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Patent 2199517 Summary

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(12) Patent: (11) CA 2199517
(54) English Title: INSTALLATION FOR BIOLOGICAL WATER TREATMENT FOR THE PRODUCTION OF DRINKABLE WATER
(54) French Title: INSTALLATION POUR LE TRAITEMENT BIOLOGIQUE DES EAUX EN VUE DE LEUR POTABILISATION
Status: Deemed expired
Bibliographic Data
(51) International Patent Classification (IPC):
  • C02F 3/12 (2006.01)
  • B01D 61/18 (2006.01)
  • B01D 65/02 (2006.01)
  • B01D 65/08 (2006.01)
  • C02F 1/44 (2006.01)
  • C02F 3/10 (2006.01)
(72) Inventors :
  • COTE, PIERRE (France)
  • SIBONY, JACQUES (France)
  • TAZI-PAIN, ANNIE (France)
  • FAIVRE, MICHEL (France)
(73) Owners :
  • VEOLIA WATER SOLUTIONS & TECHNOLOGIES SUPPORT (France)
(71) Applicants :
  • OTV OMNIUM DE TRAITEMENTS ET DE VALORISATION (France)
(74) Agent: OYEN WIGGS GREEN & MUTALA LLP
(74) Associate agent:
(45) Issued: 2007-10-02
(86) PCT Filing Date: 1996-07-25
(87) Open to Public Inspection: 1997-02-13
Examination requested: 2003-07-09
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/FR1996/001180
(87) International Publication Number: WO1997/005072
(85) National Entry: 1997-03-07

(30) Application Priority Data:
Application No. Country/Territory Date
95 09336 France 1995-07-25

Abstracts

English Abstract




This invention relates to a plant for the biological treatment of water to
produce drinking water, characterized in that it comprises at least one
biological reactor
(7) provided
with injection means (9) for injecting oxygenated gas, at least one separation
membrane
(11 for microfiltration or ultrafiltration immersed in said reactor (7), and
addition means
(10) for adding to said reactor (7) at least one pulverulent material in
suspension serving
as a support for a biomass, said pulverulent material possibly being a
reactive powder
which also allows fixation of the substrate required by said biomass.


French Abstract

L'invention concerne une installation de traitement biologique d'une eau en vue de sa potabilisation caractérisée en ce qu'elle comprend au moins un réacteur biologique (7) muni de moyens d'injection d'un gaz oxygéné (9), au moins une membrane de séparation (11) de microfiltration ou d'ultrafiltration immergée dans ledit réacteur (7), et des moyens d'adjonction (10) à l'intérieur dudit réacteur (7) d'au moins un matériau pulvérulent en suspension servant de support à une biomasse, ledit matériau pulvérulent pouvant être constitué par une poudre réactive permettant de plus de fixer le substrat necéssaire à ladite biomasse.

Claims

Note: Claims are shown in the official language in which they were submitted.



15

CLAIMS


1. Plant for the biological treatment of drinking water characterized in that
it
comprises at least one biological reactor (7) provided with means for
injecting oxygenated
gas (9), at least one separation membrane (11) for microfiltration or
ultrafiltration
immersed in said reactor (7), and addition means (10) within said reactor (7)
for adding at
least one pulverulent material in suspension serving as a support for a
biomass, said
pulverulent material possibly being made up of a reactive powder which also
allows
fixation of the substrate required by said biomass.


2. Plant according to claim 1, characterized in that said reactive powder is
chosen from the group made up of powdered activated carbon, zeolites, ion
exchange
resins and clays.

3. Plant according to claim 1, characterized in that it also comprises at
least
one anoxic denitrification unit upstream of said biological reactor (7).

4. Plant according to claim 1, characterized in that said biological reactor
(7)
has sludge drainage means (14) in its upper and lower parts.

5. Plant according to claim 1, characterized in that it comprises pre-
treatment
means (3,4) provided upstream of said biological reactor, including
clarification means
(3).

6. Plant according to claim 1, characterized in that said membranes (11) are
made up of hollow fibre membranes.


7. Plant according to claim 1, characterized in that the civil engineering
works
used for its set-up entails conversion of existing civil engineering works of
a drinking
water treatment plant with physical filtration through granular material, said
biological
reactor (7) consisting of a granular material filtration basin of said
drinking water
treatment plan.


