Note: Descriptions are shown in the official language in which they were submitted.
2~)
FIELD OF INVENTION
This invention relates to a purification process for
removing contaminants from waste waters. The process incorporates
the use of finely divided mineral or minerals to form an active
sludge to increase the concentration of and to enhance the
distribution of active micro-organisms in the reaction system
and to assist and enhance the yield of simultaneously occuring
biological and chemical reactions.
BACKGROUND OF THE INVENTION
It is important to remove contaminants from raw and/or
waste waters before discharge of such waters, because contaminants
such as those found in sewage waters, various industrial waste
waters, storm sewer waters and the like, have a destructive
effect on the environment. Existingp~oc~sses forremoving such
contaminants from waste waters entail breaking down the biodegrable
contaminants by the action of active micro-organisms and removing
other contaminants by physical and/or chemical precipitation
techniques. With such processes, several different process
steps are usually carried out in separate stages of a treatment
system requiring relatively expensive equipment and the use of
substantial areas of land. This type of treatment is not
readily scaled down for use in treating small volumes of raw or
waste waters at a site of limited size.
It is therefore an object of the invention to provide
a process and apparatus for removing contaminants from
contaminated waters with a minimum of process steps.
,,~
-- 1 --
~36~
It is another object of the invention to provide a
waste treatment process where various organic suspended solids,
nitrogen containing compounds, and phosphorous containing
compounds are removed from the waste waters by co-acting
biological and chemical reactions.
It is yet another object of the invention to provide
a process for purifying contaminated waters, which is capable
of unattended operation and readily lends itself to use in
large municipal waste water treatment systems, apartment size
waste water treatment systems, single family ~welling waste water
treatment systems, waste treatment systems on boats, ships,
recreational vehicles and the like, in shopping centres, airports,
recreational areas, such as camps, waste treatment systems in
food processing industries, fish hatcheries, pulp and paper
industries, coke processing stages of steel mills, paint
industry, and in any other type of industry, domestic area or
raw water purification wherein partially or wholly biodegradable
contaminants and non-biodegradable contaminants are to be
removed.
It is a further object of the invention to provide a
purifying process for waste water where compared to existing
systems the waste water may be processed in a more efficient
manner to thereby reduce the physical size of the treatment
system.
It is yet a further object of the invention to provide
a waste treatment process whereby waste waters are efficiently
contacted with highly concentrated activated sludge containing
-- 2 --
~36~20
the mixed active microbial population for digesting the
contaminants.
A further object of the invention is to provide waste
treatment system apparatus which is readily adapted to
miniaturization for use in locations of limited size; such as
single ~amily dwellings, boats, recreational vehicles and the
like.
SU~ARY OF THE INVENTION
_ _ _ _
These objects, advantages and features of the
invention are attained by contacting contaminated waters with
active media which includes, among other things, active micro-
organisms in activated sludge, and one or more powdered or
finely divided minerals. Thepresence of mineral in the active
media enhances the concentration and distribution of the
active micro-organisms within the reaction system and assists
in efficient microbial degradation of biodegradable contaminants
and in the precipitation of ionic species present in the
processed waste water. The selected powdered mineral or minerals
should be essentially insoluble in the waste waters and non-toxic
to the active micro-organisms.
Although the powdered mineral or minerals used have
limited solubility or are essentially insoluble in the processed
waste water they will, however, dissociate to a certain degree
to release metal ions. The released metal ions assist in the
control of the pH of the processed waste water and also combine
with other ion species in the waste water, such as phosphates,
-- 3 --
36~ 0
1 to form insoluble precipitates and thereby assist in the
removal of phosphates from the waste water. Due to the
essentially insoluble nature of the minerals used in the
process, replenishing of mineral is on an infrequent basis.
To improve the clarity of the effluent, powdered
or granular activated carbon may be added to the active media.
In addition, various treatment chemicals, such as alum and
flocculating agents, may be added to improve the quality of
the effluent according to standard sewage treatment techniques.
The use of one or more powdered minderals in waste
treatment systems particularly enhances the efficiency of
fluidized bed reaction systems. The minerals combine with or
collect on their surfaces the active micro-organisms so that
the suspended mineral particles in the fluidized bed enhance
the distribution of the micro-organisms in the waste waters as
they pass through the fluidized bed. Due to their relatively
high density, the minerals assist in maintaining a high
concentration of the mixed microbial population in the fluid-
ized bed and also permit the treatment of higher flow rates
of waste waters than could be treated by prior processes.
