to a continuous, formed article, the shape
and dimensions of which are adapted to process requirements.
Thus, the membrane can be a flat or curved sheet, a three-
dimensional article such as a rectangular or cylindrical
tube, or a complex monolith having alternating channels for
gas and aqueous medium. As a practical matter, the membrane
most o~ten will consist of a cylinder, open at both ends to
provide passage of aqueous medium through its length. Wall
thickness is not criticaL, but must be sufficient to permit
the membrane to withstand process condîtions without defor-
mation or breakage. In general, a wall thickness of at
least about 1.0 ~m is desi~ed.
The membrane can be either siliceous or nonsiliceous
metal oxides. ExampLes of siliceous materials include,
among others, glass, silica, wollastonite, bentonite, and
the like. Examples of nonsiliceous metal oxides include,
among others, alumina, spinel, apatite, nickel oxide,
titania, and the like. Siliceous materials are preferred,
-12-
~L76t;~
with glass and silica being most preferred. Of the non-
siliceous metal oxides, alumina is preferred.
The membrane must have a controlled porosity such that
at least about 90 percent of the pores have diameters of
from about 100~ to about 10,000~. Preferably, the pore
di~meter range will be fr~m about 900~ to about 9,000~, and
most preferably from about 1,500A to about 6,000~.
Methods of preparing inorganic membranes having con-
trolled porosity as described above are well known to tho e
having ordinary skill in the art and need not be discussed
in detail here. See, e.g., U.S. Patent Nos. 2,106,764,
3,485,687, 3,549,524, 3,678,144, 3,782,982, 3,827,893,
3,850,849, and 4,001,144, British Patent Specification No.
1,392,220, and Canadian Patent No. 952,289. In addition,
various porous inorganic ~aterials are commercially a~ail-
able which can be formed into shaped articles by known
methods. Among suppliers of such porous inorganic materials
are the following: Alcoa, Catalytic Chemieal Co. Ltd.,
Coors, Corning Glass Works, Davison Chemical, Fuji Davison
Co. Ltd., Harrisons & Crosfield (Paci~ic~ Inc., Kaiser
Chemicals, Mizusawa Kagaku 5O. Ltd., Reynolds Metals Company
(Chemicals Division), Rhodia, Inc. (Chemical Division), and
Shokubai Kasei Co. Ltd.
As a second requirement, in addition to controlled
porosity, the inorganic membrane must be hydrophobic. Since
the inorganic materials of which the membrane usualLy is
composed are not inherent~y h~drophobic, the property of
hydrophobicity normally must be lmparted to the membrane by
treating it either before or after the membrane is shaped or
formed. As a practical matter, such treatment will be a
post-formation treatment. The nature of the treatment is
*Trade Mark -13-
~76f~8
not critical, and e~,sent~ally any ~reatment can be employed
which will render the membrane hydrophobic. The psoperty of
hydrophobicity, however, must be imparted throughout ~he
entire void volume of the membrane, and not just to the
external surface areas.
Hydrophobicity is most conveniently imparted to the
shaped or formed membrane by ~mmerslng the membrane in an
organic solvent which contai~s dis~olved therein a suitable
hydrophobic reagent, removing the membrane from the solvent,
and allowing it to air dry. Although the concentration of
the reagent is not critical, an especially useful concen- !
tration range has been found to be fr~m about 3 to about 25
percent, weight per volume of solvent. A most convenient
concentration is 10 percent. Essentially any solvent in
which the hydrophobic reagent is soluble can be employed.