8. Plant according to claim 1, characterized in that it comprises means of
measurement (10a) for measuring concentrations of pollutants of said water, to
which
means of measurement is connected said addition means (10).

9. Process of biological water treatment to produce drinkable water,


16

characterized in that it consists of passing the water through a plant in
accordance with
claim 1, of using said addition means of said plant to permit the addition to
said reactor of
at least one pulverulent material serving as a support for the biomass and/or
the addition,
at least intermittent, to said reactor of at least one reactive powder, said
reactive powder
being added in relation to the pollutants present in the raw water and/or to
the temperature
of the drinking water to be treated.

10. Process in accordance with claim 9 characterized in that it is set in
operation when the temperature of the drinking water to be treated allows
normal activity
of said biomass permitting biological degradation of CODB and nitrogenous
pollution in
said water, and in that it consists of setting in operation said addition
means to distribute
at least one reactive powder in said reactor in relation to at least one
parameter chosen
from the group made up of pesticide content of the water, COD content of the
water and
heavy metal content of the water.


11. Process in accordance with claim 10 characterized in that it consists of
setting in operation said means of addition of at least one pulverulent
material to distribute
powdered activated carbon in said reactor in order to adsorb COD and
pesticides present
in the drinking water to be treated.


12. Process in accordance with claim 10 or 11, characterized in that it
consists
of setting in operation said means of addition of at least one pulverulent
material to
distribute a zeolite or clay in said reactor in order to adsorb the heavy
metals present in the
drinking water to be treated.


13. Process in accordance with claim 10, characterized in that it comprises a
stage consisting of maintaining within said reactor the reactive powders whose
adsorbent
properties have been exhausted, the latter subsequently forming a non-reactive

pulverulent material which serves as a fixation support for the biomass.

14. Process in accordance with claim 9, characterized in that said means of
addition of pulverulent material is set in operation when the temperature of
the drinking
water to be treated inhibits the biological activity of said biomass, in order
to distribute
within the reactor at least a first reactive powder intended to adsorb organic
compounds
and at least a second reactive powder intended to adsorb ammonia pollution.


17

15. Process in accordance with claim 12, characterized in that said first
powder is powdered activated carbon.

16. Process in accordance with either of claims 12 or 13, characterized in
that
said second powder is chosen from the group made up of zeolites and clays.

17. Process in accordance with either of claims 12 or 13, characterized in
that
it consists of renewing the first and second powders when the adsorbing
properties of the
latter are exhausted.


Description

Note: Descriptions are shown in the official language in which they were submitted.



2199-17

1
INSTALLATION FOR BIOLOGICAL WATER TREATMENT FOR THE
PRODUCTION OF DRINKABLE WATER

This invention relates to the area of filtration and purifying plants for
water
treatment.

The invention applies more precisely to the treatment of drinking water such
as in
particular underground water, either deep or karstic, or surface water.
Conventionally, plants for the treatment of drinking water generally comprise
a
succession of physicochemical treatment units such as flocculation /
sedimentation /
filtration completed by an oxidation unit.
Flocculation is a physicochemical stage whose purpose is to modify the
condition
of the colloidal particles contained in water by adding a coagulant (aluminium
polychloride, aluminium sulfate, ferric chloride, etc.) so that they may be
eliminated by
sedimentation.
The micro-organisms, micro-pollutants, compounds (ferrous iron, manganese,
etc.) which cannot be removed by flocculation are generally oxidised through
the use of
strong oxidants such as ozone, chlorine, or chlorine bioxide.
The elimination of micro-pollutants may also be made by adsorption on
activated
carbon or by stripping (forced aeration) if they are volatile.
The filtration stage intended to remove the particles in suspension is
conventionally conducted on one or more beds of pulverulent non-reactive
materials such
as sand filters.
A conventional plant for the treatment of drinking water may therefore
comprise a
flocculation unit, followed by a sedimentation unit, a filtration unit (for
example on sand)
an ozonation unit, a filtration unit on powdered or granular activated carbon
and
disinfection.

