Fraser A G, Sakrabani R, Ashley R M, Johnstone F M
Urban Water Technology Centre, University of Abertay Dundee, UK.
Water Sci Technol. 2002;45(3):265-72.
In times of high sewer flow, conditions can exist which enable previously deposited material to be re-entrained back into the body of the flow column. Pulses of this highly polluted flow have been recorded in many instances at the recently constructed wastewater treatment plant (WTP) in Forfar, Scotland. Investigations have been undertaken to characterise the incoming flows and to suggest remedial measures to manage the quality fluctuations. Initial visits to the works and incoming pipes indicated a high degree of sediment deposition in the two inlet pipes. Analyses were carried out and consequently, changes to the hydraulic regime were made. Measurements of sediment level, sediment quality, wall slime and bulk water quality were monitored in the period following the remedial works to observe any improvements. Dramatic alterations in each of the determinands measured were recorded. Analyses were then undertaken to determine long term sediment behaviour and to assess the future usefulness of existing upstream sediment traps. It was concluded that with proper maintenance of the traps, the new hydraulic regime is sufficient to prevent further significant build up of sediment deposits and reduce impacts on the WTP. Further investigations made by North of Scotland Water Authority highlighted trade inputs to the system which may also have contributed to the now managed foul flush problem.
在污水流量较大的时候，可能会出现一些情况，使得先前沉积的物质重新卷入水流柱体中。在苏格兰福尔法新建的污水处理厂（WTP），许多情况下都记录到了这种高污染水流的脉冲。已经开展了调查，以表征进入的水流特征，并提出管理水质波动的补救措施。对污水处理厂和进水管道的初步检查表明，两根进水管道中有大量沉积物。进行了分析，并因此对水力工况进行了调整。在补救工程完成后的一段时间内，对沉积物水平、沉积物质量、壁面黏液和总体水质进行了监测，以观察是否有任何改善。记录到所测量的各项指标都发生了显著变化。随后进行了分析，以确定沉积物的长期行为，并评估现有上游沉积物捕集器未来的效用。得出的结论是，通过对捕集器进行适当维护，新的水力工况足以防止沉积物进一步大量堆积，并减少对污水处理厂的影响。苏格兰北部水务局进行的进一步调查突出了该系统的行业输入，这也可能导致了目前已得到控制的污水冲淤问题。
