Field of the invention
The invention relates to non-organic solutions used for cleaning, sanitation and disinfection in industrial and non-industrial applications and synthesizing method thereof. More particularly, the invention relates to non-organic stable aqueous concentrated solutions for the said purposes and synthesizing method thereof.
Background of the invention
Cleaning, disinfection and sanitation is required in different industries as well as in non-industrial environments. For example, in industries like dairy, food processing, beverages, and bio-medical, cleaning of complete items of plant or pipeline circuits are required. In hotel industry or in a hospital, large quantities of laundry are cleaned. In hotel industry, for maintaining pool water in hygienic conditions, several organic and inorganic chemicals are used. Use of such chemicals is hazardous and expensive. Apart from that, when such chemicals are used to disinfect, microorganisms develop resistance to such chemicals. Due to such disadvantages, such chemicals find limited use for cleaning, disinfecting and sanitation.
In dairy and food processing industries, Cleaning In Place (CIP) is carried out which involves jetting or spraying surfaces or circulating cleaning solutions under conditions of increased turbulence and flow velocity.
Conventional CIP regime as described in "Cleaning in Place: Dairy, Food and Beverage Operations - edited by A. Y. Tamime" and US patent 5,064,561 A consists typically of five steps:
1. Recovering materials present in vessels, pipelines or adhered to other surfaces;
2. Washing with 1% aqueous acidic solution (acid being Hydrochloric, Nitric acid, Sulfuric acid or other mineral acid) to remove any mineral soil adhered to the surfaces;
3. Washing with 1% aqueous alkali solution (alkali generally being Sodium hydroxide);
4. Rinsing the surfaces with hot water; and
5. Sterilizing the surfaces using peroxides, aqueous ozone, alcohols, formalin or other organic/inorganic disinfectants.
Before and after each of the above steps, the surfaces are rinsed using hot water. The said conventional CIP regime has following disadvantages:
1. Use of acids and alkalis leads to downstream water pollution, especially, when nitric acid, organic detergents and disinfectants are applied.
2. Cleaning solutions are heated to a temperature higher than 50 deg C making such system and method highly energy intensive.
3. Complete automation of such CIP system, as always is the case, raises the instrumentation cost.
4. Large quantities of wastewater are generated.

5. Cycle times are inherently high increasing downtime of the plant.
6. Use and handling of toxic chemicals increases health and safety risks.
US Patent 5,567,444 discloses a system and method for CIP using an aqueous composition formed of ozone generated ex-situ in water. Ex-situ nature of cleaning agent limits its application due to its availability, cost and other factors. The method uses aqueous hydrogen peroxide and peroxialiphatic carboxylic acid which are unstable, hard to handle and not cost effective. Peroxialiphatic carboxylic acids can lead to secondary water pollution.
Laundry of linen in hospitals and hospitality industry typically follows a 4-step process, wherein:
1. The linen is first washed with detergent and alkali in hot water. The temperature of the water is in the range of 50 deg C to 80 deg C.
2. A rinse is given to the linen using tap water for removal of excess detergent and alkali.
3. A wash of acid and hot water is given followed by a rinse.
4. Finally, a need based hot water rinse again is given for removal of any further traces of chemicals and for disinfection.
Basic drawbacks of the above approach are:
1. Extensive use of chemicals and heat
2. Reduced life of the linen due to heat and chemicals
3. Downstream pollution and treatment cost
The abovementioned methods used in dairy, food processing industry, hospitals and hospitality industry are chemical and energy intensive. The said methods are not economically or environmentally suitable.
Disclosed in WO 2010144744 A2 and US 20120017379 are improvements over the abovementioned process for laundry, by inclusion of ozonated water. The principle drawback of ozone laundry is that it still needs use of conventional chemicals. Other drawback is that generation of gaseous ozone is re source-intensive, risky, and complex process. Dissolving the generated and available ozone in water itself is full of several challenges and fulfilment of several conditions.
Invention disclosed in WO 2006/070352 A2 uses an electrochemical activation process for generation of two solutions, acidic and alkaline, which are then used for laundering. The drawback of this approach is that these solutions have to be prepared only on site and there is considerable capital cost associated with the generation equipment.
Cooling Towers also need regular dose of biocides which are highly hazardous to environment, but are necessary for efficient cooling tower operation. WO 2003073848 Al mentions use of electrochemically generated sodium hypochlorite as