Such conventional installations for the treatment of drinking water in the
present
state of the art have numerous disadvantages.
Firstly, since they are made up of a multiplicity of units each reserved for
specific
treatment, they are of substantial size which may hinder their set-up. This
problem is


~~995) 17

2
especially heightened when drinking water treatment plants are to be set up in
urban
areas, that is to say where available surface area is rare and often costly.
Moreover, such plants require the assembly of numerous connections between the
different treatment units, connections which take time to install, are costly
and represent
an equivalent number of points of weakness within the plant.
As an alternative to conventional drinking water treatment systems, a method
of
membrane filtration has in particular been recently suggested which uses a
circulation
loop for the water to be treated including at least one tangential filtration
membrane with
the injection of ozone into the circulation loop.

Known drinking water plants which use membranes have the disadvantage of
being costly to set up, in particular as they cannot be adapted to existing,
conventional
installations without considerable conversion work.
The biological treatments conventionally used to treat residual waters have
been
relatively little used for drinking water plants, since they imply the use of
bacteria which
are difficult to restrict solely to those stages for which they are required,
and which may
therefore pollute the water to be made safe for drinking at subsequent stages
of treatment.
Also, such treatments must be set in operation at temperatures which allow the
micro-
organisms used to degrade the carbon and/or nitrogenous pollution contained in
the
water. However, it is more desirable to have available drinking water
treatment systems
which may be set in operation at low temperatures especially during the Winter
months.
In particular it will be noted that consideration has never been given, to the
knowledge of the applicant, to the possibility of growing activated sludge in
drinking
water that is to be treated. It is true that using said activated sludge with
conventional
clarification means would lead to a loss in biomass through release into the
clarified water
that would exceed production, thereby preventing sufficient sludge age to be
reached.
The objective of the present invention is to present a plant for the treatment
of
drinking water which does not have the disadvantages of state of the art
plants.
Another objective of the present invention is to propose a plant for the
treatment
of drinking water which uses a biological treatment stage.
A further objective of the present invention is to propose said plant which
may be


2199517
.. ~

3
set up at low cost by renovating existing drinking water plants which use
conventional
filters such as sand filters.
A further objective of this invention is to describe said plant which combines
the
advantages of biological treatment with those of treatments using compounds
allowing
the adsorption of micro-pollutants or nitrogenous pollution such as powdered
activated
carbon, clays, zeolites, etc.
A further objective of this invention is also to include in a water treatment
plant
one or more filtration membranes while nevertheless maintaining high treatment
flow
rates.

A further objective of the present invention is also to propose a drinking
water
treatment plant having high flexibility of use which may be used at
temperatures at which
there is little or no biological activity.
These various objectives and others which shall become apparent below are
reached with this invention which relates to an installation for the
biological treatment of
drinking water characterized in that it comprises at least one biological
reactor provided
with means of injecting an oxygenated gas, at least one microfiltration or
ultrafiltration
membrane immersed in said reactor, and means within said reactor for adding at
least one
pulverulent material in suspension serving as a support for a biomass, said
pulverulent
material being possibly made up of a reactive powder which also allows
fixation of the
substrate required by said biomass.
The invention is therefore original in that it proposes treating drinking
water using
an activated sludge whereas the state of the art extensively dissuaded those
skilled in the
art from using a free biomass for such process. According to the invention,
the use of an
activated sludge is made possible through the use of at least one
microfiltration or
ultrafiltration membrane which holds back the biomass within the reactor and
therefore
prevents it from migrating outside the latter. With the use of said membrane
it is also
possible to obtain a sufficiently long sludge age to permit water
purification.
The invention is also original in that it proposes the adding of at least one
pulverulent material to the reactor during drinking water treatment. Said
material
contributes towards development of the biomass by serving as a support for the
latter.


