DESC:FIELD
The present disclosure relates to a process for the treatment of a colored mixed salt.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
Biochemical oxygen demand (BOD): The term “biochemical oxygen demand” refers to the amount of dissolved oxygen (DO) consumed by biological organisms when they decompose organic matter in water.
Chemical oxygen demand (COD): The term “chemical oxygen demand” refers to the amount of oxygen consumed when the water sample is chemically oxidized.
Colored mixed salt: The term “colored mixed salt” refers to a waste salt sludge or slurry from leather, textile and dye industries that cannot be treated by using common effluent treatment plant (CETP).
Oxidation reduction potential (ORP): The term “Oxidation reduction potential (ORP)” is typically measurement for determine the oxidizing or reducing potential of a water sample. It indicates possible contamination, especially by industrial wastewater.
“Paraox”: The term ‘paraox” refers to a system for advance oxidation as described in the patent application no. IN3694/MUM/2014.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Dyes released by textile, leather and other dyeing industries constitute a re-calcitrant non-biodegradable group of pollutants and are known to have carcinogenic and mutagenic effect, with a potential toxicity to the environment.
With the advancement in dye technologies, enhancements have been made in the dye properties so that they provide resistance to fading, improved fixation to fabrics and have increased variety of shades, thereby making them highly resistant to environmental degradation, thus increasing the pollution.
Besides, dyes are known to have complex structures that are difficult to degrade. In dye industries, the residual color and the non-biodegradable complex organic chemicals are concentrated by using a reverse osmosis process to obtain a reverse osmosis reject. The reverse osmosis reject is then passed to the evaporator resulting in the formation of “colored mixed salt” which is un-usable by the industries.
Formation of un-usable “colored mixed salt” results in piling up of huge stock in the common effluent treatment plant (CETP), godowns, consuming the available area leading to space crunch. Many of the CETP’s have piled up huge quantities (around 78,000 tons) of “colored mixed salt” for over a period of 7 to 10 years for a clearance from the pollution control board for disposing in sea/suitable site (Figure 1). These “colored mixed salt” need efficient treatment, so that the same can be removed from the CETP’s. Many CETP’s have scarcity of space and are hard pressed to locate free land for dumping the “colored mixed salt” and even if they can find one, a cost is involved in effective utilization of the space and its impact on the overall operations of the CETP’s.
Further, the CETP’s have conventional biological process installed for treating the effluent having COD/BOD ratios around 2.5:1, which are not suitable for treatment of the “colored mixed salt”.
However, the textile processing mills mostly use “reactive dyes” which are water soluble and these reactive dyes are not adsorbed on the conventional “biomass” to great degree (maximum of 30% to 40% only). Thus, the remaining portion of the reactive dyes entering the conventional treatment processes escape the treatment process and remains un-treated.
The problem is worsened by the low fixation of reactive dyes relative to other classes (having 70% of fixation on average), and direct, basic and acidic dyes are adsorbed to provide over 90% fixation.
The stored colored mixed salt have “residual organic contamination” in the form of residual chemical oxygen demand and disposing these salts will be violation of standards as it will exceed the “disposable standards”.
Further, this colored mixed salt cannot be reused since it has “residual brown colour” which will import the residual colour to cotton fabrics making it unusable. Further, these salts need to be protected from extreme weather conditions to avoid spillage during rainy season. Therefore, safe disposal of the “colored mixed salt” is a big challenge.
There is, therefore, felt a need for a process for effective treatment of the colored mixed salt from textile, leather, and dye industries that mitigates the drawbacks mentioned hereinabove or at least provide an useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
An object of the present disclosure is to ameliorate one or more problems of the background or to at least provide a useful alternative.
Another object of the present disclosure is to provide a process for the treatment of a colored mixed salt.
Still another object of the present disclosure is to provide an effective process for the treatment of a colored mixed salt, which has zero discharge/waste.