a biocide. Again, the drawback of such application is that sodium hypochlorite will have to be prepared on-site which requires considerable capital cost associated with the generation equipment.
Cleaning, disinfecting and sanitation of food articles such as fruits, vegetables, fish, meat, eggs and articles used for preparing or storing food articles require non-hazardous cleaning agents which leave little or no residue. Use of electrochemical processes that include electrochemical cells having mixed metal oxide electrodes is known for such applications. Major drawback of such processes is that the chemical generated on-site lacks stability and therefore, it has to be used upon generation. Generating such chemicals is done on-site which requires equipment on-site.
Thus, there is long felt need to have a solution for cleaning, sanitation and disinfection that can be used in industrial and non-industrial applications; that remains stable for a considerably long period; is also cost effective and non-hazardous; and that can be stored and transported without affecting its stability.
Summary of the Invention
The present invention discloses a non-organic stable aqueous concentrate solution for cleaning, sanitation and disinfection for industrial and non-industrial applications and a synthesizing method thereof. It comprises substantially a mixture of sodium hypochlorite and ozone measured as available free chlorine and is stable up to 90 days.
The method of synthesizing the said non-organic aqueous concentrate comprises preparing electrolyte solution by dissolving sodium chloride; circulating the said electrolyte solution through a boron doped diamond electrochemical cell; energizing the said boron doped diamond electrochemical cell using direct current; continuing the said circulation of the said electrolyte solution through the said energized boron doped diamond electrochemical cell; and maintaining temperature of the said electrolyte solution within a suitable range.
The aqueous concentrate according to the present invention is completely non-toxic and non-organic in nature. Thus, the invention finds application not only in industries like hotels and restaurants, it finds applications in cleaning and disinfection of surfaces in hospitals; disinfection of drinking water; as biocide in cooling tower and chiller systems; laundry of white linen; in dairies and food processing industries for cleaning and sanitation of their fluid and food conveying and processing systems and apparatus.
The principal object of the present invention is to provide a non-organic cleaning, disinfection and sanitation solution which is stable in nature and at the same time is equally an effective biocide as the best organic counterpart.
It is also an object of the present invention to avoid elevating temperature more than 50 degC for the applications in dairy and laundering of linen. Additional object of the

present invention is reduced cycle time and reduced need for instrumentation. Yet another objective of the present invention is that its applications are not limited to laundry, dairy, food, beverage, and biomedical industry. Another object of the present invention is also to disclose a method of synthesizing this aqueous composition.
The main advantage of the present invention is that it can be used in industries like dairy, food processing, beverage and biomedical industry as it does not use any harsh or environmentally polluting chemicals. Yet another advantage of the present invention is that majority of the cleaning/sanitation agents are generated in-situ using electrolyte solution passed through an electrochemical cell equipped with boron doped diamond electrode/electrodes. Additional advantage of the present invention is that the stable concentrate need not be produced at point of use and therefore, it can have widespread applications as it can be produced at some convenient location and transported at several points of use. Yet another advantage of the present invention is in its ease of application due to reduced risk of exposure to hazardous chemicals, hot circulating fluids, etc. Yet another advantage of the present invention is reduced need for energy, water and other natural resources. Additional advantage of the present invention is the potential to reduce CIP/SIP cycle time, reduce instrumentation requirement and pumping requirements.
Brief Description of the drawing
Fig. 1 is a schematic diagram of the system in which the non-organic stable aqueous concentrate for cleaning, sanitation and disinfection is produced in accordance with the present invention.
Detailed description of the invention
The present invention discloses non-organic stable aqueous concentrate and a method of synthesizing the same for cleaning, sanitation, and disinfection for industrial and non-industrial applications.
Conventional methods used for cleaning, sanitation and disinfection use solutions which are organic in nature. Due to the organic nature, such solutions are highly unstable. To maintain their stability, these solutions need to be kept at a temperature of more than 50 degrees. This in turn increases the cycle time and increase in the instrument cost.
The conventional solutions used for cleaning, sanitation and disinfection have a limited number of applications and need to be generated separately depending on the type of application like laundering or dairy or food processing. In other words for one application, the solution has to be generated separately for that particular application. Whereas the non-organic stable concentrate thus produced in accordance with the present invention need not be produced at point of use and therefore,, it can have

