Liquid purification systems

New systems for the purification of liquids containing suspended solids and/or dissolved solid materials basically include a conical flocculator unit and a conjoined conical clarifier unit. The flocculator has a cylindrical lower portion, frustum middle portion and large diameter cylindrical top portion while the clarifier is essentially a large diameter cylindrical top portion over a lower frustum portion. Water or other liquid to be purified enters the flocculator lower portion via opposed, unequally sized nozzles to assume a helical flow upward past a series of deflector plates positioned at the top of the lower flocculator portion while a sludge blanket forms therein. A double flume plus slot arrangement located at the junction of the flocculator with the clarifier separates solids from liquid as fluid flow from the flocculator passes into the clarifier where it is subjected to further separation of sludge from clarified liquid with part of the sludge being recycled to the flocculator. New purification methods operated with the new systems are also disclosed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This application relates broadly to liquid purification systems and 
methods, such as treating water to clarify it for potable or industrial 
use. More particularly, it concerns flocculator/clarifier systems and 
methods for treating water and other liquids contaminated with suspended 
solids and/or dissolved solid materials. 
2. Description of the Prior Art 
Huge volumes of liquids must be treated daily to remove suspended solids 
and/or dissolved solid materials so that they will be rendered acceptable 
for potable or industrial use. A prime example is the daily treatment by 
municipalities of vast quantities of water from a variety of sources 
containing suspended solids which must be removed before the water can 
delivered to their customers. However, there are many other types of 
liquids handled in large quantities that must be treated to remove 
suspended or dissolved solids. 
Numerous different types of equipment have been developed for treating 
large volumes of liquids for solids removal in an efficient and economical 
manner. One leading industrial type is marketed by Infilco Degremont Inc., 
the assignee of the present invention, under the trademark DensaDeg.RTM. 
Clarifier which is described in an IDI brochure No. DB-555, dated March 
1990, the contents of which are incorporated herein by reference. This 
equipment combines mixing, internal and external solids recirculation, 
sludge thickening and lamellar clarification, in two conjoined vessels. 
The design of the treatment vessels is such that each compliments the 
performance of the other to the point that either vessel requires the 
other in order to optimize unit operation and treatment results. One of 
the conjoined vessels is a so-called reactor into which influent is 
charged and acted upon by a motor driven turbine running within a draft 
tube. 
The present invention provides improvements to the DensaDeg.RTM. Clarifier 
by the elimination of the motor driven turbine with attendant savings in 
maintenance of the turbine and related elements operating submerged in an 
adverse environment. Thus, a great concern with any clarifier type 
equipment is the formation of scale in lime addition applications. With 
mechanical units, which employ turbine blades, shafts, etc., which expose 
a lime slurry (in turbulence) to air, there is a greater tendency to form 
scale than where the slurry is hydraulically driven without exposure to 
air. 
Liquid treatment systems for suspended solids removal that are 
hydraulically driven for admixture of flocculants and other treating 
chemicals with the influent are known, e.g., see U.S. Pat. No. 4,146,471; 
4,765,891 and a brochure of the Walker Process Corporation of Aurora, Ill. 
entitled ClariCone.TM. (Bulletin 5W85). The present invention provides an 
improved form of hydraulically driven liquid treatment apparatus. 
OBJECTS 
A principal object of this invention is the provision of improvements in 
liquid purification systems and methods. 
Further objects include the provision of: 
1. An improved liquid purification system of a two conjoined vessel type 
that performs mixing, internal and external solids recirculation, sludge 
thickening and lamellar clarification. 
2. Such systems that can be of shorter profile, operate at higher rates and 
with reduced maintenance requirements as compared with related, prior 
known systems. 
3. An improved liquid purification method that uses hydraulic driving for 
performing chemical and influent mixing. 
Other objects and further scope of applicability of the present invention 
will become apparent from the detailed descriptions given herein; it 
should be understood, however, that the detailed descriptions, while 
indicating preferred embodiments of the invention, are given by way of 
illustration only, since various changes and modifications within the 
spirit and scope of the invention will become apparent from such 
descriptions. 