Yet another object of the present disclosure is to provide a process for the treatment of a colored mixed salts that is obtained from textiles, leather and dye industries.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a process for the treatment of a colored mixed salt. The process comprises: mixing a predetermined amount of the colored mixed salt in water to obtain a salt slurry. The salt slurry is treated with at least one oxidant capable of generating OH radicals in at least three stages for a predetermined time period to obtain a treated effluent. The treated effluent is reacted with a group II metal salt to obtain a biphasic mixture comprising a soluble salt and an insoluble salt.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates dumping site of the colored mixed salt in common effluent treatment plant (CETPs);
Figure 2 illustrates colored mixed salt collected from CETP of Thirupur, Tamilnadu in accordance with an embodiment of the present disclosure;
Figure 3 illustrates an image of the “paraox system”;
Figure 4 illustrates (a) a salt slurry prepared from the colored mixed salt, (b) a semi-treated effluent-1 obtained after a first stage (stage 1) treatment, (c) a semi-treated effluent-2 obtained after a second stage (stage 2) treatment, (d) a semi-treated effluent-3 obtained after a third stage (stage 3) treatment, (e) a side view of the beaker containing treated effluent obtained after a fourth stage (stage 4) treatment, and (f) a top view of the beaker containing treated effluent obtained after the fourth stage (stage 4) treatment of trial 1 in accordance with the process of the present disclosure;
Figure 5 illustrates (a) a colored mixed salt collected from CETP, (b) a treated salt obtained after the trial 1 in accordance with the process of the present disclosure;
Figure 6 illustrates (a) a salt slurry prepared from a colored mixed salt collected from CETP for the trial 2, and (b) a top view of diluted colored mixed salt collected from CETP for the trial 2 in accordance with the process of the present disclosure;
Figure 7 illustrates (a) a treated salt obtained after the treatment in accordance with the process of the present disclosure; (b) a colored mixed salt from CETP, a salt slurry from the colored mixed salt, an effluent-1 obtained after a first stage treatment, an effluent-2 obtained after a second stage treatment, and a pure insoluble salt obtained after third stage treatment (arranged in series from left to right); (c) a treated effluent obtained after third stage treatment of trial 2 of the process in accordance with the present disclosure; and
Figure 8 illustrates (a) a top view of a beaker containing a salt slurry prepared from the colored mixed salt for the trial 3 in accordance with the process of the present disclosure; (b) a side view of a beaker containing a salt slurry prepared from the colored mixed salt for the trial 3 in accordance with the process of the present disclosure; (c) a top view of a beaker containing treated effluent-4 obtained after the fourth stage treatment of trial 3 in accordance with the process of the present disclosure, and (d) a side view of a beaker containing treated effluent-4 obtained after the trial 3 in accordance with the process of the present disclosure.
DETAILED DESCRIPTION
The present disclosure relates to a process for treatment of a colored mixed salt.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open-ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Dyes released by textile, leather and other dyeing industries constitute a re-calcitrant non-bio-degradable group of pollutants and are known to have carcinogenic and mutagenic effect, with a potential toxicity to the environment.
With the advancement in dye technologies, enhancements have been made in the dye properties so that they provide resistance to fading, improved fixation to fabrics and have increased variety of shades, thereby making them highly resistant to environmental degradation, thus increasing the pollution.
Besides, dyes are known to have complex structures that are difficult to degrade. In dye industries, the residual color and the non-biodegradable complex organic chemicals are concentrated by using a reverse osmosis process to obtain reverse osmosis reject. The reverse osmosis reject is then passed to the evaporator resulting in the formation of “colored mixed salt” which is un-usable by the industries.
Formation of un-usable “colored mixed salt” results in piling of huge stock in the common effluent treatment plant (CETP), godowns, consuming the available area leading to space crunch. Many of the CETP’s have piled up huge quantities (around 78,000 tons) of “colored mixed salt” for over the period of 7 to 10 years for a clearance from the pollution control board for disposing in sea/suitable site (Figure 1). These “colored mixed salt” need efficient treatment, so that the same can be removed from the CETP’s. Many CETP’s have scarcity of space and are hard pressed to locate free land for dumping the “colored mixed salt” and even if they can find one, a cost is involved in effective utilization of the space and its impact on the overall operations of the CETP’s.
