Levén Lotta, Wijnbladh Erik, Tuvesson Malin, Kragelund Caroline, Hallin Sara
Institute of Agricultural and Environmental Engineering, JTI, PO Box 7033, SE-750 07 Uppsala, Sweden E-mail:
Department of Microbiology, Swedish University of Agricultural Sciences, PO Box 7025, SE-750 07 Uppsala, Sweden.
Water Sci Technol. 2016;73(4):866-72. doi: 10.2166/wst.2015.560.
Bulking and rising sludge are common problems in wastewater treatment plants (WWTPs) and are primarily caused by increased growth of filamentous bacteria such as Microthrix parvicella. It has a negative impact on sludge settling properties in activated sludge (AS) process, in addition to being responsible for foam formation. Different methods can be used to control sludge bulking. The aim of this study was to evaluate the dosage of on-site generated ozone in the recycled AS flow in a full-scale WWTP having problems caused by M. parvicella. The evaluation of the experiment was assessed by process data, microscopic analysis and microbial screening on the experimental and control line before, during and after the period of ozone dosage. The ozone treatment resulted in decreased abundance of M. parvicella and improved the settling properties, without impairing the overall process performance. Both chemical oxygen demand (COD)- and N-removal were unaffected and the dominant populations involved in nitrification, as analysed by fluorescent in situ hybridization, remained during the experimental period. When the ozone treatment was terminated, the problems with sludge bulking reappeared, indicating the importance of continuous evaluation of the process.
污泥膨胀和上浮是污水处理厂常见的问题，主要是由丝状细菌（如细小微丝菌）的过度生长引起的。它不仅会导致泡沫形成，还会对活性污泥法中的污泥沉降性能产生负面影响。可以采用不同的方法来控制污泥膨胀。本研究的目的是评估在一座因细小微丝菌导致出现问题的全尺寸污水处理厂中，循环活性污泥流中现场产生的臭氧剂量。通过在臭氧投加期之前、期间和之后，对实验线和对照线的过程数据、显微镜分析和微生物筛选来评估实验。臭氧处理使细小微丝菌的丰度降低，沉降性能得到改善，且未损害整体工艺性能。化学需氧量（COD）和氮的去除均未受影响，通过荧光原位杂交分析，参与硝化作用的优势菌群在实验期间保持不变。当臭氧处理终止时，污泥膨胀问题再次出现，这表明持续评估该工艺的重要性。