SUMMARY OF THE INVENTION 
The objects are accomplished in accordance with the invention by the 
provision of systems for the purification of liquids containing suspended 
solids and/or dissolved solid materials which comprise a flocculator unit 
and a clarifier unit, both units being of substantially equal height. 
The flocculator unit is defined by first, second and third geometric 
portions assembled vertically along a first central vertical axis. The 
first portion is lowermost and is defined by a cylinder of a first 
diameter having a closed bottom end and an open upper end. The third 
portion is uppermost and defined by a cylinder of second diameter larger 
than the first diameter having a open lower end and an open top end. The 
second portion is defined by an inverted frustum having an open low end of 
diameter equal to the first diameter and an open top end of diameter equal 
to the second diameter, the top end being integrally joined to the third 
portion lower end and the low end being integrally joined to the first 
portion upper end. 
There is a first horizontal, tangential tubular inlet into the first 
portion having a third diameter, a second horizontal, tangential tubular 
inlet into the first portion diametrically opposed to the first inlet and 
having a fourth diameter smaller than the third diameter, and a series of 
blades mounted adjacent to the upper end of the first portion that extend 
toward its center at an acute angle relative to the horizontal. 
The clarifier unit comprises fourth and fifth geometric portions assembled 
vertically along a second central vertical axis. The fourth portion is 
uppermost and defined by a fragmented cylinder of fifth diameter having a 
open lower end and an open top end. 
The fifth portion is of inverted conical shape and has an open top end of 
diameter equal to the fifth diameter, the top end being integrally joined 
to the fourth portion lower end. 
The fragmented cylinder of the fourth portion of the clarifier unit is 
joined to the cylinder of the third portion of the flocculator unit 
forming a junction area between the flocculator unit and the clarifier 
unit. 
There is flume means in the junction area for transfer of effluent from the 
flocculator unit into the clarifier unit and effluent means in the 
clarifier unit for discharging clarified liquid though on opening in the 
fourth portion of the clarifier unit. 
The clarifier unit further comprises a sludge flume defined by a 
trapezoidal plate, a pair of dependent sides, a section of the inner wall 
of the fifth portion to which the pair of sides are fastened, an open top 
end and an open bottom end. 
The third portion cylinder contains in the transfer area a flocculant 
transfer slot through which sludge may pass from the flocculant unit into 
the open top end of the sludge flume. 
Sludge collector means is positioned in the fifth portion to receive sludge 
passing out of the open bottom end of the sludge flume. In a first 
embodiment, such sludge collector means comprises a funnel, a conduit 
connected to the funnel that exits the clarifier unit through the wall of 
the fifth portion to connect with the flocculator unit for discharge of 
sludge into the flocculator unit and a pump connected into the conduit for 
forcing sludge through the conduit. 
In a second embodiment, the sludge collector means comprises a funnel, a 
stackpipe connected to the funnel and extending vertically therefrom and 
large bubble generator means for introducing large gas bubbles into the 
stackpipe adjacent to the base thereof to create an upward flow of sludge 
from the funnel through the stackpipe. 
The clarifier unit further comprises a plurality of parallel tubes open at 
both ends and positioned at an acute angle relative to the second vertical 
axis in the fourth portion of the clarifier unit through which liquid 
contained in the fifth portion may pass upwardly. Also, the fourth portion 
of the clarifier unit contains at least one collection launder positioned 
above the parallel tubes to receive liquid passing upwardly out of the 
parallel tubes and convey it to effluent means. 
In a preferred embodiment, the effluent means comprises a collection box 
fixed to the outside surface of the fourth portion cylinder and a 
discharge conduit in the collection box. 
