【作者】 詹艳慧；

【导师】 王里奥；

【作者基本信息】 重庆大学 ， 环境工程， 2005， 硕士

【摘要】 三峡水库是我国特大型水利枢纽工程,在水库全部建成后将在库岸周边形成落差30m的消落带。三峡库区消落带受江水淹没和暴露交替,泥沙冲淤交替的交互作用影响,形成具有独特自然环境过程的生态系统,使得消落带既可能是污染物的源也可能是污染物的汇。本实验选取典型消落带土壤进行了氮磷吸持释放规律研究,并进行了干湿交替后底泥氮磷释放规律研究以及土壤、底泥氮磷释放控制实验研究。研究结果表明:三峡水库消落带土壤对氨氮和磷酸盐具有一定的吸附能力,土壤对氨氮和磷酸盐吸附等温曲线满足Langmuir等温吸附方程,且淹水-落干对土壤吸附氨氮和磷酸盐有较明显影响:经淹水-落干处理后对氨氮的吸附能力得到增强,由淹水-落干前的666mg/kg增加到淹水-落干后的833mg/kg;淹水-落干后土壤吸磷能力增强,由淹水-落干前的256mg/kg增加到淹水-落干后的625mg/kg;磷零点吸持平衡浓度(EPC0)由淹水前的0.46mg/L增加到淹水后的1.47mg/L。淹水-落干对土壤磷解吸的影响明显:淹水-落干土壤磷解吸量增大,由淹水-落干前的199~264mg/kg增加到274~334mg/kg;但解吸率降低,由淹水-落干前的73.3%~80.3%降低到67.3~69.6%。模拟淹水条件下,吸附氨氮和吸磷土壤向上覆水中释放氮磷,土壤吸附的氮、磷越多,淹水氮、磷释放强度越大。土壤淹水氮磷释放依水体DO量的不同而不同,总氮好氧淹水释放量是厌氧淹水释放量的1.2~1.4倍;并且在两次淹水过程中,好氧淹水磷释放量高于厌氧淹水磷释放量。淹水-落干对土壤淹水磷释放的影响依水体DO的不同而不同,好氧淹水磷释放过程中淹水-落干对土壤磷释放的影响不明显;厌氧淹水磷释放过程中淹水-落干对土壤磷释放在第一次淹水过程中影响不明显,但在第二次厌氧淹水过程中淹水-落干增强了土壤磷释放能力。底泥中氮磷营养物质含量高,淹水条件下向上覆水中释放氮磷营养物质。曝晒对底泥淹水释放氨氮、硝态氮、总氮和总磷有明显影响:曝晒后底泥释放氨氮、硝态氮和总氮能力增强;曝晒后底泥释放总磷能力减弱。沸石对土壤氨氮释放控制效果好,氨氮释放抑制率达到了86.9%;对底泥淹水氨氮释放抑制效果好,并且氨氮释放抑制率随沸石覆盖量的增加而增加,抑制率分别为98.3%(300g沸石),99.5%(400g沸石)和99.6%(500g沸石)。沸石对土壤磷释放控制效果较好,总磷释放抑制率达到78.7%;沸石对淹水底泥总磷释放抑制率已覆盖层厚度的增加而增大,由63.9%(300g沸石)、75.1%(400g沸石)增加到81.0%(500g沸石)。方解石对土壤和底泥氨氮释放控制效果均较差,对氨氮释放没有控制效果。更多还原

【Abstract】 The Three Gorges Reservoir is the largest water conservancy and control projects in the world. After the accomplishment of the project, a 30m-meter high water-level-fluctuating zone will appear which a seasonal humid ecosystem covering 291.1 km 2. This area will be both the sink and source of pollutants as the alternately dried and flooded conditions. A mass of pollutants containing P and N will deposit on the water-level-fluctuating zone, and then will be released into the water in inundation condition. The study on the effect of the adsorption and release of P and N in water-level-fluctuating zone of Three Gorge Reservoir is very important for water environmental protection of Three Gorge Reservoir.The release of P and N from typical soil in water level fluctuating zone of the Three Gorges Reservoir and the sediment from Jialing River were studied in this research. By conducting release and adsorption experiments of P and N under simulated inundation condition, release velocity and load of soil were confirmed. By conducting release experiments of NH4+ and P covered by zeolite and calcite.The study on the adsorption properties of soil with NH4+ and PO43- showed that NH4+ and PO43- could be absorbed by soil. The results indicated that the process of NH4+ and P in the area could be adequately described with Uniform-surface Langmuir equation. Alternately dried and flooded conditions had significant influence on the adsorption properties of soil. The adsorption capacity of NH4+ was increased from 666 mg/kg to 833 mg/kg, and the sorption capacity of P was increased from 256 mg/kg to 625 mg/kg. The EPC0 was increased from 0.46 mg/L to 1.47 mg/L. Alternately dried and flooded condition had significant influence on the desorption capacity of P which increased from 199~264mg/L to 274~334mg/kg, but the desorption ratio of P was decreased from 733.3~80.3% to 67.3~69.6%.The NH4+ and PO43- were released to the simulated water from soil which had adsorbed some of NH4+ and PO43-. The release capacity was larger as increasing the amount of NH4+ and PO43- absorbed by soil, and was affected by DO in the simulated water. The ratio of the release capacity of TN between aerobic and anaerobic condition was 1.2~1.4. The release capacity of TP in aerobic condition was larger than that in anaerobic condition.The influence on P release of alternately dried and flooded was not obvious in更多还原