WO2020016837A1 - Apparatus/system for electrolytic treatment of water - Google Patents

Abstract

The present invention relates to the development of apparatus or system for electrolytic treatment of water. It particularly relates to the development of reactor for electrolytic treatment of water. More particularly, the invention relates to the development of reactor for electrolytic treatment of industrial effluent or waste water or sewerage water or drinking water. The invention also pertains to the development of method for practicing the use of developed reactor for electrolytic treatment of industrial effluent or waste water or sewerage water or drinking water. The reactor is an open top cuboidal vessel made of insulating material with a fixed permanent compartment for the incoming fluid. The fluid is the electrolyte and henceforth it will be referred as electrolyte. The electrolyte enters the fixed compartment through the INLET. There is a vertical slit of appropriate width and length, a few inches above the bottom of the reactor, for the flow of electrolyte to the other compartments where electrolysis takes place. The compartments are made by placing baffles, each baffle has a vertical slit of appropriate width and length just above the bottom to channel the flow of electrolyte, at discrete distances, and each compartment comprises an individual electrolytic cell consisting a pair of electrodes with opposite electrical polarity. Each compartment also have two OUTLET ports on the side, one at the top and the other at the bottom. The top outlet may also be used for sample collection and the bottom outlet may be used for cleaning and maintenance purposes. The two baffles of a compartment are arranged such that the vertical slits are diagonally opposite, this is to ensure a zigzag flow to attain maximum retention time and avoid hydrodynamic short-circuit.

Description

APPARATUS/SYSTEM FOR ELECTROLYTIC TREATMENT OF WATER

FIELD OF THE INVENTION The present invention relates to the development of apparatus or system for electrolytic treatment of water. It particularly relates to the development of reactor for electrolytic treatment of water. More particularly, the invention relates to the development of reactor for electrolytic treatment of industrial effluent or waste water or sewerage water or drinking water. The invention also pertains to the development of method for practicing the use of developed reactor for electrolytic treatment of industrial effluent or wastewater or sewerage water or drinking water.

BACKGROUND OF THE INVENTION Industrial wastewater streams may be contaminated by various substances that render their discharge into water ways or municipal waste treatment systems problematic or illegal. Contaminants may be organic or inorganic in nature and are often found in complex combinations. The industry and tradesmen are under obligation, to avoid polluting the wastewater whenever possible or, on the basis of laws of the land, if the wastewater contains hazardous substances, to clean up the wastewater on the basis of the state of technology. In the Recycling Management and Waste Act, the avoidance of waste has the highest priority.

The increasing demands on industry and municipalities with regard to wastewater treatment plants do not only create greater volumes of wastewater to be treated and sewage sludge to be disposed off, but often also cause problems with regard to the characteristics of the sludge and make the competent disposal of the waste more difficult. For example, the separation of the sludge in many municipal wastewater treatment plants has significantly decreased since the phosphate elimination has been started.

Innovative processes for wastewater and sludge treatment as well as the raising of the efficiency of mechanical treatment plants are thus gaining more and more in importance through the increase in the streams of waste in many areas of environment and process engineering. The difficulties arising in the exploitation/disposal of waste require always improving conditioning and treatment processes in order to reduce the amount of waste and even to recover materials.

Therefore, pre-treatment processes are necessary that enable the separation of the colloid components through filtration and sedimentation for economic and ecological reasons. Contaminates are often suspended in the wastewater and very finely emulated and distributed. In such systems the alignment of the negative charge of the particles in the same direction has a disadvantageous effect, which makes the efficient separation in mechanical installations more difficult and necessitates the use of chemical additives, such as polymeric and/or organic flocculation agents.

The pre-treatment of these waste streams can alternatively be carried out using electro physical precipitation. In that case the electrically charged particles are moved in the electrical field to the electrodes, neutralized there and thus the coagulation of the particles effected. Depending on the wastewater composition additional oxidation processes may result in the removal of certain water content substances during the application of the electro-chemical process. The knowledge of the mechanism of the various reactions is thus of particular importance for the optimization of the process and for the adjustment to the special requirements in the case of the substance systems to be treated. Therefore the consideration of the electro-chemical theory, on which this is based, is of particular importance for the development of the process. The drinking water may also require the removal of unwanted contaminants or pollutants from it to make them safe and potable.

One widely regulated parameter is“chemical oxygen demand” (COD), a measure of the quality of wastewater effluent streams prior to discharge. The COD test predicts the oxygen requirement for complete oxidation of oxidizable contaminants present in the effluent; it is used for the monitoring and control of discharges, and for assessing treatment plant performance. Chemical oxygen demand is defined as the amount of oxygen in milligrams per liter (parts-per-million, ppm) required to oxidize both organic and oxidizable inorganic compounds that are present in the effluent.