= ' ~ t

= ~ 2199517
4
Again according to the invention, the pulverulent material used may constitute
a reactive
powder contributing directly towards water treatment by adsorbing on its
surface the
substrates (organic matter, NH4) required by the biomass. These reactive
powders may
be chosen in relation to the composition of the drinking water to be treated,
in particular
in relation to its organic matter and NH4 content. Powdered activated carbon
(PAC) may
be used to permit advanced adsorption of organic matter and slight adsorption
of NH4,
whereas zeolites will be preferably used to permit advanced adsorption of NH4
and slight
adsorption of organic matter.
The plant of the invention therefore advantageously allows the association
within
one and the same reactor of the combined advantages of biological treatment
and
membrane filtration. The fixed biomass allows breakdown of biodegradable
carbon
pollution (CODB) and nitrogenous pollution, and the membranes permit both
water
filtration and elimination of matter in suspension therein while effectively
preventing
migration of the biomass. Also, said plant allows the use of reactive powders
which may
be added as required to the drinking water to be treated, particularly in
relation to the
composition of said water.
The means used to add a pulverulent material to the reactor may therefore be
used
to add to the water present in the reactor any non-reactive pulverulent
material serving as
a support for the biomass used, such as for example sand or anthracite, and
also to add to
said water one or more reactive powders of various types. It will be noted
that for the
present description the terms "reactive powders" shall be understood to mean
any powder
likely to react with one of the compounds in the drinking water to be treated,
either by
adsorption or by ion exchange, with a view to removing the content of these
compounds
in said water to be treated. These powders must also have physical
characteristics of
hardness, abrasiveness and density, allowing their fluidization in the water
present in the
reactor and making them compatible with the membranes used.
These reactive powders may advantageously, using the plant of the invexltion,
be
added to the water to be treated in relation to the composition of said water,
in particular
in relation to its micropollutant content and especially its pesticide content
(atrazine,
simazine etc.) which are compounds that are difficult to remove by biological
means.


2199517

These reactive powders may also be used to rid the water of toxic metals it
may contain
such as cadmium or lead.
In certain cases, as shall be explained below in detail, these reactive
powders may
also be used to adsorb carbon or nitrogenous pollution when the biomass used
in the
5 reactor is little or not at all active, as the temperature of the water
passing through the
reactor is too low. Therefore, the use of these reactive powders will if
necessary provide
for the functional relay of the biomass thereby bestowing upon the plant of
the invention
great flexibility of use allowing it to be set in operation whatever the
temperature of the
water to be treated may be.

The presence of membranes in the reactor allows very effective filtration of
the
drinking water to be made treated and prevents any passage of bacteria to
subsequent
stages of the treatment process.
Finally, the means of injecting oxygenated gas into the plant has four main
objectives. Firstly, it allows the supply of necessary oxygen for respiration
of the
biomass in the reactor. Secondly, it ensures fluidization of the powders also
present in
the reactor. Thirdly, it ensures thorough mixing of said powders with the
water and
finally it subjects the membranes immersed in the reactor to shaking which
prevents or at
least delays their fouling.
Said characteristic is of particular interest since it allows the conversion
of out-of-
date drinking water plants into new plants leading to improved production
without having
recourse to new civil engineering works. It is therefore possible to reduce
considerably
the costs generally incurred when setting up new equipment.
Preferably, said reactive powder is chosen from the group made up of powdered
activated carbon (PAC), zeolites, clays, and exchange resins. Powdered
activated carbon
(PAC) may preferably be used as compound to adsorb micro-pollutants in
particular
pesticides. PAC may therefore be added in particular during periods in the
year when the
water content of these compounds is especially high, particularly in Spring.
Zeolites,
clays and exchange resins may be used to entrap nitrogenous pollution in the
event of
insufficient biomass activity due to a drop in temperature or they be used to
trap metals.
It will be noted that in the present state of the art a plant for drinking
water


~- 2199517

6
treatment using non-biological means is already known, which uses both
tangential
filtration membranes and the addition of powdered activated carbon. Said plant
is
described in French patent application N 2629337. However, within said plant,
the
injection of pulverulent material is made at a recyling loop so that this
powder can be
collected as soon as its adsorbent properties are exhausted. Unlike said
plant, the plant of
the invention does not require any recycling loop which simplifies in
particular its
installation. Also, the invention distinguishes itself from the technique
described in this
document inasmuch as the reactive powders are not simply used for their
adsorbent
properties but also to serve as a support for bacteria fixation thereby
opening up the
possibility of combining biological treatment and membrane filtration.
Another French patent application N 2696440 also describes a non-biological
drinking water treatment plant using separate units for sedimentation of the
mixture with a
pulverulent reagent and for tangential filtration on membranes. In this plant
of the prior
art, the pulverulent reagent is also directed towards the sedimentation unit
via a recyling
loop and is constantly renewed as soon as its adsorbent properties are
exhausted.
The invention therefore sets itself apart from the technologies described in
these
two documents through the characteristics according to which it proposes
adding several
reactive powders directly to the reactor in which the membranes are present,
and in that it
proposes using these powders also to serve as a support for a biomass.
According to another preferential aspect of the invention that is of interest,
said
plant also comprises at least one anoxic pre-denitrification unit upstream
from said
biological reactor. The use of a denitrification basin in conjunction with a
nitrification
basin is well known in the area of residual water treatment. However, up until
now such
use was not possible for the treatment of drinking water given the risk of
bacteria being
carried towards subsequent treatment stages. Such pre-denitrification is made
possible
with the plant of the invention inasmuch as such risk is avoided through the
presence of
hollow fibre filtration membranes whose pore size is designed to prevent the
passage of
any micro-organism in the filtrates.
Also, it will be noted that in plants for the treatment of residual waters,
the sludge
from the nitrification basin is sent to the front of the plant to be treated
in the


