A plug-in modular BIO-electrocatalytic functional device for the treatment of wastewaters

Abstract

The invention pertains to a Plug-in modular functional device embedded with an electrode assembly for the treatment of pharmaceutical / industrial wastewaters. The invention provides electrochemical treatment along with biological treatment to address the challenges posed by complex industrial / chemical wastewater. The developed device presents an efficient and scalable solution for the treatment of complex organic and inorganic pollutants through bio- electrocatalytic process. It is able to achieve color removal (89.75%), COD removal (90.4%), TOC removal (90.4%), TN removal (53.74%), Amine removal (67.67%), Azo reductase activity (37.9 U). The invented device can be embedded / integrated to biological unit operation of the existing effluent treatment plants (without modification) or with a new ETP design to intensify the removal of organics and inorganics from chemical wastewater. The device improves performance of treatment in terms of carbon (COD / TOC) removal, Nutrients removal, colour removal and TDS removal by 15-35% augmented efficiency based on the nature of wastewater being treated.

Description

[0001] A PLUG-IN MODULAR BIO-ELECTROCATALYTIC FUNCTIONAL DEVICE FOR THE TREATMENT OF WASTEWATERS

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a plug-in modular bio-electrocatalytic device designed for effective treatment of wastewaters. In particular, the present invention relates to a modular plug-in functional device embedded with an electrode assembly, which provides electrochemical as well as biological treatment. The developed device can be integrated with the existing effluent / sewage treatment plants (ETP / STPs) without modification or to a new effluent treatment plant. It significantly enhances the removal of both organics and inorganics pollutants present in wastewater. The developed device finds immense application in the field of industrial wastewater treatment, this invention helps to attain the United Nations Sustainable Development Goal 6thsustainable development goal of 'clean water and sanitation.

[0004] BACKGROUND OF THE INVENTION

[0005] Wastewater often contains harmful chemicals and pollutants that can cause waterborne diseases and health problems if not properly treated. Wastewater treatment helps remove or neutralize these contaminants, making water safe for consumption and recreational use. Treated wastewater can be reclaimed and reused for various purposes, such as irrigation, industrial processes, and even potable water supply. This reduces the strain on freshwater resources and supports sustainable water management practices.

[0006] Treatment of pharmaceutical wastewater or chemical-based wastewater is an emerging challenge through biological processes. Complex pharmaceutical / industrial wastewater, particularly from bulk drug industries, characteristically contains high concentrations of both organic / inorganic pollutants. The presence of these contaminants in these complex wastewaters is a major environmental concern that needs to be addressed.

[0007] Conventional biological wastewater treatment systems are designed to take only organics / inorganics with inherent limitations and are expensive when salts / metals / emerging pollutants need to be removed. Treatment of complex domestic / industrial wastewater needs an efficient and low-cost treatment strategy to address salt, emerging pollutants, and organics / inorganics removal as the prime objective. Reference may be made to IN265268 wherein invented is a wastewater treatment apparatus that consists of an electrode assembly to add an electric charge to the wastewater and a microorganism-containing bioreactor with a raw wastewater inlet and treated wastewater outlet. The electrode assembly is placed in a flow channel between the inlet and the bioreactor so as not to obstruct in-channel wastewater flow. However, the drawbacks associated with this document is that the design is very complex and used electric charge for the treatment of waste water, whereas the present invention is very simple in design and works on in- situ potential.

[0008] Reference may be made to WO2012012647 which recites designs of reactors, parts, and operation plans for eliminating chemical oxygen demand and nitrates from any appropriate wastewater stream. Additionally, it offers operating schemes, reactor designs, and component designs intended to adjust and enhance the pH and water quality of wastewater streams. However, the drawbacks associated with this document is that it only emphasizes nitrate and COD removal while the present invention demonstrates higher efficiency in removing a wider array of pollutants, including color, TOC, TN and amines.

[0009] Reference may be made to CN103466851A which discloses a tail gas treatment system, comprising an electrolytic reaction tank, an electrolytic chlorine oxidizing tank, and a pH regulating tank. An electrolytic chlorine oxidizing tank rectifier is positioned outside the electrolytic chlorine oxidizing tank, and multiple electrodes are arranged inside the electrolytic chlorine oxidizing tank. An external power source is connected to the electrodes through the electrolytic chlorine oxidizing tank rectifier. The oxidizer is characterized by the arrangement of a wastewater inlet pump, a dosing pump, and a pH regulating tank stirrer within the pH regulating tank. The electrolytic chlorine oxidizer breaks down organic materials in wastewater through both direct and indirect electrolytic oxidations. It can remove more COD (chemical oxygen demand) and nitrogen from water at rates of more than 80% and 99%, respectively. Cl- is recycled in water, fulfilling the objective of treating waste with waste. However, the drawbacks associated with this document is that the operation of an electrolytic chlorine oxidizer involves multiple components such as pH regulation, dosing pumps, rectifiers, external power source, potentially increasing operational complexity. The present invention is a low cost operation with minimum components.

[0010] Reference may be made to US20230183112 which discloses sophisticated systems and procedures for treating livestock wastewater that simultaneously remove organics, suspended solids, and malodor (caused by volatile fatty acids) from raw wastewater at the anode chamber using an anaerobic bio electrochemical system (BES) and nitrate (nitrite) from treated wastewater at the cathode chamber. The device described in this invention consists of at least one anode chamber with at least one anode inside of it, and at least one cathode chamber with at least one cathode inside of it. An anion or cation is transported between the anode chamber and the cathode chamber via a separator that connects the two chambers. However, the drawbacks associated with this document is that specifically designed for the simultaneous removal of nitrate (nitrite) and other contaminants from livestock wastewater while the present invention is adaptable for treating complex organic and inorganic pollutants typically found in pharmaceutical and industrial wastewaters. The present invention offer a simpler operational approach and potentially lower maintenance requirements due to its modular and integrated design.