There are reports in the patent and non-patent literature for the electrolytic treatment apparatus or system or reactor for water treatment and some important patents include US patent application publication no. US 2012/0273367 Al which discloses a water purification system includes at least one flow electrolysis cell each cell comprising an input for receiving wastewater, a cathode, a non-sacrificial anode, and an output for outputting purified water. The non-sacrificial anode is capable of being operated at an input power of at least about, 1000W up to about 5000 W to form electro-oxidation cocktail, and the electro-oxidation cocktail treats the wastewater to form purified water. The US patent no. US 5,807,473 discloses an apparatus and method for electrolytically treating water which includes one or more reactors. Each reactor has a liquid containing vessel and one or more pairs of electrodes. The electrodes are suitable for a continuous anodic or cathodic operation for treating water. A power source for each reactor provides voltage and current to the electrodes. A controller maintains the voltage and current provided to the electrodes. The duration of each voltage polarity applied to each electrode is substantially the same. The polarity of the voltage to the electrodes is periodically reversed during which there a period of zero voltage is applied to the electrodes between a first polarity and a second polarity. The period of zero voltage results in a substantial reduction of back e.m.f. of the reactor which enhances the service life and efficacy of the electrodes.

The US patent no. US 6,274,028 Bl discloses a method and apparatus for purifying aqueous effluent streams to reduce COD thereof, where the method comprises direct oxidation of water-soluble organic material in an electrochemical cell that incorporates (56) References Cited Stainless Steel electrodes, whose Stability and lifetime are enhanced by inclusion of circulating metal chips.

The US Patent no. US 8,551.305 B2 discloses a method and apparatus for treating water or wastewater for drinking and/or industrial use. The method and apparatus comprises of a plurality of vertically positioned electrodes, which are placed in a treating chamber and wherein the electrodes are interconnected to one another. The positive and negative electrodes are insulated there-between. The polarity of the direct current Supply is changeable at regular intervals in order to prevent passivation of the electrodes when reaching an even abrasion. The current can preferably be pulsatory. In order to be able to keep the current density between the electrodes at a desired value, the most efficient possible electrolysis is achieved by means of a minimum total current and wherein the spacing between the electrodes are adjustable.

Though there are several prior art reports which reported for the apparatus and method for electrolytic treatment of different types of water hut none of the prior arts in the literature reported or disclosed the efficient and cost-effective reactor/apparatus and method for treatment of industrial effluent or wastewater or sewerage water or drinking water and also not having the drawbacks or limitations of the prior art or existing reactors for efficient electrolytic treatment of water. There exists several drawbacks or limitations with the prior art apparatus for effective and efficient electrolytic treatment of water. Thus, there is a critical need of providing clean and safe drinking water to the population as well as keep the surface water source contaminant free, as the former cannot be done without ensuring the latter. Keeping the“Swachh Bharat Abhiyan” as motive, this reactor is designed for the electrolytic treatment of industrial effluent, wastewater, sewerage water and drinking water via electrocoagulation and electro-floatation method. Therefore, the present inventors developed the apparatus/reactor/system for electrolytic treatment of industrial effluent or wastewater or sewerage water or drinking water and that will be not having the drawbacks or limitations of the prior arts or existing reactors and also the method for using of the developed reactor for electrolytic treatment of industrial effluent or wastewater or sewerage water or drinking water.

OBJECTIVES OF THE INVENTION

The primary object of the present invention is the development of effective and efficient apparatus for electrolytic treatment of water.

The other object of the present invention is the development of effective and efficient apparatus for electrolytic treatment of industrial effluent or wastewater or sewerage water or drinking water. The other object of the present invention is the development of reactor for electrolytic treatment of water.

The other object of the present invention is the development of reactor for electrolytic treatment of industrial effluent or wastewater or sewerage water or drinking water.

The other object of the present invention is the development of reactor for electrolytic treatment of industrial effluent or waste water or sewerage water or drinking water which is simple. The other object of the present invention is the development of reactor for electrolytic treatment of industrial effluent or wastewater or sewerage water or drinking water which is cost effective. The other object of the present invention is the development of reactor for electrolytic treatment of industrial effluent or wastewater or sewerage water or drinking water which is safe and practical to use with little technical expertise.

Yet another object of the present invention is the development of method for practicing the developed reactor for electrolytic treatment of industrial effluent or wastewater or sewerage water or drinking water.