Examples of suitable solvents i~clude, ~mong others, hexane,
cyclohexane, diethyl ether, acetone, methyl ethyl ketone,
benzene, toluene, the xylenes, nitrobenzene, chlorobenzene,
bromobenzene, chlorsform, carbon tetrachloride, and the
like. Examples of suitable hydrophobic reagents include,
among others, natural waxes such as spermace~i, beeswax,
Chinese wax, carnauba wax, and the like; synthe~ic waxes
such as cetyl palmitate, cerotic acid, myricyl palmitate,
ceryl cerotate, and the like; ali~hatic hydrocarbons such as
octadecane, eicosane, docosane, tetracosane, hexacosane,
octacosane, triacontane, pentatriacontane, and the like;
polycyclic aromatic hydrocarbons such as naphthalene,
anthxacene, phenanthrene, chrysene, pyrene, and the like;
polybasic acids such as Empol Dimer Acid and Empol Trimer
Acid (Emery Industries, Inc.~; polyamide resins such as the
Emerez Polyamide Resins (Emery Industries, Inc.);
*Trade Mark -14-
i ~7 6~ S
water-insoluble polymeric isocyanates such as poly(methylene-
phenylisocyanate) which is commer ially available as PAPI
(Upiohn Company); alkylhalosilanes such as octadecyltrichloro-
silane, di(dodecyl)difluorosilane, and the like; and similar
materials. The alkyhalosilanes are preferred, with octadecyl-
trichl~rosilane being mo~t preferred.
From the foregoing, it should be appa~ent tO o~e
having ordinary skill in the a~t that essentially any hydro-
phobic reagent which will adhere to the inorganic membrane
with a reasonable degree o permanence can be employed.
Such adherenee can be by purely physical means, such as van
der Waals attraction, by chemical means, such as ~onic or
covalent bonding, or by a comblnation of physical and chemical
means.
It should be apparent to one having ordinary skill in
the art that the configurations of the first and second
reactors are not cri~ieal to either ~he method or the
processing apparatus of the present invention. Thus, the
present inve~tion c~mprehends any confi~u~ation of each
reactor which is not inconsistent with the instant disclosure.
Most often, each reactor will be a conventional cylindrical
or tubular plug flow-type ~eactor, such as are described in
the examples. Accordingly, each reactor typically c~prises
a cylinder or t~be open at both ends which contains the
inorganic support. In the case of the fir~t reactor, such
cylinder is com~osed of any suitable material which is
impervious to both gases and li~uids. Suitable materials
include, among others, glass, stainle~s steel, gl~ss-coated
steel, pol~(tetrafluoroethylene). and the like. The first
reactor optionally is jacketed. In the case of the second
reactor, such cylinder is the controlled-pore, ~ydrophobic
*Trade Mark
-15-
1 ~ ~7 ~ ~
inorganic membrane. The second reactor also is optionally
jacketed, especially where it is either desirable or necessary
to contain, isolate, analyze, utilize, or otherwise handle
gaseous products evolved during the process of the present
invention. The jackets, if present, can be constructed from
any of the usual materials, such as those listed for the
first reactor.
In more general terms, each reactor normally will be
shaped in such a manner as to provide one or more channels
for the passage of a fluid. Where multiple channels are
provided, such chann~ls can provide independent flow of the
fluid through such channels or they can be serially connected.
The aqueous medium can flQw through such channels or around
such channels. Thus, the inorganic support can be contained
in such channels or located around such channels. For
example, given the cylindrical reactor already described,
the inorganic support can be contained within the cylinder
or tube. Alternatively, the cylinder or tube can be iacketed
and the inorganic support can be located between the jacket
and the cylinder or tube. Hence, the aqueous medium can
flow either through or around the cylinder or tube. In the
latter case with the second reactor, gaseous products will
be removed from within the cylindrical membrane. Further-
more, such gases, irrespective of whether they pass from or
into the cylindrical membrane, can be dissolved in a liquid
solvent ha-~ing a high affinity for the gases, i.e., in which
the gases have a high degree of solubility. Suitable solven~s
for many gases include silicones and fluorocarbons, among
others. The use of such a gas solvent usually is neither
necessary nor desired and, therefore, is not preferred.
-16-
~7~;68
Since the method and p~ocessi~g apparatus of the present
invention are well-suited for the production of usable
gases, it is preferred that the second, anaerobic reactor is
sealably enclosed within a jacket having a gas remo~al means
attached thereto.