The concentration of the powdered mineral in a fluid-
ized bed may vary considerably, depending upon the density
of the selected mineral and the flow rates of waste waters
through the fluidized bed. The concentration of mineral should
be sufficient to increase the density of the activated sludge
by the combination of mineral therewith so that there is an
,, ~
~3~720
effective net increase in the concentration of active micro-
organisms within the fluidized bed. The mineral is usually
finely divided and is of a particle size of 50 mesh or less
United States Standard Screens.
Various types of waste treatment system apparatus
may be used; for example, the standard activated sludge waste
treatment system may have powdered mineral introduced into
the processed waste waters to attain the advantages of this
invention. Usually waste treatment system apparatus includes
communicating chambers basically comprising an aeration chamber,
a sludge separation chamber and a clarifying chamber.
According to an aspect of the process of this
invention, a fluidized bed is provided in a waste treatment
system apparatus in order to attain the above noted features
of the invention. Such a fluidized bed may be provided at
various stages in processing apparatus, such as in a sludge
separation chamber or in a clarifying chamber.
In order to promote the various biological processes
which take place in the microbiological degradation of the
contaminants, differing concentrations of dissolved oxygen
should be maintained in the treatment system to ensure the
bio-oxidation of suspended organics, the nitrification of
ammonia compounds and respiratory denitrification of nitrites
and nitrates. Further, the mixing in the fluidized bed
promotes the precipitation of phosphorous containing compounds
by metal ions dissociated from the minerals, promotes the
-- 5 --
'' ' '
lQ3672~
1 flocculating or coagulating of the suspended solids and to
maintain a pH of the liquid favourable to the formation of
phosphates ions and the like.
More specifically the process of the invention is for
the removal of biodegradable suspended and dissolved organic
solids and nitrogeneous compounds and phosphates from contam-
inated waters by biological and chemical reactions carried
out simultaneously in the presence of an active media which
includes mixed microbial population and powdered minerals in
a reactor system operating at a pH range of 6 to 8. The pro-
cess comprises adding to the system on an infrequent basis a
finely divided mineral or mixture of minerals of a particle
size less than 50 mesh United States Standard Screens to
provide a ccncentration of mineral in such active media
ranging from approximately 10 gm./l. up to approximately
200 gm./l. The selection of mineral is determined by the
characteristics of:
a) its being non-toxic to the micro-organisms;
b) having surfaces which attract micro-organisms,
and adsorb organic compounds and phosphates to
assist in and expedite the simultaneously
occurring biological and chemical reactions,
and
c) having limited solubility in the processed
waste waters, where the metal ions released by
the mineral's dissociation in such waters react
with phosphate ions present in the processed
waste waters to form insoluble metal phosphates
at the reactor pH range of 6 to 8
30 ~ ~ - 6 -
.
1~)367ZO
1 A mixed microbial population is built up in the reactor
system by retaining and growing in the reactor the various
micro-organisms present in the waste waters on the surfaces
of the mineral particles retained in the reactor system.
By using forced air, the contaminated waters and active
media are circulated through the reactor system which comprises
at least two zones in which biological oxidation, biological
nitrification and biological denitrification reactions each
occur simultaneously with the chemical reactions throughout
the system and in which the concentration of free metal ions
of the mineral is at the mineral's solubility levels. The
circulation involves flowing the contaminated waters down-
wardly through the first zone to contact such waters with
the active media and
a) maintain the concentration of dissolved oxygen
in the zone's upstream region at approximately
1 mg./l. to 2 mg./l., to support the biological
oxidation of bio-degradable organic solids to
carbon dioxide and the biological oxidation of
nitrogeneous compounds to nitrites and nitrates,
b) controlling the duration which such waters remain
in said first zone as they flow therethrough so
that the biological reactions reduce the concen-
tration of dissolved oxygen in the downstream i:
region of the first zone to below 1 mg./l. to
thereby induce biological denitrification reactions~
At least a portion of the waters and active media from the
first zone is flowed upwardly through a second zone which
is a sludge settling zone. The biological denitrification
30 , ~ - 6a -
,i
1e~7ZO
1 reactions are continued for reducing the concentration of
nitrites and nitrates wherein the second zone the concen-
tration of dissolved oxygen is reduced to less than .5 mg./l.