[0011] Reference may be made to CN102992455 which recites a completely novel three-dimensional electrode system for purifying wastewater consisting of cathode and anode electrode plates for electrochemical catalysis oxidization that alternate inside a reactor; additionally, it includes an iron-carbon micro-electrolysis filler and a micropore aeration plate placed at the bottom of the reactor. Wastewater enters the device, passes through the holes in each stage of the electrode plates, and then exits. The micropore aeration plate at the bottom of the reactor is used to aerate tiny bubbles. The innovative three-dimensional electrode device effectively eliminates and degrades the wastewater through catalytic oxidation. This results in the complete degradation of wastewater that is difficult for biological processes to break down or in the generation of harmless or degradable wastewater with low-grade organic matters. Due to the use of singleclass effluent, the novel three-dimensional electrode device has the advantages of high operation efficiency, ease of installation, and small occupation area. It can also guarantee that the rate of chroma removal, TOC (total organic carbon), and COD (chemical oxygen demand) of wastewater that is difficult to biologically degrade is high, and it can be used to completely degrade toxic pollutants in wastewater while maintaining stable effluent quality. However, the drawbacks associated with this document is that the novel three-dimensional electrode involve multiple components such as electrode plates, micropore aeration plates, and microelectrolysis fillers. This complexity may result in challenges during installation, operation, and maintenance, especially in scaling up for larger treatment capacities while the present invention is designed for easier integration into existing or new effluent treatment plants without significant modification. The present document primarily focuses on electrochemical catalysis for pollutant degradation while the present invention integrates both electrochemical and biological treatments, combining the advantages of both methods to tackle the challenges posed by complex industrial and chemical wastewater effectively.

[0012] Reference may be made to CN201610318194.9A, that recites an electrochemical oxidation process for treating waste water from cotton dyeing. The method involves pumping wastewater into an organism fluidization system, where solid, liquid, and gas are mixed completely through three-phase fluidization, active carbon absorption, and the presence of biological flora. This process further reduces the COD and coloration in the wastewater. However, the drawbacks associated with this document is that due to its complex design scaling up the three- dimensional electrode device for large-scale applications may present challenges in terms of reactor design, electrode scaling, and maintaining consistent treatment performance while the present invention is designed for scalability and integration into existing effluent treatment plants (ETPs) without extensive modifications.

[0013] Reference may be made to the article entitled “Electrochemical degradation of diazinon from aqueous media using graphite anode: Effect of parameters, mineralization, reaction kinetic, degradation pathway and optimisation using central composite design (https: / / doi.org / 10.1080 / 03067319.2020.1742893)”, in which graphite and stainless steel electrodes were used as both anode and cathode respectively with applied current for the electrochemical degradation of diazinon. However, the drawbacks associated with this document are that the use of CCD to evaluate the effect of different parameters, while thorough, adds complexity to the experimental design. This complexity may pose challenges for practical implementation. The process is less sustainable as it requires applied current for functioning whereas the present invention works on insitu potential and is very effective in treating wastewaters from different streams.

[0014] Reference may be made to the article entitled “Design and feasibility study of novel paraboloid graphite based microbial fuel cell for bioelectrogenesis and pharmaceutical wastewater treatment (https: / / doi.or / 10.1016 / j.jece.2020.104502)” wherein a novel paraboloid graphite based MFC was built for PIW treatment where MSW was used as a substrate for the development of biofilm. However, the drawbacks associated with this document are that the study was conducted on a small scale, and the feasibility of scaling up the novel paraboloid graphite-based MFC configuration for industrial applications is not addressed. While the study aims to develop a cost-effective treatment technique, graphite can be expensive. The COD removal reported was less than that of the present invention, which is also very efficient in chroma removal.

[0015] Reference may be made to the article entitled “Development of a novel bioelectrochemical membrane reactor for wastewater treatment (https: / / doi.org / 10.1021 / es2019803)” disclosing a bioelectrochemical membrane reactor (BEMR), which takes advantage of a membrane bioreactor (MBR) and microbial fuel cells (MFC), that is developed for wastewater treatment and energy recovery. System consists of stainless-steel mesh with biofilm formed on it served as cathode and the filtration material. However, the drawbacks associated with this document is that it includes the potential for fouling and degradation of the membrane and steel mesh used in the system during extended operation. In contrast, the present invention involves the use of solid SS316L electrodes for wastewater treatment, which are more durable and have shown long-term stability plus it is a membrane less operation.

[0016] Reference may be made to the article entitled “Biocatalyst behavior under self-induced electrogenic microenvironment in comparison with anaerobic treatment: Evaluation with pharmaceutical wastewater for multi-pollutant removal

[0017] (https: / / doi.Or / 10.1016 / i.biortech.2011.08.061)” that studied biocatalyst behavior under diverse microenvironments viz., self-induced electrogenic (bioelectrochemical treatment, BET) and anaerobic treatment (AnT) microenvironments, with real-field pharmaceutical wastewater. However, the drawbacks associated with this document is that it is two system design which uses proton exchange membrane for the treatment of real-field pharmaceutical waste water in small scale while the present study is a membrane less single system design operated with 100L capacity with different waste water.