Y .
= ' r t ~ ~ 2199517

7

denitrification basin. Such sending offline is not necessary for the treatment
of drinking
water since the nitrates are present in raw water and very few nitrates are
formed in the
downstream stage of nitrification.
Preferably, the plant comprises means of pre-treatment provided upstream of
said
biological reactor and includes clarification means. This pre-treatment means
may also
include a flocculation/coagulation unit upstream of said means of
clarification. Such
means of pre-treatment may also be provided using the pre-treatment means of a
conventional plant on a renovated sand filter.
Also preferably, said biological reactor has in its lower and upper parts
sludge
drainage means. The sludge collected with these drainage means may be
redirected
towards means for sludge treatment.
According to a preferable aspect of the invention of particular interest, the
civil
engineering works for said plant entails the conversion of existing civil
engineering
works of a drinking water treatment plant with physical filtering on granular
material,
said biological reactor consisting of a granular material filtration basin of
said drinking
water treatment plant.
It will be noted in this respect that the use of denitrification means
upstream does
not prevent such renovation of an existing plant, the size of the sand filters
being such
that they may be divided up to form both a pre-denitrification basin and a
biological
reactor for nitrification and filtration on hollow fibre membranes.
Also preferably, the plant comprises means of measuring the concentrations of
pollutants in the water to be treated, to which is connected said means of
adding at least
one pulverulent material.
The invention also relates to a biological treatment process for drinking
water,
characterised in that it consists of passing the water through a plant as
described above
and using said means of addition of said plant to allow the addition to said
reactor of at
least one pulverulent material serving as a support for the biomass and/or the
addition, at
least intermittent, to said reactor of at least one reactive powder, said
reactive powder
being added in relation to the pollutants present in the raw water and/or to
the temperature
of the drinking water to be treated.


'M ) [ 1 1

2199~17

8
The process of the invention therefore also offers the original characteristic
of
reinforcing the biological support role played by the pulverulent material,
when the
conditions of drinking water treatment so require, by the addition of at least
one reactive
powder. Said reinforcement may in particular prove to be necessary when the
treatment
temperature is too low to allow biological activity of the biomass or when
there is an
increase in the load of water to be treated.
According to a variant of the invention, the process of the invention is used
when
the temperature of the water to be treated allows normal biological activity
of said
biomass permitting the biological degradation of CODB and nitrogenous
pollution in said
water, and consists of using said means of addition of a pulverulent material
to distribute
at least one reactive powder in said reactor in relation to at least one
parameter chosen
from the group made up of pesticide content, CODB content and heavy metal
content of
the water.

In practice, the temperature at which the metabolism of the bacteria is
inhibited is
in the region of 4-5 C. During the periods when the temperature of the
drinking water to
be treated is above this temperature, the plant of the invention may therefore
be used to
add at least periodically with the means provided for this purpose one or more
reactive
powders intended to break down the non-biodegradable carbon pollution, the
pesticides
and metals contained in the drinking water to be treated. The fixed bacteria
take in charge
the elimination of biodegradable carbon pollution and the removal of
nitrogenous
pollution.