Further, the CETP’s have conventional biological process installed for treating the effluent having COD/BOD ratios around 2.5:1, which are not suitable for the treatment of the “colored mixed salt”.
However, the textile processing mills mostly use “reactive dyes” which are water soluble and these reactive dyes are not adsorbed on the conventional “biomass” to great degree (maximum of 30% to 40% only). Thus, the remaining portion of the reactive dye entering the conventional treatment processes escape the treatment process un-treated.
The problem is worsened by the low fixation of reactive dyes relative to other classes (having 70% of fixation on average), and direct, basic and acidic dyes adsorbed to provide to over 90% fixation.
The stored colored mixed salt have “residual organic contamination” in the form of residual chemical oxygen demand and disposing these salts will be violation of standards act it will exceed the “disposable standards”.
This colored mixed salt cannot be reused since it has “residual brown colour” which will import the residual colour to cotton fabrics making it unusable. Further, these salts need to be protected from extreme weather conditions to avoid spillage during rainy season. Therefore, safe disposal of “colored mixed salt” is essential.
In an aspect, the present disclosure provides a process for the treatment of the colored mixed salt. The process comprises: mixing a predetermined amount of the colored mixed salt in water to obtain a salt slurry. The salt slurry is treated with at least one oxidant capable of generating OH radicals in at least three stages for a predetermined time period to obtain a treated effluent. The treated effluent is reacted with a group II metal salt to obtain a biphasic mixture comprising a soluble salt and an insoluble salt.
The process is described in detail:
Initially, a predetermined amount of a colored mixed salt is mixed in water to obtain a salt slurry.
In accordance with the present disclosure, the colored mixed salt is a waste salt sludge or slurry from leather, textile and dye industries that cannot be treated by using common effluent treatment plant (CETP).
In accordance with an embodiment of the present disclosure, the colored mixed salt comprises 70 mass % to 80 mass% of a hydrous sodium sulphate with respect to the total mass of the colored mixed salt; 15 mass% to 18 mass% of sodium chloride with respect to the total mass of the colored mixed salt; and 2 mass% to 15 mass% of complex organic molecules (i.e. color molecules or the organic impurities).
In accordance with the present disclosure, the predetermined amount of the colored mixed salt is in the range of 5 mass% to 25 mass % with respect to the total mass of the salt slurry. In an exemplary embodiment, the predetermined amount of the colored mixed salt is ~15 mass% with respect to the total mass of the salt slurry. In another exemplary embodiment, the predetermined amount of the colored mixed salt is ~10 mass% with respect to the total mass of the salt slurry.
In accordance with the present disclosure, the salt slurry has an oxidation-reduction potential (ORP) value in the range of -450 mV to -100 mV, a chemical oxygen demand (COD) value in the range of 850 ppm to 1000 ppm, and a dissolved oxygen (DO) value in the range of 0.1 ppm to 6 ppm. In an exemplary embodiment, the salt slurry has the oxidation-reduction potential (ORP) value of -240 mV, chemical oxygen demand (COD) value of 880 ppm, and dissolved oxygen (DO) value of <0.5 ppm. In another exemplary embodiment, the salt slurry has the oxidation-reduction potential (ORP) value of -260 mV, the chemical oxygen demand (COD) value of 960 ppm, and the dissolved oxygen (DO) value of 1.6 ppm. In still another exemplary embodiment, the slurry has the oxidation-reduction potential (ORP) value of -260 mV, chemical oxygen demand (COD) value of 940 ppm, and dissolved oxygen (DO) value of 5.2 ppm.
The salt slurry is treated with at least one oxidant capable of generating OH radicals in at least three stages for a predetermined time period to obtain a treated effluent.
In accordance with the present disclosure, the treated effluent is devoid of an organic matter selected from oxidizable organic molecules, complex organic molecules, straight chain compounds, semi-oxidized complex organic molecules and color.