[0018] Reference may be made to the article entitled “Anoxic bio-electrochemical system for treatment of complex chemical wastewater with simultaneous bioelectricity generation (https: / / doi.Org / 10.1016 / i.biortech.2013.10.028)” that reported Bioelectrochemical treatment system (BET) with anoxic anodic microenvironment with chemical wastewater (CW) in comparison with anoxic treatment (AxT, sequencing batch reactor (SBR)) with same parent anaerobic consortia. However, the drawbacks associated with this document is that it reports the use of graphite electrodes which are more expensive than the SS316L material. The document reports that reactor was designed such that more than 50% of the reactor volume was packed with different layers of gravel bed, coarse and medium gravels packed and fine gravel while the present invention is much simpler in terms of reactor designing and operation.

[0019] Reference may be made to the article entitled “integrated bio-electrogenic process for bioelectricity production and cathodic nutrient recovery from azo dye wastewater (https: / / doi.org / 10.1016Zi.renene.2016.03.047)’’ reporting Microbial electrochemical treatment (MET) process that was designed to evaluate complete mineralization of partially treated dye effluent obtained from anoxically operated Periodic discontinuous batch reactor (PDBR) for simultaneous bioelectricity generation and recovery of nutrients. In MET bioreactor, anode and cathode chambers were fed with designed synthetic wastewater (DSW) and PDBR dye effluents. The dye metabolite (NH+4) converted to nitrates by the activity of aerobic biocatalyst present in cathode chamber to be used as biofertilizer. However, the drawbacks associated with this document is that the use of Proton Exchange Membranes (PEM) and graphite electrodes in the reactor configuration is costlier compared to alternatives such as SS316L materials which has been used in the present invention. Moreover, the MET process used involves intricate operations, including the use of designed synthetic wastewater and specific conditions for the anode and cathode chambers which are more complex and can be challenging for practical implementations.

[0020] Reference may be made to the article entitled “Effect of anodic metabolic function on bioelectricity generation and substrate degradation in single chambered microbial fuel cell (https: / / doi.org / 10.1021 / es8012529)” wherein the influence of anodic metabolic function viz., aerobic, anoxic and anaerobic on bioelectricity generation was evaluated in single chamber mediator less microbial fuel cells (non-catalyzed graphite electrodes; open-air cathode) under similar operating conditions (pH 7; ambient temperature / pressure). However, the drawbacks associated with this document is that it reports fluctuations in bioelectricity generation under different metabolic conditions. These inconsistencies can hinder the reliability and predictability of the system, making it challenging to optimize for stable performance along with that maintaining specific operational conditions such as pH 7 and ambient temperature / pressure may be challenging in real-world applications. Moreover, the COD removal efficiency is less in compassion to the present invention.

[0021] In short, it may be summarized that the existing wastewater treatment systems focused on using membrane bioreactors, ozone reactor and sedimentation filtration device evaluated in single and dual chambered microbial fuel cells with basic scope of power production in addition to wastewater treatment that are operated in batch mode at small lab-scale operation. However, none of the reported prior arts lead to the conceptualization of a plug-in modular bio- electrocatalytic functional device for the treatment of a wide variety of wastewaters.

[0022] Accordingly, keeping in view the drawbacks of the hitherto reported prior art, the inventors of the present invention realized that there exists a dire need to provide a hybrid treatment system for the treatment of complex organic / inorganic pollutants, which combines electrocatalysis with biological treatment [bio-electrocatalysis], along with optimization of electrode stack assembly in continuous mode operation; wherein the system can be employed directly in existing effluent treatment plants (ETP) without any modification or can be integrated with the new ETPs for continuous mode operation; while improving the performance of treatment in terms of carbon (COD / TOC) removal, nutrients removal, colour removal and TDS removal by 15-35%; having membrane less operation and not having the requirement of external potential.

[0023] OBJECTIVES OF THE INVENTION

[0024] The main objective of the present invention is therefore to provide a plug-in modular bio- electrocatalytic system for the treatment of a wide variety of wastewaters, which obviates the drawbacks of the hitherto reported prior art.

[0025] Another objective of the present invention is to provide a plug-in modular functional device comprising SS316L stacked electrode assembly integrated in a single device without using membranes or externally applied electrical potential.

[0026] Still another objective of the present invention is to provide a device that can be embedded in any existing effluent / sewage treatment plants ETP / STPs to intensify the treatment process without much modifications.

[0027] Yet another objective of the invention is to provide a device that treats chemical wastewater via bio-electrocatalysis without the use of external applied potential, thus enhancing energy efficiency and sustainability.

[0028] Still another objective of the present invention is to provide two rectangular reactors with a total / working volume of 0.75 / 0.6 L; operated in three phases (OC, and AP) with various circuit connections to demonstrate the efficiency of dye degradation using SS316 L electrodes. Yet another objective of the present invention is to provide a device that operates in series circuit in close connection with SS316L electrode materials in 4 and 8 stacked assemblies with a 100 L capacity bioreactor.

[0029] Still another objective of the present invention is to provide a device with membrane less operation during waste water treatment.

[0030] Yet another objective of the present invention is to provide a device with continuous flow operation without the need of pump, allowing for low-energy, passive treatment systems.

[0031] Still another objective of the present invention is to provide a plug-in modular functional device that increase the treatment efficiency of complex wastewaters by 15-25%.

[0032] SUMMARY OF THE INVENTION

[0033] The present invention relates to a plug-in modular bio-electrocatalytic functional device designed to enhance the treatment of industrial and pharmaceutical wastewaters. The device can be integrated into existing effluent treatment plants (ETPs) or sewage treatment plants (STPs) without requiring modifications or can be included into new treatment plants. It applies a combination of electrochemical and biological processes to improve the removal of complex organic and inorganic pollutants.

