DE102017214810A1 - Device and method for water disinfection and preparation of a disinfectant - Google Patents

Abstract

The invention relates to a device, as well as an automatic and maintenance-free method for disinfecting tap water, especially of drinking water, - used, rain and industrial water and for the decomposition and decomposition of organic compounds, eg. Nitrates, urinary medications in hospitals and retirement homes. The device and the method can also be used for the production of disinfectants from drinking water.

Description

The invention relates to a device and a method for disinfecting water, in particular drinking, service, rain and industrial water. The device or the method can also be used for the production of disinfectants from drinking water and for the decomposition or decomposition of organic compounds, e.g. in hospitals and retirement homes of drugs from the urine. An advantage of the invention is that the organic compounds contained in the effluents are rapidly decomposed, usually within two to three hours, and thus they do not pollute the environment, e.g. in the sewage treatment plant, represent more.

People in Europe are getting older and take in their lives a lot of drugs to the end, the urine into the sewage system to the sewage treatment plant. There is a purification to drinking water instead. According to the Federal Environment Agency in the report of 2011 already 23 active substances from drugs in tap water were detected. The environmental impact is enormously high.

The disinfection of water is a ubiquitous task, especially in the leisure sector, such as. in motorhomes, caravans, yachts, boats and for preventing odors in mobile toilets and for water saving in urinals / urinals and especially where many millions of liters of water are consumed daily, to which certain purity requirements are attached, such. in airports, hospitals, hotels, etc. Water disinfection also plays a role in locations where no regular power supply is provided by power lines or batteries, such as in remote areas such as the UK. in the jungle, mountains and developing countries. Nevertheless, reliable water disinfection should be possible there, e.g. with the help of solar cells as a supplier of the necessary electrical energy. Furthermore, it may be necessary to easily obtain a disinfectant from drinking water.

According to DE 102014010901 A1 is transferred by applying a voltage to the immersed in an aqueous saline electrode free chlorine in a metastable state. This achieves a disinfecting or deactivating action against bacteria, bacterial spores, fungi, fungal spores, enveloped and uncovered viruses, prions, algae or mixtures thereof, including biofilm.

EP 0838434 A2 describes a process for preparing an aqueous salt solution in an electrolytic cell, the cell having a working chamber and an auxiliary chamber separated by a permeable membrane.

US 7303660 describes the cathodic and anodic chamber, which is fed simultaneously with brine and how the anodic fraction is recovered.

WO 2011/120699 A1 describes a method for producing an electrochemically activated solution. The reactors are flowed through by the saline solution to subsequently combine the cathodic fractions.

EP 1007478 B1 describes the field of electrolytic recovery of a disinfectant from a saline solution.

PCT / EP2009 / 053255 ( WO 2009/115577 ) describes electrochemically treated water with electron deficiency.

DE 102006007931 A1 describes a method for producing a disinfectant by electrochemical activation (ECA) of water and a method for disinfecting water by means of such a disinfectant.

DVGW worksheet W 229 describes the different construction methods of the electrolysis process for the production of a disinfecting chlorine-containing solution. The sodium hypochlorite solutions prepared by electrolysis according to this worksheet should contain 20 to 30 g / l of free chlorine. In DIN 19606 "Chlorine gas dosing systems for water treatment, plant construction and operation" the requirements for the solutions thus generated are laid down.

An examination of the effectiveness of disinfectants has Mr. Andreas Grunert of the Federal Environment Agency (in "drinking water disinfection - testing the effectiveness of disinfectants", Berlin 2011) described in detail. Available on the Internet at http://www.bfr.bund.de/cm/343/trinkwasserdesinfektion_pruefung_der_wirksam keit_von_desinfektionsmitteln.pdf

Object of the present invention is therefore to provide a device and a method for disinfecting drinking water and for reducing organic contaminants in wastewater, such as urine, which is universally applicable, easy and error-free to use and maintenance. Chemical additives should be avoided. The concentration of the free chlorine required for water disinfection in the process should not exceed the maximum permissible concentration and, in the case of production of the disinfectant, should not fall below the minimum required concentration of free chlorine. The obtained disinfected water should have a suitability as drinking water.

Free chlorine in the context of the present invention is the sum of the substance concentrations of elemental chlorine (Cl ₂ ), hypochlorous acid (HOCl) and hypochlorite (MOCl, with M = alkali metal or alkaline earth metal cation). In the following description of the invention, the concentrations are in mg / L unless otherwise stated.

Brief description of the invention

1. (i) einen Wasserbehälter,
2. (ii) zwei im Wasserbehälter angeordnete Elektroden, wobei die eine Elektrode die Funktion einer Anode und die andere die Funktion einer Kathode aufweist,
3. (iii) einen Micro-Controller, der so konfiguriert ist, dass er die Menge an durch Elektrolyse an der Anode generiertes Chlor elektronisch steuert,
4. (iv) einen Sensor, der so konfiguriert ist, dass er die dem Wasserbehälter zugeführte Wassermenge elektronisch misst.

1. A device for disinfecting water and for producing, in particular chlorine-containing, disinfectant from drinking water, comprising

1. (i) a water tank,
2. (ii) two electrodes arranged in the water container, one electrode having the function of an anode and the other having the function of a cathode,
3. (iii) a microcontroller configured to electronically control the amount of chlorine generated by electrolysis at the anode,
4. (iv) a sensor configured to electronically measure the amount of water supplied to the water tank.

2. The apparatus according to item 1, characterized by further comprising a photometer configured to determine the concentration of free chlorine present in the water.

3. The device according to one or more of the items 1 or 2, characterized in that the electrodes are selected from the group consisting of a support metal with a coating of mixed metal oxide (MMO) or metal oxide halides and diamond electrodes.

4. The device according to item 3, characterized in that the carrier metal is selected from the group consisting of titanium, zirconium, platinum, and palladium.

5. The device according to one or more of the items 3 or 4, characterized in that the mixed metal oxide coating comprises oxides of ruthenium, rhodium, palladium, osmium, iridium, platinum, or mixtures thereof, in particular of platinum, or in that the metal oxide halide Coating oxides / halides of ruthenium, rhodium, palladium, osmium, iridium, platinum, or mixtures thereof, in particular of platinum.