The objects of the invention are further attained by the provision of a new 
method for the purification of liquids containing suspended solids and/or 
dissolved solid materials which comprises: 
(a) introducing influent liquid to be purified tangentially into a first 
cylindrical zone of first diameter through first and second diametrically 
opposed inlet nozzles, the first nozzle having a substantially larger 
cross-sectional area than the second nozzle, 
(b) introducing flocculant producing material into the liquid, 
(c) causing the liquid to move upwardly with helical flow with gradually 
widening as it progresses upwardly through a frustum zone resulting in 
gradual decrease in velocity of helical flow and into a second cylindrical 
zone of second diameter substantially larger than the first diameter 
positioned above the frustum zone, 
(d) controlling the volume and velocity of influent liquid flow into the 
first cylindrical zone so that flocculant which forms in the helically 
flowing liquid accumulates as a rotating sludge blanket positioned in 
frustum zone and in the lower section of the second cylindrical zone with 
a layer of clarified liquid above the sludge blanket in the second 
cylindrical zone, 
(e) causing the clarified liquid to flow out of the second cylindrical zone 
via a horizontal flume into a vertically elongated clarifier zone, 
(f) causing portions of the sludge blanket to flow out of the second 
cylindrical zone via a horizontal slotted opening therein located below 
the level of the flume into the clarifier zone, 
(g) moving the sludge blanket portions downward in the clarifier zone for 
discharge therefrom by conduit means, 
(h) moving the clarified liquid upwardly in the clarifier zone through a 
plurality of parallel tubes angled with respect to the longitudinal axis 
of the clarifier zone to produce further clarification of the liquid, and 
(i) discharging portions of the liquid from the clarifier zone at a level 
above the plane defined by the top ends of the parallel tubes. 
Advantageously, controlling the volume and velocity of influent liquid flow 
comprises independently adjusting the velocity of fluid flow through the 
opposed nozzles so that the velocity of flow through one nozzle 
substantially exceeds the rate of flow through the other nozzle. 
Also, the path of the helical flow of the liquid under treatment is 
partially disturbed by a plurality of blades interposed in the path in the 
region of the junction of the cylindrical zone with the frustum zone.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring in detail to FIGS. 1-11 of the drawings, a first embodiment of 
the purification system 2 of the invention comprises a flocculator unit 4 
and a clarifier unit 6. 
The flocculator unit is defined by geometric portions 8, 10 and 12 
assembled vertically along a central vertical axis. The first portion 8 is 
a cylinder having a closed bottom end 14 and an open upper end 16. The 
second portion 10 is an inverted frustum having an open low end 18 of an 
and an open top end 20. 
The third portion 12 is a cylinder having a open lower end 22 and an open 
top end 24. 
The portions 8, 10 and 12 are integrally joined together forming the 
flocculator unit 4. 
There is a first horizontal, tangential tubular inlet 26 into the portion 8 
having a third diameter, a second horizontal, tangential tubular inlet 28 
into portion 8 diametrically opposed to the inlet 26 having a fourth 
diameter smaller than the third diameter and a drain nozzle 29. 
A series of blades 30 are mounted adjacent the upper end 16 of portion 8 
that extend toward its center at an acute angle relative to the 
horizontal. 
The clarifier unit 6 comprises geometric portions 32 and 34 assembled 
vertically along a second central vertical axis. The fourth portion 32 is 
a fragmented cylinder of fifth diameter having a open lower end 36 and an 
open top end 38. 
The fifth portion 34 is of inverted conical shape and has an open top end 
38 of diameter equal to the fifth diameter which is integrally joined to 
the fourth portion lower end 36. 
The fragmented cylinder 32 is joined to the cylinder portion 12 of 
flocculator unit 4 forming a junction area 40 (see FIG. 2). 
Flume means 42, which includes a flocculant transfer slot 43, located in 
the junction area 40 serves to transfer partially clarified effluent from 
the flocculator unit 4 into the clarifier unit 6 while permitting renegade 
flocculant in the effluent to pass through the transfer slot 43. 
FIG. 7 shows the junction area 40 viewed from inside the flocculator unit 4 
with the junction of portion 32 of the clarifier unit 6 with portion 12 of 
the flocculator unit 4 and the junction portion 34 of the clarifier unit 6 
with portion 10 of the flocculator unit 4 shown in dotted lines. FIG. 8 
shows the junction area 40 viewed from the outside of units 4 and 6 and 
the position of the clarification baffle 41. 
Effluent means 44 in the clarifier unit 6 discharges clarified liquid 
through an opening in the portion 32 of the clarifier unit 6. Means 44 
comprises an effluent collection box 45 and discharge conduit 46. 
