Department of Water Pollution Control, Universite libre de Bruxelles (ULB), Boulevard du Triomphe CP 208, 1050 Brussels, Belgium E-mail:
Water Sci Technol. 2014;69(4):903-8. doi: 10.2166/wst.2013.800.
In 2011 and 2012 the dissolved oxygen content in the low-discharge river Zenne was monitored continuously, every 5 minutes, downstream of Brussels city centre, making it possible to document the complex mechanisms by which combined sewer overflow (CSO) spills affect both the hydraulics and the oxygen balance of the hydrosystem. In addition to oxygen demand impacts, proportions of water volumes are such that the oxygen-devoid sewage water discharged from CSOs contributes significantly to the oxygen deficit observed in the river further downstream. It is shown that ensuing unexpected hydraulic behaviour, such as a full river-flow reversal, can explain the dual nature of oxygen sag following major CSO events. At times the semi-sewer river plays the role of an in-stream stormwater tank, effectively attenuating the environmental impacts of Brussels CSOs.
2011 年和 2012 年，在布鲁塞尔市中心下游，对低流量的塞纳河的溶解氧含量进行了连续监测，每 5 分钟一次，从而记录了合流污水溢流（CSO）溢出对水力学和水系统氧平衡的复杂影响机制。除了对需氧量的影响之外，由于排出的 CSO 污水没有氧，其水量比例很大，这对在河流下游观察到的缺氧有显著贡献。研究表明，随之而来的意外水力行为，如完全河流水流逆转，可以解释在大型 CSO 事件后氧气骤降的双重性质。有时，半污水河道起着河流雨水箱的作用，有效地减轻了布鲁塞尔 CSO 的环境影响。
