AU2011224073B2

AU2011224073B2 - Method for treating water

Info

Publication number: AU2011224073B2
Application number: AU2011224073A
Authority: AU
Inventors: Eugene Peenaert; Thierry Routier
Original assignee: ANALYSES MESURES POLLUTIONS AMP
Current assignee: ANALYSES MESURES POLLUTIONS AMP
Priority date: 2004-12-16
Filing date: 2011-09-15
Publication date: 2013-12-19
Anticipated expiration: 2025-12-15
Also published as: AU2011224073A1

Abstract

METHOD FOR TREATING WATER The invention relates to a method for treatment of an effluent either containing pathogens or s not, in order to reduce the impact thereof on the environment or to render the same potable. The method is characterised in comprising the following steps: i. introduction of the effluent into a vessel containing electrodes, ii. a small amount of a treatment agent generating hydroxyl ions is added to the effluent at a pH of 6 to 10 inclusive and iii. a continuous current is passed between said electrodes for a fixed period of at most 30 minutes.

Description

S&F Ref: 813220D1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Analyses Mesures Pollutions (A.M.P.), of 1, rue Joliot of Applicants: Curie, F-80200, Doingt, France Thierry Routier, of 9 rue d'en Haut, F-80140, Foucaucourt Hors Nesle, France Actual Inventor(s): Thierry Routier Eugene Peenaert Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Method for treating water The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(5595155_1) METHOD FOR TREATING WATER The present invention generally relates to the field of water treatment. In particular, the present invention relates 5 to a method for electrolytic treatment of effluents in the presence of oxidizing ions. Many industrial and public sectors use water in large amounts, and this water is found to be contaminated during the process of use. Water is an essential element for the majority 10 of large industrial food-processing companies. After having being used, most of this process water is returned to the natural environment. This water may be loaded with organic materials and it consequently becomes a source of significant pollution for the water course or the environment which 15 receives it. Among the different types of waste water, water from slaughter-houses is no doubt one of the most loaded in organic materials and pathogenic microorganisms. In a slaughter-house, the waste water results from waters of the slaughtering 20 processes, waters from cleaning, waters from condensation and waters from cooling. In other industrial sectors, water is used for cooling a product or the equipment of a manufacturing process, notably by means of cooling towers. In cooling towers, water is lost 25 by evaporation, by purging the system or as an aerosol (mist or droplets) or by entrainment of droplets. The aerosols are the portion of water which flows, carried off in the cooling towers, as small droplets and which are easily dispersed into the environment. This water contains 30 a lot of dissolved minerals, chemicals and microorganisms including Legionella and other bacteria. Many methods for treating effluents are known to this day.

