Electrocoagulation (EC) Is An Emerging Technology In Water And Wastewater Treatment. It Combines The Advantages Of Coagulation, Flotation, And Electrochemistry. It Is An Electrochemical Process That Uses Electric Current To Remove Suspended, Emulsified, Or Dissolved Pollutants From Water. Electrochemical Wastewater Treatment Technology has Begun To Regain Attention Because It Is An Environmentally Friendly Option That Can Produce The Least Sludge, does Not Require Chemical Additives, And The Smallest Footprint, Without Affecting The Water Quality After Treatment.

Electrocoagulation (EC) Is A Technique Used For wastewater treatment, Wash Water Treatment, Industrially Processed Water, And Medical Treatment. Electrocoagulation Has Become A Rapidly Growing Area Of Wastewater Treatment Due To Its Ability To Remove Contaminants That Are Generally More Difficult To Remove By Filtration Or chemical Treatment systems, Such As Emulsified Oil, total Petroleum Hydrocarbons, Refractory Organics, suspended Solids, And heavy Metals.Electrocoagulation (EC) Is A Technique Used For wastewater treatment, Wash Water Treatment, Industrially Processed Water, And Medical Treatment. Electrocoagulation Has Become A Rapidly Growing Area Of Wastewater Treatment Due To Its Ability To Remove Contaminants That Are Generally More Difficult To Remove By Filtration Or chemical Treatment systems, Such As Emulsified Oil, total Petroleum Hydrocarbons, Refractory Organics, suspended Solids, And heavy Metals.

Description:-

In Its Simplest Form, An Electrocoagulation Reactor Is Made Up Of An Electrolytic Cell With One anode and One cathode. When Connected To An External Power Source, The Anode Material Will Electrochemically corrode due To Oxidation, While The Cathode Will Be Subjected To passivation.

An EC System Essentially Consists Of Pairs Of Conductive Metal Plates In Parallel, Which Act As Monopolar electrodes. It Furthermore Requires A direct Current power Source, A Resistance Box To Regulate The current density And A multimeter to Read The Current Values. The Conductive Metal Plates Are Commonly Known As "sacrificial Electrodes." The Sacrificial Anode Lowers The dissolution potential Of The Anode And Minimizes The Passivation Of The Cathode. The Sacrificial Anodes And Cathodes Can Be Of The Same Or Of Different Materials.

The Arrangement Of Monopolar Electrodes With Cells In Series Is Electrically Similar To A Single Cell With Many Electrodes And Interconnections. In Series Cell Arrangement, A Higher Potential Difference Is Required For A Given Current To Flow Because The Cells Connected In Series Have Higher Resistance. The Same Current Would, However, Flow Through All The Electrodes. In Contrast, In Parallel Or Bipolar Arrangement The Electric Current Is Divided Between All The Electrodes In Relation To The Resistance Of The Individual Cells, And Each Face On The Electrode Has A Different Polarity.

During electrolysis, The Positive Side Undergoes Anodic Reactions, While On The Negative Side, Cathodic Reactions Are Encountered. Consumable Metal Plates, Such As iron or aluminum, Are Usually Used As Sacrificial Electrodes To Continuously Produce Ions In The Water. The Released Ions Neutralize The Charges Of The Particles And Thereby Initiate Coagulation. The Released Ions Remove Undesirable Contaminants Either By Chemical Reaction And Precipitation, Or By Causing The Colloidal Materials To Coalesce, Which Can Then Be Removed By Flotation. In Addition, As Water Containing Colloidal Particulates, Oils, Or Other Contaminants Move Through The Applied Electric Field, There May Be ionization, Electrolysis, hydrolysis, And free-radical formation Which Can Alter The Physical And Chemical Properties Of Water And Contaminants. As A Result, The Reactive And Excited State Causes Contaminants To Be Released From The Water And Destroyed Or Made Less Soluble.

It Is Important To Note That Electrocoagulation Technology Cannot Remove Infinitely Soluble Matter. Therefore, Ions With Molecular Weights Smaller Than Ca⁺² or Mg⁺² cannot Be Dissociated From The Aqueous Medium.

Advantages: -

• • EC Requires Simple Equipment And Is Easy To Operate With Sufficient Operational Latitude To Handle Most Problems Encountered In Running.
  • Wastewater Treated By EC Gives Palatable, Clear, Colorless And Odorless Water.
  • Sludge Formed By EC Tends To Be Readily Settable And Easy To De-water, Compared To Conventional Alum Or Ferric Hydroxide Sludges, Because The Mainly Metallic Oxides/hydroxides Have No Residual Charge.
  • Flocs Formed By EC Are Similar To Chemical Floc, Except That EC Floc Tends To Be Much Larger, Contains Less Bound Water, Is Acid-resistant And More Stable, And Therefore, Can Be Separated Faster By Filtration.
  • EC Can Produce Effluent With Less TDS Content As Compared With Chemical Treatments, Particularly If The Metal Ions Can Be Precipitated As Either Hydroxides Or Carbonates (such As Magnesium And Calcium. EC Generally Has Little If Any Impact On Sodium And Potassium Ions In Solution.
  • The EC Process Has The Advantage Of Removing The Smallest Colloidal Particles, Because The Applied Electric Field Neutralises Any Residual Charge, Thereby Facilitating The Coagulation.
  • The EC Process Generally Avoids Excessive Use Of Chemicals And So There Is Reduced Requirement To Neutralize Excess Chemicals And Less Possibility Of Secondary Pollution Caused By Chemical Substances Added At High Concentration As When Chemical Coagulation Of Wastewater Is Used.
  • The Gas Bubbles Produced During Electrolysis Can Conveniently Carry The Pollutant Components To The Top Of The Solution Where It Can Be More Easily Concentrated, Collected And Removed By A Motorised Skimmer.
  • The Electrolytic Processes In The EC Cell Are Controlled Electrically And With No Moving Parts, Thus Requiring Less Maintenance.
  • Dosing Incoming Waste Water With sodium Hypochlorite assists Reduction Of biochemical Oxygen Demand (BOD) And Consequent chemical Oxygen Demand (COD) Although This Should Be Avoided For Wastewater Containing High Levels Of Organic Compounds Or Dissolved Ammonia (NH4+) Due To Formation Of trihalogenated Methanes (THMs) Or Other chlorinated Organics. Sodium Hypochlorite Can Be Generated Electrolytically In An E Cell Using Platinum And Similar Inert Electrodes Or By Using External Electro Chlorinators.
  • Due To The Excellent EC Removal Of Suspended Solids And The Simplicity Of The EC Operation, Tests Conducted For The U.S. Office Of Naval Research concluded That The Most Promising Application Of EC In A membrane System was Found To Be As Pretreatment To A Multi-membrane System Of UF/RO Or microfiltration/reverse Osmosis (MF/RO). In This Function The EC Provides Protection Of The Low-pressure Membrane That Is More General Than That Provided By Chemical Coagulation And More Effective. EC Is Very Effective At Removing A Number Of Membranes Fouling Species (such As Silica, Alkaline Earth Metal Hydroxides And Transition Group Metals) As Well As Removing Many Species That Chemical Coagulation Alone Cannot Remove.