DESC:TECHNICAL FIELD
[001]. The present disclosure relates to the field of organic chemistry in general. In particular, it includes process of separation or recovery of pollutant from wastewater. In an embodiment, the process of the present disclosure involves the use of amine, such as but not limiting to alkyl amine, wherein the amine is optionally present as a solution. The pollutant being recovered from the wastewater may be a Chemical Oxygen Demand (COD) contributing organic compound. The present disclosure also relates to a system for the separation or recovery of pollutant from wastewater.

BACKGROUND
[002]. One of the most common problems faced in today’s era is water pollution. Water is contaminated due to various reasons like industrialization, mining, sewage discharge, oil leakages, marine dumping, urbanization, etc. Industries pump various harmful chemicals like organic and inorganic pollutants into water thereby increasing the hazardous chemical concentration in water. The content of organic chemicals such as terephthalic acid, p-toluic acid, isophthalic acid etc. in the water can be measured by checking Chemical Oxygen Demand (COD) level of the water.
[003]. Polymer grade terephthalic acid (1, 4-benzenedicarboxylic acid) ranks 25th in total tonnage of manufactured chemical in the world. The American Amoco process is the established technology for manufacturing polymer-grade terephthalic acid (about 75% of world production). It consists of a liquid-phase air oxidation of p-xylene using acetic acid as solvent, Co acetate, Mn acetate as catalysts and bromine as a renewable source of free radicals. In the oxidation process, terepathalic acid is obtained along with some impurities such as 4-formyl benzoic acid and p-toluic acid. The presence of small fraction of 4-formyl benzoic acid in product profile inhibits the properties of the end product (i.e., poly ethylene terephthalate). This 4-formyl benzoic acid impurity is hydrogenated back to p-toluic acid in presence of water at 250ºC under hydrogen pressure, with noble metal catalyst (Pd) on a carbon support. After crystallisation of pure terephthalic acid from the mother liquor, the waste stream typically contains 4-formyl benzoic acid and p-toluic acid (4-methylbenzoic acid). These impurities together with terephthalic, benzoic and acetic acids are found to be the main organic pollutant in the wastewaters generated by the oxidation and the purification steps. Approximately 3-4 m3 of wastewater with around 10 kg COD/m3 are produced for 1 tonne of Purified terephthalic acid (PTA) manufactured.
[004]. At present, the most commonly used methods for PTA wastewater treatment process operate in two stages, anaerobic digestion followed by aerobic treatment. The term ‘anaerobic treatment’ implies a treatment process that is carried out without oxygen in the temperature range of 35-40ºC. Anaerobic digestion of organic matter is carried out by a special mixed group of anaerobic micro-organisms, which utilize the organic matter contained in the raw water as a source of food and energy. As a result of their normal growth cycle, the micro-organisms convert organic matter to a gaseous by-product called biogas/ methane and small amount of new cell mass. However, implementation of the anaerobic digestion process has substantial drawbacks, largely responsible for its limited uptake. The anaerobic bacteria tend to be slow growing and more sensitive to changes in conditions. Several operating parameters such as pH, temperature and presence of toxic metals need to be tightly controlled in order to achieve optimum performance. Despite the methane produced by anaerobic digestion, the high initial costs required to develop an anaerobic digester and the inherent complexities associated with it continue to hamper its economic development for PTA plant wastewater treatment.
[005]. Several methods such as, advanced oxidation process (AOP), supercritical water oxidation, UV-assisted ozonation (UV/O3), ozone assisted photochemical oxidation (UV/O3/H2O2), photo-fenton oxidation (UV/H2O2/FeSO4), ozone assisted photo-fenton oxidation (UV/O3/H2O2/FeSO4) and radiation treatment using gamma ray have been used for the treatment of PTA wastewater treatment. In all the above mentioned methods, organic matter is simply converted/ oxidised to the simple molecules such as CO2. However, cost for treatment and generation of toxic intermediates and sludge, which in turn cause secondary pollution, have been identified as major limitations of these methods. Further, conventional biodegradable methods may take longer residence time if the effluent contains high initial COD or non-biodegradable organic acids.
[006]. The instant disclosure overcomes all the drawbacks observed in the prior art by providing a process for the separation/recovery of pollutant/organic compound using an amine based extractant, which recovers the COD contributing organic compound from the aqueous solution such as but not limited to wastewater with very high efficiency.

SUMMARY OF THE DISCLOSURE
[007]. In some embodiments, the present disclosure relates to a process for separation or recovery of pollutant from wastewater.
[008]. In some embodiments, the present disclosure relates to a process for separating pollutant from wastewater, said process comprising acts of:
a) modulating temperature and optionally pH of wastewater;
b) contacting the wastewater obtained from step a) with alkylamine and mixing to obtain mixture;
c) incubating the mixture of step b) to obtain upper layer comprising alkylamine along with pollutant and lower layer comprising treated wastewater; and
d) separating the upper layer comprising alkylamine along with pollutant from the lower layer comprising treated wastewater.
[009]. In an embodiment, the contacting, mixing, incubating or separating is carried out at temperature ranging from about 10°C to about 100°C, pressure ranging from about 1 atmospheres to about 10 atmospheres for a time period ranging from about 1 minute to about 120 minutes.
[010]. In an embodiment, post the modulation of temperature and pH of the wastewater, solid waste is separated from the wastewater in Solid Separation Unit [F].
[011]. In an exemplary embodiment, the solid waste is selected from group comprising but not limiting to precipitated organic acid and solid particulate matter or combination thereof.
[012]. In an embodiment, the wastewater comprises pollutant selected from group comprising aliphatic hydrocarbon or aromatic hydrocarbon or their derivatives or any combinations thereof; and wherein the hydrocarbon compound or derivatives thereof is selected from group comprising organic acid and metal salt of organic acid or combination thereof.
[013]. In an embodiment, the alkylamine is selected from secondary amine or tertiary amine or combination thereof; wherein the secondary alkylamine is alkylamine having any of C6-C10 chain length; and wherein the tertiary alkylamine is alkylamine having any of C6-C10 chain length; or any combinations thereof.
[014]. In an embodiment, pH of the wastewater is adjusted. In an exemplary embodiment, the pH is decreased from the original pH to the range of about1.0 to about 4.0.
[015]. In an embodiment, the alkylamine; is optionally present as a solution including but not limited to diluent such as chlorinated hydrocarbon, ketone, alcohol and halogenated aromatic solvent or any combinations thereof preferably long chain hydrocarbon alcohol.
[016]. In an embodiment, weight ratio of the alkylamine to the wastewater is ranging from about 0.5:100 to about 1:20, preferably about 0.5:100 to about 3:100.
[017]. In some embodiments, the present disclosure also relates to a system for separation and recovery of pollutant from wastewater using an alkylamine optionally present as a solution.
[018]. In some embodiments, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one Mixing Unit [M] fluidly connected to the at least one Heat Exchanging Unit [X], the at least one Mixing Unit is configured to receive the wastewater from the at least one Heat Exchanging Unit and alkylamine, and is configured to mix the wastewater and the alkylamine; and
c) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater.
[019]. In an embodiment of the present disclosure, the system comprises at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Mixing Unit [M], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater.
[020]. In an embodiment of the present disclosure, the system comprises at least one Solid Separation Unit [F] configured in between the at least one Heat Exchanging Unit [X] or the at least one pH Adjustment Unit [pH] and the at least one Mixing Unit [M], wherein the at least one Solid Separation Unit is configured to separate solid waste from the wastewater.
[021]. In an embodiment of the present disclosure, at least one Regeneration Unit [ERU] is fluidly connected to the at least one Settling Unit, wherein the at least one Regeneration Unit is adapted to receive the upper layer comprising alkylamine along with pollutant from the at least one Settling Unit, and is configured to separate the alkylamine and the pollutant.
[022]. In an embodiment of the present disclosure, the at least one Settling Unit is fluidly connected to at least one biological treatment assembly [ASP] to obtain the wastewater from the Settling Unit.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURE
[023]. In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figure. The figure together with detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure where:

[024]. Figure 1 depicts an exemplary embodiment of the present disclosure towards process flow diagram for treating wastewater.
[025]. Figure 2 depicts an exemplary embodiment of the present disclosure towards process flow diagram for treating wastewater.
[026]. Figure 3 depicts process scheme for separation / recovery of organic acids and reduction of COD in PTA wastewater.
[027]. Figure 4(a) depicts chemical equation for formation of acid-amine complex on extraction of organic acid using trioctylamine. Figure 4(b) depicts a vial comprising the acid-amine complex obtained. Figure 4(c) depicts chemical equation for regeneration of trioctylamine from the acid-amine complex by caustic neutralization. Figure 4(d) depicts the process set up for regeneration of trioctylamine from the acid-amine complex by caustic neutralization. Figure 4(e) depicts chemical equation for recovery of organic acids. Figure 4(f) depicts a vial comprising the recovered organic acids and metal salts such as sodium chloride. Figure 4(g) depicts sample of wastewater from the PTA plant (raw effluent) and sample of the wastewater treated using 2.5% (wt.) trioctylamine at about 50ºC for fresh treatment and up to three subsequent recycle treatments.
[028]. Figure 5 depicts solubility of the organic acids (a) terephthalic acid, (b) benzoic acid and (c) p-toluic acid.
[029]. Figure 6 depicts dissociated and un-dissociated form of organic acid.
[030]. Figure 7 depicts results of HPLC analysis of organic acids in wastewater treated with alkylamine at varying pH. The x-axis depicts the pH conditions employed and y-axis depicts the COD levels in ppm.