In this case, and as already specified above, the pulverulent material used is
preferably powdered activated carbon active to remove pesticides, and zeolites
to adsorb
the heavy metals present.
According to one interesting variant of said process, the reactive powders
whose
adsorbent properties are exhausted may be maintained in said biological
reactor, when
they form a non-reactive pulverulent material serving as a fixation support
for the
biomass.
According to a further aspect of the process of the invention, said means of
adding pulverulent material is used when the temperature of the drinking water
to be


~ 2199517
59

treated inhibits the activity of said biomass so that it distributes within
the reactor at least a
first reactive powder intended to adsorb organic compounds, and at least a
second
reactive powder intended to adsorb ammonia pollution. Therefore, when the
temperature
of the water to be treated is less than 4-5 C, the reactive powders are added
to entrap the
undesirable compounds present in the water to be treated and therefore to
substitute for
the action of the bacteria.
In this case, said first powder is preferably powdered activated carbon, and
said
second powder is preferably chosen from the group made up of zeolites and
clays.
Advantageously, the process then comprises a stage consisting of renewing the
first and second powders when the adsorbent properties of the latter come to
be
exhausted.
The invention, and the different advantages it offers will be more easily
understood with the help of the description given below which follows a non-
restrictive
embodiment of the invention, and refers to the drawings in which :
-- figure 1 represents a diagram of the plant of the present invention,
- figure 2 represents the development in time of the atrazine concentrations
of the water to be treated and of the water treated with the plant shown in
figure 1,
- figure 3 represents the development in time of ammonia concentrations in
the water to be treated and the water treated with the plant shown in figure
1.
With reference to figure 1, the raw water (RW) to be treated arrives in the
plant
represented via pipe 1.

The water is then directed towards means of pre-treatment consisting of a
coagulation/flocculation unit 3 and a clarifier 4. It will be noted that this
means of pre-
treatment is optional. Therefore, it may be envisaged to direct the water
directly into the
means of biological treatment described below, without making it pass through
said
means of pre-treatment when the water contains little or no pollutants likely
to be
coagulated. It may also be contemplated, in other embodiments, not to provide
for said
means of pre-treatment within the plant.
The coagulation/ flocculation unit 3 comprises distribution means 5 of a
coagulant
reagent (aluminium polychloride, aluminium sulfate, ferric chloride, etc.)
allowing the


= ! i '

2199517
colloidal matter in suspension in the water to coagulate. The mixture of water
and
coagulated matter is then directed towards clarifier 4 where it undergoes
sedimentation.
The sludge derived from this sedimentation is extracted at 6.
The water drawn off the top of clarifier 4 is then directed towards biological
5 reactor 7 with a holding capacity of 200 litres by pipe 8 aided by pump 8a
controlled by
the water level in reactor 7.
An ultrafiltration module 11 consisting of outer pressure hollow fibres
(filtration
from outside to inside the membrane) representing a filtering surface of 12m2
is immersed
in reactor 7. The compactness and flux of these immersed membranes 11 allow
treatment
10 rates to be obtained that are comparable to existing sand filters, that is
to say in the region
of 6 to 8 m3/mz/h. The permeate exiting this module is evacuated by pipe 12
after
aspiration pumping by pump 12a. The treated water (TW) is collected at the
exit of pipe
12 and passes into tank 13 before leaving the plant.
In accordance with the invention, means of adding pulverulent materials 10,
consisting of a bubble mixer, can be used to add to the water transiting
through reactor 7
both non-reactive powders, such as sand or anthracite serving as a fixation
support for a
biomass, and reactive powders in continuous or intermittent manner. These
reactive
powders are preferably made up of powdered activated carbon (PAC), zeolites,
clays or
ion exchange resins and are added to the water to be treated in relation to
the load of water
to be treated and to the temperature thereof.
For this purpose, a means of measurement l0a is provided to measure
concentrations of pollutants in the water to be treated, said addition means
10 for adding
pulverulent materials being connected to said measurement means 10a.
Also in accordance with the invention reactor 7 is fitted with means for
injecting
an oxygenating gas, in this instance air, consisting of two injection ramps
9,9a provided
in the lower part of the reactor. Said aeration means allows a perfectly mixed
reactor to be
obtained.
With said aeration means 9 it is possible to maintain in suspension the
powders
present in reactor, to mix the water with these powders, to provide bacteria
with
necessary oxygen and to shake the immersed membranes to prevent fouling.


~ , .

2199517
11

Defouling of membranes is therefore permanently ensured by the injection of
air
along the fibres, and cyclically by an injection of treated water sent from
tank 13 in
counter-current direction (from inside to outside the fibre) with the help of
reflux pump
17.