STATEMENT OF THE INVENTION A system for electrolytic treatment of fluid comprising vessel with at least one compartment to hold the incoming fluid from the inlet and the compartments are separated by placing baffles at regular intervals across the length of the vessel and are placed at discrete distances;

wherein each compartment have two outlets ports on the side, one at the top and the other at the bottom, the top outlet may be used for sample collection and the bottom outlet may be used for cleaning and maintenance purposes;

wherein each baffle having a vertical slit of appropriate width and length just above the bottom to channel the flow of electrolyte, at discrete distances; wherein each compartment comprises an individual electrolytic cell with pair of electrodes having opposite electrical polarity; and

wherein the vessel can be provided with lid and having provision for connecting electric cables. The vessel in the system is open top rectangular cuboidal vessel made up of insulating material.

There is long and narrow grooves are made on the bottom end of the wall of the vessel that can hold and arrest the baffles firmly at their place. The baffles of a compartment are detachable and are arranged such that the vertical slits are diagonally opposite, this is to ensure a zigzag flow to attain maximum retention time and avoid hydrodynamic short-circuit and also any adjacent compartment will have the two outlet ports on opposite side of the compartment.

The baffles are removable, interchangeable and one spare baffle having no slit or opening is also a part of the system which, when used in lieu of the baffle(s) with slit(s), limits the size and volume of the compartment and that allows flexibility of volume to both individual compartments and the overall assembly.

The electrodes for electrocoagulation are primarily of flat plate type and are selected from aluminium, iron and a combination of aluminium and iron.

The electrodes as placed between two baffles and supported at the side walls of the reactor and as the reactor is open top, electrodes are easily accessible for changing and repairs.

The plugs made of insulation material are placed between the electrodes in order to avoid accidental contact between them. The lid is made of insulating material which has several pairs of narrow slits of appropriate shape and size and the electrodes are inserted through the slits of lid.

A system for electrolytic treatment of water comprising vessel with at least one compartment (2) to hold the incoming fluid from the inlet (3) and the compartments (2) are separated by placing baffles (1) at regular intervals across the length of the vessel and are placed at discrete distances; wherein each compartment have two outlets (5) ports on the side, one at the top and the other at the bottom, the top outlet may be used for sample collection and the bottom outlet may be used for cleaning and maintenance purposes;

wherein each baffle (1) having a vertical slit of appropriate width and length just above the bottom to channel the flow of electrolyte, at discrete distances; wherein each compartment comprises an individual electrolytic cell with pair of electrodes (7) having opposite electrical polarity; and

wherein the vessel can be provided with lid (7) and having provision for connecting electric cables (6).

Method for electrolytic treatment of fluid comprising the passing or flowing of the fluid through the system developed by the present invention and the fluid is selected from water of industrial effluent, wastewater, sewerage water and drinking water.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the development of apparatus for electrolytic treatment of water. It particularly relates to the development of reactor for electrolytic treatment of water. More particularly, the invention relates to the development of reactor for electrolytic treatment of industrial effluent or waste water or sewerage water or drinking water. The invention also pertains to the development of method for practicing the use of developed reactor for electrolytic treatment of industrial effluent or waste water or sewerage water or drinking water.

The reactor is an open top cuboidal vessel made of insulating material with a fixed permanent compartment for the incoming fluid. The fluid is the electrolyte and henceforth it will be referred as electrolyte. The electrolyte enters the fixed compartment through the INLET, as mentioned in the figure. There is a vertical slit of appropriate width and length, a few mm above the bottom of the reactor, for the flow of electrolyte to the other compartments where electrolysis takes place. The compartments are made by placing baffles (as given in Fig. 1), each baffle has a vertical slit of appropriate width and length just above the bottom to channel the flow of electrolyte, at discrete distances, and each compartment comprises an individual electrolytic cell consisting a pair of electrodes with opposite electrical polarity. Each compartment also have two OUTLET ports on the side, one at the top and the other at the bottom. The top outlet may also be used for sample collection and the bottom outlet may be used for cleaning and maintenance purposes. The two baffles of a compartment are arranged such that the vertical slits are diagonally opposite, this is to ensure a zigzag flow to attain maximum retention time and avoid hydrodynamic short-circuit. Also any adjacent compartment will have the two OUTLET ports on opposite side of the reactor, this is for assuring the aforementioned objectives.

For electrocoagulation either aluminium or iron or even a combination of aluminium and iron electrodes may be used. The choice of electrode may depend on various factors like electrolyte characteristics, objective for treatment, critical parametric limits and ranges, electrical power availability, etc. The electrodes as placed between two baffles and supported at the side walls of the reactor. As the reactor is open top, electrodes are easily accessible for changes and repairs.