[0034] In an embodiment, the invention provides a plug in modular functional device comprising 4 / 8 stacked assemblies, two rectangular reactors, at least one biological unit; wherein the said 4 and 8 stacks are in series with closed circuit connections and each assembly consisting of two electrodes, the anode, which facilitates the oxidation of contaminants, and the cathode which serves as the site for reduction reactions.

[0035] In another embodiment, the invention provides a plug-in modular bio-electrocatalytic functional device to augment the treatment efficacy of chemical-based wastewaters through bio-electrochemical processes by self-induced electro-oxidation in hybrid anaerobic / anoxic operation. The designed plug-in functional device is intended to be used as direct incorporation in existing effluent treatment plants (ETP) without any modification or can be integrated with the new ETPs for continuous mode operation. In still another embodiment of the invention, the developed device functions effectively when embedded with any of the biological unit operations namely, the Activated sludge process (ASP), Membrane Bioreactor (MBR), Anaerobic digestion (AD) etc. The integration of modular functional device enhances dye and color removal, COD removal, TOC removal, TN removal, amine removal, and azo reductase activity.

[0036] In yet another embodiment, the present invention helps to remove organic / inorganic pollutants from industrial / chemical wastewater with SS316L electrode assemblies with 8 stacks. Each of the electrode unit is attached to acrylic material to hold up the electrodes and electronic wires were used for circuit connection.

[0037] In yet another embodiment, the invention provides efficient wastewater treatment, with color removal (89.75%), COD removal (90.4%), TOC removal (90.4%), TN removal (53.74%), Amine removal (67.67%), Azo reductase activity (37.9 U).

[0038] In still another embodiment of the invention, the electrodes are made up of SS 316L that improves the efficacy of wastewaters treatment and the device electrode assemblies, which operate without any membrane.

[0039] In yet another embodiment of the invention, the developed device has self-induced potential that is responsible for functioning without the requirement of external potential.

[0040] In still another embodiment of the invention, the developed device enhances dye and color removal, COD removal, TOC removal, TN removal, amine removal, and azo reductase activity.

[0041] In still another embodiment of the invention, the device improves performance of treatment in terms of carbon (COD / TOC) removal, Nutrients removal, colour removal and TDS removal by 15-35% augmented efficiency based on the nature of wastewater being treated.

[0042] In a further embodiment, the present invention provides a plug in modular bio -electro catalytic device for wastewater treatment, comprising:

[0043] 1) stacked electrode assembly (3); 2) at least two rectangular reactors (2);

[0044] 3) at least one biological unit (4);

[0045] 4) electrode holder (6);

[0046] 5) inlet (1); and

[0047] 6) outlet (7); wherein, the stacked electrode assembly comprises 4 to 8 stacked electrodes connected in series with closed circuit (5) and each assembly comprises at least one anode and one cathode; wherein, the two rectangular reactors configured to house the stacked assemblies and facilitate wastewater flow comprise total working volume between 0.61 to 0.751.

[0048] In still another embodiment, the present invention provides a plug in modular bio-electro catalytic device, wherein the electrodes are selected from the group consisting SS316L, Graphite, Grafoil, Titanium, Platinum, Nickel, Copper.

[0049] In yet another embodiment, the present invention provides a plug in modular bio-electro catalytic device, wherein the device comprising electrode assemblies (3), which operate without any membrane.

[0050] In still another embodiment, the present invention provides a plug in modular bio-electro catalytic device, wherein the anode facilitates oxidation of organic contaminants and the cathode facilitates reduction reactions.

[0051] In yet another embodiment, the present invention provides a plug in modular bio-electro catalytic device, wherein the biological unit is a sludge enriched with Priestia aryabhattai (MTTC No. 13539), Micrococcus flavus (MTTC No. 13554), Microbacterium paraoxydans (MTTC No. 13541), and Acinetobacter towneri (MTCC No. 13540) microorganisms.

[0052] In still another embodiment, the present invention provides a plug in modular bio-electro catalytic device, capable of being embedded into existing biological unit operations selected from the group consisting of activated sludge process (ASP), sequencing batch reactor (SBR), moving bed biofilm reactor (MBBR), anaerobic digester (AD), anoxic systems, either singly or in combinations thereof.

[0053] In yet another embodiment, the present invention provides a plug in modular bio-electro catalytic device, wherein it can be embedded with existing / new biological units of effluent treatment plants (ETPs) with continuous or batch mode operation.

[0054] In still another embodiment, the present invention provides a plug in modular bio-electro catalytic device, wherein it enhances color removal (89.75%), COD removal (90.4%), TOC removal (90.4%), TN removal (53.74%), Amine removal (67.67%), Azo reductase activity (37.9 U).

[0055] In yet another embodiment, the present invention provides a plug in modular bio-electro catalytic device, wherein it improves the performance of treatment in terms of carbon (COD / TOC) removal, nutrients removal, colour removal and TDS removal by 15-35% augmented efficiency based on the nature of wastewater being treated.

[0056] In still another embodiment, the present invention provides a plug in modular bio-electro catalytic device, wherein the wastewater treatment process operates under at least one of the following electrochemical phases: control (C), open-circuit (OC), closed-circuit (CC), and applied potential (AP).

[0057] In yet another embodiment, the present invention provides a plug in modular bio-electro catalytic device, wherein increasing the number of electrode assemblies in the range of 10 to 20 improves treatment performance in large-scale applications.