The sludge flume 47 in the clarifier unit 6 consists of a trapezoidal plate 
48 with an angled upper end 49, a pair of dependent sides 50, a section 52 
of the inner wall 54 of the portion 34 to which the pair of sides 50 are 
fastened, an open top end 53 and an open bottom end 55. The third portion 
cylinder 12 contains in the transfer area 40 a flocculant transfer slot 56 
through which sludge (not shown) may pass from the flocculator unit 4 into 
the upper top end 57 of the sludge flume 47. 
Sludge collector means 58 positioned in the fifth portion receive sludge 
passing out of the open bottom end 54 of the sludge flume 47. 
Referring to FIGS. 9 and 10, in a first embodiment, the sludge collector 
means 58 comprises a funnel 60, a conduit 62 that exits the clarifier unit 
through the wall 52 of the portion 34 to connect with the flocculator unit 
4 for discharge of sludge into it and a pump 64 connected into the conduit 
62 for foreing sludge through the conduit 62. 
Referring to FIGS. 12-15, in a second embodiment, system 2A comprises a 
flocculator unit 4A and clarifier unit 6A. 
In the system 2A, the sludge collector means 58A comprises a funnel 60, a 
stackpipe 66 connected to the funnel 60 and extending vertically therefrom 
to terminate in a discharge section 68. A vent tube 70 is joined to the 
stackpipe 66 at the top bend 72. There is large bubble generator means 74 
for introducing large air bubbles into the stackpipe 66 to create an 
upward flow of sludge (not shown) from the funnel 60 through the stackpipe 
66. A line 76 connects to the bubble generator means 74 for introduction 
of compressed air into the means 74 for creating the large air bubbles. 
The bubble generator means 74 and related stackpipe 66 may take a variety 
of forms as disclosed in U.S. Pat. Nos. 4,187,263; 4,293,506; 4,356,131 
and 4,569,804, the disclosures of which are incorporated herein by 
reference. 
The discharge section 68 of stackpipe 66 discharges sludge (not shown) into 
a sludge head box 78 from which it exits via discharge nozzle 80 connected 
to recycle pipe 82 that delivers the sludge into tangential tubular inlet 
28 for recycle into the flocculator unit 4a. 
The clarifier units 6 and 6a further comprise a pluraltiy of parallel 
(lamellar) tubes 82 open at both ends and positioned at an acute angle 
relative to the second vertical axis in the portions 32 of clarifier units 
6 and 6A through which liquid contained in the portions 34 may pass 
upwardly. Portions 32 also contain collection launders 84 positioned above 
the parallel tubes 82 to receive liquid passing upwardly out of the tubes 
82 and convey it to effluent means 44. In place of tubes 82, lamellar 
plates (not shown) may be used as disclosed in Infilco Degremont Inc. 
brochure no. DB585 entitled Superpulsator.TM. Clarifier and dated December 
1990, the disclosure of which is incorporated herein by reference. 
Referring to FIGS. 3 and 5, the first inlet 26 to portion 8 connects via 
pipe reducers 86, control valve 88 and Y-section 90 to raw water influent 
pipe 92. Similarly, the second inlet 28 connects via control value 94 and 
piping 96 with Y-section 90 to influent pipe 92. Typically, valve 88 will 
be of the automatically operated butterfly type and valve 94 will be of 
the manually operated butterfly type. 
The drain nozzle 29 connects with the inside of cylindrical portion 8 
through a flange 98 in its closed bottom 14 and via control valve 100 with 
the flocculator drain pipe 102. Typically, valve 100 will be a manually 
operated plug type. 
Referring to FIG. 6, the bottom 104 of frustum 34, which is surrounded by 
support skirt 106, includes a sludge blowdown nozzle 108 that connects via 
control valves 110 and 112 to the blowdown discharge pipe 114. Typically, 
valve 110 is a manually operated plug type and valve 112 is an 
automatically operated plug type. 
In operation of systems 2 and 2A, raw water flow enters the bottom portion 
8 through the diametrically opposed, horizontal, tangential inlet nozzles 
26 and 28. Typically, the nozzles are sized based on velocity of flow, one 
at 2-3 fps, the other at 8-10 fps. As raw water enters the bottom portion 
8, it is caused to rotate rapidly due to the position of the nozzles and 
the diameter of the cylinder. The rate of rotation is increased or 
decreased by operation of control valve 88 located before the larger (2-3 
fps) inlet nozzle 26, thereby diverting more or less flow through the 
smaller (8-10 fps) inlet nozzle 28. 