The baffles are interchangeable and removable. One spare baffle having no slit or opening is also a part of the invention which, when used in lieu of the baffle(s) with slit(s), limits the size and volume of the reactor. This allows flexibility of volume to both Individual compartments and the overall reactor assembly. ADVANTAGES & FEATURES OF THE REACTOR

• The design/apparatus allows highest mixing without external agitation

• The design/apparatus allows maximum contact time

• The reactor is “variable volume” type, i.e. - volume of the reactor may be adjusted using the baffle without slit or opening.

• Samples of electrolyte may be drawn from any compartment

• Both submerged and partially submerged electrodes can be used in this reactor

• Both mono-polar and bi-polar type of electrodes can be used; bi-polar arrangement is effective when all baffles are removed.

• Flow of electrolyte is a combination of single channel and multi-channel flow

• The design/apparatus allows easy access to the electrodes for maintenance, changing and repairing purpose.

APPLICATIONS OF THE REACTOR

The pollutants and adversities of contaminated water that can be treated using the reactor includes, but are not limited too:

1. Metals (including heavy metals, alkaline earth metals, etc.)

2. Oxyanions (sulphate, phosphate, chromate, silicate, arsenate, nitrate, etc.)

3. Fluoride

4. Free oil and grease

5. Emulsified oils

6. High BOD

7. High COD

Silica

9. Bacteria and viruses

10. Humic acids and other natural organic matters 11. Metal oxides

12. Phenolics

The industries whose effluents can be treated using this reactor includes, but are not limited too:

• Oil and gas exploration

• Petroleum and petrochemicals

• Pharmaceuticals

• Tannery

• Dairy and food processing

The reactor may also be used for purifying ground water and flood water for drinking purposes. BRIEF DESCRIPTION OF THE FIGURES/DRAWINGS

Figure 1: 3D (isometric) view of the reactor without the lid and electrodes Parts Description

1 Detachable baffle(s) ensure fluid to achieve maximum hydraulic residence time

2 Electrolysis chamber(s) where electrocoagulation takes place

3 Inlet line for the raw wastewater

4 Slit on baffle(s) to let the fluid flow from one chamber to the next one

5 Outlet(s) for the treated water at every chamber: the upper one for sample collection, the lower one for drainage.

• The reactor is an open top rectangular cuboidal vessel made of thick insulating material. • The vessel is compartmentalized with the help of detachable baffles placed at regular intervals across the length of the vessel. Each compartment acts as chamber for electrolysis.

• Long and narrow grooves are made on the bottom and the wall of the vessel that can hold and arrest the baffles firmly at their place.

• Each baffle has vertical slit of appropriate shape and size.

• The reactor has one inlet line for wastewater and multiple outlets of treated water.

Figure 2: 3D (isometric) view of the lid and the attached electrodes

Parts Description

6 Provision for connecting electric cables

7 Lid

Electrode pair(s)

9 Plug(s) to save the electrode pair against accidental contact with each other

• The lid is made of insulating material which has several pairs of narrow slits of appropriate shape and size.

• Electrodes are primarily of flat plate type, used in pair(s).

• The pairs of electrodes are inserted through the slits of lid.

• Plugs made of insulation material are placed between the electrodes in order to avoid accidental contact between them.

• Provisions are there at the top of the electrodes to connect electric cables.

Once placed firmly at the top of the reactor, the lid along with the pairs of electrodes would complete the electrocoagulation reactor setup. The pair of electrodes (8) would enter the electrolysis chamber (2). The working fluid would primarily be wastewater which would act as electrolyte for the process, and henceforth will be referred as electrolyte. The electrolyte enters the first compartment through the Part 3. The baffles would ensure maximum hydraulic residence time of the electrolyte inside the reactor. Each compartment also have two outlet ports on the side, one at the top and the other at the bottom. The top outlet may also be used for sample collection and the bottom outlet may be used for cleaning and maintenance purposes. The two baffles of a compartment are arranged such that the vertical slits are diagonally opposite, this is to ensure a zigzag flow to attain maximum retention time and avoid hydrodynamic short-circuit. Also any adjacent compartment will have the two outlet ports on opposite side of the reactor, this is for assuring the aforementioned objectives.

For electrocoagulation, the choice of electrode may depend on various factors like electrolyte characteristics, objective for treatment, critical parametric limits and ranges, electrical power availability, etc. The electrodes as placed between two baffles and supported at the side walls of the reactor. As the reactor is open top, electrodes are easily accessible for changes and repairs.

The baffles are interchangeable and removable. This allows flexibility of volume to both individual compartments and the overall reactor assembly.

