除磷颗粒污泥系统中不同粒径颗粒的理化特性分析

采用SBR反应器培养具有同步脱氮除磷特性的颗粒污泥.使用目数分别为100、60、40的标准检验筛将污泥颗粒按粒径大小筛分为3个等级,即150～280μm、280～450μm、>450μm进行研究,分析了不同粒径颗粒的理化特性.结果表明,颗粒化初期(第7～18 d),密实的颗粒提供良好的厌氧环境有利于加速GAOs和PAOs在颗粒内部的对底物的竞争;密实颗粒有利于PAOs的富集和加速生长,使得不同粒径颗粒含磷量存在差异:280～450μm的颗粒(以SS计)有机磷含量最高,达113.25 mg.g-1,无机磷含量最低,达15.55 mg.g-1.颗粒化后期,反应器运行第34 d,3种粒径颗粒中有机磷含量趋于一致,约为50 mg.g-1,第52 d,无机磷含量也趋于一致,约70 mg.g-1.成熟颗粒中总磷含量占11%,其中无机磷占4.24%.同时,反应器中污泥的磷含量比排水中污泥高,分析表明污泥活性和污泥龄对磷的去除效果有影响.另外,就反硝化而言,大、小粒径颗粒都有较好的厌氧反硝化能力,颗粒内部与外部溶液环境中的NO3--N浓度梯度是影响反硝化速率的重要因素.

Physicochemical Characteristics of Granules with Different Size in a Granular Sludge System for Phosphorus Removal

Aerobic granular sludge that could simultaneously remove nitrogen and phosphorus was cultivated in a sequencing batch reactor (SBR). Three groups were divided using 100-, 60- and 40- mesh sieves resulting the size ranges were 150-280 microm, 280-450 microm and > 450 microm, respectively, and the physicochemical properties of different groups were analyzed. Results showed that during the initial period of granulation (7 - 18 d), the compact granules could provide the anaerobic niche for the substrate the competition between GAOs and PAOs; and the compact granules was favorable for the enrichment and growth of PAOs, resulting in different phosphorous fractions in different size of granules: granules with the size of 280 - 450 microm exhibited the highest content of organic phosphorous faction, i.e., 113.25 mg x g(-1). In contrast, these granules showed the lowest content of inorganic phosphorous fraction, i.e., 15.55 mg x g(-1). In a later period, the content of organic phosphorous fraction in granules was similar after 34 d about 50 mg x g(-1), and the inorganic phosphorous fraction became similar after 52 d was 70 mg x g(-1), and the total organic phosphorous fraction of sludge in the reactor were higher than those in the solids effluent. The phosphorous fraction in different size granules was affected by the sludge retention time. The total phosphorous accounted for 11% of total weight of sludge, and the inorganic phosphorous accounted 4.24%. Additionally, the settling velocity, specific weight of bigger granules were higher than the smaller one, and these values were well correlated with total phosphorous. Concerning on denitrification, bigger and smaller granules showed high denitrification efficiency, and the gradient of NO3(-) -N between inside of granules and bulk solution was an important factor for denitrification rate.