The upward rate of flow of the waters is such in the
second zone to provide a quiescent region which permits
most of the active media to separate from such waters prior
to discharge of the waters from the reactor system. The
phosphate ions are precipitated simultaneously with the
above reactions in the first and second zones. The precip-
itation is brought about by the reaction of the metal ions
with the phosphate ions to form the insoluble precipitates
at the reactor pH range of 6 to 8 to thereby lower the
concentration of phosphate ions in the zones of the system.
The apparatus according to this invention for treating
waste waters comprises a first tank in which an equalization
zone is defined, a second tank in which aeration and sludge
separation zones are defined and a third tank in which a
clarifying zone is defined. Means is provided for transferring
such waters from the equalization zone to the upper region of
said aeration zone. A slanted plate is located in the
second tank with its lower end being spaced from the tank
bottom and sidewalls to define said aeration zone which
overlies said sludge separation zone. The slanted plate
extends across the second tank thereby separating the
aeration zone from the sludge separation zone. An aeration
upflow channel is provided in the second tank with its inlet
across the lower region of the tank and with its outlet
across the upper region of the tank. Means for circulating
the waters and active media up the aeration channel, out
- 6b -
~Q36~20
1 the outlet of the upflow channel, downwardly through the
aeration zone, under the lower end of the slanted plate,
along the second tank bottom and through the inlet of the
upflow channel. Means for dispersing oxygen into the active
media which flows said aeration channel is provided. The
slanted plate slopes upwardly toward the aeration channel,
the lower end of the slanted plate forms a constriction to
the circulation of the water so that the velocity of such
waters is increased along the bottom of the tank below the
sludge separation zone. A portion of the waters enters the
sludge separation zone and flows upwardly to develope a
fluidized bed of active media. The height of the sludge
separation zone is sufficient to effectively separate a
major portion of active media from the processed contamin-
ated waters in the fluidized bed. Also provided is means for
transferring the processed waters from the upper region of
the sludge separation zone to the clarifying zone of the
third tank.
DESCRIPTION OF THE DRAWINGS
The aforementioned and other objects, advantages and
features of the invention will become apparent in the
following detailed description of the preferred embodiments,
as shown in the drawings wherein:
FIGURE 1 is a schematic view of apparatus which may
be used in carrying out the process according to this inven-
tion;
FIGURE 2 is a partially cut away perspective view of
the equalization and aeration chamber according to a pre-
ferred embodiment of the invention for use in treating waste
waters; ~ - 7 -
103tj~20
1 FIGURE 3 is a cut away perspective view of the clar-
ifying chamber of the apparatus, which is in communication
with the reactor chamber shown in Figure 2 of the drawings;
FIGURE 4 is a section taken along the line 4 - 4 of
Figure 3; and
FIGURE 5 is a graph showing the settling rates of
various forms of active media.
~ .. ., . , ..._.._.
30 ~ - 7a -
lQ3672~
:1~ DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF
THE INVENTION
It is not fully understood how the powdered mineral
combines with the active micro-organism and affects the
simultaneously occuring biological-chemical reactions,
however, it is theorized that the powdered minerals provide
surfaces on which active micro-organisms locate to thereby
increase the density of the formed active sludge and the
activity of the solid surfaces assist in some way in the
chemical reaction. This expedites separation of the sludge
from the waste waters and enhances the distribution of the
micro-organisms in the active sludge as waste waters flow
therethrough and the yield from the simultaneously occuring
chemical and biological reactions. As the population of the
micro-organisms in the sludge and this helps to maintain a
high concentration of micro-organisms in the reaction system.
There are several types of minerals which may be used pro-
viding they are non-toxic to the micro-organisms, finely
divided and are essentially insoluble in the waste waters.
Examples of minerals which may be used in the process are
Cerussite, Clinoptilolite, Corundum, Diaspore, (Bauxite)
Gibbsite, Halloysite, Hematite, Kyanite, Millerite, mixtures
thereof and the like.