In accordance with the present disclosure, the predetermined time period for each stage is in the range of 30 minutes to 50 minutes. In the exemplary embodiment, the predetermined time period for each stage is 40 minutes.
In accordance with the present disclosure, the treated effluent has an oxidation-reduction potential (ORP) value in the range of +100 mV to +450 mV, a chemical oxygen demand (COD) value in the range of 20 ppm to 100 ppm, and a dissolved oxygen (DO) value in the range of 10 ppm to 25 ppm. In an exemplary embodiment, the treated effluent has the oxidation-reduction potential (ORP) value of +249 mV, the chemical oxygen demand (COD) value of 60 ppm, and the dissolved oxygen (DO) value of ~14 ppm. In another exemplary embodiment, the treated effluent has the oxidation-reduction potential (ORP) value of +420 mV, the chemical oxygen demand (COD) value of 40 ppm, and the dissolved oxygen (DO) value of ~16 ppm.
In accordance with the present disclosure, the oxidant is selected from the group consisting of hydrogen peroxide, sodium hypochlorite and ozone.
In accordance with the present disclosure, the OH radicals are generated in a paraox system. The OH radicals are generated in the range of 0.1 kg/m3 to 1 kg/m3 in the presence of an UV radiation having a wavelength in the range of 235 nm to 255 nm, an ultrasound having a power in the range of 20 Watt to 30 W, and an ozone in an amount in the range of 20 grams/hour to 30 grams/hour.
In an embodiment, the step of treating the salt slurry with at least one oxidant capable of generating OH radicals to obtain the effluent is performed in at least three stages.
In another embodiment, the step of treating the salt slurry with at least one oxidant capable of generating OH radicals to obtain the effluent is performed in four stages.
In a first stage, the salt slurry is treated by using “paraox system” with 0.8 kg/m3 of the oxidant in the presence of UV radiation at 245 nm, 25 Watt of ultrasound and 25 grams/hour of ozone, capable of generating highly potent “OH” radicals to treat the salt slurry and obtain stage-1 effluent comprising complex organic molecules (color molecules) and oxidizable organic molecules. In the first stage, a portion of complex organic molecules (color molecules) are oxidized to CO2 and water.
For “paraox system”, please refer the Indian patent application no. 3694/MUM/2014.
The complex organic molecules and oxidizable organic molecules in the stage-1 effluent are further treated in a second stage. In the second stage, the stage-1 effluent is treated by using “paraox system” with 0.6 kg/m3 of the oxidant in the presence of UV radiation at 245 nm, 25 Watt of ultrasound and 25 grams/hour of ozone, capable of generating highly potent “OH” radicals to treat stage-1 effluent and obtain a stage-2 effluent comprising a mixture of straight chain compound and semi-oxidized complex organic molecules. In the second stage, some portion of the stage-1 effluent is oxidized to CO2 and water.
The straight chain compound and semi-oxidized complex organic molecules in the stage-2 effluent are further treated in a third stage. In the third stage, the stage-2 effluent is treated by using “paraox system” with 0.4 kg/m3 of the oxidant in the presence of UV radiation at 245 nm, 25 Watt of ultrasound and 25 grams/hour of ozone, capable of generating highly potent “OH” radicals to treat stage 2 effluent and obtain a stage-3 effluent comprising a mixture of straight chain compound and semi-oxidized complex organic molecules. Till the third stage, major portion of the complex organic molecules are converted to CO2 and water.