Under normal circumstances, both reacto~s are main-
tained at ~mbient tempe~ature. Indeed, the process of the
present invention most preferably is carried out at ambi~nt
tempera~ure. While process temperatures are critical only
to the extent ~hat the microbes present in each reactor
remain viable, as a practical matter the process of the
present invention will be carried out at a temperature of
from about 10C. to about 60C. Xn those instances where an
elevated temperature is desired, such elevated temperature
usually is applied only to the first, aerobic reactor, in
which case the preferred temperature range is from about
30C. to about 35C.
One preferred embodiment of the process of the present
invention is illustrated by the examples in which a principal
product is methane which is passed through the controlled-
pore, hydrophobic inorganic membrane of the second, anaerobic
reactor. Alternatively, process conditions and microbe
choices can be made which will yield ethanol as a principal
product in the liquid effluent emerging from the second
reactor.
The present invention also provides an apparatus for
the determination of the biochemical oxygen demand (BOD) of
a biodegradable organic waste in an aqueous medium. Such
apparatus can take either of two configurations or embodi-
ments: (1) a sampling and/or sensing means serially connectedto the first, aerobic reactor described hereinbefore, which
~7668
reactor in turn ia serially ~onnected to a sampling and/or
sensing means; and (2) a sampling and/or sensing means
serially connected to the first, aerobic reactor described
hereinbefore, which first reactor is serially connec~ed to
the second, anaerobic reactox desc~ibed hereinbefore, which
second reactor is serially connected to a sampling and/or
sensing means.
As used herein, the term "sampling and/or sensing
means" is meant to include a sampling means, a sensing
means, and a sampling and sensing means.
Accordingly, the sampling and/or sensing means can be
nothing more than a port, fi~ted With, fo~ example, a stopcock
or rubber septum, to provide a means for the manual withdrawal
of a sample from the waste stream. Alternatively, such
sampling means can be an automated sampling device which
automatically removes samples of a precise si2e at predeter-
mined intervals and stores such samples for future ~andling
or analysis.
Examples of suitable sensing means include, among
others, dissolved oxygen sensor, conductivity sensor, ammonium
ion sensor, pH electrode, and the like. Actually, any
sensing means can be used which will detect measurable
differences in the organic waste-containing aqueous medium
which are the result of the biochemical conversions taking
place in the apparatus for determining BOD.
As contemplated by the present invention, a sampling
and sensing means can be any combination of a sampling means
and a sensing means. For example, an automated sampling
device can be serially connected to an automated device for
determining COD by a chromic acid oxidation procedure.
-18-
~ ~1 7 66 ~ '
Other variations and c~mb~nations, however, will be readily
apparent to one having ordinary skill in the art.
Finally, the two sampling and/or sensing means need not
be physically discrete or separate. That i5, with appropriate
connecting and waste stream directing means, a single sampling
and/or sensing means ~an be employed in the BOD apparatus of
the presen~ invention, and ~uch use is within the scope of
the instant disclosure. Thus, when using a single sampling
and/or sensing means, the waste ~tream or a portion thereof
first is passed through the sampling and/or sensing means.
The waste stream then e~te~s the aerobic reactor. Upon
exiting the aerobic reac~or (or the anaerob~c reactor if
bot~ reactors are employed), t~e waste stream or a portion
thereof is directed to the sampling and/or sensing means by
appropriate connecting and directing means which are well
known to those ha~ing ordinary skill in the art.
The prese~t ln~ention is urther described, but not
limited, by the following examples which illustrate the use
of the method and apparatus of the present invention in the
treatment of sewage. Unless otherwise stated, all tempera-
tures are in degrees Celsius.
The process empLoyed in Examples 1 and 2 is described
below, with reference to the drawing.
Sewage 1 i~ pum~ed fr~m container 2 by pump 3 to
aerobic reac~r 4 via rubber tubing 5 sealably connected to
~he pump and the aerobic reactor. The aerobic reactor
consists of inner glass tube 6 sealable enclosed within
glass jacket 7. The inner glass tube contains inorganic
carrier 8 such as that described in uOs. Patent No. 4,153,510,
3~
-19-
~ 66 ~
which is suitable for thP- accumulation of a biomass. Sewage
leaving the aerobic reactor is transported to anaerobic
reactor 9 via rubber tubing 10 sealably connected tv both
reactors. The anaerobic reactor consists of inorganic
membrane 11 and glass jacket 12 having exit port 13. The
inorganic membra~e is filled with additional inorganic
carrier 8 and is sealably enclosed within the glass jacket.