Most of these minerals are insoluble, or essentially
insoluble in water, for example Gibbsite and Hematite are
essentially insoluble whereas Corundum has a slight degree
of solubility in water. It is understood, of course,
that even the minerals which are essentially insoluble
- 8 -
1~36720
1 in water tend to dissociate and release metal ions into the
processed waste water. These released metal ions may combine
with phosphates and other ionic species in the waste water to
form insoluble precipitates. The released metal ions also
assist in the control of the pH of the system where the desired
operational range is between 6 to 8. The concentration of
mineral or minerals in the active media may range from approx-
imately 10 gm./l. up to 200 gm./l.
The powdered minerals are preferably ground so that they
pass through United States Standard Screen Mesh Size 50 and up
to 300 or more. The more finely the mineral is divided, the
larger the surface area on which the micro-organisms and
suspended solids may locate.
The waste waters when treated according to the processes
of this invention are contacted with a mixture of active micro-
organism, one or more powdered minerals, precipitates, and
other additives. This combination is referred to, as herein-
before, as the active media.
With the attendant advantages of the process of this inven-
tion, sewage treatment systems may be developed in various
sizes ranging from that which may be installed in the basement
of a single family dwelling to sizes which are capable of
handling municipal waste waters, industrial waste waters and
other sources of large volume of waste or raw waters. The
process according to this invention may be readily used in the
existing sewage treatment system, such as the activated
sludge process which treates both municipal and industrial waste.
According to a preferred embodiment of the invention, ~igure 1
shows a schematic of a reactor system in which an aspect of the
_ 9 _
1~367ZO
1 process according to this invention may be carried out.
The reactor system 10 comprises an equalization chamber
12, in a first tank, an aeration chamber 14 and a sludge sep-
aration chamber 16 in a second tank and a clarifying chamber
18 in a third tank. Air is supplied to the various air pumps
in the reactor system 10 by air line 20. Waste waters enter
the reactor system 10 by pipe 22 which feeds into the equal-
ization chamber 12. Equalization chamber 12 dampens the
effect of wide variations in the flow rate of incoming waste
waters on the hydraulics and liquid levels in the remainder of
the system.
The level of the waste waters in the equalization chamber
12 may vary from level 24 up to level 26 without substantially
affecting the levels in the aeration chamber 14 nor the sludge
separation chamber 16. An air diffuser 28 is located between
plate 30 and the wall of chamber 12 to promote mixing in the
directions of arrows 32. The mixing of the raw incoming waste
waters with the material already in the equalization chamber
tends to level out extremes in the concentration of various
types of contaminants.
The material in tne equalization chamber 12 is pumped
into the aeration chamber 14 by air pump 34. Depending on the
type of air pump used the hydrostatic head can affect the flow
rates through the pump. For higher levels of liquid in the
equalization chamber the pump may transfer the liquid at a
higher flow rate than when the liquid level is lower. The
flow rate of the waste liquid through the pump 34 determines
the flow rates of waste waters through the clarifier and, in
- 10 -
~36~;~0
1 turn, the flow rate of the effluent because the remainder of
the system is balanced hydrostatically. It is understood, of
course, where a constant flow rate of incoming waste water can
be achieved and is at a rate so as not to upset the hydraulics
of the remainder of the system, the equalization chamber 12 may
be eliminated.
The aeration chamber 14 is essentially isolated from
the sludge separation chamber 16 by a slanted partition 36. Air
diffisers 38 are positioned behind a partition 40 to draw active
media and the processed waste water from the sludge separation
chamber and lift it upwardly through aeration channel 42. The
aerated waters flow out of channel 42 into the aeration chamber
14 in the direction of arrow 44. The slanted plate 36 isolates
the waters from the sludge separation chamber 16 so that such
waters flow downwardly towards the throat 46 at the base of the
aeration chamber 14. Due to the air diffusers 38 drawing liquid
from the bottom of the tank under the sludge separation chamber
16, or zone, the velocity of the liquid increases as it passes
through the throat 46 because it acts as a constriction to the
flow. A portion of the liquid flows upwardly in the direction
of arrows 48 to create a fluidized bed in this area of the
sludge separation chamber 16. In addition, the upward flow
of the liquid lifts active media settling at the base of
the sludge separation chamber up into the fluidized bed area
to maintain a high concentration of active micro-organisms
in the fluidized bed of active media. The active micro-organisms
in the active media is therefore fluidized in this area for a
particular flow rate of the waste waters as determined by the
rate at which the air diffusers 38 pump the liquid up through
- 11 -
,.. ,~7
36~20
channel 42 and as influenced by the rate at which pum~ 34 transfers
liquid from equalization chamber 12 into the aeration chamber 14.