2 Certain treatment methods apply electrolytic techniques of the electro-flocculation, electro floatation, or electro-coagulation type. With these treatment methods, it is notably possible to decompose polluting chemical substances and to rid water of suspended solid elements. These methods are therefore more or less effective 5 for chemically cleaning the effluents without however quantitatively removing the microorganisms, either pathogenic or not, also present in the waste water. Moreover, repeated passages or dwelling periods of hours of the effluent in the treatment tank are required in order to obtain notable results, thereby leading to long treatment times and an energy overcost of the operation. The present invention proposes overcoming the drawbacks due to the known methods for treating 1o effluents, The object of the present invention is to propose a method for treating an effluent or residual water, notably loaded with microorganisms, with which chemical waste as well as said microorganisms may be quantitatively removed, during a single passage of the effluent in treatment tank. By using this method, it is notably possible to reduce the impact on the environment of highly polluted is waters, such as reclaimed waters, but also to make less polluted waters, such as river water, drinkable from the microbiological point of view. According to a first aspect of the present invention, there is provided a method for treating an effluent containing microorganisms, either pathogenic or not, in order to reduce its impact on the environment or even to make it drinkable, by a single passage of the effluent in a treatment tank, 20 wherein it comprises the following steps: (i) the effluent is introduced into the tank including electrodes, (ii) a small amount of a treatment agent which generates oxidizing ions, is added to the effluent, at a pH between 6 and 10, and (iii) a continuous current is applied between said electrodes for a determined period of 25 time according to the type of effluent, the period being 30 minutes at most, and wherein said treatment agent is selected from the group: - commercial Javel water at 9*C chlorometric, or - a hydrogen peroxide solution at 110 volumes, diluted 22 times, in an amount from 0.5 ml to 3 ml per liter of effluent, 2a The present invention relates to a method for treating an effluent containing microorganisms, either pathogenic or not, in order to reduce its impact on the environment or even to make it drinkable, characterized in that it comprises the following steps: (i) the effluent is introduced into a tank including electrodes, ii. a small amount of a treatment agent which generates oxidizing ions, is added to the effluent, after having brought the pH to a value between 6 and 12, and iii. a continuous current is applied between said electrodes 5 for a period of time determined according to the type or effluent, the latter period being 30 minutes at the most. According to various embodiments, the treatment method has the following features, if necessary combined: - said treatment agent is selected from the group of 10 oxidizing agents comprising: - XO, XOf, XO4, wherein X is a halogen; - a hydrogen peroxide solution; - or any other oxidizer capable of forming a peroxide and of releasing an oxidizing equivalent to that of 0.5 to 15 3 ml of a Javel water solution at 90 chlorometric; - the effluent is added with: - commercial Javel water at 9' chlorometric, or - a hydrogen peroxide solution, at 110 volumes, diluted 22 times, 20 in an amount from 0.5 ml to 3 ml per liter of water; - said electrodes are metal or carbon; - a continuous current with a voltage between 1 and 40 V is applied between the neighboring electrodes; - the continuous current is applied for a variable period 25 of time according to the nature of the effluents; - the effluent passes only once between the electrodes of the tank; - the microorganisms inactivated by this treatment are bacteria and/or viruses. 30 Other features and advantages will become apparent upon reading the following exemplary embodiments.

Example 1. Tests for treating reclaimed waters from slaughter. houses A determined volume of effluent from the slaughter-houses is treated according to the method of the invention: 5 - the effluent is introduced into a tank including two iron electrodes; - the pH of said effluent being, if need be, brought to a value between 6 and 10, said effluent is added with a given amount of treatment agent. Either commercial Javel water 10 at 90 chlorometric, or a hydrogen peroxide solution at 110 volumes, diluted 22 times, are used as a treatment agent, in an amount of 0.5 ml; 1.0 ml or 1.5 ml per liter of effluent; - a continuous current (5 to 40 V) is applied between said electrodes for a determined time: 15 min or 30 min. 15 The water is submitted to microbiological analysis, before and after treatment. The microbiological analysis of water samples is carried out by means of Petri dishes filled with a suitable culture medium (PCA), notably allowing growth of bacteria, as follows: 20 - a determined volume of effluent is deposited on the surface of said culture medium; - the Petri dishes are incubated at 30'C for 24-48 h; - at the end of the incubation period, the possible development of colonies is observed visually and is expressed 25 as a number of Units Forming Colonies (UFC) per ml. The working conditions as well as the obtained results are shown below in Table 1. The term "uncountable" used in the right column means that the number of observed units forming colonies is very large, so that they cannot be counted 30 accurately.

5 Javel Hydrogen Treatment Test water peroxide UFC/0.5 ml time (min) UC05 (ml) solution Al - - 0 Uncountable A2

-

15 Uncountable A3 -

-

30 1,200 BI 0.5

-

0 Uncountable B2 0.5

-

15 30 B3 0.5

-

30 180 Cl 1.0

-

0 Uncountable C2 1.0

-

15 5 C3 1.0

-

30 16 D1 - 0.5 0 Uncountable D2 - 0.5 15 8 D3 - 0.5 30 3 El - 1.0 0 Uncountable E2 - 1.0 15 200 E3 - 1.0 30 50 F1 1.5 - 0 Uncountable F2 1.5 15 10 F3 1.5

