西北干旱区流域水污染特征与控制策略—以宁夏清水河流域为例

以宁夏境内黄河最大的一级支流清水河流域为例，分析重点断面水质、水环境容量及各控制单元污染负荷特征，并提出有针对性的污染控制策略。结果表明：2015—2018年清水河三营国控断面水质无法稳定达到GB 3838—2002《地表水环境质量标准》Ⅳ类水质标准，泉眼山断面化学需氧量（COD）存在超Ⅳ类水质标准风险。流域水环境容量COD为592.83~1 238.25 t/a，氨氮为51.99~193.60 t/a，总磷（TP）为5.02~12.85 t/a；流域平水期污染负荷入河量COD为15 661.1 t/a，氨氮为1 670.2 t/a，TP为784.5 t/a，分别是平水期水环境容量（COD为940.57 t/a，氨氮为114.64 t/a，TP为8.81 t/a）的16、14和89倍。固原控制单元单位面积污染负荷入河量最高（COD为3.04 t/a，氨氮为0.22 t/a，TP为0.06 t/a），工业源与城镇生活源污染问题突出，中卫控制单元总污染负荷入河量最高（COD为 6 738.45 t/a，氨氮为868.88 t/a，TP为218.12 t/a），城镇生活源污染较严重，而吴忠控制单元禽畜养殖污染较严重。基于水质目标和各单元的污染特征，建议固原控制单元加强工业企业污水回收利用、提高城镇污水处理能力，中卫控制单元重点关注污水收集处理设施建设与改造升级，吴忠控制单元在规模化养殖场推行禽畜粪污集中处理与回用。

Water pollution characteristics and control strategies in arid areas of Northwest China: a case study of Qingshui River Basin in Ningxia

Taking Qingshui River Basin, the largest first-level tributary of the Yellow River in Ningxia, as an example, the water quality, water environmental capacity and the characteristics of pollution loads of each control unit in key sections were analyzed, and targeted pollution control strategies were proposed. The results showed that the water quality of Sanying national control section of the Qingshui River in 2015-2018 could not stably reach the Class Ⅳ water quality standard of Environmental Quality Standards for Surface Water (GB 3838-2002), and the chemical oxygen demand (COD) of Quanyanshan Section was at risk of exceeding the Class Ⅳ water quality standard. The water environmental capacity of the basin was 592.83-1 238.25 t/a for COD, 51.99-193.60 t/a for ammonia nitrogen (NH3-N) and 5.02-12.85 t/a for total phosphorus (TP). The pollution load into the Qingshui River of the basin was 15 661.1 t/a for COD, 1 670.2 t/a for NH3-N and 784.5 t/a for TP in normal water period, which was 16, 14 and 89 times of the water environmental capacity (COD 940.57 t/a, NH3-N 114.64 t/a, TP 8.81 t/a). The pollution load per unit area in Guyuan City was the highest (COD 3.04 t/a, NH3-N 0.22 t/a, TP 0.06 t/a), with outstanding problems of industrial pollution load and urban living pollution. The total pollution load in Zhongwei City control unit into the river was the highest (COD 6 738.45 t/a, NH3-N 868.88 t/a, TP 218.12 t/a), with relatively serious urban living source pollution, while Wuzhong City control unit had relatively heavy poultry-farming pollution. Based on the water quality targets and the pollution characteristics of each unit, it was recommended that the wastewater recycling and utilization of industrial enterprises be strengthened and the urban wastewater treatment capacity be improved in Guyuan City control unit; the construction, transformation and upgrading of sewage collection and treatment facilities be focused on Zhongwei City control unit; and the centralized treatment and reuse of livestock manure in large-scale farms be implemented in Wuzhong City control unit.