Aluminum-based water treatment residue (Al-WTR) generated during the drinking water treatment process is a readily available recycled material with high phosphorus (P) adsorption capacity. The P adsorption capacity of Al-WTR generated from Singapore’s water treatment plant was evaluated with reference to particle size range, adsorption pH and temperature. Column tests, with WTR amendments in sand with and without compost, were used to simulate the bioretention systems. The adsorption rate decreased with increasing WTR sizes. Highest P adsorption capacity, 15.57 mg PO43−-P/g WTR, was achieved using fine WTR particles (50% particles at less than 0.30 mm). At pH 4, the contact time required to reduce effluent P concentration to below the detectable range was half compared with pH 7 and 9. The adsorption rate observed at 40 ± 2 °C was 21% higher compared with that at 30 ± 2 °C. Soil mixes amended with 10% WTR and compost were able to maintain consistently high (90%) total phosphorus (TP) removal efficiency at a TP load up to 6.45 g/m3. In contrast, TP removal efficiencies associated with columns without WTR amendment decreased to less than 45% as the TP load increased beyond 4.5 g/m3. The results showed that WTR application is beneficial for enhanced TP removal in bioretention systems.
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机译：饮用水处理过程中产生的铝基水处理残留物（Al-WTR）是一种容易获得的，具有高磷（P）吸附能力的回收材料。从新加坡水处理厂产生的Al-WTR对P的吸附能力是根据粒径范围，吸附pH和温度进行评估的。在有堆肥和无堆肥的情况下，在砂子中使用WTR修正的柱试验被用来模拟生物滞留系统。吸附速率随WTR尺寸的增加而降低。使用细小的WTR颗粒（> 50％的颗粒小于0.30 mm）可获得最高的P吸附能力，即15.57 mg PO 4 3- -P / g WTR。在pH 4下，将废水P浓度降低到可检测范围以下所需的接触时间是pH 7和9的一半。在40±2°C下观察到的吸附速率比在30±2°C下吸附速率高21％ 。用10％的WTR和堆肥改良的土壤混合物能够在高达6.45 g / m 3 的TP负荷下始终保持较高的总磷（TP）去除效率（90％）。相反，随着TP负荷增加到超过4.5 g / m 3 ，与未经WTR修正的色谱柱相关的TP去除效率降低至不足45％。结果表明，WTR的应用有益于增强生物保留系统中的TP去除。
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