Reactor 7 is also fitted with sludge drainage means 14 in its lower part to
remove
down-drainage through pipe 15; top-drainage of reactor 7 is evacuated through
pipe 16.
Top-drainage is essentially made up of fines of pulverulent materials and down-
drainage
of sedimenting matter. Said drainage allows uniform powder granulometry in
reactor 7.
Down-drainage allows management of sludge age in the reactor according to the
following formula :
Sludge age = reactor volume / daily drainage volume
Also hydraulic residence time (HRT) of the water to be treated in the reactor
is
given by the following formula:

HRT = reactor volume / flow-rate of treated water
When said plant is set in operation, if the water arriving in reactor 7 does
not
contain any dissolved organic micro-pollution and if the temperature so
permits, the
system operates without the addition of adsorbent powder by bubble mixer 10,
in which
case the removal of ammonia is ensured by concentrated nitrifying bacteria in
reactor 7.
Powdered activated carbon or another reactive adsorbent powder is injected
into
the reactor via bubble mixer 10 when the water to be treated requires the
removal of
dissolved organic pollution (from March to August for example).
During the Winter, if the water temperature is too cold, an addition of
zeolite into
the reactor allows the ammonia concentration of the treated water to meet
drinking water
standards.


. t Y
rr r

2199517

12
Results
The plant shown in figure 1 was used to treat surface water with a net flow-
rate of
10m3/day.
Table I gives the physicochemical and bacteriological quality of the water to
be
treated (RW) and of the treated water (TW) by the plant described above.
As can be seen in Table I below, the plant allows the full or almost full
removal of
compounds in particle form. Average removal efficacy is 85% for turbidity,
100% for
iron, 80% for aluminium and 100% for germs indicating fecal contamination.

Parameters Units Mean Min Max N
Measurements
Turbidity RW 1.75 1.1 2.6 35

NTU TW 0.25 0.13 0.54 35
Iron RW 30 <20 50 8
mg/1 TW <20 <20 <20 8
Aluminium RW 305 195 345 - 8
mg/1 TW 60 35 70 8
Coliforms 37 C RW 37 600 5100 85 000 6

nb/100m1 TW 0 0 0 6
Thermotolerant nb/100m1 RW 9500 1500 26 000 6
coliforms 44 C TW 0 0 0 6
Streptococci D RW 1 225 84 3 700 6
nb/100ml TW 0 0 0 6
Anaerobic sulfate reducing RW 28 7 60 6
bacteria spores nb/100m1 TW 0 0 0 6

Table I : physicochemical and bacteriological quality of the water to be
treated and of water treated by
the system

As can be seen in figure 2, in which curve A shows the development in


=i s

2199-17

13
atrazine content of the water to be treated and in which curve B shows the
development in
atrazine concentration of treated water, the plant achieves full atrazine
removal for
concentrations of 0.400 to 0.600 mg/1 in the water to be treated with a dose
of 6.7 g/l
powdered activated carbon in raw water, a hydraulic residence time of 25
minutes and a
sludge age of 30 days. These conditions correspond to an equilibrium
concentration of 10
g/l of powdered carbon in the bioreactor.

As can be seen in figure 3, in which curve C shows the development in
ammonia content of the water to be treated and in which curve D shows the
development
in ammonia concentration of treated water, the plant also makes possible the
full removal
of ammonia by nitrifying bacteria 40 days after setting in operation. Under
the same
operating conditions as those described in the paragraph above, and with water
temperatures of 11 C, the system was gradually seeded itself with such
nitrifying
bacteria.
As can be seen in Table 3, in parallel manner the reactor "in biological
operation" ensured the removal of biodegradable organic carbon to reach
concentrations
in the treated water of 0.2 to 0.3 mg/l.

Table 3 gives the efficacy of ammonia removal by a zeolite : clinoptilolite.
A treatment rate of 30 ppm and a hydraulic residence time of 20 minutes allows
56%
removal for concentrations in the water to be treated of 0.5 mg/l. This
adsorption function
allows the residence time of the ammonia in the reactor to be extended when
biological
nitrification kinetics are slow.


