Department of Chemical Engineering, University of Barcelona, C/Martí Franquès, 1 - 6th floor, 08028 Barcelona, Spain.
Water Sci Technol. 2011;64(9):1906-12. doi: 10.2166/wst.2011.386.
Granular sludge formation was performed in a laboratory scale Sequencing Batch Reactor (SBR) fed with supernatant of anaerobic digestion of sewage sludge. This effluent was concentrated progressively in order to enhance biomass capacity without inhibiting it. During the first part of the study, ammonium nitrogen was converted to nitrate, so conventional nitrification took place. When a nitrogen load of 0.8 g N L(-1) d(-1) was treated, the effluent concentration of nitrite started to increase while the nitrate concentration decreased until it disappeared. So, partial nitrification was achieved. At the end of this study, a nitrogen load of 1.1 g N L(-1) d(-1) was treated obtaining an effluent with 50% ammonium and 50% nitrite. The volatile suspended solids concentration in the reactor reached 10 g VSS L(-1). At this point the granule morphology was quite round and no filamentous bacteria was observed. The Feret's diameter was in the range between 1 and 6 mm with an average value of 4.5 mm. Roundness value was all the time higher than 0.7. Granule density increased during the experimental period, obtaining a final value of 7.0 g L(-1).
颗粒污泥是在实验室规模的序批式反应器（SBR）中形成的，该反应器以污水污泥厌氧消化的上清液为进料。为了在不抑制生物量的情况下提高其容量，该上清液逐渐被浓缩。在研究的第一部分，氨氮被转化为硝酸盐，因此发生了传统的硝化作用。当处理 0.8 g N L(-1) d(-1)的氮负荷时，亚硝酸盐的出水浓度开始增加，而硝酸盐的浓度则下降直至消失。因此，实现了部分硝化作用。在本研究结束时，处理了 1.1 g N L(-1) d(-1)的氮负荷，得到了 50%氨和 50%亚硝酸盐的出水。反应器中的挥发性悬浮固体浓度达到了 10 g VSS L(-1)。此时，颗粒的形态相当圆润，没有观察到丝状菌。Feret 直径在 1 到 6 毫米之间，平均值为 4.5 毫米。圆形度值一直高于 0.7。颗粒密度在实验期间增加，最终值达到 7.0 g L(-1)。