-

30 15 G1 - 1.5 0 Uncountable G2 - 1.5 15 8 G3 - 1.5 30 2 Table 1 5 These results show that the treatment of waste water according to the invention leads to substantial elimination of bacteria present in said reclaimed water and this for treatment periods of maximum 30 minutes. The treatments are most effective under the following conditions: 10 - for ratios of 0.5 ml and 1 ml of Javel water at 90 Cl per liter of effluent and a treatment period of 15 mins (tests B2 and C2, respectively); - for ratios of 0.5 ml and 1.5 ml of hydrogen peroxide solution per liter of effluent and a treatment period of 30 mins (tests D3 and G3, respectively). 5 Example 2. Microbiological analyses of the reclaimed water before and after treatment Effluents from slaughter-houses or cooling towers were submitted, before and after treatment according to the invention (the continuous current being applied for a period 10 between 10 and 30 minutes), to microbiological analyses carried out at the Institut Pasteur of Lille (approved standard laboratory for analyzing water) and to the Laboratoire Sante Environnement Hygiene of Lyons, respectively. The obtained results are shown in Table 2; 15 These results show that the method for treating reclaimed water containing pathogenic microorganisms, notably from slaughter-houses or cooling towers, enables the pathogenic microorganism content to be drastically reduced or even suppressed. 20 Result Result Effluent Parameter Method before after treatment treatment Crude waters from Somatic ISO 10705- 3.14x10 4 /ml <0,5/ml bacteriophages 2/2000 a F-RNA ISO 10705 slaughter-86/m <0,5/m luter bacteriophages 1:1995 house <250 Water from Legionella Filtration 65,000 UFC/I UFC/I including tower legionella Filtration 65,000 UFC/1 <250 pneumophila UFC/I Table 2 7 Example 3. Tests for treating river waters Samples of river waters (water from the river Somme) were submitted, before and after treatment according to the 5 invention, to bacteriological analyses on Petri dishes. These analyses were carried out by the Laboratoire D6partemental of Amiens. The obtained results are shown in Table 3. These results show that treatment of river water according to the invention, applied for a period between 1 and 10 5 minutes, leads to quasi-complete elimination of the microorganisms present in said water, and this for treatment times as short as one minute and a half (Test A4) or three minutes (Test A5) . On the other hand, adding Javel water to the river water, in the absence of an electrolytic treatment, 15 is not sufficient to make the latter drinkable from the microbiological point of view (Test A3). Treatment Bacteriological Test Characteristics Result time analysis A Crude water 0 Lawn Al Crude water 1min 30sec 1 YFC Non A2 Crude water 3 min 30 UFC drinkable Crude water + A3 lml of Javel 0 6 UFC water Crude water + A4 1ml of Javel 1min 30sec 1 UFC water Crude water + AS lml of Javel 3 min 0 UFC Drinkable water Table 3 Example 4. Tests for treating waters comprising protozoa Water samples from an aeration basin of the local station of Chaulnes were observed under the microscope, before and 5 after treatment according to the invention. These observations reported the presence of many active protozoa in the untreated effluent samples. Certain samples were introduced into a tank including two electrodes and then were added with Javel water in an amount 10 of 1 ml/l; a continuous current (20 V, 2 A) was applied between said electrodes for a variable time. It was reported that after 5 min of treatment, living protozoa remained. On the other hand, all the protozoa were dead after 10 minutes of treatment according to the invention. 15 The described method for treating waste water has many advantages: - its application is simple and only requires a reactor comprising metal electrodes; - the treatment agents are ordinary and inexpensive 20 commercial products used at a low dose.

Claims

2. The method according to claim 1, wherein said electrodes are metal or carbon. is 3. The method according to claim 1 or 2, wherein the continuous current is applied for a time between 10 and 30 minutes for reclaimed waters from slaughter-houses or cooling towers.
4. The method according to any one of claims 1 to 3, wherein the continuous current is applied for a time between 1 to 5 minutes for river waters,
5. The method according to any one of claims 1 to 4, wherein the continuous current is applied 20 for a time of maximum 10 minutes for waters loaded with protozoa.
6. The method according to any one of claims 1 to 5, wherein the microorganisms inactivated by this treatment are bacteria and/or viruses.
7. A method for treating an effluent containing microorganisms, either pathogenic or not, in order to reduce its impact on the environment or even to make it drinkable, by a single passage of 25 the effluent in a treatment tank, said method substantially as hereinbefore described with reference to any one of the Examples. 8089363 10
8. Effluent when treated by the method of any one of claims 1 to 7. Analyses Mesures Pollutions (A.M.P.) Thierry Routier Patent Attorneys for the ApplicantlNominated Person 5 SPRUSON & FERGUSON OX9363