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991.
再生水补充地下水水质指标及控制技术 总被引:5,自引:0,他引:5
再生水补充地下水是扩大污水回用最有益的一种方式,具有广阔发展前景.本文分析与总结了国内外再生水补充地下水研究与应用实例、水质标准,结合我国再生水的水质特点及水文地质状况,从保护地下水资源和人体健康的角度,探讨了我国利用再生水补充地下水应控制的水质指标及控制技术.按地表回灌和井灌方式分别提出了水质基本控制项目COD、BOD、氨氮、粪大肠菌群数等22项,选择控制项目Hg、三氯甲烷等重金属和微污染有机物52项及其建议指标值,并提出了再生水处理控制技术. 相似文献
992.
993.
华北平原农田硝态氮淋溶率和淋溶负荷估计 总被引:2,自引:1,他引:2
由于化肥过度施用且强度逐渐增加,华北平原氮淋溶问题日趋严重且造成了地下水污染风险.利用1991年以来公开发表的文献中290 组农田NO3--N 淋溶试验样本(淋溶率和10个影响因素),基于Bayesian递归回归树模型初步建立了华北平原农田NO3--N淋溶迁移过程统计模型.以2008年为例,基于华北平原县域合成氮肥、复合肥施用量和1 km×1 km的影响因素和土地利用(耕地)数据,最终得到1 km×1 km的华北平原农田NO3--N淋溶率和淋溶负荷及其不确定性水平.初步结果表明:①模型校准和验证R2分别达到0.832和0.829,模拟结果相对可靠;②华北平原耕地NO3--N的淋溶率具有显著的空间分异,其中位值为15.4%(R50为12.6%~18.2%),其主要影响因素为土壤TN量、施N量、灌溉比例与降雨量的比值等;相应地,2008年淋溶负荷和淋溶量分别为995.1 Gg·a-1(833.4~1156.7 Gg·a-1);③NO3--N淋溶率较高的区域集中在太行山脉以东、黄河附近以及苏北的县(区、市),淋溶负荷贡献最大为河南(~37.7%)、江苏(~24.8%)和河北(~21.6%). 相似文献
994.
Maged M. Hamed 《Environmental Modeling and Assessment》2005,9(4):253-264
The Gulf War in 1991 created an environmental catastrophe, one of the major consequences of which was setting several oil wells on fire in the Arabian Gulf area. The total oil spilled as a result of the damaged wells was about 3.5 × 106 m3. Out of these, 3.3 × 106 m3 of oil was recovered and exported. The rest was left behind as it was not economical to collect. The oil left behind was subject to severe weathering over the past ten years. Soil and subsurface contamination pose a serious risk to the quality of the already scarce fresh groundwater resources in the area which was subject to oil spill in the study region. This paper presents the computer modeling activities carried out towards simulating the transport of the hydrocarbon contamination of the fresh groundwater resources at a study area in the Arabian Gulf region, and predicting the contamination levels at the fresh groundwater lenses in the area in the future, should current contamination levels persist in the soil and groundwater. The modeling activities relied on both semi-analytical and numerical flow and transport models. 相似文献
995.
996.
深入认识湘东北地区的水文循环过程,对规范该区水资源的有效利用和减缓该区生态环境问题具有重要意义。在2021年10月—2023年2月,对该区金井镇的大气降水和不同深度(~4.7 m和~61 m)井水每月开展样品采集和测试。该区大气降水稳定同位素值(δ18O、δD)呈现夏半年偏负、冬半年偏正,且氘盈余、水汽通量和HYSPLIT模型分析结果显示,在夏季,影响该区降水气团主要来自暖湿的海洋洋面,冬季主要来自稳定的南支西风和局地水汽输送。浅井水和深井水的δ18O和δD与该区大气降水δ18O和δD的均值接近,变幅较小且呈现夏季偏正冬季偏负的特征,说明地下水受到大气降水的补给,但可能滞后于大气降水的变化。然而,不同深度地下水对大气降水的响应机制和滞后时间,还需进一步研究。 相似文献
997.
生物法去除地下水中铁锰的影响因素 总被引:8,自引:1,他引:7
分析了生物法除地下水中铁锰的影响因素,曝气后使地下水中DO为7.0~7.5mg/L及pH为6.8~7.0时,生物滤层中的锰氧化菌能够保持较好活性及除锰能力,且工艺能够达到铁锰同除的要求.本研究提出的“成熟滤料移植”生物过滤方法,适合于对Mn2+吸附能力较强的优质锰砂滤层的接种,而对吸附能力较弱的石英砂滤层,只能采用菌量较大的实验室选择性培养基培养、驯化锰氧化菌的接种方式;锰砂和石英砂生物滤层的反冲洗强度分别控制在6~9L/(s·m2)、7~11L/(s·m2)的较低范围时,滤层的微生物相受扰动较小,反冲后铁锰去除能力能在5h内恢复.同时滤层采用1.0~1.2mm的均质滤料,在反冲洗强度较低的情况下过滤周期依然可延长至35~38h. 相似文献
998.
Spatial distribution of pH, electrical conductivity (EC), total dissolved solids (TDS), fluoride and total iron content of
ground water samples collected from the muvattupuzha river basin, Kerala, India, has been studied for pre monsoon and post
monsoon periods of year 2001. Results showed the groundwater of the basin is acidic for which the pH values ranged between
5.5 and 8.0. Average EC was found to be less than 100 μS/cm, for most of the study region. The pre monsoon minimum and maximum
TDS were found as 25.6 and 227.84 mg/L respectively, where as post monsoon values ranged between 16 and 162.56 mg/L. The relatively
low EC and TDS values found both during the seasons in the lateritic terrain of the river basin signifies the lower residence
time of ground water with the country rock. This makes the groundwater quality of this river basin as good. Pre monsoon season
samples showed high total iron content than that during the post monsoon period. During the study period values of the fluoride
contents were found to be within the permissible limits. 相似文献
999.
Siddique A Mumtaz M Saied S Karim Z Zaigham NA 《Environmental monitoring and assessment》2006,120(1-3):177-185
The ground and municipal water supply samples of Karachi city were analyzed for their fluoride contents. The fluoride contents in water samples collected from the subsurface and river sources were found below the WHO recommended value for the general health of the people. However, in some industrial areas the groundwater sample showed higher level of fluoride concentration. Continuous monitoring of water resources and cautious fluoridation is suggested to maintain proper status of fluoride concentration in the drinking water. 相似文献
1000.
Hydrochemical Changes Over Time in the Zahedan Aquifer, Iran 总被引:1,自引:0,他引:1
Khazaei E Stednick JD Sanford WE Warner JW 《Environmental monitoring and assessment》2006,114(1-3):123-143
Groundwater in the Zahedan Aquifer located in the arid southeast of Iran was chemically characterized to understand both the nature of the alluvium aquifer and the effect of human activities, specifically sewage disposal on groundwater quality. Concentrations of major cations and anions in the Zahedan Aquifer are much higher than concentrations observed in groundwater of similar settings. Although the nature of the aquifer and climatic parameters have affected the chemistry of groundwater, human impacts on the groundwater quality are more significant. The electrical conductivity in some areas of the Zahedan aquifer increased up to 7,500μS/cm in 25 years. Human influences in some areas are so prevalent, that the groundwater type changed from a Na+-HCO3
- in 1976 to a Na+-Cl- type in 2000. The impact of human influences on the groundwater quality is also indicated through observed nitrate concentration up to 4.81 meq/L in the urban area. 相似文献