Environmental Sciences and Industrial Development Department, Faculty of Postgraduate Studies for Advanced Sciences (PSAS), Beni-Suef University, Beni-Suef, Egypt; Central Laboratories for Water Quality, Fayoum Drinking Water &Sanitation Company, Egypt.
Environmental Sciences and Industrial Development Department, Faculty of Postgraduate Studies for Advanced Sciences (PSAS), Beni-Suef University, Beni-Suef, Egypt; Department of Chemistry, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt.
Sci Total Environ. 2021 Apr 20;766:144333. doi: 10.1016/j.scitotenv.2020.144333. Epub 2020 Dec 25.
Discharge of Drinking Water Treatment Plants sludge directly on surface waters without any treatment is becoming an important issue in most countries around the world, behavior is not only affecting on the water quality, but also on soil and crops. This study investigated the effect of discharge of alum sludge and the variation in the level of the Nile water (flow regime) on water and soil qualities. The water samples were analyzed for physical, chemical and microbiological parameters. In winter (closure season), the mean values of EC, TDS, major ions, pH, DO and total algae count were higher than in summer. In summer (flooding season), it was noticed that the mean values of SiO, metals, COD, BOD, TOC, nutrients and bacteriological parameters exceed winter season values. Moreover, the concentrations of Al, Fe, Mn were above WHO permissible limits and the concentrations of aggregate organic parameters exceed the FAO permissible limits in sites near the areas of sludge discharge. Most of water samples exceed the national guidelines. For soil, our findings showed that the concentrations of metals in soil samples collected from areas irrigated from canals receiving alum sludge are more (two-three times) than their concentrations from the pure sites. However, Pb concentration in the contaminated soil reaches ten times more than in the pure one. The management of sludge disposal becomes an urgent priority to save waterways, soil and crops from pollution. Finally, the variation in water flow during the winter closure period with reduction by ≈15 BCM is similar to the same reduction in the Nile flow when the Grand Ethiopian Renaissance Dam starts operation. This indicates that the long-term reduction in water flow due to the construction of this dam may cause serious environmental changes in the Nile River in Egypt.
未经任何处理就将饮用水处理厂的污泥直接排放到地表水中，这在世界上大多数国家都成为了一个重要问题。这种行为不仅会影响水质，还会影响土壤和农作物。本研究调查了铝污泥的排放以及尼罗河水位（水流状况）的变化对水和土壤质量的影响。对水样进行了物理、化学和微生物参数分析。在冬季（关闭季节），电导率、总溶解固体、主要离子、pH 值、溶解氧和总藻类计数的平均值高于夏季。在夏季（洪水季节），人们注意到 SiO₂、金属、COD、BOD、TOC、营养物质和细菌学参数的平均值超过了冬季的值。此外，Al、Fe、Mn 的浓度超过了世卫组织的允许限值，在靠近污泥排放区的地方，聚集有机参数的浓度超过了粮农组织的允许限值。大多数水样超过了国家标准。对于土壤，我们的研究结果表明，从接收铝污泥的渠道灌溉的地区采集的土壤样本中金属的浓度比从纯净地区采集的土壤样本高出（两到三倍）。然而，受污染土壤中的 Pb 浓度是纯净土壤的十倍以上。因此，迫切需要对污泥处理进行管理，以防止水道、土壤和农作物受到污染。最后，冬季关闭期间水流减少了约 150 亿立方米，与大埃塞俄比亚复兴大坝开始运行时尼罗河流减少的水量相似。这表明，由于这座大坝的建设，尼罗河水的长期流量减少可能会导致埃及尼罗河发生严重的环境变化。
