A novel phosphorous (P) removal and recovery process using a membrane bioreactor (MBR) with ferric iron dosing and acidogenic co-fermentation was developed for municipal wastewater treatment. The very different solubility of Fe(III)-P and Fe(II)-P complex and the microbial transformation of Fe(III) to Fe(II) were utilized for P removal and recovery. By means of Fe-induced precipitation, chemical P removal was effectively achieved by an MBR with a flat-plate ceramic membrane; however, the Fe(III)-P solids accumulated in the MBR that constituted a significant fraction of the activated sludge. Anaerobic co-fermentation of the MBR sludge and food waste in a side-stream allowed the extraction of P and Fe from the sludge into the supernatant. The P in the supernatant was recovered as a fertilizer resource, while the sludge was returned to the MBR tank. The experimental results show that by adding FeCl₃ at 20 mg Fe/L into the influent of domestic wastewater, about 95.6% of total P could be removed by the MBR. One fifth (20%) of the sludge in the MBR was circulated daily through the side-stream fermenters for co-fermentation with cooked rice as the model food waste. The sludge underwent acidogenesis and dissimilatory iron reduction, resulting in a drop of the pH to below 5.0 and reduction of Fe(III) to Fe(II). Owing to the high solubility of the Fe(II)-P complex, P and Fe were then dissolved and released from the sludge into the supernatant. By simply adjusting the solution pH to 8.0, the P and Fe(II) in the supernatant readily re-precipitated to form vivianite for the P recovery. Using the iron dosing MBR and side-stream sludge fermentation, an overall P recovery efficiency of 62.1% from wastewater influent can be achieved, and the problem of inorganic build-up in the MBR is effectively alleviated.

开发了一种使用膜生物反应器（MBR）的三价铁（P）去除和回收工艺，该工艺具有三价铁配铁和产酸共发酵技术，用于市政废水处理。Fe（III）-P和Fe（II）-P络合物的溶解度非常不同，并且将Fe（III）转变为Fe（II）用于P的去除和回收。通过铁诱导的沉淀，通过带有平板陶瓷膜的MBR可以有效地实现化学除磷。然而，在MBR中积累的Fe（III）-P固体占了活性污泥的很大一部分。MBR污泥和食物残渣在侧流中的厌氧共同发酵使P和Fe从污泥中提取到上清液中。回收上清液中的P作为肥料资源，而污泥则返回MBR槽。₃以20 mg Fe / L的浓度进入生活污水，MBR可以去除总磷的约95.6％。MBR中有五分之一（20％）的污泥每天通过侧流发酵罐进行循环，与米饭作为模型食物垃圾一起进行发酵。污泥进行酸生成和异化铁还原，导致pH值降至5.0以下，并将Fe（III）还原为Fe（II）。由于Fe（II）-P络合物的高溶解度，因此P和Fe溶解并从污泥中释放到上清液中。通过简单地将溶液的pH值调节至8.0，上清液中的P和Fe（II）容易重新沉淀，形成用于回收P的堇青石。使用铁计量MBR和侧流污泥发酵，废水进水的总P回收效率可达到62.1％，