Environmental Engineering Research Centre, Department of Civil Engineering , The University of Hong Kong , Pokfulam, Hong Kong , China.
Department of Civil and Environmental Engineering , The Hong Kong Polytechnic University , Hung Hom , Kowloon , Hong Kong , China.
Environ Sci Technol. 2018 Dec 18;52(24):14119-14128. doi: 10.1021/acs.est.8b03355. Epub 2018 Nov 30.
A new phosphorus (P) removal and recovery process that integrates an FeCl-dosing, membrane bioreactor (MBR), and side-stream cofermentation was developed for wastewater treatment. The Fe and P species and their transformation mechanisms via aerobic and anaerobic conditions were investigated with X-ray absorption near edge structure (XANES) spectroscopy. In the new treatment system, 98.4% of the total P in domestic wastewater was removed and retained in activated sludge in the MBR. During the subsequent acidogenic cofermentation with food waste, P in the MBR sludge was released and eventually recovered as vivianite, achieving an overall P recovery efficiency of 61.9% from wastewater. The main pathways for P removal and recovery with iron dosing and acidogenic fermentation were determined by XANES analysis. The results showed that Fe-enhanced P removal with the MBR was mainly achieved by precipitation as ferric phosphate (24.2%) and adsorption onto hydrous iron oxides (60.3%). During anaerobic fermentation, transition from Fe(III)-P to Fe(II)-P complex occurred in the sludge, leading to Fe(II) dissolution and P release. The pH decrease and microbial Fe reduction were crucial conditions for effective P extraction from the MBR sludge. The efficiency of P recovery increased with an increase in the fermentation time and organic load and a decrease of pH in the solution.
一种新的磷（P）去除和回收工艺，集成了 FeCl 加药、膜生物反应器（MBR）和侧流共发酵，用于污水处理。采用 X 射线吸收近边结构（XANES）光谱法研究了铁和磷物种及其在有氧和厌氧条件下的转化机制。在新的处理系统中，生活污水中的总磷（P）有 98.4%被去除并保留在 MBR 中的活性污泥中。随后在与食物垃圾的产酸共发酵中，MBR 污泥中的磷被释放出来，并最终以蓝铁矿的形式回收，从而实现了从废水中回收磷的总效率为 61.9%。XANES 分析确定了铁加药和产酸发酵过程中磷去除和回收的主要途径。结果表明，MBR 中 Fe 增强的磷去除主要通过磷酸铁（24.2%）的沉淀和水合氧化铁（60.3%）的吸附来实现。在厌氧发酵过程中，污泥中发生了从 Fe(III)-P 到 Fe(II)-P 配合物的转变，导致 Fe(II)溶解和 P 释放。pH 值下降和微生物铁还原是从 MBR 污泥中有效提取磷的关键条件。随着发酵时间、有机负荷的增加和溶液 pH 值的降低，磷回收效率提高。