DETAILED DESCRIPTION
[031]. To overcome the non-limiting drawbacks as stated in the background and to provide for simple and efficient process for extraction or recovery of organic compound, the present disclosure provides for process which facilitates removal of organic compound from aqueous solution such as but not limited to wastewater.
[032]. The present disclosure relates to a process for separating pollutant from wastewater, said process comprising acts of:
a) modulating temperature and optionally pH of wastewater;
b) contacting the wastewater obtained from step a) with alkylamine and mixing to obtain mixture;
c) incubating the mixture of step b) to obtain upper layer comprising alkylamine along with pollutant and lower layer comprising treated wastewater; and
d) separating the upper layer comprising alkylamine along with pollutant from the lower layer comprising treated wastewater.
[033]. The present disclosure also relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one Mixing Unit [M] fluidly connected to the at least one Heat Exchanging Unit [X], the at least one Mixing Unit is configured to receive the wastewater from the at least one Heat Exchanging Unit and alkylamine, and is configured to mix the wastewater and the alkylamine; and
c) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater.
[034]. In an embodiment of the present disclosure, the wastewater of step a) is modulated to a temperature ranging from about 10ºC to about 100ºC and pH of about 1.0 to about 4.0; wherein the modulating of the temperature is carried out in Heat Exchanging Unit [X]; wherein modulation of the pH is carried out in pH Adjustment Unit [pH]; wherein post the modulation of temperature and pH of the wastewater, solid waste is separated from the wastewater in step a) in Solid Separation Unit [F].
[035]. In another embodiment of the present disclosure, the contacting and the mixing is carried out in Mixing Unit [M]; the incubating of step c) is carried out in Settling Unit [S]; and wherein the contacting, mixing, incubating or separating is carried out at temperature ranging from about 10°C to about 100°C, pressure ranging from about 1 atmospheres to about 10 atmospheres for a time period ranging from about 1 minute to about 120 minutes.
[036]. In yet another embodiment of the present disclosure, the upper layer of step d) is separated from the lower layer by decantation; wherein the upper layer of step d) is treated to recover the alkylamine and the pollutant separately; wherein the treating is carried out by technique selected from group comprising solvent extraction, caustic neutralization, filtration and distillation or any combinations thereof; and wherein the treating is carried out in unit selected from group comprising Settling unit [S] and Regeneration Unit [ERU] or combination thereof; and wherein the lower layer of step d) is further treated in at least one Biological Treatment Assembly [ASP] to obtain aqueous wastewater.
[037]. In still another embodiment of the present disclosure, the system comprises at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Mixing Unit [M], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater.
[038]. In still another embodiment of the present disclosure, the system comprises at least one Solid Separation Unit [F] configured in between the at least one Heat Exchanging Unit [X] or the at least one pH Adjustment Unit [pH] and the at least one Mixing Unit [M], wherein the at least one Solid Separation Unit is configured to separate solid waste from the wastewater.
[039]. In still another embodiment of the present disclosure, at least one Regeneration Unit [ERU] is fluidly connected to the at least one Settling Unit, wherein the at least one Regeneration Unit is adapted to receive the upper layer comprising alkylamine along with pollutant from the at least one Settling Unit, and is configured to separate the alkylamine and the pollutant.
[040]. In still another embodiment of the present disclosure, the at least one Settling Unit is fluidly connected to at least one biological treatment assembly [ASP] to obtain the wastewater from the Settling Unit.
[041]. In still another embodiment of the present disclosure, the at least one Mixing Unit comprises an inlet port fluidly connected to an alkylamine source through a first passage.
[042]. In still another embodiment of the present disclosure, the system comprises a bypass passage fluidly connected between: at least one of the at least one Regeneration Unit [ERU] and the at least one Settling Unit [S]; and the first passage.
[043]. In still another embodiment of the present disclosure, the system is operational in mode selected from group comprising batch mode, semi-continuous mode and continuous mode, or any combinations thereof; the Heat Exchanging Unit [X] is a heat exchanger selected from group comprising shell heat exchanger, tube heat exchanger and flash evaporator or any combinations thereof; the Solid Separation Unit [F] is selected from group comprising nustch filter, bag filter and press filter or any combinations thereof; the Mixing Unit [M] is selected from group comprising stirred vessel reactor, plug flow reactor, static mixer, jet mixer and pump mixer or any combinations thereof; the Settling Unit [S] is selected from group comprising gravity settling vessel and centrifuge settler or combination thereof; the Biological Treatment Assembly [ASP] is activated sludge assembly; and the Regeneration Unit [ERU] is selected from group comprising distillation column, filtration unit and extraction column or any combinations thereof.
[044]. In still another embodiment of the present disclosure, the wastewater comprises pollutant selected from group comprising aliphatic hydrocarbon or aromatic hydrocarbon or their derivatives or any combinations thereof; and wherein the hydrocarbon compound or derivatives thereof is selected from group comprising organic acid and metal salt of organic acid or combination thereof; wherein the organic acid is selected from group comprising benzoic acid, p-toluic acid, terephthalic acid, 4-carboxy benzoic acid, trimellitic acid, acetic acid, 4-methyl benzoic acid, isophthalic acid and orthophthalic acid or any combinations thereof; wherein cation in the metal salt of organic acid is selected from group comprising sodium, magnesium and potassium or any combination thereof, and wherein anion in the metal salt of organic acid is selected from group comprising terephthalate, acetate, benzoate, isophthalate, trimetillate, methyl benzoate, phthalate, carboxy benzoate or any combinations thereof.
[045]. In still another embodiment of the present disclosure, the wastewater is selected from group comprising industrial wastewater, purified terephthalic acid (PTA) wastewater, petrochemical wastewater, pharmaceutical industry wastewater and isophthalic acid wastewater or any combinations thereof; wherein the alkylamine is selected from secondary amine or tertiary amine or combination thereof; wherein the secondary alkylamine is alkylamine having any of C6-C10 chain length; and wherein the tertiary alkylamine is alkylamine having any of C6-C10 chain length; or any combinations thereof.
[046]. In still another embodiment of the present disclosure, the alkylamine is selected from group comprising trihexylamine and trioctylamine or combination thereof.
[047]. In still another embodiment of the present disclosure, the alkylamine is present in a solution, wherein the solution is diluent selected from group comprising chlorinated hydrocarbon, ketone, alcohol and halogenated aromatic solvent or any combinations thereof preferably long chain hydrocarbon alcohol; and wherein weight ratio of the alkylamine to the wastewater is ranging from about 0.5:100 to about 1:20, preferably about 0.5:100 to about 3:100.
[048]. In still another embodiment of the present disclosure, the solid waste is selected from group comprising precipitated organic acid and solid particulate matter or combination thereof.
[049]. As used herein, the term ‘method’ and ‘process’ have the same scope and meaning and are used interchangeably.
[050]. As used herein, the term ‘wastewater’ refers to water produced as a by-product of industrial or commercial activities. In an embodiment, the wastewater employed in the present disclosure is in treated or untreated form.
[051]. As used herein, the term ‘PTA wastewater’ ‘PTA plant wastewater’ or ‘Purified Terephthalic Acid wastewater’ refers to wastewater generated from PTA manufacturing industry.
[052]. As used herein, the term ‘pollutant’ refers to undesired substance(s) or contaminant(s) present in the wastewater. In an embodiment, the undesired substance(s) or contaminant(s) may cause harm to living beings or environment or equipment or any industrial/commercial setup. In an embodiment of the present disclosure, the pollutant is in a form selected from a group comprising solid, liquid and gas or any combinations thereof.
[053]. As used herein, the term ‘modulate temperature’ refers to increasing, decreasing or maintaining temperature.
[054]. As used herein, the term ‘modulate pH’ refers to increasing, decreasing or maintaining pH.
[055]. As used herein, the term ‘modulating’ and ‘adjusting’ have the same scope and meaning and are used interchangeably.
[056]. As used herein, the term ‘effluent’ and ‘wastewater’ have the same scope and meaning and are used interchangeably.
[057]. As used herein, ‘g’ and ‘gm’ are used interchangeably to refer to the unit gram.
[058]. As used herein, the term ‘organic compound’ and ‘pollutant’ have the same scope and meaning and are used interchangeably.
[059]. The present disclosure relates to a process of treating wastewater by using amine such as alkylamine or recovery of organic compound from wastewater by using amine such as alkylamine.
[060]. In an embodiment, the process of treating wastewater or recovery of organic compound from wastewater using amine such as alkylamine optionally present as a solution.
[061]. In an embodiment, the present disclosure employs reactive liquid-liquid extraction utilizing an extractant such as alkylamines. In an embodiment, the process of the present disclosure provides high selectivity and enhances the recovery of valuable organic compounds. The extractant in the organic phase reacts with the organic compound in the aqueous phase and the reaction complexes formed are then solubilized in the active diluent organic phase.
[062]. In a non-limiting embodiment, the wastewater includes but is not limited to PTA plant wastewater, industrial wastewater, petrochemical wastewater, pharmaceutical industry wastewater and isophthalic acid wastewater or any combinations thereof.
[063]. In an embodiment of the present disclosure, the organic compound extracted from wastewater includes aliphatic or aromatic compounds or their derivatives or any combination thereof.
[064]. In a non-limiting embodiment of the present disclosure, the wastewater comprises organic compound / pollutant selected from a group comprising aliphatic hydrocarbon or aromatic hydrocarbon or their derivatives or any combinations thereof. In an embodiment of the present disclosure, the wastewater comprises organic compound selected from a group comprising organic acid or its corresponding metal salt.
[065]. In a non-limiting embodiment of the present disclosure, the organic compound / pollutant in wastewater is organic acid selected from group comprising benzoic acid, p-toluic acid, terephthalic acid, 4-carboxy benzoic acid, trimellitic acid, acetic acid, 4-methyl benzoic acid, isophthalic acid and orthophthalic acid or any combinations thereof.
[066]. In an embodiment of the present disclosure, the organic compound / pollutant in wastewater is metal salt of organic acid selected from group comprising benzoic acid, p-toluic acid, terephthalic acid, 4-carboxy benzoic acid, trimellitic acid, acetic acid, 4-methyl benzoic acid, isophthalic acid and orthophthalic acid or any combinations thereof.
[067]. In an embodiment of the present disclosure, cation in the metal salt of organic acid is selected from group comprising sodium, magnesium and potassium or any combination thereof; and anion in the metal salt of organic acid is selected from group comprising terephthalate, acetate, benzoate, isophthalate, trimetillate, 4-methyl benzoate, phthalate and 4-carboxy benzoate or any combinations thereof.
[068]. In a non-limiting embodiment of the present disclosure, the metal salt of organic acid is selected from group comprising sodium terephthalate, sodium acetate, sodium benzoate, sodium isophthalate, sodium-trimetillate, 4-methyl sodium benzoate, sodium phthalate, 4-carboxy sodium benzoate, magnesium terephthalate, magnesium acetate, magnesium benzoate, magnesium isophthalate, magnesium-trimetillate, 4-methyl magnesium benzoate, magnesium phthalate, 4-carboxy magnesium benzoate, potassium terephthalate, potassium acetate, potassium benzoate, potassium isophthalate, potassium-trimetillate, 4-methyl potassium benzoate, potassium phthalate and 4-carboxy potassium benzoate or any combinations thereof.
[069]. In a non-limiting embodiment of the present disclosure, the wastewater is preferably PTA plant wastewater.
[070]. In an embodiment, the PTA plant wastewater comprises organic compound selected from but not limited to organic acid such as terephthalic acid, isophthalic acid, acetic acid, para-toluic acid, benzoic acid, 4-carboxy benzoic acid, 4-methyl benzoic acid and orthophthalic acid; and metal salts of the said organic acid wherein cation in the metal salt is selected from a non-limiting group comprising sodium, magnesium and potassium; or any combinations thereof.
[071]. In an embodiment, the process of the present disclosure is for treating wastewater by extracting the various COD contributing organic compounds/pollutants using amine based extractants. In an exemplary embodiment, the amine based extractant is an alkylamine.
[072]. In an embodiment, on adding alkylamine to the wastewater, the carboxylic acid group associated with the organic acid forms a complex with alkyl amines called acid-amine complex, provided the organic acids are in the un-dissociated form. The optimal pH for separation of the complex formed is on the basis of the (acid dissociation constants) pKa of each organic acid present in the wastewater.