widespread applications as it can be produced at some convenient location and transported at several points of use.
The conventional methods generate solutions which are harsh or environmentally polluting chemicals, whereas the non-organic stable concentrate thus produced in accordance with the present invention provides an environmentally friendly and non-hazardous.
The present invention discloses a non-organic aqueous concentrate for cleaning, sanitation, and disinfection for industrial and non-industrial applications that remains stable for a period of 40 to 90 days.
The aqueous concentrate in accordance with the present invention substantially is a mixture of sodium hypochlorite and ozone in the range of 5,000 to 40,000 ppm measured as available free chlorine. The preferred range of the mixture of sodium hypochlorite and ozone is 5,000 to 15,000 ppm.
The present invention also discloses a method of producing the said aqueous concentrate. Principle variables which are to be considered for generation of stable concentrate solution in accordance with the present invention are as follows:
• pH of the electrolyte
• Concentration of inorganic salts (sodium or potassium salts of chloride)
• Concentration of oxidants measured as free Chlorine
• Temperature of the electrolyte solution
• Current and Voltage
Following are the principle elements of the method to produce the stable concentrate in accordance with the present invention:
1. Electrolyte storage tank 10
2. Electrochemical reactor equipped with at least one boron doped diamond electrode 30 (either coated as thin film on suitable substrate or single wafer or structured electrode) arranged in either monopolar or bipolar or combination of both
3. Pumping device/circulation pump 20 for passing the electrolyte solution 80 from the electrochemical reactor either once or multiple times
4. Direct current power source to energize the electrochemical reactor 40
5. Cleaning solution storage tank
The method in accordance with the present invention is based on various steps and the schematic diagram of the system is shown in Fig. 1.
As shown in Fig. 1, saturated NaCl solution 50 is dosed into the electrolytic storage tank 10. Fresh water 70 is also supplied to the electrolytic storage tank 10. Temperature Controller Chiller 60 maintains the temperature of the contents of the electrolytic storage tank 10 at the desired temperature. Circulation pump 20 pumps

the mixture of NaCl and fresh water 90 to the electrochemical reactor equipped with boron doped diamond electrode 30. Power supply and control assembly 40 provides power supply to electrochemical reactor equipped with boron doped diamond electrode 30. Electrolyte solution 80 is generated inside the electrochemical reactor equipped with boron doped diamond electrode 30 and is sent to the electrolytic storage tank 10.
As a first step, saturated NaCl solution 50 is dissolved in the ratio of 3 to 90 grams per litre of fresh water 70 in the electrolytic storage tank 10. The quantity of saturated NaCl solution 50 to be dissolved in fresh water depends on the quantity of the nonorganic aqueous stable aqueous concentrate to be produced and the type of the application for which the non-organic aqueous stable aqueous concentrate is to be used.
In the second step, the mixture of NaCl and fresh water 90 is pumped using a circulation pump 20 into the electrochemical reactor equipped with boron doped diamond electrode 30 at a rate of 2,000 to 25,000 litres per hour. The circulation rate has to be constantly monitored to ensure smooth generation of the non-organic aqueous stable aqueous concentrate. Boron doped diamond electrodes have tremendous hardness, physical and chemical stability as compared to the normal electrodes used for electrolysis. Boron doped diamond electrodes provide much advanced ozone generation in higher amount as compared to the normal electrodes. Boron doped diamond electrodes used in the said system are monopolar or bipolar or combination of both. Either the anode or cathode or both can be boron doped diamond electrode.
The third step is energizing the electrochemical reactor equipped with boron doped diamond electrode 30 using direct current provided by the power supply and control assembly 40 in the range of 2 to 120 amperes. The aim of passing the mixture of NaCl and fresh water 90 through the electrochemical reactor equipped with boron doped diamond electrode 30 arranged in monopolar or bipolar or combination of both is to generate mixed oxidants in-situ in desired quantity in the resulting electrolyte solution 80. Direct current ensures smooth ozone generation through the said the electrochemical reactor equipped with boron doped diamond electrode 30. Electrolysis inside the electrochemical reactor equipped with boron doped diamond electrode 30 generates the electrolyte solution 80. In-situ generation of mixed oxidants is effective at low temperatures.
Thereafter, the said electrolyte solution 80 is sent to the electrolytic storage tank 10 and circulated through the said system for 10 to 1,800 minutes depending on the volume of the electrolyte solution 80 in the electrolytic storage tank 10. 1. Flow rate across the electrochemical reactor equipped with boron doped diamond electrode 30 is kept to prevent any accumulation of gases across the electrode surface.
The temperature of the generated electrolyte solution 80 is maintained between 2 deg C to 50 deg C during the circulation using the temperature controller chiller 60.