Rubber tubing 14, sealably connected to the exit port of the
jacket, leads to p~mp 15 which removes gas ~methane) from
air space 16 enclosed by the jacket. Such gas in turn is
collected by any suitable means such as by the displacement
of water in an inverted vessel Cnot shown). Sewage effluent
17 then is transported, via rubber tubing 18 sealably con-
nected to the anaerobic reactor, to receiving vessel 19.
The sewage employed in each of the examples was obtaine~
from the inlet pipe to the Corning, New York, Municipal
Sewage Waste Treatment Pla~t. The sewage was stored at 4-
6C. Prior to use, the sewage was filtered through cheese-
cloth and glass wool to remove coarse particulate matter.
Sewage was collected either weekly or biweekly.
ExamPle 1
Pump 3 consisted of a Fluid Metering pump, RPlG6CSC
(Fluid Mete~ing, Inc., ~y~ter Ba~, ~.Y.), which was connected
to aerobic reactor 4 with a 14-in h length of rubber tubing.
A 20-inch length of rubber tubing was attached to the intake
side of the pump and led from a flask containing sewage.
The aerobic reactor consisted of a Pharmacia K16/20
column (Pharmacia Fine Chemicals, Uppsala, Sweden) wi~h
water jacket; the water jacket was left vented to the
atmosphere. The column was charged with 24 g. of cordierite
-20-
~117~f~8
(CGZ) carrier having a pore diameter distribution of 2-9
and an average pore di~uneter of 4.51~l. The carrier was
seeded with sewage microbes by 1Owing ~hrough the reactor
sludge obtained previously from a municipal anaerobic di~estor.
The inorganic membra~e 11 of anaerobic reactor 9 was a
5ilica membrEn~, prepared in ~cordance wlth known procedures;
see, for example, U.S. Patent Nos. 3,678,144, 3,782,9~2, and
3,827,893. The membrane was appro~imately 18 cm. long with
cross-sectional dimensions of 10.5 mm. i.d. a~d 15.5 mm.
o.d. The average pore diamete~ of the membrane was 3500
with a pore diameter di~tribution of 2000-3600~. ~all
poroslty was 60 percent and pore volume was 0.89 cc/g. The
m~mbrane was rendered hydrophobic by placing ~t in 75 ml. o
a ten percent solution of octadecyltrichlorosil~ne in acetone
and allowing it to soak overnight. The m~mbrane then was
removed from the solution, washed with 500 ml. of acetone,
and air-dried.
The membrane was mounted in a Yharmacia K16/20 water
jacket by me~s of the ~tandard rubber sealing ring and
threaded locking ring and was charged with ten g. of the CG~
carrier. Both reactors together had a total void or fluid
volume of about 30 ml.
The two reactors were coupled with about four inches of
rubber tubing. One of the ports of the anaerobic reactor
jacket was ~ealed by attaching a Qhort pie e of Tygon tubing
thereto and elosing the tu~ing by means of a clamp. The
other port was attached to a Buchler Polystaltic Pump (Buchler
Instruments, Inc., Fort Lee, N.J.) with a length of thick-
walled Tygon tubing. Gas evolved ~nd passed through the
membrane was collected by the displacement of wa~er in a
calibrated cylinder inverted in water-filled, large, shallow
*Trade Mark -21-
~ 66~
vessel. The rate of gas evolution was observed and the
collected gas was analyzed a~ least daily b~ mass spectroscopy.
In addition, the chemical oxygen demand (COD) of the sewage
used as feed and the effluent eme~ging from the anaerobic
reactor wexe determined periodically b~ standard, well-known
colorimetric dichromate oxidation procedures.
The process was run ~or a period of about nine months.
Although data were generated on a dail~ basis, except for
COD analyses, weekly averages of the data are presented in
Table I; in the table, COD analyses are averaged where more
than one analysis was obtained per week.