Acid dissociation constants (pKa) of certain organic acids at 25°C is provided in Table 1. At high pH values, the organic acid is mostly dissociated, hence is not suitable for reactive extraction, and in such cases ion exchange separation is employed. In another embodiment, adjusting pH of the organic acid solution below its pKa, makes the organic acid in its un-dissociated form, thereby making it more favourable for separation by reactive extraction (Figure 6). In an embodiment of the present disclosure, reactive extraction of organic acid and salts thereof is possible when they are in an un-dissociated form, which occurs at lower pH conditions. In an embodiment of the present disclosure, if pH < pKa, organic metal salt converts into organic acid (un-dissociation). In another embodiment of the present disclosure, metal salt converts into its corresponding organic acid on lowering the pH, and this organic acid forms a complex with the alkylamine to form the acid-amine complex.

Table 1:
Organic acid pKa @ 25 °C
Terepthalic acid
4-Carboxy benzoic acid
Benzoic acid
Ortho pthalic acid
Trimellitic acid
Para toluic acid
Isophthalic acid 3.51
1.76
4.19
2.89 and 5.51
2.721
4.36
3.7 and 4.6

[073]. In an embodiment of the present disclosure, the pH of the wastewater is adjusted. In another embodiment, the pH of the wastewater is adjusted to a range of about 1.0 to about 4.0. In yet another embodiment, the pH of the wastewater is adjusted to a range of about 1.0 to about 3.5. In still another embodiment, the pH of the wastewater is adjusted to a range of about 1.0 to about 3.0. In still another embodiment, the pH of the wastewater is adjusted to a range of about 1.0 to about 2.5. In still another embodiment, the pH of the wastewater is adjusted to a range of about 2.0 to about 3.0. In still another embodiment, the pH of the wastewater is adjusted to a range of about 2.0 to about 2.5. In another embodiment, the pH is adjusted/decreased by employing bronsted/protic acids such as but not limiting to HCl.
[074]. In an exemplary embodiment, the pH of the waste water is adjusted by decreasing the pH from original pH to a range of about 2.0 to about 2.5.
[075]. In a non-limiting embodiment of the present disclosure, the alkylamine is selected from secondary amine or tertiary amine or combination thereof. In an embodiment, the secondary alkylamine is alkylamine having any of C6-C10 chain length preferably having any of C6-C8 chain length; and the tertiary alkylamine is alkylamine having any of C6-C10 chain length preferably having any of C6-C8 chain length; or any combinations thereof.
[076]. In an embodiment of the present disclosure, the secondary amine or tertiary amine comprises a C6-C10 alkyl chain preferably C6-C8 alkyl chain length
[077]. In an exemplary embodiment of the present disclosure, the alkylamine is selected from group comprising trihexylamine and trioctylamine or combination thereof.
[078]. In another exemplary embodiment of the present disclosure, the alkylamine is Alamine® 336 (having about 95% of TOA and about 5% of C8 alkyl chain secondary amine).
[079]. In an embodiment, the amine used in the instant process is a tertiary amine, which has good extractability for carboxylic acids. However, due to its high viscous and corrosive properties, the tertiary amine is employed in the form of a solution in an organic diluent.
[080]. In an embodiment of the present disclosure, the amine such as alkylamine is present in a solution, wherein the solution is selected from but not limited to diluent such as organic diluent including but not limiting to chlorinated hydrocarbon, ketone, halogenated aromatic solvent, long chain hydrocarbon alcohol and high molecular weight alcohol or any combinations thereof. In a preferred embodiment, the diluent is long chain hydrocarbon alcohol. In an exemplary embodiment, the diluent is octanol.
[081]. In another embodiment, diluents with functional group significantly affect the extraction behavior of an amine. In yet another embodiment, functional group in diluents are selected from but not limited to chlorinated hydrocarbon, ketone, alcohol and halogenated aromatic solvent or any combinations thereof.
[082]. In a non-limiting embodiment, organic diluent enables a greater solvation of the acid-amine complex because of its polar properties.
[083]. In an embodiment, the weight ratio of the alkylamine to the wastewater used in the process of the present disclosure is ranging from about 0.5:100 (i.e. about 1:200) to about 1:20, preferably about 0.5:100 to about 3:100, more preferably about 0.5:99.5 to about 1:30.
[084]. In an embodiment, the said ratio range of the alkylamine to wastewater increases extraction of organic compounds / pollutants by the process of the present disclosure. Beyond this range, extraction efficiency of organic compounds decreases.
[085]. In an embodiment of the present disclosure, the extractant used is an alkylamine, which is not an ionic liquid. Amine based ionic liquid is a weak ionic liquid, which may get dissolved in water imparting high acidity to the water, which is not recommended. In an embodiment of the present disclosure, use of alkylamine such as but not limiting to TOA as extractant is more economical over use of ionic liquid as extractant.
[086]. In an embodiment of the present disclosure, regeneration of the extractant and recovery of pollutant such as organic acids and their metal salts from the wastewater is highly efficient. In an embodiment, the process of the present disclosure extracts pollutant such as organic acids (aliphatic or aromatic acids) and their metal salts with high efficiency.
[087]. In another embodiment, the alkylamines or the organic phase alkylamines are regenerated back with high accuracy and are reused for recovery of further organic acids from the wastewater/effluent.
[088]. In a non-limiting embodiment, the secondary or tertiary alkylamine is regenerated using caustic wash, hence the acid-amine complex is broken down to free secondary or tertiary amine and the sodium salt of carboxylic or sodium salt of terephthalic acids in the aqueous phase. Thereafter, the organic alkyl amine is separated by decantation process.
[089]. In an embodiment of the present disclosure, the extractants (alkylamines) are regenerated by caustic wash to the organic phase containing acid-amine complex.
[090]. In an embodiment, the acid-amine complex hence formed is separated by employing techniques such as but not limited to phase separation, sedimentation, gravity separation and centrifugation; or any combinations thereof. In a non-limiting exemplary embodiment, solvated acid-amine complex is present in the organic diluent/medium.
[091]. In a further embodiment, the reactive liquid-liquid extraction process of the present disclosure replaces or eliminates the cost intensive and time consuming anaerobic digestion process, usually practiced in wastewater treatment such as in the PTA wastewater treatment process. In an alternative embodiment, the COD level of wastewater/effluent after extraction with amine is suitable for feeding to activated sludge aerobic treatment method to further reduce the COD levels as per the required standard. In a non-limiting embodiment, the instant process is followed by aerobic treatment.
[092]. In a preferred embodiment, the process of extraction of organic compound from the wastewater reduces/decreases the COD levels of wastewater, thereby complying with discharge standards.
[093]. Chemical Oxygen Demand (COD) indicates the amount of oxidisable organic compounds present in water (expressed as parts per million or milligrams per liter of water). Higher the chemical oxygen demand, higher the amount of pollutant in the test sample. In an embodiment, the COD is measure of water quality and indicates amount of oxidisable chemical pollutant present in the wastewater. Thus, in an embodiment, the reduction in COD of a wastewater sample after treatment with the amine extractant is used to calculate the percentage (%) of extraction of pollutant such as organic compound from the sample.
[094]. In an embodiment of the present disclosure, the COD level of water is detected using normal laboratory method of analysis.
[095]. In an exemplary embodiment of the present disclosure, the COD level of water is detected using potassium dichromate method.
[096]. In an embodiment of the present disclosure, the COD level of wastewater is reduced by the method of the present disclosure from a range of about 8000 to 10000 ppm to about 300 to about 2000 ppm, preferably about 500 to 1200 ppm.
[097]. In a preferred embodiment, during the process of extraction of pollutant such as organic compound from the wastewater, the process decreases/reduces the COD level of wastewater.
[098]. In an embodiment, the process of the present disclosure recovers organic acids from the PTA effluent, thereby COD load on the wastewater/effluent is decreased to almost 70-95%, and recovery of organic acids increases the overall yield of the Terepthalic acid production in a typical PTA plant production.
