Although on-line chemical cleaning has been extensively employed for maintaining the MBR permeability, little attention has been given to the negative impacts of such prevalent membrane cleaning practice. This study thus comparatively investigated the potential release of dissolved organic matter (DOM) from activated sludge upon the exposure to different kinds of frequently-used cleaning reagents, i.e. NaClO, H₂O₂, HCl and NaOH. It was found that NaClO at 50 and 80 mg L⁻¹ triggered significant release of DOM, while NaOH strongly promoted soluble nitrogen release. However, the DOM generation induced by H₂O₂ in the range of 0–80 mg L⁻¹ was nearly negligible. The combined analysis by EEM-PARAFAC and LC-OCD-OND further revealed that NaClO-triggered DOM mainly originated from the breakdown of humic substances and other small humics with molecular weight (MW) less than 500 Da. In contrast, proteins and other biopolymers with higher MW highly contributed to DOM induced by NaOH. Most of DOM detected in this study belonged to low molecular weight (LMW) substances, which were not considered readily biodegradable or physically retainable by microfiltration membrane. It appears from this study that DOM generated from suspended activated sludge during membrane cleaning with different chemicals should be taken into serious consideration when water recycle and reuse are concerned.

尽管在线化学清洗已广泛用于维持MBR渗透性，但很少有人关注这种普遍的膜清洗实践的负面影响。因此，本研究比较了暴露于不同种类的常用清洁剂（例如NaClO，H ₂ O ₂，HCl和NaOH ）时活性污泥中溶解有机物（DOM）的潜在释放。发现50和80mg L ^-1的NaClO触发了DOM的显着释放，而NaOH强烈地促进了可溶性氮的释放。但是，由H ₂ O ₂诱导的DOM生成范围为0–80 mg L ^-1几乎可以忽略不计。EEM-PARAFAC和LC-OCD-OND的组合分析进一步表明，NaClO触发的DOM主要源自腐殖质和分子量小于500 Da的其他小腐殖质的分解。相反，具有更高分子量的蛋白质和其他生物聚合物对由NaOH诱导的DOM做出了重要贡献。在这项研究中检测到的大多数DOM属于低分子量（LMW）物质，这些物质不易被微滤膜生物降解或保留。从这项研究看来，当考虑到水的循环利用和再利用时，应认真考虑在用不同化学物质进行膜清洗过程中悬浮的活性污泥产生的DOM。