6. The device according to one or more of items 1 to 5, characterized in that the sensor (i) is a capacitive sensor or (ii) an air-flow capacitive bifunctional sensor configured to measure the differential amount of water in the Electronically, or (iii) an ultrasonic sensor that measures the water level in the tank and passes it to the microcontroller.

7. The device according to one or more of items 1 to 6, characterized in that the micro-controller is programmable and configured to evaluate the signals of the sensor and controls the power supply to the electrodes so that the concentration of free chlorine in the water does not exceed the maximum permissible limit, preferably 1.2 mg / l, more preferably 1.0 mg / l, particularly preferably 0.6 mg / l.

1. (i) einen Wasserbehälter,
2. (ii) zwei Elektroden umfassend einen Titanträger, beschichtet mit Edelmetalloxiden ausgewählt aus der Gruppe bestehend aus Iridium-/Ruthenium-Mischoxid,
3. (iii) einen digitalen Micro-Controller, der so konfiguriert ist, dass er die Bildung von freiem Chlor elektronisch steuert, und
4. (iv) einen elektronischen, kapazitiven Sensor, der so konfiguriert ist, dass er die dem Wasserbehälter zugeführte Wassermenge misst und entsprechende Informationen an den Micro-Controller weiterleitet.

8. The device according to one or more of the items 1 to 7, comprising

1. (i) a water tank,
2. (ii) two electrodes comprising a titanium support coated with noble metal oxides selected from the group consisting of iridium / ruthenium mixed oxide,
3. (iii) a digital microcontroller configured to electronically control the formation of free chlorine, and
4. (iv) an electronic, capacitive sensor configured to measure the amount of water supplied to the water reservoir and to pass corresponding information to the microcontroller.

A method of disinfecting water and producing disinfectant from drinking water using the apparatus as defined in one or more of items 1 to 8.

10. The method according to item 9, characterized in that the concentration of free chlorine in the water 6.0 mg / l or less, 1.2 mg / l or less, more preferably 0.6 mg / l or less, particularly preferred 0.3 to 0.6 mg / l.

The chloride ions converted by oxidation into chlorine and / or hypochlorite originate from the treated tap water or waste water itself or can be added to it, for example in the form of an addition of sodium chloride / aqueous sodium chloride solution. Chlorine (oxidation level 0) and hypochlorite (oxidation level +1) are known as oxidizing agents.

list of figures

• 1 zeigt eine Messreihe von unabhängigen Messungen in grafischer Weise.
• 2 zeigt den aus den Messungen errechneten Mittelwert einschließlich der statistischen Abweichung von der Konzentration (mg/l) pro Zeit (Min.).
• 3 zeigt Eichkurven für Volumen von 50 Liter und 100 Liter und deren Abhängigkeit vom Wasservolumen.
• 4 zeigt die Produktion von Chlor in Abhängigkeit von der Konzentration der Kochsalzlösung.
• 5 zeigt die Messung des zeitabhängigen Zerfalls des freien Chlors nach dessen Produktion.
• 6 zeigt die zeitabhängige Wirkung von Chlor (0,9 mg/l) nach 25 Minuten und 45 Minuten.
• 7 zeigt die Betriebsweise des Desinfektionszyklus.

The drawings relate to the embodiment according to the invention as follows:

• 1 shows a series of independent measurements graphically.
• 2 shows the average calculated from the measurements including the statistical deviation from the concentration (mg / l) per time (min).
• 3 shows calibration curves for volumes of 50 liters and 100 liters and their dependence on the volume of water.
• 4 shows the production of chlorine depending on the saline concentration.
• 5 shows the measurement of the time-dependent decay of free chlorine after its production.
• 6 shows the time-dependent effect of chlorine (0.9 mg / l) after 25 minutes and 45 minutes.
• 7 shows the operation of the disinfection cycle.

Detailed description of the invention

The present invention relates to a modern, digital and maintenance-free device for water disinfection and a method for disinfecting water, especially drinking water. The device and the method are suitable for the degradation of organic compounds contained in urine. The invention further relates to a device and a method for producing disinfectants from tap water according to § 11 of the Drinking Water Ordinance (TrinkwV) of 2001 in the version of the announcement of 10 March 2016. The inventive method comprises the electrochemical activation (ECA) of water by Electrolysis via two electrodes, preferably without chemical additives. If the following is the production of disinfected water, so it is also the production of disinfectant (from drinking water) meant, and vice versa. The disinfectant obtained from drinking water is water, preferably without further additives, which contains the minimum / maximum amount of free chlorine described below.

On the one hand, the advantages of this digitized method are that the water obtained (drinking water or disinfectant) does not fall below the prescribed free chlorine concentration and is also user-friendly, ie the user does not have the opportunity to make operating errors. The device can furthermore be dimensioned small, in particular for portable operation.

The inventive method is primarily used for water disinfection in the leisure sector, such as motorhomes, caravans, yachts, boats and odor prevention in mobile toilets and water to urinals / urinals especially where daily many millions of liters of water Airports, hospitals, hotels that need to be parked. The method and apparatus according to the invention is also suitable for water disinfection or preparation of a disinfectant using solar cells generated electrical energy in places where conventional power supply through power lines or batteries is not possible, such as geographically remote locations. In addition, urine and other organic impurities contained in the wastewater, eg medicines or their secreted residues, can be broken down. They are decomposed into their starting components, usually water and carbon dioxide, so that the burden of the wastewater is significantly reduced.

Drinking Water Sensors:

The generator or the process carried out with it should meet the drinking water regulations, as explained above. For this purpose, a measurement of the water flow is necessary to determine the added amount of water or the level in a container. By controlling the water flow, the resulting amount of water when switching on the electrodes is known.

However, not every sensor is suitable for the method according to the invention. For example, when using the device according to the invention in motorhomes, the space required and the costs are relevant. The cost and the service life are also of interest in other areas. Basically eligible sensors are, for example, capacitive level sensors, turbine sensors, ultrasonic level sensors, float switches, flow sensors, bifunctional air-flow sensors, inductive sensors or ultrasonic sensors.