[099]. In an embodiment of the present disclosure, extraction of the pollutant from the wastewater ranges from about 60% to about 95%, preferably from about 70% to about 90%, more preferably from about 75% to about 85% by weight of the initial pollutant present in the wastewater.
[0100]. In another embodiment, the treated water produces less sludge during the aerobic process, after tertiary water treatment methods.
[0101]. In another embodiment, the extracted/recovered organic acids such as but not limiting to p-toluic acid and 4-formyl benzoic acid are recycled back to main oxidation reaction of p-xylene.
[0102]. In another embodiment of the present disclosure, the COD contributing organic acid compounds are recovered back with addition of acid such as HCl to the aqueous phase containing metal salts of organic acid (such as but not limiting to sodium salt of terephthalate); hence net process yield increases marginally.
[0103]. In an embodiment, the treated water COD is suitable for feed input to activated sludge aerobic process for further reduction of COD of the wastewater/effluent.
[0104]. The present disclosure also relates to process of extracting or recovering or separating organic compound / pollutant, from aqueous solution such as but not limited to wastewater, wherein said process comprises acts of:
a) subjecting the aqueous solution present at high temperature to heat exchanging unit to reduce the temperature and thereafter adjusting the pH; facilitating precipitation of solid and separating the same from the aqueous wastewater solution;
b) mixing amine optionally present in a solution and aqueous wastewater obtained from the above step and thereafter separating the aqueous wastewater layer and amine layer containing recovered organic compound;
c) subjecting the separated amine layer to recycling and/or regeneration; and subjecting separated aqueous wastewater layer to aerobic treatment assembly.
[0105]. In an embodiment, the present disclosure relates to a process for separating pollutant from wastewater, said process comprising acts of:
a) modulating temperature and optionally pH of wastewater;
b) contacting the wastewater obtained from step a) with alkylamine and mixing to obtain mixture;
c) incubating the mixture of step b) to obtain upper layer comprising alkylamine along with pollutant and lower layer comprising treated wastewater; and
d) separating the upper layer comprising alkylamine along with pollutant from the lower layer comprising treated wastewater.
[0106]. In another embodiment, the present disclosure relates to a process for separating pollutant from wastewater, said process comprising acts of:
a) modulating temperature and pH of wastewater;
b) contacting the wastewater obtained from step a) with alkylamine and mixing to obtain mixture;
c) incubating the mixture of step b) to obtain upper layer comprising alkylamine along with pollutant and lower layer comprising treated wastewater; and
d) separating the upper layer comprising alkylamine along with pollutant from the lower layer comprising treated wastewater.
[0107]. In an embodiment, the present disclosure relates to a process for separating pollutant from wastewater, said process comprising acts of:
a) modulating temperature and optionally pH of wastewater; post the modulation of temperature and pH, solid waste is separated from the wastewater.
b) contacting the wastewater obtained from step a) with alkylamine and mixing to obtain mixture;
c) incubating the mixture of step b) to obtain upper layer comprising alkylamine along with pollutant and lower layer comprising treated wastewater; and
d) separating the upper layer comprising alkylamine along with pollutant from the lower layer comprising treated wastewater.
[0108]. In an embodiment, the amine is an alkyl amine selected from secondary amine or tertiary amine or combination thereof having any of C6-C10 chain length. In an embodiment the alkylamine optionally present in a solution and aqueous wastewater are mixed at temperature ranging from about 10ºC to about 100ºC, preferably about 30ºC to about 80ºC; pressure ranging from about 1 atmospheres to about 10 atmospheres, preferably about 1 atmospheres to about 2 atmospheres; and time duration ranging from about 1 min to about 120 min, preferably about 20 min to about 50 min.
[0109]. In another embodiment, the ratio of aqueous wastewater to amine optionally present in a solution is ranging from about 100:0.5 to about 20:1, preferably about 100:0.5 to about 100:3.
[0110]. In another embodiment, the extracted/recovered organic compound /pollutant comprises but is not limited to one or more of organic acid such as terephthalic acid, p-toluic acid, 4 methyl benzoic acid, 4 carboxy benzoic acid, trimellitic acid, acetic acid, isophthalic acid and orthophthalic acid; metal salts of the organic acids and various other organic compounds present in the wastewater.
[0111]. In an embodiment of the present disclosure, the wastewater in step a) is modulated to a temperature ranging from about 10ºC to about 100ºC and pH of about 1.0 to about 4.0, preferably about 1.5 to about 3.5, more preferably about 2.0 to about 3.0; wherein the modulating of the temperature is carried out in Heat Exchanging Unit [X]; wherein modulation of the pH is carried out in pH Adjustment Unit [pH]; wherein the solid waste is separated from the wastewater in step a) in Solid Separation Unit [F]. In an embodiment of the present disclosure, the contacting and the mixing is carried out in Mixing Unit [M]; the incubating of step c) is carried out in Settling Unit [S]; and wherein the contacting, mixing, incubating or separating is carried out at temperature ranging from about 10°C to about 100°C, pressure ranging from about 1 atmospheres to about 10 atmospheres for a time period ranging from about 1 minute to about 120 minutes. In an embodiment of the present disclosure, the upper layer of step d) is separated from the lower layer by decantation; wherein the upper layer of step d) is treated to recover the alkylamine and the pollutant separately; wherein the treating is carried out by technique selected from group comprising solvent extraction, caustic neutralization, filtration and distillation or any combinations thereof; and wherein the treating is carried out in unit selected from group comprising Settling unit [S] and Regeneration Unit [ERU] or combination thereof; and wherein the lower layer of step d) is further treated in at least one Biological Treatment Assembly [ASP] to obtain aqueous wastewater.The present disclosure also relates to a system for the extraction or recovery of organic compound from aqueous solution such as but not limiting to wastewater including but not limiting to PTA/Isophthalic acid wastewater using an amine, such as but not limiting to alkyl amine, wherein the amine is optionally present as a solution.
[0112]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one Mixing Unit [M] fluidly connected to the at least one Heat Exchanging Unit [X], the at least one Mixing Unit is configured to receive the wastewater from the at least one Heat Exchanging Unit [X] and alkylamine, and is configured to mix the wastewater and the alkylamine; and
c) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit [M], the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater.
[0113]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one Mixing Unit [M] fluidly connected to the at least one Heat Exchanging Unit [X], the at least one Mixing Unit is configured to receive the wastewater from the at least one Heat Exchanging Unit [X] and alkylamine, and is configured to mix the wastewater and the alkylamine;
c) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit [M], the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater; and
d) at least one Regeneration Unit [ERU] fluidly connected to the at least one Settling Unit, wherein the at least one Regeneration Unit is adapted to receive the upper layer comprising alkylamine along with pollutant from the at least one Settling Unit, and is configured to separate the alkylamine and the pollutant.
[0114]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one Mixing Unit [M] fluidly connected to the at least one Heat Exchanging Unit [X], the at least one Mixing Unit is configured to receive the wastewater from the at least one Heat Exchanging Unit [X] and alkylamine, and is configured to mix the wastewater and the alkylamine;
c) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit [M], the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater; and
d) at least one biological treatment assembly [ASP] fluidly connected to the at least one Settling Unit to obtain the wastewater from the Settling Unit.
[0115]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one Mixing Unit [M] fluidly connected to the at least one Heat Exchanging Unit [X], the at least one Mixing Unit is configured to receive the wastewater from the at least one Heat Exchanging Unit and alkylamine, and is configured to mix the wastewater and the alkylamine;
c) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater;
d) at least one Regeneration Unit [ERU] fluidly connected to the at least one Settling Unit, wherein the at least one Regeneration Unit is adapted to receive the upper layer comprising alkylamine along with pollutant from the at least one Settling Unit, and is configured to separate the alkylamine and the pollutant; and
e) at least one biological treatment assembly [ASP] fluidly connected to the at least one Settling Unit to obtain the wastewater from the Settling Unit.
[0116]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Mixing Unit [M], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater;
c) at least one Mixing Unit [M] fluidly connected to the at least one pH Adjustment Unit [pH], the at least one Mixing Unit is configured to receive the wastewater from the at least one pH Adjustment Unit and alkylamine, and is configured to mix the wastewater and the alkylamine; and
d) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater.
[0117]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one Solid Separation Unit [F] configured in between the at least one Heat Exchanging Unit [X] and the at least one Mixing Unit [M], wherein the at least one Solid Separation Unit is configured to separate solid waste from the wastewater;
c) at least one Mixing Unit [M] fluidly connected to the at least one Solid Separation Unit [F], the at least one Mixing Unit is configured to receive the wastewater from the at least one solid Separation Unit and alkylamine, and is configured to mix the wastewater and the alkylamine; and
d) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater.
[0118]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Solid Separation Unit [F], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater;
c) at least one Solid Separation Unit [F] configured in between the at least one pH Adjustment Unit [pH] and the at least one Mixing Unit [M], wherein the at least one Solid Separation Unit is configured to separate solid waste from the wastewater;
d) at least one Mixing Unit [M] fluidly connected to the at least one Solid Separation Unit [F], the at least one Mixing Unit is configured to receive the wastewater from the at least one pH Adjustment Unit and alkylamine, and is configured to mix the wastewater and the alkylamine; and
e) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater.
[0119]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Mixing Unit [M], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater;
c) at least one Mixing Unit [M] fluidly connected to the at least one pH Adjustment Unit [pH], the at least one Mixing Unit is configured to receive the wastewater from the at least one pH Adjustment Unit and alkylamine, and is configured to mix the wastewater and the alkylamine;
d) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater; and
e) at least one Regeneration Unit [ERU] fluidly connected to the at least one Settling Unit, wherein the at least one Regeneration Unit is adapted to receive the upper layer comprising alkylamine along with pollutant from the at least one Settling Unit, and is configured to separate the alkylamine and the pollutant.
[0120]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Mixing Unit [M], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater;
c) at least one Mixing Unit [M] fluidly connected to the at least one pH Adjustment Unit [pH], the at least one Mixing Unit is configured to receive the wastewater from the at least one pH Adjustment Unit and alkylamine, and is configured to mix the wastewater and the alkylamine;
d) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater; and
e) at least one biological treatment assembly [ASP] fluidly connected to the at least one Settling Unit to obtain the wastewater from the Settling Unit.
[0121]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Mixing Unit [M], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater;
c) at least one Mixing Unit [M] fluidly connected to the at least one pH Adjustment Unit [pH], the at least one Mixing Unit is configured to receive the wastewater from the at least one pH Adjustment Unit and alkylamine, and is configured to mix the wastewater and the alkylamine;
d) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater;
e) at least one Regeneration Unit [ERU] fluidly connected to the at least one Settling Unit, wherein the at least one Regeneration Unit is adapted to receive the upper layer comprising alkylamine along with pollutant from the at least one Settling Unit, and is configured to separate the alkylamine and the pollutant; and
f) at least one biological treatment assembly [ASP] fluidly connected to the at least one Settling Unit to obtain the wastewater from the Settling Unit.
[0122]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Solid Separation Unit [F], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater;
c) at least one Solid Separation Unit [F] configured in between the at least one pH Adjustment Unit [pH] and the at least one Mixing Unit [M], wherein the at least one Solid Separation Unit is configured to separate solid waste from the wastewater;
d) at least one Mixing Unit [M] fluidly connected to the at least one Solid Separation Unit [F], the at least one Mixing Unit is configured to receive the wastewater from the at least one pH Adjustment Unit and alkylamine, and is configured to mix the wastewater and the alkylamine;
e) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater; and
f) at least one Regeneration Unit [ERU] fluidly connected to the at least one Settling Unit, wherein the at least one Regeneration Unit is adapted to receive the upper layer comprising alkylamine along with pollutant from the at least one Settling Unit, and is configured to separate the alkylamine and the pollutant.
[0123]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Solid Separation Unit [F], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater;
c) at least one Solid Separation Unit [F] configured in between the at least one pH Adjustment Unit [pH] and the at least one Mixing Unit [M], wherein the at least one Solid Separation Unit is configured to separate solid waste from the wastewater;
d) at least one Mixing Unit [M] fluidly connected to the at least one Solid Separation Unit [F], the at least one Mixing Unit is configured to receive the wastewater from the at least one pH Adjustment Unit and alkylamine, and is configured to mix the wastewater and the alkylamine;
e) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater; and
f) at least one biological treatment assembly [ASP] fluidly connected to the at least one Settling Unit to obtain the wastewater from the Settling Unit.
[0124]. In an embodiment, the present disclosure relates to a system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Solid Separation Unit [F], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater;
c) at least one Solid Separation Unit [F] configured in between the at least one pH Adjustment Unit [pH] and the at least one Mixing Unit [M], wherein the at least one Solid Separation Unit is configured to separate solid waste from the wastewater;
d) at least one Mixing Unit [M] fluidly connected to the at least one Solid Separation Unit [F], the at least one Mixing Unit is configured to receive the wastewater from the at least one pH Adjustment Unit and alkylamine, and is configured to mix the wastewater and the alkylamine;
e) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater;
f) at least one Regeneration Unit [ERU] fluidly connected to the at least one Settling Unit, wherein the at least one Regeneration Unit is adapted to receive the upper layer comprising alkylamine along with pollutant from the at least one Settling Unit, and is configured to separate the alkylamine and the pollutant; and
g) at least one biological treatment assembly [ASP] fluidly connected to the at least one Settling Unit to obtain the wastewater from the Settling Unit.
[0125]. In an embodiment of the present disclosure, the at least one Mixing Unit comprises an inlet port fluidly connected to an alkylamine source through a first passage.
[0126]. In an embodiment of the present disclosure, the system comprises a bypass passage fluidly connected between:
at least one of the at least one Regeneration Unit [ERU] and the at least one Settling Unit [S]; and
the first passage.
[0127]. In a non-limiting embodiment, the system is operational in either batch mode or semi-continuous mode or in continuous mode.
[0128]. In an embodiment, the separation/recovery of the organic compound from aqueous solution such as but not limiting to wastewater is carried out by subjecting the aqueous solution such as wastewater from storage tank [St] to heat exchanging unit [X], pH adjustment unit [pH], solid separation unit [F], mixing unit [M], settling unit [S], aerobic treatment assembly [ASP] and Regeneration Unit [ERU] or any combinations thereof.