A minor portion of the aerated waste waters as it
leaves channel 42 flows across the top of reactor chamber 14 and
empties back into the equalization chamber 12 through the
opening 50 provided in the partition 52 of the reactor system.
In this manner the active media including micro-organisms is
introduced into the equalization chamber for purposes of
beginning the biological and chemical degradation of contaminants
in the waste waters and also to offset variations in concentrations
of contaminants in the incoming waste waters.
The concentration levels of dissolved oxygen in the
aeration chamber 14 and the sludge separation chamber 16 vary
a substantial amount to provide an aerobic environment in which
the mixed population of micro-organisms oxidize the organics
and nitrify the ammonia compounds to form metal nitrates and
nitrites and to provide an essentially anoxic environment in
the same system whereby the mixed microbial population denitrify
the nitrates and nitrites to form free nitrogen. The dissolved
oxygen levels in the upper portion of aeration chamber 14 are
the highest due to passage of waste waters through aeration
chamber 42. The oxygen levels are usually in the range of
1 mg./l up to 2 mg./l. As the waste waters and active media
flow downwardly in the reactor chamber 14 the level of dissolved
oxygen decreases due to the take-up of oxygen in the biological
oxidation of degradable organics and the nitrification of the
ammonia compounds. The dissolved oxygen is at a lower level in
the throat area 46 of the reactor and may be less than 0.5 mg./l.
- 12 -
1~36720
The environment in the chamber 16, therefore, approaches anoxic
conditions and as a result the mixed microbial population begins
respiratory denitrification of the nitrates and nitrites to
remove oxygen molecules therefrom and release free nitrogen from
the system. The denitrification of nitrates and nitrites is
continued in the fluidized bed area of arrow 48. A portion of
the active media in the fluidized bed area is extracted as
shown by arrow 54 and returned to the aeration channel 42.
Above the fluidized bed area 48 the active micro-organisms,
precipitates and other solids separate from the processed waste
liquid in the quiescent zone 57. The processed waste waters
flow into the clarifier 18 via conduit 56.
The concentration of the micro-organisms in the
active media can become high, particularly in the fluidized
bed area of the sludge separation chamber due to the inherent
efficiencies of a fluidized bed. It has been found that the
concentration of active media in the mixed liquor is in excess
of 20 gm./l. Due to the characteristics of the fluidized bed
the active media do not flow out through conduit 56 to clarifier
18 unless there is an excess caused by growth in the microbial
population.
Biochemical reactions are carried out also in
clarifier 18. To ensure that active micro-organisms are in
the clarifier without relying on excess being transferred by
conduit 56, air pump 58 is provided to pump active media which
contain micro-organisms into clarifier 18 through conduit 60.
Chemicals such as alum and flocculating agents may be introduced
into the clarifier in accordance with standard sewage treatment
procedures.
- 13 -
~Q36~20
The clarifier serves to separate the suspended
solids from the waste waters and to further reduce the level
of contaminants in such waters to provide a clear odourless
effluent with concentration of phosphates, nitrates, nitrites,
ammonia and BOD which is safe for the environment.
The clarifier 18 has a fluidized bed formed in the
general area 62 by the arrangement of the hydraulics shown in
the drawings in the directions of the arrows. Air pumps 64
withdraw liquid from the fluidized bed area in the direction
of arrows 66 and lift the liquid upwardly in annular channel
68. The material flows over into and downwardly in channel
70 as it is combined with effluent coming from the sludge
separation chamber 16. The quantity of dissolved oxygen in
the processed waste waters in the channel 70 of the clarifier
is usually below 1.0 mg./l, so that in essence the mixed
microbial population finds itself in an anoxic environment.
The respiratory denitrification of the nitrites and nitrates
is continued where remaining organic matter adsorbed on the
particulate mineral surfaces serve as a source of carbon to
support the biological reactions. As the material exits from
channel 70 it flows upwardly in the direction of arrows 71.
