Output Table: Water Composition

aqion main output table (physico-chemical parameters and elements)

aqion displays the results of the hydrochemical calculations in different ways. One example is shown in the right screen­shot. In this table, three aqueous solutions (each in one column) are shown and compared:1

Input – the input water itself (raw data)

Output 1 – the solution in chemical equilibrium (and after charge-balance adjustment)

Output 2 – the same like Output 1, but with mineral-water interaction (incl. redox reactions)

The values in the last two columns differ only when mineral phases precipitate and/or dissolve or when redox reactions are present. [In this example, no minerals precipi­tate,2 but some minor redox reactions take place that change the redox potential.]

Physico-Chemical Parameters

The table shown above contains the following physico-chemical parameters (rows from top to bottom):

pH pH value of the solution
pe pe value of the solution
Eh redox potential in mV (related to standard hydrogen electrode)
T temperature of the solution in °C
Ionic strength ionic strength in mmol/L
TDS total dissolved solids in mg/L
EC electrical conductivity in µS/cm (at sampling temperature)3
EC_25 temperature-compensated value EC25 in µS/cm at 25
Alkalinity total alkalinity (M alkalinity) in meq/L or ppm CaCO34
CH carbonate hardness or temporary hardness in meq/L or ppm CaCO34
TH total hardness in meq/L or ppm CaCO35
C.B.E. charge-balance error (CBE) in percent6

Element Concentrations – The lower section of the table lists the total element concentrations in mg/L (or in mmol/L if the upper checkbox mol is activated).

Upper Menu Bar

mol checkbox to switch between concentration units: mg/L ⇔ mmol/L
digits specifies the number of digits after the decimal point
Ions opens a table of all ions and aqueous complexes (complete speciation)7
Minerals opens a table of the precipitated or dissolved mineral phases (if any) and the saturation indices
Export writes the table(s) into text files (for Excel or other programs)
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Lower Menu Bar

Save Out 1 stores8 the calculated solution shown in column Output 1
Save Out 2 stores8 the calculated solution shown in column Output 2
Last line jumps to the last table row (relevant only for large tables)
« back returns to the main window
next » displays next panel with relevant data of the carbonate system (buffer capacities, alkalinity, CO2 partial pressure) and the calcite-carbonate system (SI, LSI)

Remarks & Footnotes

  1. The idea behind Output 1 and Output 2 is explained here. ↩

  2. An example of mineral precipitation is given here. ↩

  3. The program provides three calculation methods for EC, which can be selected in Settings in the upper menu bar of the main window. ↩

  4. To switch between units “meq/L” and “ppm CaCO3”, click the upper mol checkbox. ↩ ↩2

  5. Also named “general hardness” GH (reminiscent of the German “Gesamthärte” = total hardness). ↩

  6. The CBE is non-zero only in the first column (input water); after charge-balance adjustment CBE becomes zero – see the last two columns. ↩

  7. Another example for aqueous speciation is presented here. ↩

  8. The calculated solutions in Output 1 and Output 2 can be saved for successive combination of reaction processes. This, however, is only allowed in aqion PRO. ↩ ↩2

[last modified: 2020-12-30]