The sensor, in particular the capacitive sensor, available for example from the company - First Sensor and 90 × 35 × 20 mm measures the amount of water supplied to the water tank by air displacement and evaluates the capacity change due to the bending of a membrane and the resulting change in the plate spacing as Sensor effect off. The membrane is formed here, as in a condenser microphone, as a capacitor plate. The capacitance changes are quite small, so that suitable processing electronics with high sensitivity must be integrated. As a differential pressure sensor, the capacitive sensor detects the pressure difference between two gases or liquids via a differential capacitor.

The capacitive sensor measures the inflow of water in the water tank and accordingly sends a signal to the micro-controller. The addition of water displaces the air from the drinking water tank via the sensor through the vent pipe. Due to its dimensions, a capacitive sensor is also suitable for portable / mobile use, for example in mobile homes, on yachts, etc. as well as in remote locations.

A device with a turbine sensor, which is to measure the added amount of water, is rather less suitable for retrofitting, for example in already operated vehicles due to handling and lack of space. However, this sensor can be considered directly in vehicle manufacturing and easily installed. It is suitable for retrofitting urinals, for example in airports or hospitals.

The flow sensor is suitable if the connections of the water tank are easily accessible or installed directly, for example, in the manufacture of motorhomes or the planning of urinals.

The bifunctional air-flow sensor always calculates the resulting water absorption or release. It can be used in drinking water tanks with an opening. The air-flow capacitive-bifunctional sensor measures the displaced and inflowing air in the water tank through a vent hose and sends corresponding signals to the micro-controller. By removing water from the tank, the air is guided in the opposite direction into the tank. Due to its dimensions, the air-flow capacitive-bifunctional sensor specially developed for the method according to the invention is also suitable for portable / mobile use, for example in motorhomes, yachts, aircraft, room air / ESA, etc. as well as in remote locations.

The air-flow bifunctional sensor evaluates the capacity change due to the bending of a membrane and the resulting change in the plate distance as a sensor effect. The membrane is used here, as in a condenser microphone, as a capacitor plate. The capacity changes are rather small, so that suitable processing electronics with high sensitivity must be integrated. As a differential pressure sensor, the capacitive sensor detects the pressure difference between two gases / air or liquids via a differential capacitor.

The ultrasonic sensors are generally well suited for the inventive method, because they allow an individual adaptation to the object, claim only a small space and can be installed directly on the drinking water lid. Thus, they are suitable for new but also for old vehicles.

For example, all sensors can read the water level in the drinking water tank or water volume at any time using an app and WLAN.

Micro-controller

The micro-controller is used to control the energy consumption (load of the battery) for the production of the disinfectant according to the Drinking Water Ordinance. It receives and evaluates the signals from the sensor and delivers the on-time according to the TrinkwV to the 12 volt battery, so that the electrodes only produce a maximum of 0.6 mg / l free chlorine according to the added amount of water or the inflow of urine. The current density of about 1.5 amps / two electrodes is applied. The micro-controller is fully programmable, so you can vary the turn-on time at any time.

A micro-controller is preferably and programmed so that the polarity of the electrodes is automatically reversed at regular intervals, for example every 1 to 5 minutes, every 2 or 3 minutes, to prevent deposits from forming on the electrodes, such as limescale , Commercially available micro-controllers may have small dimensions, such as 80 x 55 x 35 mm. He may have a button for a special activation in the event that the user after the addition of water only in a few weeks or months, the system again in operation. Furthermore, the user can treat the stagnant water at will at any time. It is called stagnant water when the water in the pipes or in the tank for more than 4 to 5 days or less rests. Stagnation water re-forms biofilm due to chemical, physical and microbial processes. The user can activate the electrodes at any time by a button on the micro-controller and thus cause the formation of the disinfected water / disinfectant.

Among other things, the micro-controller has a memory for the last added amount of water, so that once again a disinfection cycle is switched on automatically or manually at any time.

The micro-controller switches the power supply to the electrodes after reaching a predetermined desired state, in particular after reaching the target content of free chlorine in the water, so that the battery is no longer used. This increases the reliability and avoids unforeseen dead batteries and / or high power consumption. The apparatus of the present invention may be operated on the conventional power grid via a transformer and rectifier to produce the required DC current for operation of the electrodes or on a (e.g., rechargeable) battery, particularly at a voltage of 12 volts (e.g., car battery). However, it is also possible to use controllers that can be powered by a battery with a voltage of 24 V or other voltages.

electrodes

At the surfaces of the MMO electrodes (MMO: mixed metal oxide), a redox reaction takes place, whereby the disinfectant is formed in the water. The electrodes should have good corrosion resistance and necessarily a high conductivity and be very thin.

Different methods of making MMO electrodes are described in the prior art:

EP 2447395 A2 describes the composition of the electrodes for the electrolytic chlorine production from metal oxide or mixed oxide. It describes an electrode at least consisting of an electrically conductive substrate and a catalytically active coating in which the catalytic active layer is based on two catalytically active components containing at least iridium, ruthenium or titanium as a metal oxide or mixed oxide or mixtures of said oxides.

DE 40 32 417 A1 describes a RuO ₂ -TiO ₂ coating with a gradient structure. In this case, the ruthenium content decreases towards the anode surface in the layer from 40 to 20 mol%. The anodic oxidation should thus take place almost exclusively at the interface to the electrolyte and thus avoid a life-reducing volume erosion.

EP 0 867 527 A1 describes the preparation of a ternary oxide mixture of TiO ₂ , RuO ₂ and IrO ₂ for different electrode applications with a layer applied from the first layer to the surface towards the outermost layer with increasing gradient of the ratio of metal oxides of noble metals to oxide of the valve metal from 13 to 100 moles -%. Since the uppermost layer consists only of noble metal oxides, at least in the case of chlorine production, the abovementioned disadvantages of pure noble metal oxides are to be expected, in particular the insufficient long-term stability.

It has been shown that the sol-gel technique is a very good alternative to the thermal decomposition of noble metal salts. In this case, mixed oxides can be prepared by the controlled hydrolysis and condensation of precursor compounds.

