胃酸がpH1.5前後らしいので、結構強い酸性ですね。
これの処理費用で岩手県は年間5億ちょいかかってるらしくて大変そうです。
たしかに、これをそのまま川に流すわけにはいきませんもんねえ(^^;)

Stomach acid has a pH of about 1.5, apparently, so that sure is some fairly strong acidity.

It seems the processing expenses cost Iwate Prefecture about ¥500 million a year, which must be really major. There's definitely no way they could let it flow into the river as-is, could they. (^^;)