[0058] In another embodiment, the present invention provides a process for treatment of wastewater using the developed plug in modular bio-electro catalytic device, wherein the steps comprising: a) introducing wastewater in the system through the inlet (1); b) initiating bio-electrochemical treatment by harnessing the reducing agents produced through bio-electro catalytic oxidation of organic substances; c) facilitating direct / indirect anodic oxidation mechanism where in direct oxidation contaminants adheres to the anode surface and undergoes degradation through electron transfer mechanism and in indirect anodic oxidation the mediators are used to facilitates electron transport between the electrode and organic compounds.

[0059] In still another embodiment, the present invention provides a process for treatment of wastewater using the developed plug in modular bio-electro catalytic device, wherein the reducing agents are selected from the group consisting of nitrates, heavy metals, and sulfur based compounds.

[0060] The key Features of the modular integrated device developed in the instant invention include:

[0061] 1. Design:

[0062] • The device is modular and plug-in, i.e. it can be easily added to current wastewater treatment setups or included in new designs.

[0063] • It uses SS 316L electrodes arranged in stacks, which are durable and resistant to corrosion, ensuring long-term use.

[0064] 2. Electrode Materials:

[0065] • Three types of electrode materials were tested: Graphite, Grafoil, and Stainless Steel 316L (SS316L).

[0066] • SS316L was found to be the most effective, achieving high rates of color, COD (Chemical Oxygen Demand), and nutrient removal.

[0067] 3. Optimized Conditions:

[0068] • Experiments were conducted to optimize electrode materials, configurations (series, parallel, hybrid), and microenvironment conditions (aerobic and anoxic). E.g An anoxic environment is one where oxygen is absent but nitrate (NO3-) or nitrite (NO2- ) is present.

[0069] • The best performance was observed with SS316L electrodes in a series circuit configuration with 8 stacks.

[0070] 4. Bio-Electrocatalytic Process:

[0071] • The device operates through a bio-electrocatalytic process, which enhances the breakdown and degradation of organic compounds

[0072] • This process improves the removal of pollutants such as dyes, amines, and total organic carbon (TOC).

[0073] 5. Integration with Biological Units:

[0074] • The functional device can be integrated with various biological treatment processes such as Activated Sludge Process (ASP), Membrane Bioreactor (MBR), and Anaerobic Digestion (AD). • This integration improves the overall efficiency of wastewater treatment, to achieve better removal rates for a range of pollutants.

[0075] 6. Scalability and Efficiency:

[0076] • The device can handle different scales, from small laboratory setups to larger pilot- scale reactors.

[0077] • It shows high removal efficiencies in both synthetic and real-field composite dye wastewater, achieving significant reductions in COD, color, and nutrient levels.

[0078] DETAILS OF BIOLOGICAL RESOURCES USED IN THE INVENTION The microorganisms used for the purposes of the present invention were isolated from the Bio- electrocatalytic system. CSIR-IICT, Hyderabad, Telengana, 500007 and deposited with MTCC, IMTECH, Chandigarh, India. The complete details in this regard are provided in Table 7.

[0079] Table 7

[0080] BRIEF DESCRIPTION OF DRAWINGS

[0081] In the drawings, like reference characters generally refer to the same or similar parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

[0082] FIG. 1: Color removal by functional device with stacked SS316L electrode assembly.

[0083] FIG. 2: Azo reductase activity by functional device with stacked SS316L electrode.

[0084] FIG. 3: COD removal by functional device with stacked SS316L electrode assembly. FIG. 4: Sulphates removal by functional device with stacked SS316L electrode assembly.

[0085] FIG. 5: Phosphates removal by functional device with stacked SS316L electrode assembly.

[0086] FIG. 6: Nitrates removal by functional device with stacked SS316L electrode.

[0087] FIG. 7: Bio-electrocatalytic treatment for self-sustainable operation with synergy. In this FIG. 7 -

[0088] >- Item No. 1 illustrates the wastewater inlet;

[0089] >- Item No. 2 illustrates the module chamber;

[0090] >- Item No. 3 illustrates the electrode stack;

[0091] >- Item No. 4 illustrates the sludge zone;

[0092] >- Item No. 5 illustrates the resistor;

[0093] >- Item No. 6 illustrates the electrode hanger;

[0094] >- Item No. 7 illustrates the outlet tank

[0095] DETAILED DESCRIPTION OF THE INVENTION

[0096] The present invention provides a plug in modular functional device for waste water treatment, comprising 4 or 8 stacked assemblies, two rectangular reactors, and at least one biological unit. The 4 / 8 stacks are connected in series by closed circuit connections. Further each assembly consists of two electrodes;

[0097] • An anode, which facilitates the oxidation of contaminants, and

[0098] • A cathode which serves as the site for reduction reactions; wherein, electrodes are made of SS316L stainless steel, Graphite, Grafoil.

[0099] In an aspect, the present invention provides an integrated plug-in modular bio-electrocatalytic device for the treatment of complex wastewaters with: color removal (89.75%), COD removal (90.4%), TOC removal (90.4%), TN removal (53.74%), Amine removal (67.67%), Azo reductase activity (37.9 U). The plug-in modular bio-electrocatalytic device improves the efficacy of wastewaters treatment by using three electrode materials selected from but not limited to Graphite, Grafoil, and Stainless Steel 316L, that are conductive and bio-compatible. Other metal based conductive material like Titanium, Platinum, Nickel, Copper also posses a good electrical conductivity which can be used, but SS316L being more economic was selected.

