SBAR内不同有机负荷下2种好氧颗粒污泥形成及除磷性能

在SBAR中首先采用低有机负荷继而提高负荷的方法成功培养出2种不同类型的好氧颗粒污泥。在长期培养过程中,对SBAR系统中的微生物特征包括污泥浓度、SVI沉降指数等指标及系统对废水中COD和氮磷去除性能进行评估。在稳定阶段,通过在不同浓度NaCl溶液中测试和对比SBAR内2种颗粒污泥的沉降性能。结果表明,系统经过89 d的低有机负荷(0.75 kg COD/(m3·d))运行,小颗粒污泥缓慢形成,表面光滑,外观规则为近似球形;大幅度提高有机负荷(1.6 kg COD/(m3·d))促使大颗粒污泥的快速形成,多数为椭球形,并且颗粒边缘清晰透明;经过93 d稳定运行,成熟的小颗粒和大颗粒的平均直径分别为0.35 mm 和1.35 mm;随着大颗粒污泥的增多,系统除磷效果明显增强;在不同盐浓度(0%~15%)条件下大颗粒污泥比小颗粒污泥沉降速度更高;小颗粒污泥在大于2%的NaCl溶液出现悬浮现象而大颗粒仅在15%的NaCl溶液出现悬浮现象,进一步说明大颗粒污泥密度相对较大。

Formation of two typical aerobic granules cultivated in one single SBAR and phosphorus removal performances at different organic loading rates

Two different types of aerobic granular sludge were cultivated successfully under the low organic loading rate followed by increased organic loading rate in single SBAR. During the long-term operation, microbial characteristics (including MLSS and SVI), COD, nitrogen and phosphorus were measured in the system. At the steady period, the settling ability of two matured granular sludge was analyzed in different concentrations of sodium chloride solution.Results showed that small granules formed slowly after 89 days of operation under low organic loading rate (0.75 kg COD/(m3·d)), small granules were almost spherical with regular shapes and smooth surface. Substantially increased organic loading rate (1.6 kg COD/(m3·d)) promoted the fast development of big granules. Most of big granules were ellipsoid with a clear and transparent edge. The average diameters of mature small and big granules were 0.35 mm and 1.35 mm, respectively. With the formation of a large number of big granules in SBAR system, the efficiency of total phosphorus removal was obviously enhanced. In the settling experiment, the settling velocity of big granules was more than that of small granules. Big granules were initially suspended only at salt concentration of 15% while small granules suspended once the salt concentration was higher than 2%, which indicated that big granules had a bigger density compared with small granules.