. r i
1 . ~

2199517

14
Parameters Unit 1 2
[CODB] Water to be treated mg/1 0.8 0.7
[CODB] Treated water mg/i 0.2 0.3

Table 2: Removal of CODB by the biological reactor

[N-NH4+] Water to be treated n1 0.5
[N-NH4+] Treated water mg/1 0.22
Adsorption yield % 56
Table 3 : Ammonia adsorption yield by clinoptilolite.

Such plant therefore offers great flexibility of use since it makes possible
the removal of a great number of pollutants of different natures and is
operational
whatever the temperature may be of the water to be treated.
Also, the above-described plant has the advantage of being possibly set up
on the basis of an existing drinking water treatment plant using a sand
filter. Reactor 7
may therefore be formed in the basin which originally housed the sand bed used
for
filtration. The invention therefore offers an interesting renovation solution
for such
conventional plants and allows improved production of drinking water at low
cost.
The example of embodiment described here is not intended to reduce the
extent of application of he invention. It may therefore be envisaged to make
modifications
thereto while still remaining within the limits of the invention. In
particular it may be
envisaged to equip the plant with a denitrification area upstream from reactor
7 or, as
already mentioned, to do away with the pre-treatment means consisting of the
flocculation-
sedimentation unit and the clarifier. It may also be envisaged to use
different reactive
powders to those mentioned.

Representative Drawing

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Administrative Status

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Administrative Status

Title Date
Forecasted Issue Date 2007-10-02
(86) PCT Filing Date 1996-07-25
(87) PCT Publication Date 1997-02-13
(85) National Entry 1997-03-07
Examination Requested 2003-07-09
(45) Issued 2007-10-02
Deemed Expired 2014-07-25

Abandonment History

There is no abandonment history.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $300.00 1997-03-07
Registration of a document - section 124 $100.00 1997-05-20
Maintenance Fee - Application - New Act 2 1998-07-27 $100.00 1998-07-06
Maintenance Fee - Application - New Act 3 1999-07-26 $100.00 1999-07-12
Maintenance Fee - Application - New Act 4 2000-07-25 $100.00 2000-07-10
Maintenance Fee - Application - New Act 5 2001-07-25 $150.00 2001-07-03
Maintenance Fee - Application - New Act 6 2002-07-25 $150.00 2002-07-25
Request for Examination $400.00 2003-07-09
Maintenance Fee - Application - New Act 7 2003-07-25 $150.00 2003-07-11
Maintenance Fee - Application - New Act 8 2004-07-26 $200.00 2004-07-21
Maintenance Fee - Application - New Act 9 2005-07-25 $200.00 2005-07-20
Maintenance Fee - Application - New Act 10 2006-07-25 $250.00 2006-07-24
Registration of a document - section 124 $100.00 2007-06-13
Final Fee $300.00 2007-06-13
Maintenance Fee - Application - New Act 11 2007-07-25 $250.00 2007-07-06
Maintenance Fee - Patent - New Act 12 2008-07-25 $250.00 2008-07-17
Maintenance Fee - Patent - New Act 13 2009-07-27 $250.00 2009-07-20
Maintenance Fee - Patent - New Act 14 2010-07-26 $250.00 2010-07-09
Maintenance Fee - Patent - New Act 15 2011-07-25 $450.00 2011-07-12
Registration of a document - section 124 $100.00 2012-06-08
Maintenance Fee - Patent - New Act 16 2012-07-25 $450.00 2012-07-19
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
VEOLIA WATER SOLUTIONS & TECHNOLOGIES SUPPORT
Past Owners on Record
COTE, PIERRE
FAIVRE, MICHEL
OTV OMNIUM DE TRAITEMENTS ET DE VALORISATION
OTV SA
SIBONY, JACQUES
TAZI-PAIN, ANNIE
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Abstract 1997-03-07 1 18
Description 1997-03-07 14 711
Claims 1997-03-07 3 118
Drawings 1997-03-07 2 38
Cover Page 1997-11-14 1 39
Cover Page 2007-09-07 1 35
Assignment 1997-03-07 3 156
PCT 1997-03-07 30 1,300
Correspondence 1997-03-27 2 77
Assignment 1997-05-20 4 164
Prosecution-Amendment 2003-07-09 1 39
Fees 2002-07-25 2 106
Correspondence 2007-06-13 1 37
Assignment 2007-06-13 5 186
Assignment 2012-06-08 9 358