-22-
~176~3
~ ~ ~ O ~ ~ ~ OD
a~
.~,
~ l l l l l l l l l l l l
~e
' ~1
11111
~1 I ~1 o a~ ~ 1~ o 1~ o o~
G~ ~ i -~ -~ ~ ~
~ ,, ~ ~ ~ ~ ~ o ~ o~ ~ ~ ,,
W ~ ~ C~l , ~ ,~ ~ ~ ~ U~ C~l
001-- 1~ ~ ~ ~ U~ ~ U~ ~ ~ ~O
g 00 J
~ C~l ~r{~o U~ ~ ~ ~ ~ ~ ~ o ~_
~ ~ ~ ol ,r ~ ~ ~
~ ~ o
E~ C~ o
~3 '~1 ~ ~ ~ c~
U~
a c~ ~ ~ ~o o co o c~ ~ o ~ ~ ~
e~ ~i ~ I~ ~ ~ 1-- `D ~D ~ I~ O ~i
C ~
o o
~! ~ ~ C~i O ~ ~ ~ C`l ~ _i O O
~o_
C~ ~
00 0~ o u~ o o o r~ O
~,c o o o o
~I
.~, I
3~ o
--23--
1~17668
~1
6 , ~ ,,~ v
I I I o~ ~ I o
:~ U~ U~ ~ Ln ~D ~ `D
0~
Ul Ul o o U~
:~ I I I ~1 ~o ~ o C~ ~ l_ I ,~
O
I o I ~n U'l C~ `* o o o co
& ~I ri O O r~O O O O O O ,-i
_~ ~ ~ ~ O ~ ~
c: 5 c~ ~ o a~
~: ~1 P, ~
_ ~ ~ ~ o
O O
Cd C~
W ~ I~ ~ ~ o ~ C~
O C~ I t-') `D Lr) ~ u~ u~ u~ r~ r~ ~ ~_ ,1
5~ ~ ~
P ~D ~D O C~ C`l ~ C`l ~ u~ ~ C~l Ul
U~ _ O _i ~1 0 ~1 ~ ~ ~ O
C~ 6
C` ~i ~ OD 0~ O C~
--24--
J ~117668
~'ttt ~
CJ ~0 ~ `D C~l (~ `D r~ ~' ~ I
O ~J i O Ul O O U) O O ~ r~
~, ol ~ ~ ~ ~ ~ ~
U~OOOOOOO1`
u~ ~ ~ o cO a~ u~
. ~
~1 O ~D u~ ~ ~ ~ C" ~ ~ ~r
_l ~ ¢l-iooooooooo
I ,~ u-\ a~ ~ ~ ~ OQ O~ ~ ~
E z~~ o
~ I 1~
~ ~ ~ c~
~ ~ ~ ~1 ~
c~ ~ E ~ u~ x) o
O O 0
~) I ~1 ~i C~ ~1
~- U~
~ ~ C~
E~ ~ ~ ~ ~ O o~
C~ C~ I ~ ~O ~D ~ ~ ~O 1~ ~ 1~ r~
~ .~
t~ O
r O ~ ~ ~`I C`J c~l ~ ~1 ,~
tq
a~
O
~, C l~ 1 ~ O
E
--25--
o
1766~
W
,, ~ , V
~:s a)
Q
I~
~: a
~U JJ ~
,C ~C ~ 'I
U
~3 n
~ ,t
O h O
~ ~
0 ~ ~4 ~ 0 ~
S~ ~ ~ o
O O
0 0 ~ --I ~
J~ X ~ ~ I~
bO al ~ sJ ~ . ~ 3
o a~
cq * o P~ Ei
~ o
.~: 3 ~ u ~ ~n O
ta ~ g ,, ~ ~ ~ O o
n~ s ~ ~ ~ V
a~ ~ ~ ~ ~ 0 c~
s~ æ o
~ ~ o ~
_i ~ h _I ~ ~ ~ ~ O
n 3 ~ O ~ a) ~ c~ s~ Ej t,o
o ~ .c ~ ~ ~
C~ ~ O ~ S~ ~~1 3
0 ~
~ oq ~ u
W ~ ,G a ~ o
0 3 ~ ~ a~
o
u ~ ~ o a) ~
0 ~ ~ ~ ~ 0 ~ ~ ~d J ~ I Oq
~a ~ o
~ ~,2 ~ c~ ~ 3 ~ o
O ~ e s~
a~ 3 ~ O
d O ~
Fl ~ R o~ . o ~--I at o ~i bO
:~ ~s3
S b~ O ~ ~ ~ ~ ~ ~ ~
t ~ 0 ~-rl ~ 0 C~ C~ ~ h
c) ~ ~ Q 3 ~ ~ O
~t ~ O o v mu~ S ;'
5~ ~ o ~ ~ ~ ~ w
IJ ~ .,{,r:: ~ ~n u o~ O
O ~ 0
~26-
7~
Example 7
The procedure of Example 1 was repeated, except that
the aerobic reactor was charged with 19 g. of CGZ carrier,
the carrier in the aerobic reactor was not seeded, the
inorganic membrane of the anaerobic reactor was an alumina
