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Effective ways to raise pH of effluence?


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As we scale up to full production I'm finding it hard to raise the pH of stillage before we dump it. I dumped more than a pound of calcium hydroxide in a 50g barrel of stillage and I barely raised the pH 0.2. I'm assuming that calcium hydroxide is probably the best wait to raise pH. Is there anything I'm missing? Cause it seems pretty expensive to raise the pH to where it needs to be before I can dump it.

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We use soda ash (Sodium carbonate) which works well enough at a smallish scale and is relatively easy to source and safeish to handle. It depends on the stillage, but it's about 2 - 3 lb to bring 900 L of whiskey stillage up to 5 pH.

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22 hours ago, Foreshot said:

………………………. to raise the pH of stillage before we dump it. ………………………..


19 hours ago, DrDistillation said:

……………………….………….. You talking about bottling pH correct?


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Thanks for the replies.

And so down the rabbit hole I go.

Below is a really good article on Soda Carbonate vs Soda Ash for pH and total alkalinity. The total alkalinity isn't relevant as that's not a part of my local water co's requirements.


And Soda Carbonate vs sodium hydroxide:


pH level:


Calcium carbonate pH  9.4

Calcium hydroxide pH 12.4

So it looks like Calcium hydroxide is the correct route to follow to raise the pH the most, but it seems not to be working for me - maybe because my stillage is too acidic? (total acidity vs pH)

This really is not a fun way to spend time since it's a waste product...


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I dont see anything in your links that suggest using calcium hydroxide instead of sodium carbonate. I would look at the solubility, a quick google suggests that calcium hydroxide is "is only slightly soluble in water (0.16g Ca(OH)2/100g water at 20°C) forming a basic solution called lime water. The solubility decreases with increasing temperature. "The solubility decreases with increasing temperature. "

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Yeah, I did not really present anything that meaningful other than the difference in pH. I don't think solubility matters if you mix the solution well, does it? It just has to be present. A base and acid interact in close proximity regardless of carrier solution, yes? Eventually the calcium hydroxide would flocculate where the calcium carbonate would stay in solution. So after time C. Carbonate would do a better job even though it's a lower pH? 

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