redox.ppi

# titrate with C (like glucose)

SPECIATION
  jobTitle                             "Development of redox zones (A&P, Fig 9.17)"
  calculationType                      custom
  calculationMethod                    1
  resolution                           1                             # just one iteration since REACTION has its own looping mechanism
  selectedOutputLines                  auto                          # copy all lines in selected.out to out file

PLOT
  plotTitle                            "Development of redox zones<br>(using REACTION)"
  xtitle                               "Carbon added (mmol/L)"
  ytitle                               "Concentration (mmol/L)"
  customXcolumn                        C                             # heading from out file (derived from selected.out)
  lines                                O2 NO3- Mn+2 As(V) As(III) Fe+2 SO4-2 S-2 CH4  # headings from out file (derived from selected.out)

CHEMISTRY

SELECTED_OUTPUT
  -reset false
  -high_precision true
USER_PUNCH
  headings C O2 NO3- Mn+2 Fe+2 SO4-2 S-2 CH4 As(V) As(III)
-start
10 addedc=step_no*0.572/100
20 punch addedc, 1000*tot("O(0)")/2, 1000*tot("N(5)"), 1000*tot("Mn"), 1000*tot("Fe(2)"),\
 1000*tot("S(6)"), 1000*tot("S(-2)"), 1000*tot("C(-4)"), 1000*tot("As(5)"), 1000*tot("As(3)")
-end

SOLUTION 1
  pH    7.1
  Na    1.236
  K     0.041
  Mg    0.115
  Ca    0.067
  Cl    1.467
  N(5)  0.058
  S(6)  0.085
  As(5) 0.075
  Alkalinity 0.26
  O(0)  0.124

EQUILIBRIUM_PHASES
  Goethite 0 2.5e-3                                                  # start with some
  FeS(ppt)  0 0                                                      # start with none
  Pyrolusite  0 4e-5                                                 # start with some

REACTION 1
  CH2O; 0.572e-3 in 100 steps                                        # internal looping by REACTION data block
INCREMENTAL_REACTIONS true
END