mem~rane, and the anaerobic reactor was charged with 18.4 ~.
of the CGZ carrier.
The alumina membrane was prepared in accordance with
well-known procedures. Briefly, 300 g. of SA alumina con-
taining three percent by weight ~f carbowax was isostatic-
ally pressed at 1,758 kg./cm.2 (25,000 psi) in a mold which
consisted of a cylindrical mandrel having a diameter of 1.9
cm. and a cylinder with rubber sleeve having an inner diameter
of 3.65 cm. The resulting cylindrical tube had the following
cross-sectional d~mensions: i.d., 1.9 cm., and o.d., 2.62
cm. The tube was turned on a ~athe to an o.d. of 2.4 cm.
The tube was about 36 cm. in length. The tube then was
fired in a furnace as follows: The furnace was heated to
500 (from ambient temperature~ at 50 per hour and held at
500 for two hours. The temperature then was increased to
1550 at a first rate of 50 per hour to 950 and a second
rate of 100 per hour to L550, at which temperature the
furnace was held for five hours. The furnace then was
cooled at 100 per hour to 950, and at 50 per hour to
ambient tempera~ure. The resulting alumina controlled-pore
membrane had an i.d. of 1.43 cm., an o.d. of 1.75 cm. 9 and a
wall thic~ness of 2.0 mm. Pore di~meter distribution was
fr~m 3500~ to 4500~, with an average pore di~eter of 4000~.
Wall porosity was 46.8 perce~t and pore volume was 0.22
cc./g. The membrane was rendered hydrophobic by placing it
~1~7~;68
in 50 ml. of acetone containing ten percent octadecyltri-
chlorosilane and allowing it to react overni~ht at ambient
temperature. The membrane then was removed from the acetone
solution and washed four times with 50-ml. portions of
acetone. The membrane was air-dried for four hours, and
then was heated at 120 for 1.5 hours.
The data obtained from ~his example are summariæed in
Table II, again as weekly averages.
-28-
68
h tO ,Q t~
~ o I
n ~1 o o o o o
U :~ O ~ r~ O _I I
O ~o ~ ~ o r~
o o o o
~:: c~
I O O O
~ l
_I o ~ I~
a) o . . . O
_I ~ ~ I ~o ~ ~u~ o
~ :: Z~
~3 ~ ~ I o ~ o ~u~ ~
H ~ ~ o l ~ 3
o c~l oo ~ i~ ~ ~ ~
E~ ~ C~ ~
q~ u~ (n
O ~ _l oo a~a~,~. 'a
I ~ ~ c~
~ ~o v
Ul ~ O ~
O ~ O U~ O
1~ ~ O ~ ~ ~ ~ ~
.C U~
~_ .