Due to the configuration of the chamber 18 with the outwardly
sloping sidewalls, the flow rate of the liquid is highest at
the bottom and decreases as it flows upwardly to effectively
form a fluidized bed of active media in the area 62. Above the
active media a layer 72 of light particles or sludge is formed
from which a portion of solids is extracted by skimmer 74 and
either returned to the aeration chamber 14 by conduit 76
or a portion thereof discarded by conduit 78.
Flocculating agents and coagulants may be added to
- 14 -
lQ367ZI)
complete the removal of phosphates and other undesirable
suspended solids in accordance with standard sewage treatment
techniques to provide clarified waste water in the upper portion
80 of the clarifier. Any solids floating on the top of the
waters are removed by skimmer 82 and returned to the aeration
chamber 14 by conduit 84. The effluent leaves the clarifier
by conduit 86 where floating solids are separated from the
effluent by trap 88.
The powdered mineral or minerals may be added to the
aeration chamber or the clarifier. The minerals are then
circulated amongst the remaining chambers via the hydraulics
of the system. A major portion of the mineral circulates in
the clarifying chamber due to its greater size. As discussed,
in the fluidized bed area 62, the top layers 72 thereof contain
predominantly the biological solids mixed with the precipitates
and some minerals. The lower portion of the fluidized bed
contains the major portion of the powdered minerals. Thus,
the excess sludge which is removed by skimmer 72 is mostly non-
degradable solids, excess biological solids, the formed
precipitates and some minerals which are recirculated. The
oxygen required to continue the bio-oxidation of remaining
organic matter and ammonia in the fluidized bed 62 is introduced
by air diffusers 64. A small amount of active media is
recirculated to the clarifier via lines 60 and 61 to supplement
the active micro-organisms in the clarifier. During the cold
weather, the activity of the micro-organisms in the fluidized
bed of the clarifier can be increased by adding methanol or
some other acceptable source of carbon in addition to organic
matter already present in waters to satisfy the diet of
Y~;X
,"",,,~ ;,.
1~36q20
the micro-organisms.
As can be appreciated, the waste waters as contacted
with the active media, are treated in various chambers of the
treatment system to provide a clarified effluent which after
disinfection by ozone treatment or the like, is safe for
discharge into the environment. The treatment system provides
by selected hydraulics a fluidized bed which enhances the
removal of contaminants from waste waters in an efficient
manner. Such a system can be considerably miniaturized for
use in limited quarters such as in the treatment of domestic
sewage in apartment buildings, townhouse developments, single
family dwellings or the like. It is understood, however,
that the system can also be substantially enlarged to handle
very high volumes of municipal waste liquids. Figures 2
through to 4 show a preferred embodiment of the inventive
apparatus for the treatment of domestic sewage.
Figure 2 shows the equalization chamber 90, the
aeration chamber 92, and the sludge separation chamber 94.
The clarifying chamber is located at the back as shown in
shadow at 96. This system is therefore analogous to and
functions in the same manner as the system schematically shown
in Figure 1. Raw sewage waters are fed into the equalization
chamber 90 where the level in the equalization chamber may go
as high as level line 98. The equalization chamber 90 is
separated from the aeration chamber 94 by partition 100. The
processed waste waters in the aeration chamber 92 are returned
to the equalization chamber 90 via the V-shaped opening 102
provided in the partition 100. The mixture of active media and
- 16 -
~36~20
raw sewage waters in the equalization chamber is lifted into
the aeration chamber 92 by air pump 104 and discharged in the
direction of arrow 106.
The rate at which air pump 104 pumps the waste
waters into the aeration chamber 92 varies depending on the
height of hydrostatic head of the waste liquid in the
equalization chamber. If there is a large influx of waste
waters to raise the level in the chamber 90~ the air pump 104
pumps at an increased rate. The flow rate in the aeration
chamber and the remaining chambers depands upon the flow rate
of waste waters through the air pump 104. The equalization
chamber 90 therefore dampens extremes in flow rates of
incoming raw sewage.