[0129]. Figure 1 is an exemplary embodiment of the present disclosure which illustrates block diagram of the system [100] for separating/recovering organic compound/pollutant from aqueous solution such as but not limiting to wastewater. The system is operated in either batch or semi-continuous or continuous mode. The Storage Tank [St] stores the wastewater such as but not limited to the PTA/isophthalic acid wastewater, from which the organic compound has to be extracted or recovered. The Storage Tank is fluidly connected via stream 1 to the Heat Exchanger Unit [X]. The stream 1 carrying the wastewater, for ex.: PTA wastewater stored in the storage tank [St] to the Heat Exchanging Unit [X]; is at a high temperature of around 150ºC. In the Heat Exchanging Unit, the wastewater is cooled down to ambient temperature ranging from about 30ºC to about 80ºC. In an embodiment the Heat Exchanging Unit is a heat exchanger selected from but not limiting to shell heat exchanger, tube heat exchanger and flash evaporator or any combinations thereof. In a non-limiting embodiment, at this prevailing temperature ranging from about 40ºC to about 60ºC, solids such as but not limiting to terephthalic acid and para toluic acid get precipitated out. The Heat Exchanging Unit is fluidly connected to the pH Adjustment Unit [pH], for decreasing the pH of the wastewater to range from about 1.0 to about 4.0, preferably 2.0 to about 3.5, more preferably from about 2.0 to about 2.5. In an embodiment, the pH adjustment is carried out by addition of acids such as but not limited to bronsted/protic acids like hydrochloride acid (HCl). In an embodiment, the pH Adjustment Unit is any vessel wherein pH is maintained. The pH Adjustment Unit is fluidly connected via stream 3 to the Mixing Unit [M]. The extractant, i.e. alkylamine optionally present as a solution, is fed into the mixing unit via stream 4. The alkylamine and wastewater stream coming from the streams 4 & 3 respectively; is mixed in the Mixing Unit [M]. In an embodiment, the Mixing Unit is including but not limited to stirred vessel reactor, plug flow reactor, static mixer, jet mixer, pump mixer or any combinations thereof. The streams are fed to Mixing Unit [M], wherein the temperature in M is ranging from about 10ºC to about 100ºC, with pressure ranging from about 1 to about 10 atmospheres. In yet another embodiment, the weight ratio of PTA wastewater to alkylamine solution is in the range of about 100:0.5 to about 20:1. The time required for sufficient mixing/ extraction varies from about 1 min to about 120 min. In an embodiment, organic compound such as but not limited to terephthalic acid, p-toluic acid, 4 methyl benzoic acid, 4 carboxy benzoic acid, trimellitic acid, acetic acid, isophthalic acid, orthophthalic acid, metal salt of the organic acid or any combinations thereof; and various other organic compounds present in the PTA wastewater stream are extracted/ recovered into the alkylamine solution. In an embodiment, the outlet of Mixing Unit [M] is directly fed to the Settling Unit [S], where separation of the alkylamine solution takes place from the aqueous wastewater stream. In an embodiment, the Settling Unit [S] is including but not limited to gravity settling vessel and centrifuge settler or combination thereof. The Mixing Unit and the Settling Unit may be either jointly or separately present in the system. The separated / treated aqueous wastewater (lower layer) is collected separately via stream 6; which is fluidly connected to the Aerobic Treatment Assembly [ASP].
[0130]. In an embodiment, the separated / treated aqueous wastewater stream6, is pH adjusted to neutral before being sent for further removal of COD contributed by unextracted organic compounds by known aerobic/activated sludge process. The aqueous stream generated from aerobic treatment assembly is discharged via stream 9. The sludge generated from aerobic treatment assembly is discharged via stream 10.
[0131]. In an embodiment, the upper alkylamine layer is separated via stream 7 and is termed as recycle alkylamine, which is sent for further mixing with the fresh PTA wastewater stream in the Mixing Unit via stream 5; likewise alkylamine solution can be recycled. The stream 7 connects the Settling Unit [S] with the Regeneration Unit [ERU]. In an embodiment, the Regeneration Unit is the extractant Regeneration Unit. A small portion of the alkylamine solution is regenerated by using caustic solution (NaOH). The regenerated alkyl amine solution stream 8 can be used for further extraction of pollutant / organic compound from wastewater. The stream 8 connects the Regeneration Unit [ERU] with the stream 4, which in turn is connected to the Mixing Unit.
[0132]. Figure 2 is an exemplary embodiment of the present disclosure which illustrates block diagram of the system [200] for separating/recovering organic compound/pollutant from aqueous solution such as but not limiting to wastewater. The system is operated in either batch or semi-continuous or continuous mode. The Storage Tank [St] stores the wastewater such as but not limited to the PTA/isophthalic acid wastewater, from which the organic compound has to be extracted or recovered. The Storage Tank is fluidly connected via stream 1 to the Heat Exchanger Unit [X]. The stream 1 carrying the wastewater, for ex.: PTA wastewater stored in the storage tank [St] to the Heat Exchanging Unit [X]; is at a high temperature of around 150ºC. In the Heat Exchanging Unit, the wastewater is cooled down to ambient temperature ranging from about 30ºC to about 80ºC. In an embodiment the Heat Exchanging Unit is a heat exchanger selected from but not limiting to shell heat exchanger, tube heat exchanger and flash evaporator or any combinations thereof. In a non-limiting embodiment, at this prevailing temperature ranging from about 40ºC to about 60ºC, solids such as but not limiting to terephthalic acid and para toluic acid get precipitated out. The Heat Exchanging Unit is fluidly connected to the pH Adjustment Unit [pH], for decreasing the pH of the wastewater to range from about 1.0 to about 4.0, preferably 2.0 to about 3.5, more preferably from about 2.0 to about 2.5. In an embodiment, the pH adjustment is carried out by addition of acids such as but not limited to bronsted/protic acids like hydrochloride acid (HCl). In an embodiment, the pH Adjustment Unit is any vessel wherein pH is maintained.
[0133]. The pH Adjustment Unit is fluidly connected to the Solid Separation Unit [F] via stream 11, which helps in the removal of solid waste such as but not limiting to the precipitated solids, particulates etc. from the process stream. In an exemplary embodiment, the Solid Separation Unit is filter system including but not limiting to nustch filter, bag filter and press filter or any combinations thereof. In another embodiment, the Solid Separation Unit [F] is fluidly connected via stream 12 to the Mixing Unit [M]. The extractant, i.e. alkylamine optionally present as a solution, is fed into the Mixing Unit via stream 4. The alkylamine and wastewater stream coming from the streams 4 & 12 respectively; is mixed in the Mixing Unit [M]. In an embodiment, the Mixing Unit is including but not limited to stirred vessel reactor, plug flow reactor, static mixer, jet mixer, pump mixer or any combinations thereof. The streams are fed to Mixing Unit [M], wherein the temperature in M is ranging from about 10ºC to about 100ºC, with pressure ranging from about 1 to about 10 atmospheres. In yet another embodiment, the weight ratio of PTA wastewater to alkylamine solution is in the range of about 100:0.5 to about 20:1. The time required for sufficient mixing/ extraction varies from about 1 min to about 120 min. In an embodiment, organic compound such as but not limited to terephthalic acid, p-toluic acid, 4 methyl benzoic acid, 4 carboxy benzoic acid, trimellitic acid, acetic acid, isophthalic acid, orthophthalic acid, metal salt of the organic acid or any combinations thereof; and various other organic compounds present in the PTA wastewater stream are extracted/ recovered into the alkylamine solution. In an embodiment, the outlet of Mixing Unit [M] is directly fed to the Settling Unit [S], where separation of the alkylamine solution takes place from the aqueous wastewater stream. In an embodiment, the Settling Unit [S] is including but not limited to gravity settling vessel and centrifuge settler or combination thereof. The Mixing Unit and the Settling Unit may be either jointly or separately present in the system. The separated / treated aqueous wastewater (lower layer) is collected separately via stream 6; which is fluidly connected to the Aerobic Treatment Assembly [ASP].
[0134]. In an embodiment, the separated / treated aqueous wastewater stream6, is pH adjusted to neutral before being sent for further removal of COD contributed by unextracted organic compounds by known aerobic/activated sludge process. The aqueous stream generated from aerobic treatment assembly is discharged via stream 9. The sludge generated from aerobic treatment assembly is discharged via stream 10.
[0135]. In an embodiment, the upper alkylamine layer is separated via stream 7 and is termed as recycle alkylamine, which is sent for further mixing with the fresh PTA wastewater stream in the Mixing Unit via stream 5; likewise alkylamine solution can be recycled. The stream 7 connects the Settling Unit [S] with the Regeneration Unit [ERU]. In and embodiment, the Regeneration Unit is including but not limited to distillation column, filtration unit and extraction column or any combinations thereof. In an embodiment, the Regeneration Unit is the extractant Regeneration Unit. A small portion of the alkylamine solution is regenerated by using caustic solution (NaOH). The regenerated alkyl amine solution stream 8 can be used for further extraction of pollutant / organic compound from wastewater. The stream 8 connects the Regeneration Unit [ERU] with the stream 4, which in turn is connected to the Mixing Unit.
[0136]. In an exemplary embodiment of the present disclosure, process scheme for reduction of COD in PTA wastewater by separation / recovery of pollutants / organic acids is depicted in Figure 3.

