摘要 |
<p>In the biological purificn. of waste water with low-to-high concns. of organic matter and total N, in which the water is aerated or loaded with O2 in 2 stages, a partial stream of the waste water/activated sludge mixt. from the 2nd stage is recycled to the 1st stage, and the waste water/activated sludge from the 2nd stage is sepd. in a settling tank to which the settled activated sludge from the 1st stage is fed, and the purified water is withdrawn, a predetermd. redox potential is not exceeded in the aeration or the O2-loading in the 1st stage.</p> |