~ _I ~ V U~
C~) El ~ ~ ~a
g o~
_I
~ ~ ~ ~q
aJ ~ O
a~ ~ O O O
~! ~ 0 U~ -i 0
_ C~l ~ ~ ~ ~ ~ O
a~
_l
V 0~ ~
~1
C~ ¢
CJ
--29--
1~7668
Example 3
The proeedure of Example 1 was repeated with some
changes in equipment. The aerobie reactor consisted of a
Lab-Crest column, without jacket, 400 x 15 mm. The reactor
was charged with 50 g. of CGZ carrier. The anerobic reactor
consisted of an outer jacket 31.1 cm. in length and a fritted
glass membrane 30.5 cm. in length and 1.6 cm. in diameter.
The membrane, which was fused to the outer Jacket, consisted
of three sections of fritted glass tubing of equal length
which had been fused together. The total length of the
anaerobic reactor was 40.6 cm. The membrane had a pore
diameter distribution of 3-6~ and an a~erage pore diameter
of 4.5~. The membrane was made hydrophobic by allowi~g it
to react with 130 ml. of ten percent octadecyltrichlorosilane
in acetone at ambient temperature for about three days. The
membrane then was removed from the acetone solution and
washed successively with two 130-ml. portions of acetone,
two 130-ml. portions of methanol, and a 130-ml. portion of
acetone. The membrane was air-dried by aspiration. The
anaerobic reactor was charged with 23 g. of CGZ carrier.
The gas pump was a Cole-Parmer Masterflex peristaltic pump.
The results are summarized in Table III. The membsane,
however, passed liquid water during the time ~he process was
in operation, demonstrating that the pore diameters of the
fritted glass membrane in general were too large.
-30-
~1~7668
~1,,,, o ~ I ~ o u~
0 r ~ o u~ ~ co ~ O
I I I I ~ ~ I a~
C~l
I II O U~ I U~ ~ ~ I
o oo ~ ~ ~ o r~ r~
oJ --~1 1 ~ ~ o o o o
~d , 1 a~ ~ O
X O
P~ ~3 ~ I ~ ~ .* U~ ~O CO O
$:~ `--Zl Cl~ oc~ r_ ~D LO ~;t ~ ~ ~I C`l
C~ ~
SII
~a 0~ D O
U
O ~ I o o ~ o r~ ~ ~
`
O o~
~ i ~ -i o o
rn
c~ ,r
r,~ ~
co ~ c~ ~ o a~ ~ o o ~ o
~0 0 ~ OC~ ~i _i C~i ~J ~ ~ U'~
--I
V I ~I ~ ~ ~ o ~ CO ~ O
1~766~
~,q
o
Ul
a~
~ ~ e
a~
~Lt J .
O
, ~,
C~ ~
O
q~
~ a~
_
o
o o
O ~ rl
g
~_ o X
H al ~l ~J au
CO
J^~
O
0~
~ N O
¢ ~ h
u o aJ a~
E~ I h
O C~
O ~ ,~
t~ ~ O O
0
O ~ ~ ~
C)
5~
S~ rl O
t) ~ S~
o ~n ,~
O
O
c~
~v ~
u~ ~
~1 ¢~-~ ¢
t~
-32-
~1~L7~
Example 3 also illustrates a preferred embodiment of
the process of the present invention, which embodiment com-
prises establishing an additional microbe colony on the gas-
space side of the inorganic membrane of the anaerobic
reactor. Most preferably, such microbes will be photo-
qynthetic ~icrobes, ex~mples of which include, ~mong others
Rhodospirillum rubrum, Chromatium Sp., Chlorobium thiosulf-
atophilum, loropseud~monas ethylica, Chorella SP.. Scenedesmus
SP., lamydomonas Sp., Ankistrodesmus Sp., Chondrus Sp.,
Corallina Sp., Callilhæmnion Sp., and the like.
-
The examples which follow illustrate one embod~ment ofthe B~D apparatus of the present invention.
Example 4
A two-liter reagent bottle with a side arm at the
bott~m was connected, ~ia a length of Tygon tubing attached
to the side arm, to the inlet port of a Fluid Metering, Inc.