[0137]. Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon description provided herein. The embodiments herein provide various features and advantageous details thereof in the description. Descriptions of well-known/conventional methods and techniques are omitted so as to not unnecessarily obscure the embodiments herein. Further, the disclosure herein provides for examples illustrating the above described embodiments, and in order to illustrate the embodiments of the present disclosure certain aspects have been employed. The examples used herein for such illustration 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 following examples should not be construed as limiting the scope of the embodiments herein.

EXAMPLE
EXAMPLE 1:
[0138]. The PTA wastewater is subjected to the instant process for extraction or recovery of organic compounds. About 97.5 gm of PTA wastewater having about 8000-8400 ppm of organic COD is mixed with about 2.5 gm of 1:1 ratio of Trioctylamine (TOA) and 1-octanol mixture. The contents are stirred at about 50ºC for about 30 min. The contents of the flask are then transferred to separating funnel, the COD of the lower aqueous layer is measured to be in the range of 400 to 700 ppm. The upper organic phase is sent for regeneration.

EXAMPLE 2:
[0139]. COD level of wastewater obtained from PTA plant is detected by potassium dichromate method, and is found to be about 8786 ppm. 97.5 gm of wastewater having temperature of around 140ºC is cooled down to temperature of about 50°C in the heat exchanging unit [X]. pH of the cooled wastewater from the heat exchanging unit is adjusted to 2.5 in the pH adjustment unit. The wastewater is then mixed with about 2.5 gm of Tri-octyl amine in the mixing unit [M] at temperature of about 50ºC, at atmospheric pressure; and time duration of about 30 min. The weight ratio of the amine to wastewater is about 2.5:97.5. The pollutants in the wastewater stream are separated/ extracted/ recovered into the amine phase. The mixture from the mixing unit is fed to settling unit [S], where separation of upper layer comprising the amine and the recovered pollutant takes place from the lower layer comprising the treated aqueous wastewater. The COD level of the separated treated wastewater obtained is about 500 ppm. The percentage of extraction is about 95%.
[0140]. The separated aqueous wastewater is further fed into the biological treatment assembly [ASP], for further reduction of COD levels.
[0141]. The separated upper layer of amine is recycled by entering the mixing unit and settling unit, after which the amine is subjected to regeneration in the regeneration unit [IRU] to separate the remaining pollutants and the amine. The regenerated amine is used for further extraction.
EXAMPLE 3:
Example 3(a): Liquid-Liquid Extraction
[0142]. Initially, PTA wastewater solution is taken in a 1L beaker (initial pH 4.4) and its pH is adjusted to 2.5 by addition of few drops of 10% HCl solution. From this solution, about 97.5 gm of wastewater (effluent) is taken into three neck round bottom flask. To this about 2.5 gm of TOA (Trioctylamine) is added. The contents of the flask are stirred using overhead stirrer in a water bath at temperature of about 50°C for about 30 min. The contents are transferred into a separating flask and the phases are allowed to separate for about 10-15 min. The TOA forms an acid-amine complex with organic acid present in the wastewater [figures 4(a) and 4(b)]. Organic phase comprising TOA along with organic acids/salts thereof float in the upper phase. The raffinate (i.e., the treated wastewater) is in lower aqueous phase and is completely separated by decantation; COD value of this sample is analysed. The separated 2.5 gm of TOA (weight increased to about 2.6 gm) is further reused in another cycle with about 97.5 gm of fresh wastewater solution (pH adjusted), as per the above process. Similarly, the initial 2.5 gm of TOA is reused for about 3 times. The results are tabulated in the below Table 2.

Table 2:
Temperature 50 °C (positive experimental data)
Concentration of TOA 2.5%
COD of wastewater in ppm Initial Fresh
Treatment 1st Recycle 2nd Recycle 3rd Recycle
8786 522 1317 1932 1757
%Reduction 94 85 78 80

[0143]. It is observed that TOA decreases the COD of effluent from 8786 ppm to 522 ppm i.e., (94% of extraction). Regenerated TOA decreases the COD of effluent providing about 78-85% of extraction. Comparative view of samples of untreated wastewater and wastewater treated with the alkylamine is depicted in Figure 4(g). As can be observed from the Figure 4(g), the color of the untreated (extreme left) and treated wastewater significantly changes. The change in color of the treated wastewater is due to removal of pollutants such as organic acid and their metal salts, by the alkylamine treatment.
Example 3(b): Regeneration of TOA
[0144]. After 4 recycles of the above process, the TOA is regenerated from the upper organic phase by using caustic wash (10% NaOH) solution. About 2.5 – 2.9 gm of TOA is washed/stirred with required amount of about 10% NaOH solution till the mixture attains the basic pH (8.0-8.5). After about 10 min of stirring, contents of the mixture is separated by using separating flask, wherein the upper layer contains the regenerated TOA [Figures 4(c) and 4(d)]. This regenerated TOA is further used for liquid-liquid extraction of organic acids from fresh PTA wastewater.
[0145]. During the extraction step of 3 recycles, the TOA is converted into acid-amine complex, and its weight increases from 2.5 (TOA) to 2.85 gm (Acid-amine complex). Increase of this 0.35 gm is due to the addition of organic acids from aqueous PTA wastewater to the TOA resulting into acid-amine complex.
[0146]. During regeneration step, the yield of TOA from Acid-amine complex is observed to be of about 85% since weight of organic phase acid-amine complex 2.85 gm decreases to about 2.13 gm and as initial TOA used for the extraction step is 2.5 g).

Example 3(c): Recovery of organic acids
[0147]. Recovery of the organic acids from the reaction products enables overall economics of the entire process. The lower aqueous layer obtained as per Example 3(b), contains metal salts of organic acid such as sodium terephthalate, sodium acetate, etc. These metal salts are recovered by adding about 10% HCl solution to the aqueous layer till the mixture attains acidic pH of about 2-2.5, to ensure that the respective organic acids are reformed along with regeneration of metal salt such as NaCl [Figures 4(e) and 4(f)]. Here organic acids are slightly soluble (limited by temperature) in water and excess amount beyond their solubility limit is precipitated. Solubility of organic acids – terephthalic acid, benzoic acid and p-toluic acid is depicted in Figures 5(a)-(c). The metal salt such as sodium chloride formed is in soluble form (high solubility limit).
[0148]. The organic acids is further purified from this reaction mixture by evaporation of water or water wash (required amount), so that salt (such as sodium chloride, having higher solubility compared to the organic acids at that particular temperature) present in the mixture is washed away
[0149]. Crystallization or precipitation of the organic acids obtained is carried out by cooling. Since organic acids have less solubility in water, upon cooling they are crystallized initially. Filtration of the crystallized organics acids from the mother liquor results in obtaining the organic acids with high purity.

EXAMPLE 4:
[0150]. Wastewater obtained from PTA plant is subjected to one cycle of liquid-liquid extraction of the present disclosure as per the protocol of Example 3(a) using alkylamine in wastewater, at varying ratios as depicted in Table 3. About 2.5 gm of TOA is employed independently with about 97.5 gm, 195 gm, 292 gm, 390 gm and 585 gm of wastewater. The reduction in COD levels of the wastewater is tabulated in Table 3. TOA decreases the initial COD of wastewater by 82-94% when used at a ratio of about 1:39, 1:78, 1:116.8, and 1:156. However, only about 57% reduction in COD is observed when the ratio of alkylamine : wastewater is 1:234.

Table 3:
Temperature 50°C
Amount of TOA: Wastewater (in grams) 2.5: 97.5 2.5: 195 2.5: 292 2.5: 390 2.5: 585
Ratio of TOA: Wastewater (w/w) 1: 39 1: 78 1: 116.8 1: 156
1: 234
COD of wastewater in ppm Initial=
8786 522 922 1327 1592
3743
% Reduction of COD - 94 89 85 82 57.4

EXAMPLE 5:
[0151]. Wastewater obtained from PTA plant is subjected to one cycle of liquid-liquid extraction of the present disclosure as per the protocol of Example 3(a) using alkylamine in wastewater, at varying pH as depicted in Table 4. Initial COD of the wastewater sample (represented as F-1601) is 8798 ppm. About 2.5 gm of TOA is employed with about 97.5 gm of wastewater at pH of about 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 and 4.9. The COD levels of the treated wastewater at each pH condition and final pH of the treated wastewater is tabulated in Table 4. TOA significantly decreases the initial COD of wastewater from about 8798 ppm to about 316-733 ppm at initial pH of about 1.0 – 4.0. However, no reduction in COD is observed at initial pH of 4.9.

Table 4:
Initial pH of the wastewater COD of treated wastewater) Final pH
(treated wastewater)
1.0 462 1.2
1.5 513 2.0
2.0 522 3.4
2.5 456 3.6
3.0 316 3.9
3.5 733 4.2
4.0 525 4.4
4.9 8798 4.8

[0152]. Further, HPLC analysis for various organic acids viz. isophthalic acid (IPA), benzoic acid (Bz-acid), orthophthalic acid (OPA), trimellitic acid (TMA) and p-toluic acid (PTA) is carried out for treated wastewater samples (experimented at various pH values about 1.0 to 4.5). The results obtained are depicted in Figure 7, wherein it is observed that lowering the pH results in better extraction.
ADVANTAGES
[0153]. The present disclosure enables the extraction or recovery of COD contributing organic compound in wastewater using amine extractants.
[0154]. The present disclosure relates to a simple process of extraction of the organic compounds from wastewater.
[0155]. The instant process takes lesser time when compared with the long hydraulic retention time (residence time) involved in anaerobic digestion process. In an embodiment, the process of the present disclosure employing liquid-liquid extraction requires less residence time (about 10-50 min), wherein retention time in anaerobic digestion process is longer (about 24 hours).
[0156]. The process of the instant disclosure can replace or eliminate the cost intensive anaerobic digestion process, typically practiced in the PTA wastewater treatment process.
[0157]. In the present process, the extractants (amines) are regenerated by caustic wash to the organic phase containing acid-amine complex.
[0158]. In the present process, COD contributing organic acid compounds are recovered with HCl to the aqueous phase containing sodium salt of terephthalate hence net process yields can be increased marginally.
[0159]. In the present process, the water produced after treatment can be reused for crude-terephthalic acid purification process after being treated with necessary tertiary treatment methods such as but not limiting to ultrafiltration, reverse osmosis, etc.
[0160]. The present disclosure is able to successfully overcome the various deficiencies of prior art and provide for a process for extraction or recovery of organic compound.
[0161]. Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based on the description provided herein. The embodiments herein provide various features and advantageous details thereof in the description. Descriptions of well-known/conventional methods and techniques are omitted so as to not unnecessarily obscure the embodiments herein.
[0162]. The foregoing description of the specific embodiments fully reveals 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 in this disclosure 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.
[0163]. Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” wherever used, 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.
[0164]. With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[0165]. 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.
[0166]. Any discussion of documents, acts, materials, devices, articles and 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.
[0167]. While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications 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 modifications in the nature of the disclosure or the preferred embodiments 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.