The active media is circulated through aeration
chamber 92 and sludge separation chamber 94 by way of air
diffusers 108 which are placed behind a partition 110. An
intake 112 is provided at the base of the reactor as more
clearly shown in Figure 4. An aeration channel 114 is defined
between the partition 110 and the backwall 116 of the aeration
chamber. Waste waters and active media are lifted up through
channel 114 by air diffusers 108 and spilt over the top of
partition 110 into the aeration chamber 92. The waste waters
and active media move downwardly in aeration chamber 92 and are
caused to flow to the front of the chamber in direction of
arrow 117 by slanted baffle plate 118. The baffle extends all
the way across chamber 92 to its sidewalls 100 and 101 to
isolate chamber 92 from chamber 94. The waste waters travel
into the sludge separation chamber 94 through gap 120
- 17 -
~3~720
1 at the base of baffle 118. The gap 120 constitutes a constric-
tion to the flow of liquid so that the liquid velocity is
increased as a portion of the liquid rises in direction of
arrow 121 to thereby create a fluidized bed in sludge separation
chamber 94. The mineral present in the active media assists
in retaining the active micro-organisms in the fluidized bed
so that in the upper portion of chamber 94, skimmer 122 takes
off the processed waste waters and transfers them by air pump
124 through the conduit 132 in the direction of the arrow 126.
A small portion of active media may be continuously circulated
from the aeration chamber 92 to the clarifier 96 by way of air
pump 128 through conduit 134 in the direction of arrow 130.
Turning to Figure 3, the active media and processed
waste water enter the clarifier chamber 96 via a funnel-shaped
downflow channel 136. The base 138 of the funnel-shaped
channel is above the bottom 140 of the clarifier to define a
gap 142 as shown in Figure 4. From this point the material
flows upwardly in the direction of arrow 146 to create a fluid-
ized bed of active media in the area 144. Slanted plates 148 and
150 define a chamber 145 around funnel-shaped channel 136.
The plates 148 and 150 extend upward a sufficent distance to
provide a volume of adequate size to ensure the formation and
maintenance of a fluidized bed in chamber 145. Air lifts 152
and 154 are located between plates 148 and 150 and the respective
outside walls 149 and 151 of the clarifier. The air lifts have
intakes at 156 and 158 to withdraw material from the base of the
sludge settling chambers 160 and 162 and lift the material
upwardly and direct it into the funnel-shaped chamber 136. The
- 18 -
.30
,, .,
1~36~20
location of intakes 156 and 158 assist in the settling of
sludge in chamber 160 and 162. The openings 164 and 166 are
directed in a manner so as to cause the material in the funnel-
shaped channel 136 to form a vortex in the funnel-shaped
chamber to assist in the mixing of the material. The air
lifts 152 and 154 add some oxygen to the active media so that
the biological oxidation of contaminants may continue as the
active media and waste water descends in chamber 136.
Active media and waste water from the fluidized bed
144 are lifted directly from the fluidized bed by air lift 168
and dumped into chamber 136 so as to ensure a level of active
media in the downflow portion of funnel-shaped chamber 136.
Floatable solids are skimmed off the surface by
skimmers 170 and 172 and returned to the aeration chamber and
to the equalization chamber by conduit 174 and 176. A portion
of settled sludge is extracted from sludge settling chamber
160 by air lift 178 and returned to the equa~ization chamber
by pipe 180. Some of the returned sludge may be discarded
through T-junction 181 in pipe 180.
The clarified effluent which is above the fluidized
bed area 146 and the sludge settling chamber 148 is removed
from the clarifier by separator 182. A baffle plate 184 is
located beneath the separator 182 to deflect the upflowing
lighter suspended solids of the fluidized bed away from the
separator 182.
The selected mineral or minerals may be added to the
clarifier where, due to the recycling of active media between
-- 19 --
~lQ3f~20
the clarifier and the aeration chamber, the system equalizes
with a ma~or portion of mineral circulating in the clarifier
and the minor portion circulating in the aeration and sludge
separation chambers.
The effluent from separator 182 may be collected in
a sump and periodically pumped from the sum for discharge.
As previously discussed, flocculating agents and chemicals which
cause precipitation of ion species in the waste waters may be
added to the clarifying chamber. The addition of these treatment
materials may be by metering pump where the quantity added is
based on the quantity of effluent. It follows that with the
use of a sump for collecting effluent, each time the sump pump
is activated to discharge a predetermined quantity of effluent,
the metering pump can be activated to dispense the desired
quantities of treatment chemicals.
