低C/N比条件下亚硝化颗粒污泥的培养及成因分析

利用柱形SBR反应器,以自配低C/N比废水为基质,以普通活性污泥为种泥,通过逐步缩短沉降时间和提升进水负荷培养亚硝化颗粒污泥,并对该过程进行考察.结果表明:系统运行40 d后,获得成熟的亚硝化颗粒污泥,颗粒污泥颜色为黄色,平均沉降速率达60.8 m·h-1,其中粒径大于0.45 mm的约占总数的96％；出水中亚硝酸盐累积率稳定在75％ ～ 80％,亚硝酸盐累积速率达0.6～0.8 kg·m-3·d-1；DO、温度和SRT都不是导致亚硝酸盐积累的关键因素,高浓度FA是造成本研究亚硝化成功实现的主要原因；颗粒污泥SBR的单周期反应过程可依次划分为COD迅速降解阶段、第一过渡阶段、氨氮去除优势阶段、第二过渡阶段和饥饿阶段5部分；另外,研究中还发现进水COD对颗粒污泥的形成和亚硝化过程的实现具有重要贡献.

Granulation of granular nitrosation sludge at low C/N ratio

The formation of granular nitrosation sludge by seeding conventional activated sludge in column-type sequencing batch reactors (SBR) using synthetic wastewater at low C/N ratio was investigated. The matured granules, with yellow color and settling velocity of 60.8 m·h^-1, formed in the reactor by gradually decreasing setting time and increasing influent loading rate in 40 days. Granules with diameters larger than 0.45 mm accounted for about 96% of the total. The ratio of nitrite accumulation in effluent was 75%~80%, and values of nitrite accumulation loading rate were as high as 0.6~0.8 kg·m^-3·d^-1. Of the factors tested, high concentration of free ammonia posed greater impact on the nitrosation than DO, temperature and sludge retention time. The reaction in one cycle of SBR granular sludge could be divided into five stages in order, i.e. COD rapid degradation, first transition, predominant removal of ammonia, second transition and starvation. It was found that the presence of influent COD played a positive role in the formation of granules and the realization of nitrosation.