The remaining straight chain compound and semi-oxidized complex organic molecules in the stage-3 effluent is further treated in a fourth stage. In the fourth stage, the stage-3 effluent is further treated by using the “paraox system” with 0.2 kg/m3 of the oxidant in the presence of UV radiation at 245 nm, 25 Watt of ultrasound and 25 grams/hour of ozone, capable of generating highly potent “OH” radicals to treat stage 3 effluent and obtain a stage-4 effluent (treated effluent) devoid of complex organic molecules, oxidizable organic molecules, straight chain compound and semi-oxidized complex organic molecules. In the fourth stage, all the complex organic molecules, oxidizable organic molecules, straight chain compound and semi-oxidized complex organic molecules are converted to CO2 and water leaving a colourless effluent. The complete conversion of the complex organic molecules, oxidizable organic molecules, straight chain compound and semi-oxidized complex organic molecules in the fourth stage to CO2 and water are confirmed by measuring the values of COD, DO and ORP.
Hydroxyl radicals are highly reactive and unstable. Most notably hydroxyl radicals are produced from the decomposition of hydrogen peroxides (HOOH), by the reaction of excited atomic oxygen with water/waste water. Hydroxyl radical is often referred to as the detergent of the troposphere because it reacts with many pollutants for their removal. It also has an important role in eliminating some greenhouse gases such as methane and ozone.
In an exemplary embodiment, a salt slurry is treated in a first stage of treatment by using 0.8 kg/m3 of OH radicals generated in the paraox system to obtain stage 1 effluent. Stage 1 effluent is further treated in a second stage of treatment by using 0.6 kg/m3 of OH radicals generated in the paraox system to obtain stage 2 effluent. Stage 2 effluent is further treated in a third stage of treatment by using 0.4 kg/m3 of OH radicals generated in the paraox system to obtain stage 3 effluent. Stage 3 effluent is further treated in a fourth stage of treatment by using 0.2 kg/m3 of OH radicals generated in the paraox system to obtain a treated effluent. In the embodiment, OH radicals are generated in the presence of the UV radiation having the wavelength of 245 nm, the ultrasound having the power of 25 Watt, and the ozone in an amount of 25 grams/hour in each stage of treatment of the salt slurry in the paraox system.
A group II metal salt is reacted with the treated effluent to obtain a biphasic mixture comprising a soluble salt and an insoluble salt.
In accordance with the present disclosure, the group II metal salt is an alkaline earth metal salt selected from the group consisting of calcium chloride and barium chloride. In an exemplary embodiment, the group II metal salt is barium chloride.
In accordance with the present disclosure, the group II metal salt is in an amount in the range of 0.1 mass% to 5 mass% with respect to the total mass of the biphasic mixture. In an exemplary embodiment, the group II metal salt is in the amount of 0.68 mass% with respect to the total mass of the biphasic mixture.
The biphasic mixture is allowed to settle to obtain a residue having an insoluble salt and a clear solution having a soluble salt.
In an embodiment, the biphasic mixture is settled by using a clarifier.
In accordance with the present disclosure, the soluble salt is sodium chloride.
In accordance with the present disclosure, the insoluble salt is a group II sulphate salt selected from barium sulphate and calcium sulphate. In an exemplary embodiment, the insoluble salt is barium sulphate.
The clear solution is separated to obtain a soluble salt, and the residue is dried to obtain an insoluble salt.
The clear solution so separated can be reused in leather, textile or dye industries.
The insoluble salt so obtained has high purity and can be used for various applications.
The process of the present disclosure reduces the area required for salt drying beds by half. The suspended solids in the salt slurry can be separated and disposed of as chemically treated primary sludge.
The process of the present disclosure can destroy/oxidize tough pollutants such as ammonical nitrogen and carcinogenic chloro-carbons, phenols and the like that are present in the colored mixed salt to CO2 and water.
The process of the present disclosure does not produce NO and is free of obnoxious smell. The process of the present disclosure can produce clear solution that can be reused.
In accordance with the present disclosure, the process is physio-chemical, so continuously running the apparatus/system is not mandatory unlike biological process.
The process of the present disclosure produces the effluent in conformity to the standards of Central Pollution Control Board and Ministry of Environment and Forest.
The process of the present disclosure can occupy lesser space compared to the conventional biological processes.
The process of the present disclosure can be installed as a pre-treatment, a post-treatment, a polishing treatment or standalone treatment. Near complete removal of the color can be achieved by using the process of the present disclosure and this will help to a great extent for reducing the colour of the salt.
