Have you got any futher data on the quality of your water that allow you to assess the redox level of your system? If it is a more or less aerobic system, you can assume the the iron is quantitativly oxidiced (Fe(III))

Dear Kouakou,

To know the stable form (predominant) of iron, you must know the water pH and redox potential of your water. Then, we must refer to the Pourbaix diagram which gives the form (speciation of iron) and the oxidation state. Under usual conditions (pH between 4.5 and 9), soluble iron is usually in the ferrous state (Fe 2+) for natural waters.

With my best regards

Prof. Bachir ACHOUR

If the Fe concentration is appreciable another approach is to plug the data into an equilibrium speciation model.  That will tell you if the charge balance is in the ball park.

Thank you very much Sirs, for your answers. Actually, I have the PH, TDS,   Conductivity, Turbidity, Colour, TSS, Ca, Mg, HCO3, Cl, Na+, K+, NO3-, NO2-, NH4, SO4, PO4, Mn and Fe, BUT NOT THE REDOX POTENTIAL.

Hello Kouakou Valentin Koffi , I have the same questions, I want to know that you had use to calculated mg/L to meq/L Fe, because in the report is Fe Total , my dates are pH : 7.08 CE: 250.4 uS/cm and TDS: 127 mg/L.

I hope your answers

Thank you.@

mEq= mg/atomic weight * valence

Thank you David Olasehinde , but my report have Fe Total then ¿ what valence do you use?

Valence is Fe2+ or Fe3+

Yes, David Olasehinde but ¿what valence do you use to convert in meq/L, Fe2+ or Fe+3?

http://www.unitslab.com/fr/node/2

for future seekers i found this practical online tool to convert mg/L to meq https://bit.ly/38E5Vmb

I've been searching online for how to do this but my head is starting to hurt. 📷 I've never been good at math and forget chemistry! I found a conversion formula but it was for Ca and you have to know the valence or something like that so I thought I'd try looking up "valence of CaCO3" but that didn't work. I probably wasn't even on the right track. This is what I was looking at;

milliequivalents per liter (meq/L) - meq/L is another method of expressing concentration, when the analytes are dissolved and disassociated in solution. meq/L is also equal to millimoles of charge per liter (mM+/L or mM-/L depending on valence). To calculate meq Ca/L from the reported value in mg/L, we must know something about calcium.

Calcium has a molecular weight of 40.08 grams/mole Calcium has a valence of +2 The equivalent weight = (40.08grams/mole)/(2 equivalents/mole) = 20.04 grams/eq To convert to mg/meq you simply multiply g/eq by 1000 mg/g and divide by 1000 meq/eq, thus g/eq = mg/meq If your sample contains 30 mg Ca/L, what is the concentration in meq/L?

Meq Ca/L = (30 mg Ca/L)/(20.04 mg/meq) = 1.50 meq Ca/L

Anyways, I just want to know if you have alkalinity test results of 110 mg/L, what is that in meq/L? (I'd like to know how to solve the problem too for future reference)

Thanks for solution.