Seawater can be introduced or intrude in sewer systems and can thereby negatively influence biological wastewater treatment processes. Here we studied the impact of artificial seawater on the enhanced biological phosphate removal (EBPR) process performance by aerobic granular sludge (AGS) with synthetic wastewater. Process performance, granule stability and characteristics as well as microbial community of a seawater-adapted AGS system were observed. In seawater conditions strong and stable granules formed with an SVI₅ of 20 mL/g and a lower abrasion coefficient than freshwater-adapted granules. Complete anaerobic uptake of acetate, anaerobic phosphate release of 59.5 ± 4.0 mg/L PO₄^3--P (0.35 mg P/mg HAc), and an aerobic P-uptake rate of 3.1 ± 0.2 mg P/g VSS/h were achieved. The dominant phosphate accumulating organisms (PAO) were the same as for freshwater-based aerobic granular sludge systems with a very high enrichment of Ca. Accumulibacter phosphatis clade I, and complete absence of glycogen accumulating organisms. The effect of osmotic downshocks was tested by replacing influent seawater-based medium by demineralized water-based medium. A temporary decrease of the salinity in the reactor led to a decreased phosphate removal activity, while it also induced a rapid release of COD by the sludge, up to 45.5 ± 1.7 mg COD/g VSS. This is most likely attributed to the release of osmolytes by the cells. Recovery of activity was immediately after restoring the seawater feeding. This work shows that functioning of aerobic granular sludge in seawater conditions is as stable as in freshwater conditions, while past research has shown a negative effect on operation of AGS processes with NaCl-based wastewater at the same salinity as seawater.

海水可引入或侵入下水道系统，从而可能对生物废水处理过程产生负面影响。在这里，我们研究了人工海水对合成废水中好氧颗粒污泥（AGS）增强生物磷酸盐去除（EBPR）工艺性能的影响。观察了海水适应性AGS系统的工艺性能，颗粒稳定性和特性以及微生物群落。在海水条件下，与适应淡水的颗粒相比，SVI ₅为20 mL / g且结实，稳定的颗粒形成的磨损系数更低。乙酸完全厌氧摄取，磷酸无氧释放为59.5±4.0 mg / L PO ₄ ^3--P（0.35 mg P / mg HAc），有氧P摄取率为3.1±0.2 mg P / g VSS / h。主要的磷酸盐累积生物（PAO）与具有很高钙富集的淡水基好氧颗粒污泥系统相同。积累了磷脂酶I，并且完全没有糖原累积生物。通过用脱矿质水基介质代替进水海水基介质，测试了渗透性地震的影响。反应器中盐度的暂时降低导致磷酸盐去除活性降低，同时还导致污泥快速释放COD，最高可达45.5±1.7 mg COD / g VSS。这很可能归因于细胞释放渗透压剂。恢复海水供应后立即恢复活动。这项工作表明，好氧颗粒污泥在海水条件下的功能与在淡水条件下一样稳定，而过去的研究表明，使用与海水相同盐度的NaCl基废水对AGS工艺的运行具有负面影响。