Almost 30% to 40 % of the area being occupied by the existing effluent treatment plant can be freed and utilized for other purposes using the process of the present disclosure.
The need of resin based organic scavenger unit will not be required as through “paraox system”, the effluent colour removal is near complete and it avoid concentration of the colors for further treatment.
The process of the present disclosure changes the treatment process from conventional biological process to a physio-chemical process (advanced oxidation process) that requires less retention time at each stage of treatment for advanced oxidation process which is in hours and not in days and conserves around 50% of more space as compared to the conventional processes. The process of the present disclosure reduces the size of colored mixed salt drying beds.
In the process of the present disclosure, the organic pollutants (non-biodegradable organic pollutants) can be oxidized into CO2 and water, leaving “no biosolids or sludge”. The process of the present disclosure oxidizes the residual color completely without leaving any residue and also prevents the formation of chloramines. The formation of chloramines is critical disadvantage of conventional process.
The process of the present disclosure converts the colored mixed salt to reusable and salable by-product, which has a good potential and sale value in the market. The process of the present disclosure allows the formation of corresponding by-product sodium chloride and sulphate salt of alkali earth metal, a most valuable salt for textile industries to use in the water baths. Huge quantity of sodium chloride can be produced as “by-product”. The recovered sodium chloride can be used as “mordant” to be used in dyeing cellulosic fibers. Sodium chloride is widely used in almost all of the textile industries. Since, the recovered salt is precipitated as a single salt, it has high purity. Overall space occupied required is lesser when compared to existing installations and the recovered salt will have wide application.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment but are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further illustrated herein below with the help of the following experiments. The experiments used herein are intended merely to facilitate an understanding of the ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the experiments should not be construed as limiting the scope of embodiments herein. These laboratory-scale experiments can be scaled up to an industrial/commercial scale and the results obtained can be extrapolated to an industrial/commercial scale.
EXPERIMENTAL DETAILS:
The colored mixed salt for performing the process of the present disclosure was collected from Thirupur, Tamilnadu, India. Figure 2 depicts the colored mixed salt sludge.
Example 1:
Details Of Lab Scale Pilot Trials
1. 6.0 kg of “mixed colour salt” with 7.5% moisture content was taken for conducting lab scale pilot trials.
2. This was mixed and stirred well in 35 liters of tap water to prepare 10% salt slurry.
3. 10% salt slurry was treated in a lab scale pilot plant of paraox system (see figure 3 for paraox system).
4. The pilot plant was equipped with a:
a. 100-liter syntax tank.
b. Feed pumps of capacity 0.8 to 1.0 m3/hr. capacity of suitable material of construction.
c. 0.06 lph dosing pumps.
d. 10 inch 10 microns bag filter.
e. 10 inch 10 micron cartridge filter.
f. 10 grams Ozonator.
g. 2 no’s of 36.0 Watts UV lamps.
h. A sand filter.
i. Activated carbon filter.
5. 10% salt slurry was treated in the pilot plant in 4 stages.
6. Each stage run length was 40 minutes from the time the raw salt solution pumping and up to the activated carbon filter.
7. In all, 4 stages were conducted with a total run length of around approximately 240 minutes (4.0 hours).
8. At the end of the trials the Dark brown colour salt solution became colourless crystal color solution was obtained (from the dark brown color salt solution).
9. The colorless salt solution was further treated with a 3 liters 10% Barium chloride solution to obtain a bright white colour “insoluble Barium Sulphate” insoluble salt with a clear liquid separated instantaneously. The clear liquid is soluble sodium chloride. Commercial grade barium chloride is around 90% pure having less than 0.5% calcium chloride.