Depending on the type of application and the volume required, the current supplied to the electrochemical reactor equipped with boron doped diamond electrode 30 is discontinued after suitable duration of circulation. The electrolyte solution 80 at such point has a pH between 5-10 and becomes the non-organic stable aqueous concentrate ready to be stored in appropriate containers suitable for the particular application.
Best method of performing the invention
Cleaning, sanitation and disinfection in accordance with the present invention are performed using the electrolyte solution 80 having mixed oxidants Ozone and Hypochlorite generated at temperature between 2 deg C to 50 deg C and a pH between 5-10. More particularly, the concentrate in accordance with the present invention is diluted for removal of soil, proteinaceous soil, fatty or carbohydrate containing soil residue from a solid surface, linen, etc. followed by its subsequent disinfection or sterilization.
The mixture of sodium hypochlorite and ozone in the non-organic aqueous concentrate in accordance with the present invention can be in the range of 5000 to 40000 ppm measured as available free chlorine; however, the preferred range is 5000 to 15000 ppm.
The best method for generation of non-organic stable aqueous concentrate as mentioned in the description is as follows:
3 to 90 gram of saturated NaCl solution 50 per litre of fresh water 70 can be dissolved inside the electrolytic storage tank 10; however, the preferred quantity is from 25 to 50 grams of saturated NaCl solution 50 per litre of fresh water 70 according to the best method of performing the present invention.
The said electrolyte solution 80 can be circulated through the electrochemical reactor equipped with boron doped diamond electrode 30 at the rate of 350 to 25,000 litres per hour; however, the preferred circulation rate is 500 to 25,000 litre per hour.
The electrochemical reactor equipped with boron doped diamond electrode 30 can be energized using direct current in the range of 50 to 2,500 mA/cm2; however, the preferred range is from 50 tol,000 mA/cm2.
The electrolyte solution 80 can be circulated through the energized electrochemical reactor equipped with boron doped diamond electrode 30 for a duration from 10 to 1,800 minutes; however, the preferred duration is from 120 to 1,800 minutes.
The temperature of the electrolyte solution 80 using the temperature controller chiller 60 can be maintained between 2 to 50 deg C; however, the preferred range of temperature is between 25 to 40 deg C.
The examples described below illustrate and do not limit the scope of application of the present invention.

Example 1:
A 50 litre batch of non-organic stable concentrate was prepared by dissolving 40 gram of NaCl solution 50 per litre of fresh water 70 in the electrolytic storage tank 10 and circulating it through electrochemical cell equipped with boron doped diamond electrode 30. Current density across the electrochemical cell equipped with boron doped diamond electrode 30 was maintained at 1,000 mA/cm . Circulation rate across the electrochemical cell equipped with boron doped diamond electrode 30 was maintained at 2,500 litre per hour. Circulation was continued through the energized electrochemical cell equipped with boron doped diamond electrode 30 for 120 minutes. After 120 minutes of circulation, the charge measured as free available Chlorine (FAC) was 7,850 ppm.
Example 2:
A 50 litre batch of non-organic stable concentrate was prepared in accordance with the setup mentioned beforehand by dissolving 40 gram of NaCl solution 50 per litre of fresh water 70 in the electrolytic storage tank 10 and circulating it through electrochemical cell equipped with boron doped diamond electrode 30. Current density across the electrochemical cell equipped with boron doped diamond electrode 30 was maintained at 850 mA/cm2. Circulation rate across the electrochemical cell equipped with boron doped diamond electrode 30 was maintained at 8 litres per minute. Circulation was continued through the energized electrochemical cell for 120 minutes. After 120 minutes of circulation the charge measured as free available Chlorine (FAC) was 7,920 ppm.
Example 3:
Non-organic stable concentrate prepared in accordance with the example 1 or example 2 was stored in a polypropylene container away from sun light. Free available Chlorine was measured in the stored sample each day and stability of the sample was tested. Results of the measurement are shown the graph below ( X axis -number of days, Y-axis — Free Available chlorine as ppm):


