Discharge pH requirements

Definition

Local discharge requirements set the allowable pH range for releasing treated water, in the chapter between 5 and 11. Solutions must be neutralized into this window before disposal.

The mandatory neutralization to meet discharge limits is what forced caustic addition to the spent acid, setting the stage for the over-neutralization. Meeting the window after overshooting to 13.4 required mixing reserved acid back in drum by drum. Discharge limits are an operational constraint that makes controlled neutralization unavoidable.

Related concepts

Neutralization · Acid cleaning of scale · Over-neutralization

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Part of The Blueprint of Water · 🛠️ operations