Caravelli A, Giannuzzi L, Zaritzky N
Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET, 47 y 116, La Plata 1900, Argentina.
Environ Technol. 2007 Feb;28(2):137-46. doi: 10.1080/09593332808618778.
Activated sludge is the most widely used biological process for wastewater treatment. Inorganic and organic compounds are removed by a biotic community in the aeration basin. Problems of these systems are loss of settleability and poor sludge compaction due to excessive growth of filamentous micro-organisms. The filamentous bulking can be controlled by the addition of chemical agents. Strong oxidants, such as chlorine, are utilized to eliminate filamentous bacteria; however, these substances also tend to attack floc-forming bacteria and to cause process breakdown. Besides, chlorine may become hazardous owing to the formation of chemical products as chloramines. Surfactant addition constitutes an interesting alternative for the control of filamentous bulking. In this work the effect of a surfactant Triton X-100 (octylphenol ethoxylate), on the respiratory activity (RA) of pure cultures of a filamentous (Sphaerotilus natans) and a floc-former microorganism (Acinetobacter anitratus) was evaluated. In the concentration range tested (60-220 mg l(-1)), the surfactant was observed to exhibit high RA specific inhibition of the filamentous micro-organism with no significant effect on the floc-forming bacteria. Light microscopy observations showed that the surfactant induced cell lysis, leaving only empty sheaths in the case of filamentous micro-organisms. A kinetic equation to predict the microbial RA fraction of a S. natans pure culture as a function of surfactant concentration and contact time was proposed. The effect of Triton X-100 on the inactivation of pure cultures of both micro-organisms was compared to that of chlorine. Triton X-100 results were adequate to eliminate filamentous bacteria emerging as an alternative for filamentous bulking treatment.
活性污泥法是污水处理中应用最广泛的生物处理工艺。曝气池中，无机和有机化合物通过生物群落得以去除。这些系统存在的问题是，丝状微生物过度生长导致沉降性能丧失和污泥压实性差。丝状膨胀可通过添加化学药剂来控制。强氧化剂，如氯，被用于消除丝状细菌；然而，这些物质也往往会攻击絮凝形成菌并导致工艺故障。此外，由于形成氯胺等化学产物，氯可能会变得具有危险性。添加表面活性剂是控制丝状膨胀的一个有趣替代方法。在这项研究中，评估了表面活性剂吐温X-100（辛基酚聚氧乙烯醚）对丝状微生物（浮游球衣菌）和絮凝形成微生物（反硝化不动杆菌）纯培养物呼吸活性（RA）的影响。在所测试的浓度范围（60 - 220 mg l(-1)）内，观察到该表面活性剂对丝状微生物表现出较高的RA特异性抑制作用，而对絮凝形成菌没有显著影响。光学显微镜观察表明，该表面活性剂会导致细胞裂解，对于丝状微生物而言，只剩下空的鞘。提出了一个动力学方程，用于预测浮游球衣菌纯培养物的微生物RA分数与表面活性剂浓度和接触时间的函数关系。将吐温X-100对两种微生物纯培养物的灭活效果与氯的效果进行了比较。吐温X-100的效果足以消除作为丝状膨胀处理替代方法出现的丝状细菌。