Model RP G-6 pump ~Fluid Metering, Inc., Oyster Bay, New
York). The outlet port of the pum~ was attached, again via
Tygon tubing, to the bot~om of a vertically-mounted 9 x 150
mm. Fisher and Porter chr~matographic column Cobtained from
Arthur H. Thomas Co., Philadelphia, Pa. ~ . The column was-
charged with 6.5 g. of the CGZ carrier described in Example
1. The top of the column was connected b~ Tygon ~ubing to
the inlet por~ of a cell ha~ing sealably mounted therein ~he
dissolYed oxygen sensor of a Di~fusion Ox~gen Analyzer
(International Biophysics Corp., Irvine, Cal.). The outlet
port of the cell was conne~ted wlth Tygon tubing to a
reeeiving vcssel. Another dissolved oxygen sensor was
placed in the reagent ~ottle which served as a waste stream
reservoir. Each dissolved oxygen sensor was standardized
*Trade Mark _ 3 3 _
1~L~ 7 ~;8
against air-saturated water at 21.9% saturation.
The column was seeded by continuously recirculating a
volume of sewage through the column at a flow rate of L
ml./min. for five days. A sterile, standard BOD solution
containing 150 mg/litcr each o~ glutamic acid and glucose
was passed through the column at 0.37 ml./min. for 24 hours
as a preco~ditioning to insure adequate bioaccumNla~ion
prior to collecting oxygen uptake data. The standard BOD
solution then was pas~ed through the column or immobilized
aerobic microbe reactor. The effluent percent saturation
was measured at three different flow rates. In each case,
the perce~ saturation of the feed in the reservoir was
21.9% and the effluent percent saturation reading stabilized
within 20-~0 min. after cha~ging the flow rate. The results
are summarized in Table IV.
TABLE_IV
Oxygen Uptake In An Ae~obic
~ae~
Flow Rate (ml /min.) Effluent ~/O 5aturation
0.19 7a
0 37 10
2.07 18.5
Decreased to 4.5 after an additional 12 hours.
From Table IV, it is apparent that oxygen uptake is
inversely proportional to the flow rate. Oxygen uptake,
expressed as the percentage of dissolved oxygen consumed,
is summarized in TabLe V and was calculate~ in accordance
with the following formNl~:
-34-
% 2 consumed = Feed % SaF nd-O/Efft,% Sa~ n x 100
TABLE V
Percentage of Dissolved Oxygen Consumed
In An Aerobic Reactor BOD Apparatus
Flow Rate, ml./min. ~ 2 Consumed
0. 19 68a
0.37 54
2.07 16
alncreased to 79% after an additional 12 hours.
Exam~le 5
The procedure of Example 4 was repeated, except that
the c~lumn was seeded with 200 ml. of an overnight tryptic
soy broth culture of Escherichia coli (109 ceIls/ml.) and
the standard BOD solution was replaced with sterile broth.
A~ter the 24-hour preconditioning period, the effluent pPr-
cent saturation was measured ~nd found to be 0%; the broth
percent saturation origi~ally was 21~9~/o~ Thus, 10Q% of
the dissolved oxygen was consumed.
Examples 4 and 5 clearly demonstrate the feasibility of
measuring a difference in an organic waste-containing aqueous
medium, T~hich difference is the result of biochemical con-
ver~ions (oxidations) taking place in the BOD apparatus
aerobic reactor.
Such a measurable differe~ce ~hen is readily correlated
to B~D by known procedures. For one example sf such a
correlation, see I. Karube et al., Biotechnol. Bioen~., 19,
1535 (1977). Thus, for a given aerobic reactor (or aerobic
reactor and anaerobic reactor serially connected), passing
standard solutions having varying concentrations of organic
~7~1
material at a given flow rate will yi.eld a set of, for
example, oxygen uptake data. The BOD values of such standard
solutions can be determined by conventional methods ~o give
a set of conventional BOD values. The two sets of data then
can be combined in graph fonm to give a standard curve ~or
each flow ra~e employed. The BO~ of any organic waste in an
aqueous medium then is determined quickly and simply by
passi~g such aqueous medium through the BOD apparatus and
comparing the data obtained with the appropriate standard
curve.
-36-