Example 4:
The following example outlines an application of non-organic stable concentrate for the cleaning of food preparation areas. In a conventional method, food preparation areas and containers are cleaned with high volumes of hot water with detergents plus sodium hydroxide and quaternary ammonium salts.
In the trial of non-organic stable concentrate, the hot water and chemicals were replaced with water dosed with the non-organic stable aqueous concentrate in accordance with the present invention to give a Free Available Chlorine concentration between 50-150 ppm. The temperature of the water was ambient. Cleanliness of the surfaces was measured in terms of total viable counts and coliform using a swab. Results of the measurement are as follows:

AREA pre clean
cfu/swab post clean
cfu/swab

Depositor Coliforms only 800 <10

Total Viable Count 30,000 <10

Blender Coliforms only 400 <10

Total Viable Count 150,000 <10

Pre Clean Roasted Veg Bin Coliforms only 2,200 <10

Total Viable Count 80,000 <10



Stainless Steel Table Coliforms only <100 <10

Total Viable Count 10,000 <10

Pepperoni Bin Coliforms only 400 <10

Total Viable Count 5,000,000 <10

Mayonnaise Bin Coliforms only 200 <10

Total Viable Count 80,000 <10

Oily Dressing Bin Coliforms only 2,300 <10

Total Viable Count 40,000 <10

Example 5:

Following example outlines application of the invention for cleaning in place (CIP) in a small dairy. Non-organic stable concentrate was dosed in regular water to achieve a Free Available Chlorine (FAC) of around 50-150 ppm; the resulting solution was then used for CIP of milk conveying pipelines at a temperature of 40 deg C. This was a replacement of the aggressive cleaning of milk conveying pipes at 90 deg C using Acid and Alkali solution. Results of the test were measured on Bactoscan. The results are as follows:

We claim:
1. A non-organic aqueous concentrate for cleaning, sanitation, and disinfection for industrial and non-industrial applications that remains stable for a period of 40 to 90 days, the concentrate comprising substantially a mixture of sodium hypochlorite and ozone in the range of 5,000 to 40,000 ppm measured as available free chlorine.
2. The concentrate of claim 1 wherein the preferable range of the mixture of sodium hypochlorite and ozone is 5,000 to 15,000 ppm.
3. A method of synthesizing a non-organic aqueous concentrate for cleaning, sanitation, and disinfection for industrial and non-industrial applications that remains stable for a period of 40 to 90 days, the concentrate being substantially a mixture of sodium hypochlorite and ozone in the range of 5,000 to 40,000 ppm measured as available free chlorine, and the method comprising the steps of:
a. preparing electrolyte solution by dissolving 3 to 90 gram of sodium chloride per litre of water;

b. circulating the said electrolyte solution through a boron doped
diamond electrochemical cell at a rate of 350 to 25,000 litres per hour;.
c. energizing the said boron doped diamond electrochemical cell using
direct current in the range of 50 to 2,500 mA/cm2;
d. continuing the said circulation of the said electrolyte solution through
the said energized boron doped diamond electrochemical cell for a
duration of 10 to 1,800 minutes;
e. Maintaining the temperature of the said electrolyte solution between 2
to 50 deg C.
4. The method of claim 3 wherein preferably 25 to 50 grams of sodium chloride is dissolved per litre of water for preparing the said electrolyte solution.
5. The method of claim 3 wherein the said electrolyte solution is circulated through the said boron doped diamond electrochemical cell preferably at a rate of 500 to 2,500 litres per hour.
6. The method of claim 3 wherein the said boron doped diamond electrochemical cell is energized using direct current preferably in the range of 50 to 1,000 mA/cm2.
7. The method of claim 3 wherein the said electrolyte solution through the said energized boron doped diamond electrochemical cell is circulated preferably for duration of 120 to 1,800 minutes.
8. The method of claim 7 wherein temperature of the electrolyte solution is maintained preferably between 25 to 40 deg C.