The electrodes used according to the invention consist of a support metal (expanded metal) with a mixed oxide coating arranged thereon, in particular of the support metal and a coating of MMO / MOX, such as titanium anodes with MMO / noble metal oxides of the platinum group (ruthenium, rhodium, palladium, osmium, iridium, platinum ) with other dopants of ruthenium or iridium compounds or a mixture of both as main constituents. Platinized titanium anodes and platinized niobium anodes have no significance in connection with the device / method according to the invention. An exemplary electrode has the following specifications: Titanium expanded mesh type F (6 × 3 × 1 × 1 mm, OF 2.22 surface factor); Max. Current load with MMO 167: 30 A / dm ² . Specific resistance of the Ti material is 0.48 [(ohm × length × current) / cross section); the layer thickness of the MMO coating is 5 μm.

Alternatively, according to the invention, doped diamond electrodes made of various carrier materials can also be used, for example boron-doped diamond electrodes. The diamond electrodes form radicals / oxidants and decompose organic compounds in water and carbon dioxide. The decomposition of organic impurities in the waste water is believed to occur according to the following equations (1) to (3) or (4): H ₂ O → ^• OH + H ⁺ + e ^- (1) 2 ^• OH → H ₂ O ₂ (2) H ₂ O ₂ → O ₂ + 2H ⁺ + 2e ^- (3)

Overall reaction: 2H ₂ O → O ₂ + 4H ⁺ + 4e ^- (4)

Suitable carrier materials are all customary materials known to the person skilled in the art, for example plastic carriers. In this case, the surface may be coated. Particularly suitable are fluorinated plastic surfaces as support materials. These can then be coated with boron-doped diamond to give chemically resistant electrodes.

The boron-doped electrodes provide excellent electrical conductivity of the diamond particles, which as such have no electrical conductivity. Thus, the particular electrochemical properties of the boron-doped diamond used in the electrolysis and highlighted. It is also known that boron-doped diamond electrodes, by radical formation, purify water by oxidation and convert toxic substances into environmentally friendly substances.

As the electrolyte solution to be disinfected water or drinking water is used, in which the electrodes are arranged, so are immersed in whole or in part.

An exemplary device (also called "system" or "generator") for generating the disinfected water / disinfectant contains two electrodes in tap water as the electrolyte solution, which are connected to a 12 volt power source. In the case of production of disinfectants they form under tension from tap water and minerals contained therein by the direct current numerous oxidizing agents, such as free chlorine, hypochlorous acid, sodium, calcium hypochlorite, hydrogen peroxide, percarbonates / peroxides, hydroxyl radicals, ozone, etc. In the production of disinfected water is the operation identical.

The optional photometer according to the invention can be used to comply with the TrinkwV to be able to determine the free chlorine concentration present in the water at any time.

• - Zwei, vorzugsweise rautenförmige, MMO-Streckmetall-Elektroden, vorzugsweise aus einem Titanträger. Eine Elektrode ist beispielsweise nach Bedarf 250 × 50 × 0,2 mm, die andere ist beispielsweise 246 × 46 × 0,2 mm groß. Für die Urinale sind die Elektroden entsprechend kleiner. Die Innenaussparung der Gehäuse ist entsprechend kleiner. Die beiden Elektroden können sich nicht berühren. Die beiden Elektroden sind durch eine Polymerfolie getrennt, vorzugsweise beträgt der Abstand der Elektroden 0,1 bis 0,3 mm, beispielhaft 0,2 mm. Die Elektroden können durch Hafterungsclips miteinander befestigt sein. Die Elektroden-Kabelanschlüsse können in einer Spezialkammer in Epoxidharz gegossen und verbunden sein. Die Elektroden sind mit 0,1 bis 20 %, vorzugsweise 1 %, Edelmetalloxiden der Platingruppe Iridium- und Ruthenium-Mischoxid beschichtet und sind typischerweise mit jeweils einem Leiter mit Teflonmantel verbunden. Sie sind vorzugsweise in ein dafür konzipiertes Kunststoffgehäuse aus PVDF eingelegt. PVDF eignet sich dabei wegen seiner guten thermischen und chemischen Beständigkeit als Auskleidung. Die Elektroden mit dem Gehäuse befinden sich im Trinkwassertank. Das Gehäuse kann auf der Innenseite des Tanks, beispielsweise mit Hilfe zweier Halterungen, befestigt sein,
• - einen vorzugsweise digitalen Micro-Controller, der die Chlor-Produktion elektronisch steuert, wobei eine optionale Schalttaste eine Wiederholung des letzten Chlor-Produktionsvorgang auslösen kann,
• - einen vorzugsweise elektronischen Air-Flow kapazitiv-bifunktionalen Sensor, der die zugegebene oder vorhandene Wassermenge durch die Luftverdrängung/-zufuhr aus dem Wassertank misst und entsprechende Informationen an den Micro-Controller weiterleitet,
• - einen Ultraschallsensor alternativ zum Air-flow Sensor, der die Höhe des Wasserstandes misst und diese Information an den Micro-Controller weiterleitet, sowie
• - notwendige Kabelverbindungen zwischen den einzelnen Elementen der Vorrichtung.

Preferably and by way of example, a device according to the invention comprises:

• - Two, preferably diamond-shaped, MMO-expanded metal electrodes, preferably of a titanium support. For example, one electrode is 250 × 50 × 0.2 mm as needed, and the other is 246 × 46 × 0.2 mm, for example. For the urinals, the electrodes are correspondingly smaller. The inner recess of the housing is correspondingly smaller. The two electrodes can not touch. The two electrodes are separated by a polymer film, preferably the distance between the electrodes is 0.1 to 0.3 mm, for example 0.2 mm. The electrodes can be fastened together by adhesion clips. The electrode cable connections can be cast in a special chamber in epoxy resin and connected. The electrodes are coated with 0.1 to 20%, preferably 1%, noble metal oxides of the platinum group iridium and ruthenium mixed oxide and are typically connected to one conductor each with Teflon sheath. They are preferably inserted in a specially designed plastic housing made of PVDF. PVDF is suitable as a lining because of its good thermal and chemical resistance. The electrodes with the housing are located in the drinking water tank. The housing may be fixed to the inside of the tank, for example by means of two brackets,
• a preferably digital micro-controller which electronically controls the chlorine production, wherein an optional switching key can trigger a repetition of the last chlorine production process,
• a preferably electronic air-flow capacitive-bifunctional sensor, which measures the added or existing amount of water by the air displacement / supply from the water tank and forwards corresponding information to the micro-controller,
• - An ultrasonic sensor as an alternative to the air-flow sensor, which measures the height of the water level and forwards this information to the micro-controller, as well
• - Required cable connections between the individual elements of the device.