As is appreciated by those skilled in the art,
several different types of flocculating agents may be used in
accordance with standard sewage treatment techniques.
Particularly useful agents a~e the cationic polyelectrolyte
type such as "CATFLOC" (trademark) sold by Calgon Corporation.
Figure 5 illustrates the effect the addition of a
mineral has on the settling rate of the active media. Curve 1
shows the settling time for standard activated sludge; Curve 2
shows the settling time for the combination of standard
activated sludge with activated carbon; and Curve 3 shows the
settling time for the combination of mineral, activated carbon
and active micro-organisms. Curve 3 is substantially below
- 20 -
1036720
Curve 1. It is therefore apparent that the addition of
minerals to the active micro-organisms substantially increases
the density of the active media so as to assist in the settling
of sludge.
Example 1
The reactor system shown in Figures 2, 3 and 4,
was used to treat raw domestic sewage from an apartment building
in TORONTO, CANADA. The total volume of sewage processed
varied from 100 to 360 Imp. Gallons per day on a batchwise
flow basis.
For purposes of comparison, two experimental runs
were carried out. Run #l had the mineral Gibbsite added to
the active micro-organisms together with powdered activated
carbon, coagulant and alum. Run #2 had all the ingredients of
Run #l plus the addition of methanol to the clarifier. The
flocculating agent and alum were added to achieve maximum
clarity in the effluent.
The operating parameters of the process are shown
in Table 1 and the quantitative results of the tests are shown
in Table 2. Average values are noted for samples taken.
~/
- 21 -
`` 1~367ZO
TABLE 1
OPERATING DATA RUN #l RUN #2
TOTAL SYSTEM'S VOLUME
(Imp.Gal.) 350 350
REACTOR & SLUDGE SEPARATION
CHAMBER VOLUME (Imp.Gal.) 240 240
CLARIFYING CHAMBER VOLUME
(Imp.Gal.) 110 110
FLOW RATE OF SEWAGE
(Imp.Gal./Day) 100-200 100-200
PROCESS AIR (SCFM) 6 6
DISSOLVED OXYGEN:
Aeration Chamber (mg./l.)1.0-2.0 1.0-2.0
Clarifier (mg./l.) 0.0-1.0 0.0-1.0
SUSPENDED SOLIDS
Aeration Chamber (gm./l/)100 100
ACTIVE MEDIA
Mineral - Gibbsite (lb.) 200 200
Activated Carbon (lb.) 30 30
Micro-organisms Yes Yes
TREATMENT CHEMICALS
Alum (mg./l. of effluent) 100 100
"CATFLOX" (mg./l. of effluent) 5 5
Methanol (mg./l. of effluent) --- 300
- 22 -
..
J~Q;~7~20
+ +
~ O ~ I CS~ ~ ~D I ~
* U~
E~ O o In o o n _l 1`
Z ~ ~ UO~ o ~ ~, ,, o o
V V \l I~
+ +
, ~ ~ ~ , ~
~1 n
* In
o o ,`o I , ~ I`
. o
Z~ U~ o~ o o o o
~~ \~ VV ~
m
g
~ o
o o o o
o ~ o o o o
li3
U~ O I I I I ~
O O O O o ~ 1`
O OD O ~ O
~i
u~
t~ H
h ~
-- o
~ u~
~ H _ . o o
~ O
C u~ O E~ \
U~ ~Z o
1~1 a u~ ~ ~
~ ~ ~Lr) I I I
a a~ ~ ~
EO~ ~ ~ ~ ~; ~ ~-
1~)36720
Referring to Table 2, the amount of ammonia in Run #l
was substantially removed, however, there was still a high level
of nitrates in the system. The addition of methanol to the
clarifier in Run #2 provided the additional source of carbon needed
to satisfy the diet of the micro-organisms to promote the
respiratory denitrification of the nitrates and nitrites as
evidenced by the substantial reduction in level of nitrates to
1.5 mg./l. The use of mineral in fluidized beds of a sewage:
treatment system of the type disclosed herein provides for the
efficient removal of contaminants from waste liquid as illustrated
in Tables 1 and 2.
Although the preferred embodiments of the invention
have been discussed herein in detail, it will be understood by
those skilled in the art that variations may be made to the
inventive process and apparatus without departing from the spirit
of the invention or the scope of the appended claims.
- 24 -
