Electrochemistry � A route to efficient coagulation in water

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					              Electrochemistry –
A route to chemical free water and wastewater
                  treatment
            Institute of Water Weekend School
                          Nov 2010
         Part of the Modern Water Group
Established to build and exploit a portfolio of water technologies
 to address problems of the availability of fresh water and the
treatment and disposal of wastewater.




                                                                     2
Technology portfolio:
• Manipulated Osmosis (MO) Desalination
   •     Membrane desalination
   •     Plant demonstrates up to 30% energy saving, reduces
         chemical consumption and other operating costs compared
         with traditional methods
• Evaporative cooling systems
       • Reduces power consumption by up to 90%
       • Reduces capex by up to 50%
       • Uses seawater, brackish water or effluent in place
         of potable water
• Cymtox CTMTM
   •     Real-time online water toxicity monitor
   •     Quicker, more cost effective and more accurate than competitors
• Aguacure
   •     Electrocoagulation
                                                                           3
   • Introduction to Electrochemistry

   • Electro-coagulation

   • AguaCure Technology

   • Applications
          •   Metal Finishing – Automotive Industry
          •   Municipal Wastewater Treatment

   • Summary and Conclusions




Part of the Modern Water Group                        4
   Electrochemistry



   • Chemical reaction                           R1 + R2            P1



   • Electro-chemical reaction                           R 1 + e-
     P1

          •   Electron behaves “as a reagent”
          •   Electrical current regulates rate of reaction
Part of the Modern Water Group                                           5
   Electrochemistry
                    Chemical                Electro-
                    coagulatio              chemical
                        n                  coagulation

     FeCl3                          NaOH

                       Na+                    Fe3+
                             OH-                PO43-
                     Fe3+
                             3Cl-

                       PO43-
                      FePO4                   FePO4



Part of the Modern Water Group                           6
Introduction
          Electro-coagulation
          AC to DC Conversion



                                e-
                -
               eFe2/3+
                                            H2

                              Fe(OH)-        OH-
                          3

                                        Fe(OH)+2
                  Fe2/3+
                                 H+

              Fe(OH)3

                                      Fe(OH)2H2

                                                   7
                 Fe2/3+                      OH-
   Resource analysis

   • Commercial FeCl3 (40% solution)
         40%)
          •   13.8% in Fe
   • Mild steel
          •   99.85% in Fe

               For delivery of 1000kg of Fe
                From FeCl3      From mild
                                  steel
                 7250kg are      1002kg are
                   needed          needed


Part of the Modern Water Group                8
   Electro-coagulation

   • Induced precipitation using low levels
     of electricity as the driver for
     treatment

   • Removal of contaminants from water
     and wastewater

   • Replaces chemical dosing - move
     towards ‘chemical free’ treatment

   • Smaller footprint

   • No chemical handling/storing
Part of the Modern Water Group                9
   AguaCure Technology




                                 Electrode Packs
                                  • Interchangeable
                                  • Easy to maintain
                                  • Even wear

Part of the Modern Water Group                         10
   AguaCure Technology
                                 Modular cells
                                  • Flexible expansion
                                  • Controlled flow
                                  • Clean in place




                                     From source
          To separation



Part of the Modern Water Group                        11
   Applications



                                                       Metal Finishing
                    Acid Mine Drainage                                           Municipal Wastewater




      Aggregate Extraction                                                                 Drinking Water




Part of the Modern Water Group                                     Dairy Wastewater                         12
                                   Contaminated Soil
   Metal finishing – Automotive industry
                                 P removal


                      Inlet conditions         Target
                           8 m3/h
                       200 - 400 ppm         25 ppm PO43-
                           PO43-
                   1600 µS.cm-1 (avg)




Part of the Modern Water Group                              13
   Metal finishing – Automotive industry
                                 P removal




Part of the Modern Water Group               14
   Metal finishing – Automotive industry
                                                                     P removal
                    400
                    375
                    350                                                                            Raw Wastewater
                    325                                                                            Treated Wastewater
                    300
                    275
                    250
     [PO43-] mg/L




                    225                                                                                                           • Consistently within target
                    200
                    175
                    150                                                                                                           • 6 kWh/kg PO43-removed
                    125

                                                                                                                                 • 1.04 g Fe per g of PO43-removed
                    100
                     75
                     50
                     25
                      0
                          0   5   10   15   20   25   30   35   40   45   50   55   60   65   70   75   80   85   90   95   100 105 110
                                                                      Total Run Hours




Part of the Modern Water Group                                                                                                                               15
     Metal finishing – Automotive industry
                                   P removal
 Sample comparison - Dry and wet samples of chemically and electrochemically treated
    phosphate waste




                                          Chemically
                                           treated
                                            sample                     Electrochemically
Electrochemically                                                      treated sample
treated sample



  Part of the Modern Water Group                                                  16
        Municipal Wastewater Treatment
                                 P removal


                      Inlet conditions       Target
                          4 m3/h
                       3 – 9 ppm P           1 ppm P
                     Secondary stage,
                     post trickle-bed
                           filter




Part of the Modern Water Group                         17
        Municipal Wastewater Treatment
                                 P removal




Part of the Modern Water Group               18
                Municipal Wastewater Treatment
                                         P removal
                                                                     • P removed
                                                                       consistently below
           10
                                                                       1 ppm target
           9

           8
                                                                       Regular operation
           7
                                                                     • 1.29 g Fe/g PO43-removed
           6
                                                                     • 13 kWh/kg PO43-removed
  mg/L P




                                                            Inlet
           5
                                                            Outlet
           4
                                                                       “Spring shedding”
                                                                     • 3.87 g Fe/g PO43-removed
           3

           2
                                                                     • 40 kWh/kg PO43-removed
           1

           0
                29/03   30/03    01/04      16/04   20/04




Part of the Modern Water Group                                                                    19
                           Municipal Wastewater Treatment
                                                 BOD, COD, Total P, TSS
                                                       Contaminant Removal

                   100.0


                    90.0


                    80.0


                    70.0
% removal




                    60.0
                                                                                                                     •  BOD removal 60 – 90%
       % Removal




                                                                                                           BOD

                    50.0
                                                                                                           COD
                                                                                                           Total P
                                                                                                                     •  COD removal 70 – 90%
                    40.0
                                                                                                           TSS
                                                                                                                     •  Total P removal 85 –
                    30.0
                                                                                                                     • 99% removal 40 – 95%%
                                                                                                                        TSS
                    20.0


                    10.0


                     0.0
                           29/03/2010   30/03/2010   01/04/2010     16/04/2010   20/04/2010   23/04/2010




Part of the Modern Water Group                                                                                                            20
  Summary and Conclusions
  • EC viable / reliable alternative to Ferric chloride/sulphate
    dosing
      • Minimises chemical handling and storage
      • Surety of supply
      • Quality of supply


  • Automotive sector
      • Over 60% savings on disposal cost through reduction of sludge
        volume
      • Further savings achievable through full automation and continuous
        treatment vs. batch treatment

  • Municipal wastewater
          • 1 ppm consent achieved
          • Significant reductions (40-99%) in multiple parameters
Part of the Modern Water Group                                              21
           •   BOD, COD, Total P, TSS
   Contact AguaCure

                   Duarte Tito, PhD, MSc, Lic

                   E: duarte.tito@aguacure.com
                   T: +44 (0)1248 361501
                   M: +44(0)7833 240842
                   W: www.aguacure.com




Part of the Modern Water Group                   22

				
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