Biofouling in fertilizer-drawn forward osmosis (FDFO) for water reuse was investigated by spiking pure bacteria species Pseudomonas aeruginosa PAO1+GFP and using three different fertilizers KNO₃, KCl and KH₂PO₄ as draw solutions. The performance of FO process for treating synthetic wastewater was assessed and their influence on the membrane fouling and in particular biofouling was evaluated relative to the type of different fertilizers used and their rates of reverse diffusion. FO performances using KNO₃ as draw solute exhibited severer flux decline (63%) than when using KCl (45%) and KH₂PO₄ (30%). Membrane autopsy indicated that the mass of organic foulants and biomass on fouled membrane surface using KNO₃ as draw solute (947.5mg/m² biopolymers, 72µm biofilm thickness and 53.3mg/m² adenosine triphosphate) were significantly higher than that using KCl (450mg/m² biopolymers, 33µm biofilm thickness and 28.2mg/m² ATP) and KH₂PO₄ (440mg/m² biopolymers, 35µm biofilm thickness and 33.5mg/m² ATP). This higher flux decline is likely related to the higher reverse diffusion of KNO₃ (19.8g/m²/h) than KCl (5.1g/m²/h) and KH₂PO₄ (3.7g/m²/h). The reverse diffused potassium could promote the organics and bacterial adhesion on FO membrane via charge screening effect and compression of electrical double layer. Moreover, reverse diffused nitrate provided increased N:P nutrient ratio was favorable for the bacteria to grow on the feed side of the FO membrane.

中文翻译：

---

养分反向渗透过程中养分逆向扩散对膜生物结垢的影响

通过掺加纯细菌铜绿假单胞菌PAO1 + GFP并使用三种不同的肥料KNO ₃，KCl和KH ₂ PO ₄作为汲取溶液，研究了肥料回用正渗透（FDFO）中的生物污染。评估了FO工艺处理合成废水的性能，并评估了它们对膜结垢（尤其是生物结垢）的影响（相对于所使用的不同肥料的类型及其反向扩散速率）。与使用KCl（45％）和KH ₂ PO ₄相比，使用KNO ₃作为吸引溶质的FO性能表现出更严重的通量下降（63％）（30％）。膜尸检表明，使用KNO ₃作为牵引溶质（947.5mg / m ²生物聚合物，72μm生物膜厚度和53.3mg / m ²三磷酸腺苷）时，污垢膜表面上的有机污垢和生物质的质量明显高于使用KCl（450mg）的质量。 / m ²生物聚合物，33µm生物膜厚度和28.2mg / m ² ATP）和KH ₂ PO ₄（440mg / m ²生物聚合物，35µm生物膜厚度和33.5mg / m ² ATP）。这种较高的通量下降可能与KNO ₃（19.8g / m ² / h）比KCl（5.1g / m ² / h）和KH的较高反向扩散有关₂ PO ₄（3.7g / m ² / h）。反向扩散的钾可以通过电荷屏蔽作用和双电层的压缩来促进有机物和细菌粘附在FO膜上。此外，反向扩散的硝酸盐提供了增加的N：P营养比，有利于细菌在FO膜进料侧生长。