The redox reaction due to current flow causes i.a. formed from sodium and chloride salts, depending on the pH, chlorine, hypochlorous acid and / or sodium hypochlorite.

Definitions and measurement methods

The term "free chlorine" refers to the sum of the substance concentrations of elemental chlorine (Cl ₂ ), hypochlorous acid (HOCl) and hypochlorite salts (MOCl; M = alkali metal or alkaline earth metal cation). The concentration data are in mg / l. However, in aqueous solution elemental chlorine is only stable in the acidic range above pH <2. At pH values between 6.5 and 8.5, the predominant component for disinfection, the hypochlorous acid (HOCl), is present in aqueous solution.

By the term "bound chlorine" is meant the chlorine content, e.g. has reacted with nitrogen compounds to chloramines and thus is not or not fully available for the disinfecting effect.

The term "total chlorine" (= free and bound chlorine) means the sum of all oxidizing chlorine compounds, including any chloramines present. If chlorine dioxide is present during the measurement (for example, photometric measurement), it will also be measured. For the quantitative determination of the chlorination, the free chlorine is generally measured. In the case of high chloramine contents, the total chlorine content is additionally measured in order to determine the content of bound chlorine from the difference.

For the disinfecting effect, only the proportion of free chlorine is interesting. The disinfecting effect is strongly pH-dependent. This is due to the fact that, depending on the pH, different chlorine compounds are present.

At a pH of 7.0, as with tap water, about 74% HOCl arise at 7.5 only about 50% HOCl and at a pH of 8.0 already less than 20% HOCl. This dissociation equilibrium between HOCl and NaOCl is reversible, ie if the pH of the water in which chlorine is already present is increased or reduced, the HOCl content in the water also increases or decreases.

For the above reasons, control of the pH by an acid addition of donor or sodium chloride is omitted, since it is the aim of the method according to the invention to ensure safe disinfection but also a simple application of the method according to the invention. This preferably excludes the addition of substances to disinfected water.

The determination of the free chlorine takes place after DIN 38408 G4 ( DIN 1984 ). The sample is added to this with a buffer to adjust a pH between 6.2 and 6.5. To DIN 38408 DPD (N, N-diethyl-1,4-phenyldiamine) is added to cause a color change. This is caused by oxidation of the DPD.

The determination of the total chlorine content is analogous. However, additional potassium iodide solution is added to release the bound chlorine to the measurement solutions. The determination of the bound chlorine takes place by difference formation from the measured concentrations of the total chlorine and the free chlorine. Calibration is performed with iodide / iodate calibration solutions based on molecular iodine.

To measure the total chlorine content, a second sample with a buffer pH between 6.2 and 6.5, DPD and potassium iodide is added. Iodide is oxidized to iodine by oxidation giving off an electron pair. The free electron pair reduces the chlorine atom to chlorine gas / neutral chlorine, which in turn reacts with the DPD and produces red color under conjugation. The determination of the free chlorine can also be carried out by means of the photometer e.g. Photometer MultiDirect from Lovibond.

According to §11 of the TrinkwV, a concentration of 1.2 mg / l free chlorine may be used for the treatment of drinking water. After completion of the treatment, 0.1 to 0.3 mg / l free chlorine must still be detected, so that effective disinfection is ensured when using the drinking water as a disinfectant. For exceptional cases, § 11 TrinkwV stipulates that higher concentrations of free chlorine of up to 1.2 mg / l may be used for treatment (maximum 1.2 mg / l after preparation) for a short time.

In order to comply with the legal limit values, it is necessary to determine these concentrations in the water and, accordingly, to regulate the electrolysis process in such a way that the limit values are observed. The micro-controller used according to the invention is preferably configured to generate free chlorine in a concentration of 1.0 to 1.2 mg / l in order then to have a concentration of between 0.05 and 0.5 mg / l for a certain cycle, preferably between 0, 1 and 0.3 mg / l to guarantee. For safe maintenance of the free chlorine concentration, the calibration of the disinfection cycle or the mode of operation of the microcontroller is used according to the invention. Alternatively, the optional photometer or paper strip and DPD could also be used.

The chlorite concentration has limit values whose compliance must be monitored. According to the WHO guideline, it is currently ≤ 0.8 mg / l, but according to EU legislation only ≤ 0.6 mg / l. In Austria ÖNORM M 6215 gives the following values: with pH 6.5 to 7.4 at least 0.3 mg / l free chlorine, with pH 7.4 to 7.8 at least 0.5 mg / l , with a maximum concentration of 1.2mg / l for indoor pools and 2.0mg / l for outdoor pools. For comparison, the WHO requires the use of ≥ 0.5 mg / l up to a maximum of 5.0 mg / l of free chlorine for the safe disinfection of drinking water, with a minimum content of 0.2 mg / l for the consumer.

application

The device according to the invention is intended primarily for the leisure industry, in particular for the removal of biofilms in the drinking water system of motorhomes, caravans, ships, boats and sailing boats and for the elimination of urine odor from the urinals. However, the device according to the invention can also be used for other purposes, such. B. in hospitals, medical practices or other areas. The device works independently and requires only a very small space of about 50mm × 40mm × 30mm for the sensor.

The aqueous disinfectant solution produced by the device according to the invention is pH, tasteless and odorless. The formed free chlorine is stable only for a defined time and thus does not represent any environmental impact, as shown by the measurements shown below.

The device according to the invention can be used for example in a motor home for the toilet to prevent odor of fecal matter. A sensor is attached either under the toilet seat or on the rinsing water box. When the user is sitting on the toilet seat or when folding the toilet seat, a signal is sent to the micro-controller, which automatically switches on the electrodes and produces disinfectants according to need and concentration.

The device according to the invention can also be used in space travel in the manned ISS missions, where hardly any space and no disposal options exist.

The device according to the invention can also be operated by solar energy independently of a stationary power supply (conventional power grid) or a battery. By means of a solar cell, the drinking water can be disinfected by a device according to the invention, independently of a current connection from the river, pond, pond, lake, pond or pool, simply after filtration with a fine cloth. This particular application makes the invention particularly interesting for developing countries.

