污水管道中油脂沉积物的形成机理及控制方法的研究进展

Study on the Formation of Fat, Oil and Grease(FOG) Deposits in Sewer Pipes

在世界各国,以餐饮业为主的污水管道堵塞问题频发,由管道堵塞引起的污水外溢事故给居民健康及生态环境造成了极大的危害。长期以来,管道堵塞问题被归咎于餐饮企业所排放的油脂在管道中固化而导致的过水能力下降。而已有研究表明,上述"固化油脂"实为以金属离子脂肪酸盐为主的混合物,即"油脂沉积物(FOG deposits)"。本文主要综述了油脂沉积物的形成机理及当前油脂沉积物的控制方法。油脂沉积物的形成主要涉及到两个反应过程,一为污水中大量存在的金属离子与油脂经降解后形成的游离自由脂肪酸所发生的皂化反应;二为金属离子脂肪酸盐对污水中富余金属离子及油脂的凝聚反应。油脂沉积物的控制方法分为机械清除法及生物化学控制法,其中生物化学控制法以微生物法去除为主。文献调研表明,对于油脂沉积物形成的影响机理以及油脂沉积物控制的优化运行仍缺乏相关研究,因此需要更多试验研究对油脂沉积物理论进行完善。

Among the world nations, line blockage is always a serious problem that causes a lot of damage like sanitary sewer overflows（SSOs）. So long, the blockages have been simplistically portrayed to fat, oil and grease（FOG） accumulation in sewer pipes. However, recent study proved the ＂chief criminal＂ to SSOs is actually FOG deposit, one compound of several calcium salts of free fatty acids. The formation mechanism of FOG deposit mainly involves into three processes： 1） the aggregation of excess calcium compressing the double layer of free fatty acid micelles; 2） saponification between free fatty acid and positive metal ions like calcium ion; 3） the previously formed deposit acts as a core attracting un-reacted FFAs and calcium ion, also debris in waste water. This paper attempts to review the formation mechanisms of FOG deposits, the factors that influence the formation process is also discussed. It is excepted that this review could provide a holistic view of the recent researches on FOG deposit formation and the removal.