Trial 1: Treatment of a colored mixed salt in accordance with the present disclosure
Characteristics of the colored salt
Sample Identification Colored mixed salt bag was collected from Thirupur, Tamilnadu
Sample Preparation 6.0 kg of colored mixed salt was taken for trial and diluted in 35 litres of Corporation water having TDS of 120 ppm (see figure 4(a)).
pH 1.0
T.D.S. (By HENA handheld meter) 14,500 ppm
C.O.D (raw) 880 ppm
Dissolved Oxygen Less than 0.5 ppm
Oxidation-reduction potential (O.R.P.) (-) 240
Color Brownish

Characterization of semi-treated effluent-1 (stage 1) (see figure 4(b))
pH 1.0
T.D.S. (By HENA hand held meter) 12,300 ppm.
C.O.D after treatment 320 ppm
% Reduction in C.O.D. 63.40%
Color Very Pale yellow (Almost Colour less).
Dissolved Oxygen Around 16.8 ppm
O.R.P. +349
Change in O.R.P. From -240 to +349

Characterization of semi-treated effluent-2 (stage 2) (see figure 4(c))
pH 1.0
T.D.S. (By HENA hand held meter) 12,400 ppm.
C.O.D after treatment 180 ppm
% Reduction in C.O.D. 79.54%
Color Very Pale yellow (Almost Colour less).
Dissolved Oxygen Around 15.8 ppm
O.R.P +380
Change in ORP From -240 to +380

Characterization of treated effluent-3 (stage 3) (see figure 4(d))
pH 1.0
T.D.S. (By HENA hand held meter) 12,300 ppm.
C.O.D after treatment 60 ppm
% Reduction C.O.D. 93.2 %
Color Almost colorless
Smell Milt Oxidizing Chemical smell
Dissolved Oxygen Around 14.0 ppm
O.R.P. +249
Change in O.R.P. From (-)240 to (+)400

Characterization of treated effluent-4 (step 4)
The treated effluent-4 appeared clear (see figure 4(e) and 4(f)).
Figure 5(a) illustrates the colored mixed salt collected from CETP and figure 5(b) illustrates the purified insoluble salt obtained after the treatment of colored mixed salt.
Trial 2: Treatment of the colored mixed salt in accordance with the present disclosure
Characterization of diluted colored mixed salt (see figure 6(a)-6(b))
pH 8.4
T.D.S. (By HENA hand held meter) 11,260 ppm
C.O.D. 960 ppm
Color Dark brown.
Dissolved Oxygen 1.6 ppm

Figure 6(a) and 6(b) illustrates a diluted colored salt collected from CETP for the process of trial 2.
Characterization of treated effluent obtained after the treatment (see figure 7(a)-7(c))
pH 8.4
T.D.S. (By HENA hand held meter) 8,400 ppm.
C.O.D after treatment 40 ppm
% Reduction C.O.D. 95.83%
Color Colorless.
Dissolved Oxygen Around 15.8 ppm

Figure 7 (a) illustrates the treated salt obtained after the treatment in accordance with the present disclosure. Figure 7 (b) illustrates the colored mixed salt from CETP, diluted colored mixed salt solution, effluent-1 obtained after stage 1 treatment, effluent 2 obtained after stage 2 treatment, effluent 3 obtained after stage 3 treatment, and the purified insoluble salt obtained after stage 4 treatment. Figure 7 (c) illustrates treated effluent obtained after stage 4 treatment.

Trial 3: Treatment of the colored mixed salt in accordance with the present disclosure
Characterization of diluted colored mixed salt collected from CETP (see figure 8(a)-8(b))
pH 8.4
T.D.S. (By HENA hand held meter) 50,500 ppm
C.O.D. 940 ppm
Color Brownish yellow
Dissolved Oxygen 5.2 ppm

Characterization of treated decolorized effluent 4 obtained after stage 4 treatment (see figure 8(c)-8(d))
pH 8.4
T.D.S. (By HENA hand held meter) 42,100 ppm.
C.O.D after treatment 40 ppm
% Reduction in COD 95.83%
Color Colorless.