The device according to the invention can also be used as a replacement for the maintenance-requiring waterless urinals / urinals in airports, service areas, restaurants, hospitals and the like. be used. The device according to the invention offers several advantages over a conventional toilet, both for the environment, e.g. every time a urinal is used, it requires several liters of water per urinal flush, as well as for the operator. These are both economic in terms of running costs in terms of water consumption compared to other toilets as well as ecologically important. Modern waterless urinals require monthly maintenance and acidic chemicals. Only then can they be freed from urine stone. Furthermore, a lighter barrier fluid for urine must be provided so that the heavy urine can flow through the barrier fluid without mixing with it and thus the smell is clearly suppressed.

In industrialized countries, the device according to the invention is due to the simplicity and the price of importance. There are e.g. Numerous biocides used for the circulation when cooling the injection molding machines. Because of the intensive use of biocides or fertilizers on agricultural land, the environmental impact is very high. Through the material cycle these pass directly or indirectly into sewage treatment plants. The hydroxyl radicals decompose these by means of the diamond electrodes, in particular the nitrates and thus they bring about a significant relief of the environment and health.

The device according to the invention can be used in waters and in the area of swimming pools (whirlpools, etc.). The chlorinated water in swimming pools is an enormous burden on the mucous membranes, respiratory tract, skin and environment. For example, the diamond electrodes eliminate all these disadvantages.

Another application for the device according to the invention are sewage treatment plants. In the 1990s, wastewater treatment plants were overturned due to the formaldehyde and biocide pollution due to the emptying of faeces on campsites from motorhomes and caravans. Even after the prohibition of formaldehyde, various measures were taken to prevent biocide use in the RV area or to reduce the treatment plant load. These have led to cumbersome emptying controls and certification of motorhomes for the environmentally friendly sanitary products.

The aqueous solution prepared according to the method of the invention can also be used as a disinfectant everywhere where a proper disinfection of water, especially in compliance with the Drinking Water Ordinance 2001, is required. This would be the case with the water supply of schools, hotels or other catering establishments and sports clubs, hospitals, nursing homes, commercial enterprises, railway stations, airports, commercial kitchens, disinfection of rainwater in cisterns, drinking water on ships, discoloration of laundry, cooling water treatment in injection molding, rotary -, Milling, drilling, cutting or other machine tools, as well as in air conditioning and humidification systems and for osmosis systems, in the dosing in drinking and waste water of livestock farms and slaughterhouses, and as an addition in water for cut flowers.

For the electrochemical processes at the electrodes:

Electrochemical activation is the technology for producing metastable substances. The electrolytic drinking water disinfection by means of two electrodes causes a reliable killing of pathogenic microorganisms by the reduction factor five (3). Furthermore, the disinfection also causes a medium-term degradation of biofilms, which are deposited in the management system of motorhomes. The life functions of bacteria, fungi and viruses are thus prevented. The water quality (smell, color, taste, etc.) is not affected by this disinfection method.

Theoretical basics

As with electrolysis, oxidation occurs at the anode during electrochemical activation and reduction at the cathode. The electrodes remain neutral by delivery of the electrons, d. H. there is a chemical redox equation for the dissociated salts.

Tap water is an electrolyte solution containing various minerals, e.g. Sodium, potassium chloride, small amounts of calcium or magnesium sulfate, chloride or carbonate.

The preparation of the disinfectant or the disinfected water is carried out by applying a 12 V or 24 V DC, which is obtained from a battery, with an induced electric field between the electrodes. It is operated electrolysis. In this case, a direct current of 1 to 2 amperes, preferably about 1.3 A flows through the electrodes.

The negatively charged cathode attracts the positively charged cation, here it is the hydrogen atoms which supply two electrons to the hydrogen atoms according to Equation (1) given below. The two hydrogen atoms each take on an electron, so are reduced and form a hydrogen molecule.

Not only does this chemical reaction according to (1) occur at the electrodes, but numerous other reactions (equations 2 to 10) occur. Since the hydrogen concentration generated by the generator is very low, a detonating gas reaction is excluded here. The hydrogen formed escapes through a ventilation pipe.

Dissociation of the water: 2H ₂ O → 2H ⁺ + 20H ^- at the cathode 2H ⁺ + 2e ^- → H ₂ 2H ₂ O + 2e ^- → H ₂ + 2OH ^- (1)

In addition, the dilute water / electrolyte solution first becomes slightly alkaline due to the formation of hydroxide ions.

At the anode, according to the following reaction equations (2) and (3), in particular the chemical oxidants oxygen (O ₂ ) and chlorine (Cl ₂ ) are produced. The chlorine molecule disproportionates and forms chloride and hypochlorite ions according to equation (4), which are known to be effective and highly reactive in disinfecting water. Therefore, the anodes are to be made extremely reactive in comparison to the cathodes. Since the micro-controller constantly changes the current direction (polarity reversal), both electrodes are manufactured and used identically. It should also be noted that due to the formation of H ₃ O ⁺ ions, the dilute water / electrolyte solution is acidic: 6H ₂ O → O ₂ + 4H ₃ O ⁺ + 4e ^- (2) 2Cl ^- → Cl ₂ + 2e ^- (3)

These can turn with suitable cations, such as Na ⁺ , K ⁺ , H ⁺ from the electrolyte solution or a H ₃ O ⁺ ion to the corresponding metal salt or to the corresponding acids, ie to hypochlorous acid HOCl and hydrogen chloride or dilute Hydrochloric acid (HCl), react: Cl ₂ + 3H ₂ O <===> 2H ₃ O ⁺ + OCl ^- + Cl ^- (4)

The acid-base reaction between the hydroxide ions and the acids formed hardly lead to a pH change.

Further, from the aforementioned materials formed at the anode, further substances can be produced by secondary reactions, which are also known to be effective in terms of disinfecting water. These are in particular hydrogen peroxide (H ₂ O ₂ ), reaction equation (5), ozone, reaction equation (6), chlorine dioxide, reaction equation (7), chlorates (ClO ₃ ^- ), reaction equation (8) and various radical reaction equations (9 ) and (10): 4H ₂ O → H ₂ O ₂ + 2H ₃ O ⁺ + 2e ^- (5) O ₂ + 3H ₂ O → O ₃ + 2H ₃ O ⁺ + 2e ^- (6) Cl ^- + 4OH ^- → ClO ₂ + 2H ₂ O + 5e ^- (7) 3OCl ^- → ClO ₃ ^- + 2Cl ^- (8) 5H ₂ O → HO ₂ + 3H ₃ O ⁺ + 3e ^- (9) H ₂ O ₂ + H ₂ O → HO ₂ + H ₃ O ⁺ + e ^- (10).

