Hi,

before fixing the pH of water, may be you should track the pH of the feed and pH in the reactor. It might be possible that you have low pH in your feed, which can be balance by the alkaline water. Moreover, there is often an accumulation of VFAs in reactor, which causes the decrease in pH. Adding water with high pH might be beneficial for your digester. Nevertheless, if you want to buffer the water, you can use hydrochloric acid for adjusting the pH of water and use it in the reactors. Good Luck.

If you are only looking for an reagent for pH regulation in anaerobic digestion. I would recommend hydrochloric acid (1 M or 3 M).

Hi,

Generally digester have a good buffering capacity and pH does not usually varies with the addition of small amount of water. Basic thing, if the pH of water is ~9, it is not pure water, but has contamination, it would be preferable to use pure water, it will automatically remove the problem.

Follow up, please measure the pH of the digestate and analyze the effect of water (if any) on the pH of reactors. pH adjustment with acid should be done as the last option.