As the flow moves upward through the bottom portion 8, it passes through 
blades 30 which are mounted at the top 16 of the bottom portion 8 and 
extend toward its center at an angle of approximately 45.degree.. The 
blades serve two purposes: (1) they act as a static mixer to improve the 
formation of flocculant, and (2) they dissect the rotational flow vector 
into smaller, less forceful flow vectors allowing for smoother rotation of 
the flocculant within the middle portion 10. As the flow moves upward into 
the portion 10, its rotation gradually slows through the expanding cross 
section. 
The sludge blanket (not shown) which is formed in portion 10 provides an 
ideal solids contact medium due to its continuous helical rotation. The 
flocculant particles are forced to travel distances representative of long 
conventional sedimentation basins. The gradual reduction in rotation is 
representative of conventional tapered flocculation. As the solids build 
within the blanket, a distinct sludge separation line between solids and 
water is developed. In the flocculator units 4 and 4A only a 18-inch 
(approximate) depth of separated water is maintained above the blanket. 
The separated water and flocculant are withdrawn from the flocculator 4 and 
controlled by the use of two mechanisms. The first mechanism for the 
withdrawal and control of the separated water is the horizontal flume 42 
which connects the flocculator units 4 or 4A to the clarifier units 6 or 
6A respectively. 
Both separated water and some solids move through the flume 42. Flume 42 
terminates at some distance within the clarifier units 6 or 6A. Prior to 
flowing out of flume 42, the liquid flow encounters the slot 43 cut in the 
bottom of the flume 42. Slot 43 allows the additional removal of solids 
from the separated water stream. 
The solids move toward the bottom of the clarifier unit 6 or 6A within 
flume 47, while the separated water (with some flocculant) moves toward 
the bottom of the clarifier unit 6 or 6a outside of flume 47. 
The second mechanism for the withdrawal and control of the separated solids 
from the flocculator unit 4 is slot 56. The solids discharged through the 
slot 56 move downward through enclosed sloped flume 47 which terminates at 
its open bottom end 54. The solids from both the flume 42 and the sloped 
flume 47 move downward between wall 52 and plate 48 to discharge beneath 
the flume 47 into a steeply sloped cone bottom 104 of frustum 34. 
Thickened solids (not shown) are blown down from the bottom of the 
clarifier unit 6 or 6a typically by use of two ultrasonic sludge detectors 
(not shown) which sense high and low sludge levels or by timed interval. 
The separated water flowing from the flume 42 moves downward, and travels 
beneath vertical baffle 41 which separates the lamellar tubes 82 from the 
zone following flume 42. 
Clarified water is collected via the launders 84 placed above the lamellar 
tubes 82. The collection launders 84 feed collection box 45 with effluent 
which exists through nozzle 46. 
In system 2, sludge is withdrawn from clarifier unit 6 and recycled via 
funnel 60, line 62, pump 64 and inlet nozzle 28 to the flocculator unit 4. 
In system 2, sludge is withdrawn from clarifier unit 6 and recycled via 
funnel 60, stackpipe 66 and its extension 68 with the assist of bubble 
generator 74, head box 78, discharge nozzle 80, line 82 and inlet nozzle 
28 to the flocculator unit 4A. 
An air compressor, at grade or on an elevated platform (not shown), 
provides compressed air to line 76 to generate the large bubbles which 
lift the solids through the stackpipe 66. The air can be controlled to 
increase or decrease the rate of recycle. 
The solids in the head box 78 are easily sampled to determine their 
concentration. The nozzle 80 in the clarifier portion 32, which enters the 
head box 78, provides the opening through which the collected solids flow 
into pipe 82 connecting the head box 78 to the inlet nozzle 28 piping to 
the flocculator unit 4a. 
A basic control package for system 2 or 2A (not shown) will typically 
consist of a potentiometer for operation of the larger inlet nozzle 
control valve 88, the air compressor and air controls (system 2A only) and 
the sludge detector controls for sludge blowdown.