• - die genaue Qualitätskontrolle ist fast nicht möglich,
• - die meisten Verfahrensparameter werden empirisch ermittelt,
• - das Leitungswasser der Elektrolytlösung ist immer unterschiedlich,
• - die Herstellungsbedingungen sind nie identisch und können auf folgende Parameter bezogen werden: das Fassungsvermögen der Tanks, unterschiedliche Werkstoffe der Tanks sowie der Durchmesser der Entlüftungsschläuche und die Verweilzeit des zu desinfizierenden Wassers an den Elektroden.

Disadvantages of the process of electrochemical activation are generally the following aspects:

• - the exact quality control is almost impossible
• most process parameters are determined empirically,
• - the tap water of the electrolyte solution is always different,
• - the conditions of manufacture are never identical and can be related to the following parameters: tank capacity, different tank materials and the diameter of the ventilation hoses and the residence time of the water to be disinfected at the electrodes.

All these disadvantages are excluded in the method according to the invention. The micro-controller changes the direction of the electrical current in controlled and specific intervals. Therefore, the other ion concentrations formed are irrelevant small. Thus, the disinfectants are formed stoichiometrically. Through the vent hose all traces of gases formed such. As ozone, oxygen, hydrogen u. a. escape.

As a physico-chemical process, electrochemical activation is a combination of electrochemical, electrophysical, and chemical actions. This process proceeds with minimal heat generation with dissolved ions and molecules at a partial stress near the surface of the electrodes.

The tap water is dissociated into hydrogen cation and hydroxide anion / hydronium ion due to the specific surface area of the diamond electrode.

In principle, the following chemical reactions with a standard redox potential can take place in an ECA cell / reactor: O ₂ + H + e ^- HO ₂ E0 = - 0.13V (A) 2H ⁺ + 2e ^- H ₂ E0 = 0.00V (B) HO ₂ + H ⁺ + e ^- H ₂ O ₂ E0 = +1.50V (C) O ₃ + 2 H ⁺ + 2e ^- O ₂ + H ₂ O E0 = +2.07 V (D) OH ^- + H ⁺ + e ^- H ₂ O E0 = +2.85V (E) H ₂ O + e ^- + H ⁺ OH ^- E0 = - 2.93 V (F) OH + e ^- OH ^- E0 = +2.02V (G)

The equations shown are not a complete list, but give an example of some reactions that can take place. They show that in the electrolysis of water, H ⁺ and OH ^- ions, H and OH radicals, H ₂ , O ₂ , HO ₂ , peroxides, O ₃ are also generated as redox reactions.

The problem with the application of this technology is the formation of undesirable disinfection by-products. These include the organic trihalomethanes (THM) and adsorbable, organically bound halogens (AOX) as well as the inorganic risk substances chlorate and perchlorate. The total ion concentration in the drinking water is so minimal that these formed products are below the labeling limit and thus can be ignored.

Free agents / oxidants (FAOx) are essential chloramine compounds. The main components of the invention are the following chemical compounds: • Hypochlorous acid HOCl • sodium hypochlorite NaOCl • sodium chloride NaCl

Consequently, the HOCl concentration of the individual chemical components is determined by the current density, the pH and other important process parameters.

To remove limescale deposits on the electrode surfaces, for example, a polarity reversal is performed regularly and automatically every 2 minutes or at longer intervals. The time intervals are also adjustable and can be directed in particular to the water hardness of the different tap water, with a pole reversal in soft water only after a longer period of time, in particular between one and three hours, with harder water, especially after five to ten minutes. For very hard water, the electrodes can be cleaned once a year with citric acid or complexing agent.

As a direct result of the electrolysis, hydrogen and ozone are produced. A small proportion of hydroxides remains in the solution. This is done in a variety of forms and not just as hydrogen peroxide.

The additional supply of sodium chloride leads to further reactions. Cl ₂ and OH ^- can react as follows:
Anode: 2H ₂ O → 4H ⁺ + O ₂ + 4e ^- (2) 2NaCl → Cl ₂ + 2e ^- + 2Na ⁺ (11) Cl ₂ + H ₂ O → HCl + HOCl (12)
cathode 2H ₂ O + 2e ^- → 2OH ^- + H ₂ 2 NaCl + 20H ^- → 2 NaOH + 2Cl ^-

• AOP: Advanced Oxidation Processes (weitergehende Oxidationsverfahren)
• AOX: Absorbierbare organisch gebundene Halogene
• DNP: Desinfektionsnebenprodukt(e)
• TOC: Total Organic Carbon (gesamter organischer Kohlenstoff)
• PVDF: Polyvinylidendifluorid
• MMO/MOX: Mischmetalloxid/ Platingruppe/Metalloxidhalogen bzw. Übergangsmetall als Kationen
• DPD: N,N-Diethyl-1,4-phenyldiamin

List of abbreviations used:

• AOP: Advanced Oxidation Processes
• AOX: Absorbable organically bound halogens
• DNP: disinfection by-product (s)
• TOC: Total Organic Carbon (total organic carbon)
• PVDF: polyvinylidene difluoride
• MMO / MOX: mixed metal oxide / platinum group / metal oxide halogen or transition metal as cations
• DPD: N, N-diethyl-1,4-phenyldiamine

In the following embodiment, the present invention will be further explained in a non-limiting manner.

Embodiment:

Production of chlorine:

The ECA processes according to the invention have been carried out in 10, 50 and 100 l tap water with and without sodium chloride.

The generator produced in 10 minutes in 10 liters of tap water 1.2 mg / l free chlorine. It was thus guaranteed that in this liter range the concentration for disinfection permitted and necessary for drinking water regulation was controllable over the running time. In particular, it could be guaranteed that the maximum value of 1.2 mg / l Cl was not exceeded. This was confirmed by many measurements of chlorine production per minute in 10 liters of tap water. 1 shows a series of measurements of independent measurements.

