Preamble.
This software is a calculation program, according to known and tested method in water treatment speciality : HALLOPEAU & DUBIN method, to modify, supplement and implement by the author (Software Protection : Act 92-597 of 1 July 1992 on the Intellectual Property Code).
(contact the author for a price quot - not downloadable software).
See : J. Hallopeau - " Les équilibres carboniques dans les eaux " - Terres et Eaux, 1960/1961.

All formulations are explainable : thermodynamic laws, equilibrium equations, acido-basic reactions, etc.
Proposed option are according as study and treatment of natural waters.
And also, it test by many usage : laboratory studies or "in the field" (treatment station for drinking water and industrial waters), including automatic tryouts.
For calculations with iteration procedure, it use dichotomic method, which to allow more fastness to good accuracy : mathematic feedback value = from 0.01 to 0.1 according to events.

- EQUILWIN is a software coded to run under Windows. No problem using interfaces WINDOWS 7 to 10 (32/ 64 bits).

Please Note - Equil v5/v6, old version was developed with Quick Basic V4.5, and thus, is a software running under DOS command prompt (Windows <Vista).
Mouse is not usable : most actions are controlled by the keyboard key presses (numbers or letters).
So, majority of actions are ordered with keyboard, by presses on keys (figures or letters).
Very often it should be noted that the required answer Y(es), and key "Enter", are equivalent.

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Program bounds.

The pressure is close to atmospheric pressure.
With regard to calculation of pH, program account of an acidity which holds can be noncarbonic (sulphuric, hydrochloric, etc) and in this case, uses formulas of pKa.
In principle, EQUILWIN program announces all excessive introduced or calculated values, and, in majority of cases, continuation of calculations is allowed.

The majority of water treatments are available and allows to simulate the chemical action in ionic equilibrium such as calcium/carbonates/CO2 balance.

Only five parameters are needful for current calculations :
Temperature, pH, alcalinity, calcium and dry residue (else conductivity or resistivity).

Initial reference is requested, but this is optional.

• introduction (or not) the maximum value of the saturation index to balance (initial value, by default : + 0.1)
  (used in treatment for the correction of aggression and remineralization).
• introduction (or not) the parameters required to calculate the index Larson (chlorides and sulphates)

NB. Equilwin for : registration of each water or session (persistent or not).

• pHs or notional pH for CaCO3 saturation (Saturation pH) : pH must be request to be with respect to equilibium saturation state of calcium carbonate (CaCO3), as constant alkalinity rate.
• Free carbonic gas (CO2),
• Saturation index (Langelier Saturation Index as LSI or SI) :
  is defined as pH(actual)-pHs, and,
  • is positive for oversaturation (calcifying water),
  • is negative for undersaturation (aggressive water) with respect to limestone (calcium carbonate, CaCO3),
  • is between -0,01 and +0,01 : water in equilibrium.
• Alk/CaO : Alcalinity / Calcium report (expressed in CaO equivalents according to Hallopeau).
• Aggressive CO2 : fitted in with excessive free carbonic gas (carbon dioxyde) causing destruction of limestone (CaCO3), only to aggressive water (LI < -0.01).

Note : CCPP (calcium carbonate precipitation/dissolution potential) : defines the mass of CaCO3 to be (theorically) precipited from, or dissolved into, a water to attain saturation with respect to CaCO3.
In this last case (dissolved), CCPP has a negative value.

• Ryznar Stability Index or RYZNAR Index (RI) : 2pHs-pH, give indication of corrosive tendancy, or calcifying state (scaling) of water.

On the other hand, tendancy direction of water is indicated : aggressive, scaling or in equilibrium (balance) ; and also proposition of correction (stabilization / recarbonation).

Equilwin example (agressive water) :

Next these results, potential choices :

Some choices according as water treatments, but are used, only to simulate action on calcium-carbonic equilibrium.
Note : for the majority of proposed chemicals, demand input of purity input (pure product amount) in %.

• It can test :
• by injection of chemicals(5 available products),
• percolation (filtration with limestone),
• with aeration (exclusively to carbonic acidity).
  Note : proposed subroutines, for example :
  • Aeration (common system), with stopping place to free CO2 about 6 mg/l amount,
  • Strong aeration (stripping tower),
    (who allows also, to choose free residual CO2).

Example (Equilwin picture) :

In addition, for all reagents the purity (% of pure product) can be introduced (optional).

Flocculation (coagulation) :
Allows to simulate coagulation (process of agglomeration and precipitation of particles).

Can test itself by action to introduce of coagulant reagent (6 products).

• Aluminium sulfate,
  • solid "lump" 14 H₂O, as Al₂O₃ with 17/18%,
  • or liquid (aqueous solution), as Al₂O₃ with 8,2%.
• WAC /WAC HB[high basicity], aluminium polychlorides,
• Ferric chloride ,
• Ferric chlorosulfate.

Note : proposed menus allow,

• either to continue to treat water,
• or to change amount (without changing coagulant),

Please, note that values of increase in some elements (not introduce at beginning) are announced: sulphates and/or chlorides.

Remark : this option will be present in other menus (Equil 6), to change pH of water, before or next treatment.

The pH decreasing (acidification), if that's possible, (control by program), can be carried out by 6 reagents :

• sulphuric (sulfuric) acid,
• hydrochloric acid,
• nitric adid,
• carbon dioxide,
• phosphoric acid,
• acetic acid.

Also, 4 basic reagents are proposed :

• lime,
• caustic soda,
• washing soda (sodium carbonate),
• baking soda (sodium bicarbonate).

And, for all reagents, purity (pure product %) can be introduced (optional).
It should be noted that values of increase in some elements (not introduce at beginning) are announced: sulphate, chloride or sodium.

Equilwin example (wanted pH : 7.5, lime as 80% of purety) :

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Recarbonation :
Allows to increase bicarbonated-calcic mineralization.
(should the occasion, until equilibrium pH [pHeq]
EquilWin test recarbonation by action of :

• carbonic gas (CO₂) + lime
• carbonic gas (CO₂) + calcium carbonate
• carbonic gas (CO₂) + non-burnt dolomite
• carbonic gas (CO₂) + burnt dolomite

Note : calculation stop is with wanted alkalinity, and/or with alkalinity AND pH value if lime used).

(Equilwin picture)

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Softening:
Allows to reduce bicarbonated-calcic species or calcium.
(three options, after introduction of desired calcium value)

Is therefore :
- Use of alkaline reagent :

• lime,
• caustic soda.

- Ions exchange resins (input of Total Hardness or magnesium), sodium.

Remark : this program is not a dimensioning software for device and ion exchange product, it's just one approach of resin volumes to use (cationic resin), and water to be treated (calculation of by-pass).

(Equilwin picture)

Is therefore : 4 tasks,

• Feed of acid reagent (6 products),
• Feed of basic reagent (4 products),
• Feed of calcic reagent (2 products),
• Feed of chlorination reagent(chlorine gas or 3 bleach solutions).

(Equilwin picture)

Notes:
. we can test the mixture of initial water in memory (or registered Equilwin water), with a second water, which we introduce the five essential parameters.
Also, a graph is drawn, also we can determine the final condition of a water after blending several waters for variant fractions.

Values expressed in mol/liter.

This calculation is carried out on the water in characterization (currently).

(Equilwin picture, example)

Pierre Ravarini - August 2015. 

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