Dissolved Oxygen Around 15.8 ppm

TECHNICAL ADVANCEMENTS
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of a process for the treatment of a colored mixed salt that:
• utilizes “paraox advanced oxidation system”;
• oxidizes the organic pollutants (non-biodegradable organic pollutants) into CO2 and water, and leaving “no biosolids or sludge;
• eliminates the further generation of “colored mixed salt”;
• recovers the salts which have high salable value;
• generates reusable liquid (salt solution) which can be reused in a dye bath;
• shifts to zero waste disposal (ZWD) from zero liquid discharge (ZLD);
• steps toward achieving “wealth from waste”;
• releases valuable land being occupied by the storage of mixed salt;
• generates very less sludge and requires maximum 20% of existing area for storing the sludge (coming with raw effluent only);
• needs “much less” retention time for treatment; and
• conserves the free space available at the site, whatever suspended solids that comes along with the raw effluent will alone be separated and settled as sludge (maximum 300 mg/l); and helps reducing the space occupied by the sludge drying beds, which saves by about 50% to 60% of the space being by the sludge drying beds.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1. A process for the treatment of a colored mixed salt, said process comprising the following steps:
(i) mixing a predetermined amount of said colored mixed salt in water to obtain a salt slurry;
(ii) treating said salt slurry with at least one oxidant capable of generating OH radicals in at least three stages for a predetermined time period to obtain a treated effluent; and
(iii) reacting said treated effluent with a a group II metal salt to obtain a biphasic mixture comprising a soluble salt and an insoluble salt.
2. The process as claimed in claim 1, wherein said group II metal salt is an alkaline earth metal salt selected from the group consisting of calcium chloride and barium chloride.
3. The process as claimed in claim 1, wherein said group II metal salt is in an amount in the range of 0.1 mass% to 5 mass% with respect to the total mass of the biphasic mixture.
4. The process as claimed in claim 1, wherein said treated effluent has:
• an oxidation-reduction potential (ORP) value in the range of +100 mV to +450 mV;
• a chemical oxygen demand (COD) value in the range of 20 ppm to 100 ppm; and
• a dissolved oxygen (DO) value in the range of 10 ppm to 25 ppm.
5. The process as claimed in claim 1, wherein said OH radicals are generated in a paraox system; wherein said OH radicals are generated in the range of 0.1 kg/m3 to 1 kg/m3 in the presence of an UV radiation having a wavelength in the range of 235 nm to 255 nm, an ultrasound having a power in the range of 20 Watt to 30 Watt, and an ozone in an amount in the range of 20 grams /hour to 30 grams/hour.
6. The process as claimed in claim 1, wherein said oxidant is selected from the group consisting of hydrogen peroxide, sodium hypochlorite and ozone.
7. The process as claimed in claim 1, wherein said colored mixed salt comprises:
• 70 mass% to 80 mass% of a hydrous sodium sulphate with respect to the total mass of the colored mixed salt;
• 15 mass% to 18 mass% of sodium chloride with respect to the total mass of the colored mixed salt; and
• 2 mass% to 15 mass% of complex organic molecules.
8. The process as claimed in claim 1, wherein said biphasic mixture is allowed to settle to obtain a residue having said insoluble salt and a clear solution having said soluble salt.
9. The process as claimed in claim 1, wherein said clear solution is separated to obtain soluble salt, and said residue is dried to obtain said insoluble salt.
10. The process as claimed in claim 9, wherein said soluble salt is sodium chloride; and said insoluble salt is group II sulphate salt selected from barium sulphate and calcium sulphate.
11. The process as claimed in claim 1, wherein said predetermined amount of said colored mixed salt is in the 5 mass% to 25 mass% with respect to the total mass of the salt slurry.
12. The process as claimed in claim 1, wherein said predetermined time period for each stage is in the range of 30 minutes to 50 minutes.
13. The process as claimed in claim 1, wherein said treated effluent is devoid of an organic matter selected from oxidizable organic molecules, complex organic molecules, straight chain compounds, semi-oxidized complex organic molecules and color.

Dated this 11th day of April, 2023

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant