Note: Descriptions are shown in the official language in which they were submitted.
-1-
METHOD AND SYSTEM FOR TREATING WATER
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates generally to water treatment and in particular
to
a method and apparatus for treating contaminated water.
2. Description of Related Art
Produced water is one of the major by-products in the process of exploration
and production of oil. Its composition may vary, however depending on the
process it may include (but is not limited to):
a. Dissolved and dispersed oil compounds;
b. Dissolved formation minerals;
c. Production chemical compounds,
d. Production solids (including formation solids, scale and corrosion
products, bacteria, waxes, and asphaltenes );
e. Dissolved gases.
The US Geological Survey operates under the estimate of 7 barrels of water
for 1 of oil. The Provincial Government of Alberta, Canada, estimates a 3/1
ratio. Given these large quantities of water that are produced by such
process, it will be appreciated that an efficient means of cleaning such water
for reuse is required.
SUMMARY OF THE INVENTION
According to a first embodiment of the present invention there is disclosed a
system for treating water derived from an industrial process comprising
removing solid material from said water with a centrifuge and passing said
water
through a plurality of tanks, each of said plurality of tanks including a
plurality of
cells in which said water passes sequentially through said plurality of cells
in
each of said plurality of tanks, wherein at least one of said cells contains a
quantity of a dried macrophye biomass.
CA 3040777 2019-04-23
-2-
Other aspects and features of the present invention will become apparent to
those ordinarily skilled in the art upon review of the following description
of
specific embodiments of the invention in conjunction with the accompanying
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate embodiments of the invention wherein similar
characters of reference denote corresponding parts in each view,
Figure 1 is a perspective view of an apparatus for treating
wastewater
according to a first embodiment of the present invention.
Figure 2 is a schematic representation of the system of Figure 1.
Figure 3 is a schematic view of one of the tanks of the system of
Figure 1.
Figure 4 is a cross sectional view of one of the cells of the system
of Figure
1.
Figure 5 is a schematic illustration of one channel of the stages of the
system of Figure 1.
DETAILED DESCRIPTION
Referring to Figure 1, an apparatus and system for treating according to a
first
embodiment of the invention is shown generally at 10. Although the
apparatus 10 is illustrated in Figure 1 as being contained within a frame or
skid, as are commonly known for portable use, it will also be appreciated that
the system may be utilized as separate elements or installed in arrangement.
In particular, the apparatus 10 comprises a frame 12 housing the elements
which comprise the system comprised of a centrifuge 20 and a plurality of
tanks 30. As illustrated in Figure 1, the system may comprise first second and
third tanks 32, 34 and 36, respectively as will be more fully described below.
Optionally, the system 30 may include a pump 14 adapted to pump the waste
water through the remaining components. The system may be formed as a
single sequence of the centrifuge 20 and tanks 30 or may optionally have
more than one of each element so as to provide redundancy.
CA 3040777 2019-04-23
-3-
With reference to Figure 2, a schematic view of the system 30 is illustrated.
As illustrated in Figure 2, the system 30 may include first and second
channels 16 and 18 which each includes a centrifuge 20 and first, second and
third tanks 32, 34 and 36. As illustrated, the waste water may enter at an
entrance 22 which may be connected to a source of waste water in any
manner known and a discharge 24 which discharged the treated water to any
desired location and may be connected to any other subsequent systems.
The system 30 includes a pump 14 before each centrifuge 20. The system 30
may optionally include a further pump 14 after each centrifuge and before the
tanks. As illustrated in Figure 2, the system may include cross-pipes 26
extending between each channel 16 or 18 and the opposite channel. The
cross-pipes 26 may include valves 27 as do each channel 16 or 18 along with
pressure 28 gauges. The valves permit the contents of each channel to be
mixed with each other as well as to isolate one or more of the tanks for
maintenance.
Turning now to Figure 3, a schematic of one of the tanks 30 is illustrated. In
particular, the view of the tank 30 is Figure 3 is illustrated as a horizontal
cross section. Each tank includes a plurality of cells, 40, 42, 44, 46, 48, 50
and 52 therein. Although the cells are illustrated in Figure 3 as upright,
other
configurations may also be utilized. As illustrated, the waste water is
directed
through each of the cells 40 through 52 in sequence. Each of the cells may
include a different media so as to remove a different contaminant from the
waste water as will be further described below.
As set out above, the system 30 can be organized into 5 steps of removing
contaminants from waste water. As illustrated in Figure 5, the schematic of a
single channel is illustrated having a centrifuge 20 and first, second and
third
tanks 32, 34 and 36. The first step is performed by the centrifuge 20 wherein
solid wastes 21 are removed for disposal. It will be appreciated that with
such
removal, the results will be improved by reducing the contamination of the
absorbents by the particulate material and in particular the due to the BOD
Biochemical Oxygen Demand and COD Chemical Oxygen Demand
CA 3040777 2019-04-23
-4-
Thereafter, the second and third steps may be performed in the first tank 32.
The second step comprises the removal of oils, greases and other petroleum
based contaminants. In the second step, an absorbent plant based material
(SORB) is utilized. In particular, in one embodiment of the present invention,
the first, second and third cells of the first tank may be utilized for such
first
step. It will be appreciated that due to the removal of oils and greases by
the
SORB, that the subsequent filtering is improved due to preventing the
subsequent filtration media from becoming contaminated with the oil and
grease.
The third step may also be performed in the first tank 32 such as within cells
4
through 7 by way of non-limiting example and consists of removal of phenols
and other contaminants. The fourth step may be performed in the second
tank 34 and consists of removal of ammonia (NH3) and sodium chloride
(NaCI) along with nitrates, nitrites with the use of activated charcoal and
sedimentary rock. In step five, all resident residues will be removed by a
combination of the SORB, activated charchol and a final filter in the third
tank
36. The tank and cell contents are summarized for the above example in the
following table.
30
CA 3040777 2019-04-23
-5-
Table 1: Example of Cell Contents
TANK 1 TANK 2 TANK 3
Cell 1 SORB SORB SORB
Cell 2 SORB SORB Activated coal
Cell 3 SORB sedimentary rock Reactivated coal
and activated coal
Cell 4 Activated coal and sedimentary rock Reactivated coal
SORB and activated coal
Cell 5 - Activated coal sedimentary rock Reactivated coal
and activated coal
Cell 6 Activated coal and sedimentary rock Reactivated coal
SORB and activated coal
Cell 7 Activated coal sedimentary rock Filter
and activated coal
It will be appreciated that depending upon the waste water that the system is
to be utilized with, the distribution of steps may be varied in location and
size
within the tanks and cells.
As set out above, SORB is utilized to remove oils and greases from the waste
water. The SORB comprises a natural absorbent element obtained from the
crushing and drying processes of the macrophyte biomass. Macrophytes are
aquatic plants that live on and/or in any aquatic environments (including
fresh
and salty water). In the present system, any suitable macrophyte may be
used. In particular example of such suitable SORB include, but are not limted
to Eichomia crassipes, Pistia stratiotes, Salvinia auriculate e Potamogeton
natans. The SORB is prepared by drying the plant material to a dryness of
less than 5% water by weight although it will be appreciated that other
moisture levels may also be useful as well. After drying the plant materials
are then crushed or otherwise reduced in size to meet the requirements for
that particular stage of filtration as illustrated below with respect to the
third
cell 46 of the first tank 32. After the drying process the biomass assumes
special characteristics that confer high absorption power (due to its external
CA 3040777 2019-04-23
-6-
capillary structure) and retention (due to its internal cellular structure
that is
porous).
It also has the characteristic of being hydrophobic, which guarantees sorption
only of contaminants that are mixed in the effluents to be treated.
As illustrated in Figure 4, one of the cells 46 of the first tank 32 may be
formed
with varying levels of a mesh through first, second, third and fourth stages
60,
62, 64 and 66, respectively. Each of the first, second, third and fourth
stages
60, 62, 64 and 66 may have different screen opnenings or filtration sizes. In
particular the third cell 46 of the first tank may, as set out above, comprise
a
SORB step wherein the first, second, third and fourth stages 60, 62, 64 and
66 are filled with granular SORB material. By way of non-limiting example,
the first stage may be filled with particles of SORB of a mesh 50 size
granular
size wherein the second stage includes particles of a mesh 8, the third stage
having particles of a mesh 1/4" and the fourth stage having particles of a
mesh
3/8" as are commonly known. As illustrated, the water enters the cell
proximate to a bottom 47 and exits proximate to a top thereof. A transfer pipe
54 then transfers the water to the bottom of the next cell. It will be
appreciated that the depth of each cell and stage within that cell will depend
upon the particulars of the waste water and the contaminants therein. The
level of compaction of each of the stages within the cell may also be varied
to
ensure that the effluent can flow into the cell.
The present system is designed to increase the efficiency of the treatment of
waste water. In particular, such water treatment systems may be useful in
particular for use in treating waste water resulting from the petrochemical
industry, such as marine loading and unloading terminals, prospecting
platforms, oil capture at prospecting of underground wells and oil capture at
refineries by way of non-limiting example. In particular, the present system
is
useful in the retention of oils and greases, as well as phenols, cyanides,
sulfides, ammonia, suspended solids and other components from such waste
water.
CA 3040777 2019-04-23
-7-
While specific embodiments of the invention have been described and
illustrated, such embodiments should be considered illustrative of the
invention only and not as limiting the invention as construed in accordance
with the above description.
CA 3040777 2019-04-23
