Centre of Environmental Technology and Engineering, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
Water Sci Technol. 2011;63(8):1689-94. doi: 10.2166/wst.2011.336.
Net phosphorus removal from waste stabilisation pond (WSP) systems is governed by the rate of phosphorus incorporation into the sludge layer and the rate of phosphorus release from this sludge back to the overlying wastewater. Luxury uptake of phosphorus by microalgae has been shown to occur under WSP conditions in the laboratory; however, the significance of this mechanism and the fate of polyphosphate contained in the settled solids have not previously been investigated. In this work the analysis of sludge samples from three WSP showed that up to 71% of the total phosphorus in the sludge was in the form of polyphosphate. This indicates that polyphosphate accumulation could potentially be an important mechanism for phosphorus sequestration in WSP and challenges the common view that chemical precipitation is the predominant phosphorus removal mechanism in these systems. The release of phosphate from WSP sludge samples was monitored in the laboratory. The samples from two different pond systems had release rates in the order of 4.3 microgP/gTSS.d. However, the third sample which was collected during an algal bloom had a release rate of 12.4 microgP/gTSS.d. Phosphate release from fresh microalgal sludge grown under laboratory conditions was also studied and was shown to have a release rate of 160 microgP/gTSS.d. Analysis of polyphosphate during the experiments on laboratory grown microalgal sludge showed that polyphosphate was indeed degraded resulting in phosphate release. Interestingly, after the initial release phase phosphorus was assimilated by the biomass and some polyphosphate was reformed. It is likely that this is due to bacterial growth in the sludge.
从污水稳定塘（WSP）系统中去除总磷受到磷向污泥层中的掺入速度和从该污泥层向污水中释放的速度的控制。已在实验室条件下表明，在 WSP 条件下微藻会发生奢侈性吸收磷；然而，这种机制的重要性以及沉淀固体中所含多磷酸盐的命运尚未得到研究。在这项工作中，对三个 WSP 的污泥样品进行的分析表明，污泥中总磷的 71%以多磷酸盐的形式存在。这表明多磷酸盐的积累可能是 WSP 中磷固定的一个重要机制，并挑战了化学沉淀是这些系统中主要磷去除机制的常见观点。在实验室中监测了 WSP 污泥样品中磷酸盐的释放。来自两个不同池塘系统的样品的释放速率为 4.3μgP/gTSS.d。然而，在藻类大量繁殖期间采集的第三个样品的释放速率为 12.4μgP/gTSS.d。在实验室条件下培养的新鲜微藻污泥的磷酸盐释放也进行了研究，结果表明其释放速率为 160μgP/gTSS.d。在实验室培养的微藻污泥的实验中对多磷酸盐的分析表明，多磷酸盐确实被降解，导致磷酸盐释放。有趣的是，在初始释放阶段之后，磷被生物质吸收，并且一些多磷酸盐被重新形成。这很可能是由于污泥中的细菌生长所致。