[0100] The device of the present invention further provides bio-electrocatalytic dye remediation / degradation with respect to microenvironments (aerobic (Ae) and anoxic (Ax)) against four electrochemical phases (control (C), open-circuit (OC), closed-circuit (CC) and applied potential (AP)). In another aspect, the present invention provides four reactors with a total / working volume of 0.25 / 0.20 L and fabricated using graphite, SS 316L, and grafoil electrodes acting as both anode and cathode which are operated in each individual experimental setup with varied combinations to derive the optimized condition for dye / complex wastewater remediation. In optimization studies, SS 316L, graphite, and grafoil electrodes performed effectively in the removal of COD / TOC, dye / amine, and nutrients.

[0101] In yet another aspect, the present invention provides two rectangular reactors with a total / working volume of 0.75 / 0.6 L, operated in CC mode with various circuit connections to demonstrate the efficiency of dye degradation using SS 316L electrodes. The circuitry and electrochemical operation resulted in the overall electron flux, which developed an in-situ potential for enhancing the breakdown and degradation of organic compounds.

[0102] In still another aspect, the functional device operated with the series circuit in close connection with SS 316L electrode materials in 4 and 8 stacked assemblies with a 100 L capacity bioreactor. It was evaluated with a range of wastewaters at the best-optimized conditions discussed above to acquire the maximized treatment efficiency. Increment in numbers of electrode assembly (10-20 stacked assembly) for large scale treatment process may even result in higher treatment efficiency.

[0103] In yet another aspect, the present invention provides a device with 8 stacked assembly resulting in high treatment efficiency in terms of color removal (FIG.l), Nutrient removal (FIGs. 3-6), Azo reductase activity (FIG. 2) as compared to 4 stacked and control (No electrode assembly). The developed plug-in functional device can be easily incorporated in any existing or new ETP / STP to augment the treatment performance thereof with reference to carbon, salts and nutrients removal (FIG. 7).

[0104] The plug-in modular bio-electrocatalytic functional device developed in the instant invention intensifies the wastewater treatment process. The device can be incorporated in any existing ETP / STPs without much modifications so as to increase the treatment efficiency by 15-25%.

[0105] Three electrode materials (Graphite, Grafoil, and Stainless Steel 316L) that are conductive and bio-compatible were studied for pharmaceutical / chemical-based wastewater treatment. Optimization experiments were conducted to understand the bio -electrocatalytic influence on dye remediation with respect to microenvironment (Aerobic (Ae) and Anoxic (Ax)) against four electrochemical phases (Control (C), open-circuit (OC), closed-circuit (CC) and applied potential (AP)) on dye degradation.

[0106] Four reactors with a total / working volume of 0.25 / 0.20 L and graphite, SS316L, and Grafoil electrodes as both anode and cathode were operated in each individual experimental setup with varied combinations to derive the optimized condition for dye / complex wastewater remediation. In optimization studies, SS316L, Graphite, and Grafoil electrodes effectively removed contaminants in dye-based wastewater treatment, including COD / TOC, dye / amine, and nutrients.

[0107] Later, the invention focused on designing two rectangular reactors with a total / working volume of 0.75 / 0.6 L and operated them in three phases (OC, and AP) with various circuit connections to demonstrate the efficiency of dye degradation using SS316 L electrodes. The circuitry and electrochemical operation resulted in the overall electron flux, which developed in-situ potential for increased breakdown and degradation of organic compounds.

[0108] Based on the above conditions finalized from the optimization experiments, the functional device was operated with the series circuit in close connection with SS316L electrode materials in 4 and 8 stacked assemblies with a 100 L capacity bioreactor and then evaluated with a range of wastewaters.

[0109] According to a preferred embodiment of the invention, it discloses:

[0110] • The use of stacked SS316L electrodes as both anode and cathode;

[0111] • Treatment of chemical water via Bio-electrocatalysis without the use of externally applied potential;

[0112] • Membrane less operation;

[0113] • Continuous flow operation without the use of pump;

[0114] • A Single, integrated system design.

[0115] The invention introduces a plug-in modular bio-electrocatalytic functional device that can be integrated with existing and new effluent treatment plants (ETP / STPs) without modification. The unique aspect of combining specific electrode materials and configurations for enhanced wastewater treatment imparts novelty to the instant invention. The detailed optimization of electrode materials, configurations, and microenvironment selections indicate the inventive step of the instant invention over existing technologies, especially the deployment of SS316L electrodes in a stacked configuration.

[0116] The invention is designed for practical use in wastewater treatment plants, for industrial need and for efficient treatment of complex waste waters.

[0117] EXAMPLES

[0118] The following examples are given by way of illustration only and therefore should not be construed to limit the scope of the present invention in any manner.

[0119] Example 1: Screening of electrodes for bio-compatibility

[0120] The instant invention initially focused on screening electrodes for the treatment of designed synthetic dye-based wastewater (Azo dye black 10B) with a COD load of 3g / L in batch mode operation to enhance treatment efficiency with Bio-electrocatalytic activity. With an initial dye load of 500 mg / L, the maximum color removal of 89.75% was observed with the SS316L electrodes, followed by grafoil and graphite of 87.75% and 67.5%, respectively. COD removal of 90.4% was observed with SS316L electrode, and 87.5% and 88% with grafoil and graphite electrodes, respectively (Table 1). Amine removal and azo reductase activity were analyzed to understand the treatment efficiency of the individual electrodes and the effectiveness of a batch mode system for color removal.