From the measurements the mean value including the statistical deviation from the concentration (mg / l) per time (min) was calculated. These are in 2 shown. It can be considered as a calibration curve for production per time.

From the calibration curve, it can be seen that 0.85-1.05 mg / L free chlorine is produced after 9 minutes. The maximum value of 1.2 mg / l is clearly and reliably undercut. It is also clear that the minimum value of 0.1 mg / l is clearly and reliably exceeded after 3 minutes.

Analogous to this method, a calibration curve for the volumes 50 liters and 100 liters was recorded in each case. It can be seen that the calibration curve also depends on the volume of water. This can be considered by the micro-controller during the disinfection cycle. 3 shows the corresponding calibration curves.

Production of free chlorine with the addition of common salt:

The production of chlorine under the addition of common salt could be significantly increased. 4 shows the production of chlorine depending on the amount of sodium chloride in 10 liters of water.

It was found that the more saline was added, the faster a respective concentration of free chlorine was reached. The desired free chlorine content of 0.9 mg / l could be achieved after about 1.5 minutes, for example, with the addition of 2 g of common salt / 10 l of tap water. The production time was reduced by 6 times compared to production without the addition of common salt.

If the user absolutely needs the production of free chlorine z. B. within 15 minutes, then 20 g of sodium chloride are added to 100 liters of water.

Decay of free chlorine:

5 shows a measurement of the decay of free chlorine with time after production. The decays of different initial concentrations are plotted. The addition of common salt has no effect on the decomposition process.

The favored range of 0.1 to 0.3 mg / l lasted the longest after a production of about 0.9 mg / l. This corresponded to a duration of free chlorine production of 9 minutes.

In 6 the range of action after a production of 0.9 mg / l is clarified. After about 25 minutes, the value of 0.3 mg / l free chlorine was reached and after a total of 45 min, the minimum value of 0, 1 mg / l below. This corresponded to an effective range of action of the produced disinfectant of 20 min.

Disinfection cycle: The operating results of the disinfection cycle are shown in the presented measurement results (see Fig. 7).

By way of example, the disinfecting cycle of 10 liters of water without the addition of common salt then looks like this: $$\text{production}+\text{waiting period}+\text{effective time}=9\text{min}+25\text{min}+20\text{min}=54\text{min}$$

The respective times define a disinfection cycle and scale with the volume of water. They can be varied with the software of the microcontroller. Also, the micro-controller can measure the amount of water contained and thus knows which calibration he should use at what volume. As a result, the guidelines of the Drinking Water Ordinance can be guaranteed automatically and maintenance-free over a desired period of time.

Power and energy consumption:

With a supply voltage of 12 V, the generator had a power of 19.5 watts during production. A current of approx. 1.3 A flowed through the electrodes.

The energy consumption of the method according to the invention is very low due to the fact that the generator actually generates power only for the fraction of a disinfection cycle. Considering the above example of a disinfection cycle of 54 minutes with the production of 9 minutes, the generator would have an energy consumption of about 78 Wh per day. With a conventional car battery of approximately 1000 Wh, the generator can work for 12 days, ensuring that the desired water remains antibacterial throughout the entire period.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102014010901 A1 [0004]
• EP 0838434 A2 [0005]
• US 7303660 [0006]
• WO 2011/120699 A1 [0007]
• EP 1007478 B1 [0008]
• WO 2009/115577 [0009]
• DE 102006007931 A1 [0010]
• EP 2447395 A2
• DE 4032417 A1 [0047]
• EP 0867527 A1 [0048]

Cited non-patent literature

• DIN 38408 G4 [0066]
• DIN 1984 [0066]
• DIN 38408 [0066]

Claims (10)

Device for the disinfection of water and for the production of disinfectants from drinking water, comprising (i) a water tank, (ii) two electrodes arranged in the water container, one electrode having the function of an anode and the other having the function of a cathode, (iii) a microcontroller configured to electronically control the amount of chlorine generated by electrolysis at the anode, (iv) a sensor configured to electronically measure the amount of water supplied to the water tank. The device according to Claim 1 , characterized in that it further comprises a photometer configured to determine the concentration of free chlorine present in the water. The device according to one or more of Claims 1 or 2 , characterized in that electrodes are selected consisting of a support metal with a coating of mixed metal oxide (MMO) or metal oxide halides with diamond electrodes. The device according to Claim 3 , characterized in that the carrier metal is selected from the group consisting of titanium, zirconium, platinum and palladium. The device according to one or more of Claims 3 or 4 , characterized in that the mixed metal oxide coating comprises oxides of ruthenium, rhodium, palladium, osmium, iridium, platinum, or mixtures thereof, in particular of platinum, or in that the metal oxide halide coating comprises oxides / halides of ruthenium, rhodium, palladium, osmium, Iridium, platinum, or mixtures thereof, in particular of platinum. The device according to one or more of Claims 1 to 5 characterized in that the sensor (i) is a capacitive sensor or (ii) an air-flow capacitive bifunctional sensor configured to electronically measure the differential amount of water in the water reservoir, or (iii) an ultrasonic sensor incorporating the Water level in the tank measures and forwards to the micro-controller is. The device according to one or more of Claims 1 to 6 , characterized in that the micro-controller is programmable and configured to evaluate the signals from the sensor and to control the power supply to the electrodes such that the concentration of free chlorine in the water is within the permissible upper limit, in particular 1.2 mg / l does not exceed. The device according to one or more of Claims 1 to 7 comprising (i) a water container, (ii) two electrodes comprising a titanium support coated with noble metal oxides selected from the group consisting of iridium / ruthenium mixed oxide, (iii) a digital microcontroller configured to receive the Electronically controlling free chlorine formation; and (iv) an electronic capacitive sensor configured to measure the amount of water supplied to the water reservoir and to pass the corresponding information to the microcontroller. A method of disinfecting water and producing disinfectants from drinking water using the device as in one or more of Claims 1 to 8th Are defined. Method according to Claim 9 , characterized in that the concentration of free chlorine in the water does not exceed 1.2 mg / l and, preferably over a fixed period 0.1 to 0.3 mg / l.

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