Figure 3. Front, top and side view of the Reactor for electrolytic treatment.

Figure 4. Reactor cover with electrodes. Figure 5. The graph showing the results of COD removal efficiency of the developed system in the field scale trial of the system which was carried out at the Sewerage Treatment Plant (STP) of IIT Guwahati.

Figure 6. The graph showing the analysis of various parameters for field trial of the prototype system was carried out at the OIF Focation HZH, Makum. Figure 7. The picture showing the developed system/reactor with preferred embodiments.

The present invention is now described with the following preferred embodiment to practice with the developed system:

300 LPH

Sewerage Treatment Site @ IIT Guwahati

A field scale trial of the system was carried out at the Sewerage Treatment Plant (STP) of IIT Guwahati. -Testing of DC power supply unit with actual load

-Testing the capability of the electro-coagulation reactor

-Feasibility of using a RDVF as thickener

-COD removal efficiency - 87.6%

Oil India Limited Location HZH, Makum

300 LPH - Field Trial

A field trial of the prototype system was carried out at the OIL Location HZH, Makum

• Effective treatment of effluent with the system prototype

• System/reactor to be tested

• Real time monitoring of effluent for Retention time and Flow Rate

• Determining Scale-up factors

• Identification of design limitations (if any)

• Came to identify that we will be requiring a flocculator Analysis

Pic : Removal Parameter Percentage

State Pollution Control Board Assam, Analysis Report for Oil Effluent as following:

Claims

We Claim,

1. A system for electrolytic treatment of fluid comprising vessel with at least one compartment to hold the incoming fluid from the inlet and the compartments are separated by placing baffles at regular intervals across the length of the vessel and are placed at discrete distances;

wherein each compartment have two outlets ports on the side, one at the top and the other at the bottom, the top outlet may be used for sample collection and the bottom outlet may be used for cleaning and maintenance purposes;

wherein each baffle having a vertical slit of appropriate width and length just above the bottom to channel the flow of electrolyte, at discrete distances; wherein each compartment comprises an individual electrolytic cell with pair of electrodes having opposite electrical polarity; and

wherein the vessel can be provided with lid and having provision for connecting electric cables.

2. The system as claimed in claim 1 wherein the vessel is open top rectangular cuboidal vessel made up of insulating material.

3. The system as claimed in claim 1 wherein the long and narrow grooves are made on the bottom end of the wall of the vessel that can hold and arrest the baffles firmly at their place.

4. The system as claimed in claim 1 wherein the baffles of a compartment are detachable and are arranged such that the vertical slits are diagonally opposite, this is to ensure a zigzag flow to attain maximum retention time and avoid hydrodynamic short-circuit and also any adjacent compartment will have the two outlet ports on opposite side of the compartment.

5. The system as claimed in claim 1 wherein the baffles are removable, interchangeable and one spare baffle having no slit or opening is also a part of the system which, when used in lieu of the baffle(s) with slit(s), limits the size and volume of the compartment and that allows flexibility of volume to both individual compartments and the overall assembly.

6. The system as claimed in claim 1 wherein the electrodes for electrocoagulation are primarily of flat plate type and are selected from aluminium, iron and a combination of aluminium and iron.

7. The system as claimed in claim 1 or 6 wherein the electrodes are placed between two baffles and supported at the side walls of the reactor and as the reactor is open top, electrodes are easily accessible for changing and repairs.

The system as claimed in claim 1 wherein the plugs made of insulation material are placed between the electrodes in order to avoid accidental contact between them.

9. The system as claimed in claim 1 wherein the lid is made of insulating material which has several pairs of narrow slits of appropriate shape and size and the electrodes are inserted through the slits of lid.

10. A system for electrolytic treatment of water comprising vessel with at least one compartment (2) to hold the incoming fluid from the inlet (3) and the compartments (2) are separated by placing baffles (1) at regular intervals across the length of the vessel and are placed at discrete distances;

wherein each compartment have two outlets (5) ports on the side, one at the top and the other at the bottom, the top outlet may be used for sample collection and the bottom outlet may be used for cleaning and maintenance purposes; wherein each baffle (1) having a vertical slit of appropriate width and length just above the bottom to channel the flow of electrolyte, at discrete distances; wherein each compartment comprises an individual electrolytic cell with pair of electrodes (7) having opposite electrical polarity; and

wherein the vessel can be provided with lid (7) and having provision for connecting electric cables (6).

11. Method for electrolytic treatment of fluid comprising the passing or flowing of the fluid through the system as claimed in claims 1 to 10.

12. Method as claimed in claim 11 wherein the fluid is selected from water of industrial effluent, wastewater, sewerage water and drinking water.