[0121] Table 1: Results of optimization of electrodes for bio-compatibility

[0122] COD - Chemical oxygen demand; Color R - Removal of color; COD R - Removal of COD;

[0123] TN R - Removal of total nitrogen; Amines R - Removal of amines; mg / L - milligram per liter; U - Azo reductase activity in units. Example 2: Circuit optimization for maximum electron flux

[0124] Based on the example 1 with designed synthetic wastewater, this invention further focused on real-field composite dye wastewater with a higher COD load of 1.1 g / L in continuous mode operation using series, parallel, and hybrid circuit configurations using SS316 L electrodes. The maximum COD removal reached 51.8% in the series circuit configuration, and a 73.2% color removal was observed, followed by parallel mode operation with 63% color and 46.5% COD removal. The hybrid mode was found to be less feasible compared to the other two. With the optimization of screening of electrodes in batch mode operation, the invention focused on circuit optimization using series and parallel circuit configurations to generate the maximum electron flux for enhancing the treatment efficiency at a COD load of 3 g COD / L for a 48-hour retention time. This mode of operation leads to higher degradation of dye wastewater with respect to the time, with substrate removal by the end of experiment representing 89% and 69% COD and color removal, respectively, with the series circuit configuration and 87% and 65.4% with the parallel configuration (Table 2). Electrode stacks connected in a series connection generated more voltage compared to the parallel configuration, leading to more electrocatalytic activity in the system. The invention later focused on the operation of 100 L reactor with 1g COD / L and lOmg / L of designed synthetic wastewater.

[0125] Table 2: Results of optimized conditions in circuit variation for maximum electron flux

[0126] COD - Chemical oxygen demand; Color R - Removal of color; COD R - Removal of COD; TN R - Removal of total nitrogen; Amines R - Removal of amines; mg / L - milligram per liter; U - Azo reductase activity in units.

[0127] Example 3: Optimization of electrode stack assembly in continuous mode operation with designed synthetic wastewater (DSW)

[0128] With the optimized conditions mentioned above (Example 1 & 2), which include SS 316L electrodes in a series circuit, the invention further focused on continuous mode operation at a semi-pilot scale, using a 100 L reactor with designed synthetic wastewater (DSW). The DSW operation started with an initial organic load (OL) of 1 g COD / L, leading to a higher removal rate of 61.8% with an 8-stcaked electrode assembly. The maximum color removal of 86% was observed with 8- stacked electrodes, and the process was subsequently optimized for various wastewater streams in continuous mode operation (Table 3).

[0129] Table 3: Results of optimized conditions for electrode stack assembly

[0130] COD - Chemical oxygen demand; Color R - Removal of color; COD R - Removal of COD; TN R - Removal of total nitrogen; IC R- Removal of inorganic carbon; N R - Removal of nitrates; S R - Removal of sulphates; P R - Removal of phosphates; Amines R - Removal of amines; U - Azo reductase activity in units; mg / L - milligram per liter.

[0131] Example 4: Optimization of circuit configuration in continuous mode operation with real- field composite dye wastewater

[0132] Based on the Example 2, with designed synthetic wastewater, this invention further focused on real-field composite dye wastewater with a higher COD load of 1.1 g / L in continuous mode operation using series, parallel, and hybrid circuit configurations. The maximum COD removal reached 51.8% in the series circuit configuration, and a 73.2% color removal was observed, followed by parallel mode operation with 63% color and 46.5% COD removal (Table 4). The hybrid mode was found to be less feasible compared to the other two.

[0133] Table 4: Results of optimized conditions for circuit configuration with real-field composite dye wastewater

[0134] COD - Chemical oxygen demand; DL (abs) - Dye load in absorbance: Color R - Removal of color; COD R - Removal of COD; TN R - Removal of total nitrogen; IC R- Removal of inorganic carbon; N R - Removal of nitrates; S R - Removal of sulphates; P R - Removal of phosphates; mg / L - milligram per liter.

[0135] Example 5: Optimization of bio-electrocatalytic functional device treatment efficiency for pharmaceutical wastewater

[0136] Based on Examples 1 and 2, with an initial organic load (OL) of 382 mg / L, this invention was focused on the treatment of pharmaceutical wastewater. The reactor was operated with variation in wastewater with different organic load in continuous mode operation. The maximum treatment, achieving 71.6% COD removal, was obtained with the series connection of 8-stacked electrodes (Table 5). Subsequently, the reactor was operated with combined industrial wastewater using 8-stacked SS316L electrodes to enhance the functional device’s performance. Further, the process was optimized by increasing the organic load of the wastewater to achieve the best organics / inorganics removal performance.

[0137] Table 5: Results of bio-electrocatalytic treatment efficiency for pharmaceutical wastewater

[0138] COD - Chemical oxygen demand; COD R - Removal of COD; IC R - Removal of inorganic carbon; TC R - Removal of total carbon; N R - Removal of nitrates; S R - Removal of sulphates; P R - Removal of phosphates; mg / L - milligram per liter; L / H - liters per hour. Example 6: Optimization of bio-electrocatalytic functional device treatment efficiency for composite chemical-based wastewater

[0139] Finally, the continuous mode module was operated based on the Example 5 with a COD load of 983 mg / L of combined pharmaceutical wastewater. This invention focused on bio- electrocatalytic treatment using SS 316L electrodes at a higher OL to evaluate the efficiency of the plug-in device. The maximum COD and TN removal reached 59.17% 43.72%, respectively (Table 6).

[0140] Table 6: Results of bio-electrocatalytic treatment efficiency for combined chemicalbased wastewater

[0141] COD - Chemical oxygen demand; COD R - Removal of COD; TN R - Removal of total carbon; IC R - Removal of inorganic carbon; N R - Removal of nitrates; S R - Removal of sulphates; P R - Removal of phosphates; mg / L - milligram per liter; L / H - liters per hour.