REFERENCE NUMERAL TABLE
Sl. Nos. Reference Nos. Description
1 100 System.
2 200 System.
3 X Heat Exchanging Unit.
4 pH pH Adjustment Unit.
5 F Solid Separation Unit.
6 M Mixing Unit.
7 S Settling Unit.
8 ERU Regeneration Unit.
9 ASP Aerobic Treatment Assembly.
10 Stream 1 Connected to Heat Exchanging Unit for receiving aqueous solution such as wastewater.
11 Stream 2 Connects Heat Exchanging Unit with pH Adjustment Unit.
12 Stream 3 Connects pH Adjustment Unit with Mixing unit
13 Stream 4 Connected to mixing unit for entry of alkylamine.
14 Stream 5 Connects separated upper alkylamine layer from Settling Unit to stream 4 to enter Mixing Unit.
15 Stream 6 Connects separated aqueous wastewater from the Settling Unit to Aerobic Treatment Assembly.
16 Stream 7 Connects Settling Unit with Regeneration Unit.
17 Stream 8 Connects regenerated alkylamine solution from Regeneration Unit to stream 4 to enter Mixing Unit.
18 Stream 9 Connected from the Aerobic Treatment Assembly for generated aqueous stream.
19 Stream 10 Connected from the Aerobic Treatment Assembly for generated sludge.
20 Stream 11 Connects pH Adjustment Unit with Solid Separation Unit.
21 Stream 12 Connects Solid Separation Unit with Mixing Unit. ,CLAIMS:1. A process for separating pollutant from wastewater, said process comprising acts of:
a) modulating temperature and optionally pH of wastewater;
b) contacting the wastewater obtained from step a) with alkylamine and mixing to obtain mixture;
c) incubating the mixture of step b) to obtain upper layer comprising alkylamine along with pollutant and lower layer comprising treated wastewater; and
d) separating the upper layer comprising alkylamine along with pollutant from the lower layer comprising treated wastewater.
2. A system for separating pollutant from wastewater, the system comprising:
a) at least one Heat Exchanging Unit [X] adapted to receive wastewater, wherein the at least one Heat Exchanging Unit is configured to modulate temperature of the wastewater;
b) at least one Mixing Unit [M] fluidly connected to the at least one Heat Exchanging Unit [X], the at least one Mixing Unit is configured to receive the wastewater from the at least one Heat Exchanging Unit and alkylamine, and is configured to mix the wastewater and the alkylamine; and
c) at least one Settling Unit [S] fluidly connected to the at least one Mixing Unit, [M] the at least one Settling Unit receives a mixture comprising the wastewater and the alkylamine from the at least one Mixing Unit, and is configured to allow settling of the mixture to obtain upper layer comprising alkylamine along with pollutant, and lower layer comprising treated wastewater.
3. The process as claimed in claim 1, wherein the wastewater in step a) is modulated to a temperature ranging from about 10ºC to about 100ºC and pH of about 1.0 to about 4.0; wherein the modulating of the temperature is carried out in Heat Exchanging Unit [X]; wherein modulation of the pH is carried out in pH Adjustment Unit [pH]; wherein post the modulation of temperature and pH of the wastewater, solid waste is separated from the wastewater in step a) in Solid Separation Unit [F].
4. The process as claimed in claim 1, wherein the contacting and the mixing is carried out in Mixing Unit [M]; the incubating of step c) is carried out in Settling Unit [S]; and wherein the contacting, mixing, incubating or separating is carried out at temperature ranging from about 10°C to about 100°C, pressure ranging from about 1 atmospheres to about 10 atmospheres for a time period ranging from about 1 minute to about 120 minutes.
5. The process as claimed in claim 1, wherein the upper layer of step d) is separated from the lower layer by decantation; wherein the upper layer of step d) is treated to recover the alkylamine and the pollutant separately; wherein the treating is carried out by technique selected from group comprising solvent extraction, caustic neutralization, filtration and distillation or any combinations thereof; and wherein the treating is carried out in unit selected from group comprising Settling unit [S] and Regeneration Unit [ERU] or combination thereof; and wherein the lower layer of step d) is further treated in at least one Biological Treatment Assembly [ASP] to obtain aqueous wastewater.
6. The system as claimed in claim 2, wherein the system comprises at least one pH Adjustment Unit [pH] adapted to receive wastewater configured in between the at least one Heat Exchanging Unit [X] and the at least one Mixing Unit [M], wherein the at least one pH Adjustment Unit is configured to modulate pH of the wastewater.
7. The system as claimed in claim 2 or 6, wherein the system comprises at least one Solid Separation Unit [F] configured in between the at least one Heat Exchanging Unit [X] or the at least one pH Adjustment Unit [pH] and the at least one Mixing Unit [M], wherein the at least one Solid Separation Unit is configured to separate solid waste from the wastewater.
8. The system as claimed in claim 2, wherein at least one Regeneration Unit [ERU] is fluidly connected to the at least one Settling Unit, wherein the at least one Regeneration Unit is adapted to receive the upper layer comprising alkylamine along with pollutant from the at least one Settling Unit, and is configured to separate the alkylamine and the pollutant.
9. The system as claimed in claim 2, wherein the at least one Settling Unit is fluidly connected to at least one biological treatment assembly [ASP] to obtain the wastewater from the Settling Unit.
10. The system as claimed in claim 2, wherein the at least one Mixing Unit comprises an inlet port fluidly connected to an alkylamine source through a first passage.
11. The system as claimed in claim 2, 8 or 10, wherein the system comprises a bypass passage fluidly connected between: at least one of the at least one Regeneration Unit [ERU] and the at least one Settling Unit [S]; and the first passage.
12. The process as claimed in any one of claims 3-5 or the system as claimed in any one of claims 2 or 6-9, wherein the system is operational in mode selected from group comprising batch mode, semi-continuous mode and continuous mode, or any combinations thereof; the Heat Exchanging Unit [X] is a heat exchanger selected from group comprising shell heat exchanger, tube heat exchanger and flash evaporator or any combinations thereof; the Solid Separation Unit [F] is selected from group comprising nustch filter, bag filter and press filter or any combinations thereof; the Mixing Unit [M] is selected from group comprising stirred vessel reactor, plug flow reactor, static mixer, jet mixer and pump mixer or any combinations thereof; the Settling Unit [S] is selected from group comprising gravity settling vessel and centrifuge settler or combination thereof; the Biological Treatment Assembly [ASP] is activated sludge assembly; and the Regeneration Unit [ERU] is selected from group comprising distillation column, filtration unit and extraction column or any combinations thereof.
13. The process as claimed in claim 1 or the system as claimed in claim 2, wherein the wastewater comprises pollutant selected from group comprising aliphatic hydrocarbon or aromatic hydrocarbon or their derivatives or any combinations thereof; and wherein the hydrocarbon compound or derivatives thereof is selected from group comprising organic acid and metal salt of organic acid or combination thereof; wherein the organic acid is selected from group comprising benzoic acid, p-toluic acid, terephthalic acid, 4-carboxy benzoic acid, trimellitic acid, acetic acid, 4-methyl benzoic acid, isophthalic acid and orthophthalic acid or any combinations thereof; wherein cation in the metal salt of organic acid is selected from group comprising sodium, magnesium and potassium or any combination thereof, and wherein anion in the metal salt of organic acid is selected from group comprising terephthalate, acetate, benzoate, isophthalate, trimetillate, methyl benzoate, phthalate, carboxy benzoate or any combinations thereof.
14. The process as claimed in claim 1 or the system as claimed in claim 2, wherein the wastewater is selected from group comprising industrial wastewater, purified terephthalic acid (PTA) wastewater, petrochemical wastewater, pharmaceutical industry wastewater and isophthalic acid wastewater or any combinations thereof; wherein the alkylamine is selected from secondary amine or tertiary amine or combination thereof; wherein the secondary alkylamine is alkylamine having any of C6-C10 chain length; and wherein the tertiary alkylamine is alkylamine having any of C6-C10 chain length; or any combinations thereof.
15. The process as claimed in claim 1 or the system as claimed in claim 2, wherein the alkylamine is selected from group comprising trihexylamine and trioctylamine or combination thereof.
16. The process as claimed in claim 1 or the system as claimed in claim 2, wherein the alkylamine is present in a solution, wherein the solution is diluent selected from group comprising chlorinated hydrocarbon, ketone, alcohol and halogenated aromatic solvent or any combinations thereof preferably long chain hydrocarbon alcohol; and wherein weight ratio of the alkylamine to the wastewater is ranging from about 0.5:100 to about 1:20, preferably about 0.5:100 to about 3:100.
17. The process as claimed in claim 3 or the system as claimed in claim 7, wherein the solid waste is selected from group comprising precipitated organic acid and solid particulate matter or combination thereof.