[0142] Example 7: Dominant microbial strain in mixed consortia in biological unit operation

[0143] The continuous mode module operated had diverse range of microbial species out of which Bacillus being the dominant. The major microbial species present in the mixed consortia were Priestia aryabhattai (MTTC No. 13539), Micrococcus flavus (MTTC No. 13554), Microbacterium paraoxydans (MTTC No. 13541), and Acinetobacter towneri (MTCC No. 13540).

[0144] ADVANTAGES OF THE INVENTION

[0145] • Modular and Plug-in Design - o The developed functional device can be easily integrated directly in any existing or new ETP / STPs without need of much modification. o The integration of the modular functional device enhanced the removal of wide range of pollutants present in the industrial and chemical waste water.

[0146] No External Power Requirement - The developed functional device works on in-situ potential, contributing to overall energy efficiency, reducing operation cost and sustainability.

[0147] • Membrane-less Operation -Eliminates membrane fouling and the maintenance issues associated with conventional membrane -based treatment systems Stacked Electrode Configuration o - Use of SS316L, Graphite, and Grafoil electrodes in 4 or 8 stacked arrangements enhances surface area for electrochemical reactions, resulting in higher degradation rates of pollutants. o The use of SS316L electrode assembly ensures durability and resistance to corrosion, extending lifespan of the device.

[0148] • The developed device offers a cost-effective solution for improving wastewater treatment methods.

[0149] • Improved Treatment Efficiency

[0150] Demonstrated performance includes high removal efficiencies: o Color: -89.75% o COD and TOC: -90.4% o Total Nitrogen: -53.74% o Amine compounds: -67.67% o Azo reductase activity: -37.9 U

[0151] - These improvements reflect significant advancement over conventional treatment systems.

[0152] The developed device allows easy installation, maintenance and scalability.

Claims

We claim:

1. A plug-in modular bio-electro catalytic device for wastewater treatment, comprising:(a) stacked electrode assembly (3);(b) at least two rectangular reactors (2);(c) at least one biological unit (4);(d) electrode holder (6);(e) inlet (1); and(f) outlet (7); wherein, the stacked electrode assembly comprises 4 to 8 stacked electrodes connected in series with closed circuit (5) and each assembly comprises at least one anode and one cathode; wherein, the two rectangular reactors configured to house the stacked assemblies and facilitate wastewater flow comprise total working volume between 0.61 to 0.751.

2. The plug-in modular bio-electro catalytic device as claimed in claim 1, wherein the electrodes are selected from the group consisting SS316L, Graphite, Grafoil, Titanium, Platinum, Nickel, Copper.

3. The plug-in modular bio-electro catalytic device as claimed in claim 1, wherein the device comprising electrode assemblies (3), which operate without any membrane.

4. The plug-in modular bio-electro catalytic device as claimed in claim 1, wherein the anode facilitates oxidation of organic contaminants and the cathode facilitates reduction reactions.

5. The plug-in modular bio-electro catalytic device as claimed in claim 1, wherein the biological unit is a sludge enriched with Priestia aryabhattai (MTTC No. 13539), Micrococcus flavus (MTTC No. 13554), Microbacterium paraoxydans (MTTC No. 13541), and Acinetobacter towneri (MTCC No. 13540) microorganisms.

6. The plug-in modular bio-electro catalytic device as claimed in claim 1, wherein the deviceis capable of being embedded into existing biological unit operations selected from the group consisting of activated sludge process (ASP), sequencing batch reactor (SBR), moving bed biofilm reactor (MBBR), anaerobic digester (AD), anoxic systems, either singly or in combinations thereof.

7. The plug-in modular bio-electro catalytic device as claimed in claim 1, wherein the device can be embedded with existing / new biological units of effluent treatment plants (ETPs) with continuous or batch mode operation.

8. The plug-in modular bio-electro catalytic device as claimed in claim 1, wherein the device enhances color removal (89.75%), COD removal (90.4%), TOC removal (90.4%), TN removal (53.74%), Amine removal (67.67%), Azo reductase activity (37.9 U).

9. The plug-in modular functional device claimed in claim 1, wherein the device improves the performance of treatment in terms of carbon (COD / TOC) removal, nutrients removal, colour removal and TDS removal by 15-35% augmented efficiency based on the nature of wastewater being treated.

10. The plug-in modular bio-electro catalytic device as claimed in claim 1, wherein the wastewater treatment process operates under at least one of the following electrochemical phases: control (C), open-circuit (OC), closed-circuit (CC), and applied potential (AP).

11. The plug-in modular bio-electro catalytic device as claimed in claim 1, wherein increasing the number of electrode assemblies in the range of 10 to 20 improves treatment performance in large-scale applications.

12. A process for treatment of wastewater using the plug-in modular bio-electro catalytic device as claimed in claim 1, wherein the process comprising the steps of: a) introducing wastewater in the system through the inlet (1); b) initiating bio-electrochemical treatment by harnessing the reducing agents produced through bio-electro catalytic oxidation of organic substances; c) facilitating direct / indirect anodic oxidation mechanism where in direct oxidation contaminants adheres to the anode surface and undergoes degradation throughelectron transfer mechanism and in indirect anodic oxidation the mediators are used to facilitates electron transport between the electrode and organic compounds.

13. The process as claimed in claim 12, wherein the reducing agents are selected from the group consisting of nitrates, heavy metals, and sulfur based compounds.

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