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排序方式: 共有241条查询结果,搜索用时 31 毫秒
1.
保障水稻稳定增产事关国家粮食安全。水中的农药、化肥、重金属等物质随稻田尾水流出,排入周边水域,易造成水体面源污染。生物炭具有原材料丰富、孔隙结构发达、比表面积大、离子交换能力强、成本效益高等优势,已被广泛应用于环境修复领域。生物炭经适当改性能增加吸附活性位,提高吸附性能。在促沉净化材料中添加生物炭或生物炭基材料,可增强稻田面源污染促沉净化装置效能,提高稻田尾水利用率,助推农业绿色发展。本文介绍了稻田尾水的特点、常见处理技术及治理意义,阐述了生物炭及生物炭基材料在稻田尾水净化中的应用,展望了稻田尾水防治工作待深入开展的方向,并提出了生物炭材料在参与废水处理上存在的问题,以期为促进生态循环农业发展提供参考。 相似文献
2.
There is an increasing trend to require more efficient use of water resources, both in urban and rural environments. A major mechanism that can be used to achieve greater efficiencies is the reuse of water that once would have been discarded into the environment after use. The reuse of water for agricultural irrigation is often viewed as a positive means of recycling water due to the potential large volumes of water that can be used. Recycled water can have the advantage of being a constant, reliable water source and reduces the amount of water extracted from the environment. In addition, in some cases treatment requirements may be need to be less than for water used in an urban environment due to less potential human contact. There are concerns and unknowns, however, about the impact of the quality of the recycled water, both on the crop itself and on the end users of the crops. Water quality issues that can create real or perceived problems in agriculture include nutrient and sodium concentrations, heavy metals, and the presence of contaminants such as human and animal pathogens, pharmaceuticals and endocrine disruptors. Social attitudes to the use of crops that have been irrigated with recycled waters and the resulting impact on market value of crops are also a major consideration. This paper will discuss the benefits from using different types of recycled water and outline the current knowledge and opinions relating to risks such as water quality issues. 相似文献
3.
污灌区有机氯农药的土—气交换行为与影响因素分析 总被引:1,自引:0,他引:1
以我国东北典型污灌区为研究区域,获取相关数据及模型参数,并应用逸度方法探讨了有机氯农药的土-气交换行为及其分馏效应。研究结果表明,在土壤有机质含量一定的情况下,日均温度最大时有机氯农药六六六(HCHs)和滴滴涕(DDTs)之间土-气分配系数(KSA)的差异比日均温度最小时高出一个数量级,HCHs比DDTs更容易挥发重新释放进入环境中而进行二次分配,土壤有机质质量分数每提高1%而引起的KSA值的变化率不同,且这种变化会随着有机质质量分数的提高而趋于平稳;辛醇-气分配系数(KOA)与土-气交换逸度分数ff呈负相关关系,当土壤有机质质量分数为1%、2%和3%时,其相关系数分别为-0.743(P0.05)、-0.763(P0.05)、-0.776(P0.05);应用土-气浓度比(Cs/a),进一步判定土壤浓度和大气浓度在其他参数不变的情况下,将会对HCHs及DDTs的土-气交换行为产生影响;HCHs与DDTs的初次分馏及二次分馏效应进一步说明土壤性质及其自身的理化性质均会对分馏效应产生影响。 相似文献
4.
斜板上流式厌氧污泥床处理低浓度有机废水的试验研究 总被引:13,自引:0,他引:13
本文报告了用16.1升斜板上流式厌氧污泥床在常温下处理低浓度有机废水的启动和运行试验研究。试验使用稀释酒精废水为模拟处理基质,启动阶段仅用77天时间,装置水力负荷达到2m3/(m3.d),COD去除率达到78.9%,此时进水COD浓度为767.8mg/L。在第二阶段试验中,仅用一天时间,装置就恢复了时隔半年的正常运行。以后在温度12℃以上,HRT为12小时,进水COD浓度在660.0~982.0mg/L范围的129天稳定运行中,平均COD去除率为76.1%。结果表明:采用该工艺处理低浓度有机废水在技术上是可行的,具有启动快,运行稳定,工艺控制简便的优点。水浸没的成组浅层斜板在UASB/ITS反应器中有良好的污泥截留能力和稳流效果,容易生成大颗粒污泥。颗粒污泥最大粒径可达5mm,SVI为18.2ml/g。颗粒污泥中以甲烷丝菌为优势菌。 相似文献
5.
利用专利微生物治理硝基苯和苯胺混合废水 总被引:3,自引:0,他引:3
利用专利微生物菌种,采用兼氧——好氧的生化法工艺流程,处理混酸硝化法生产硝基苯产生的硝化废水及硝基苯气相催化还原法生产苯胺产生的苯胺废水。 相似文献
6.
Settling velocity characterization of aquacultural solids 总被引:5,自引:0,他引:5
A top-loading settling column is described and used to characterize the settling properties of the solids in the discharge water from a commercial rainbow trout production facility. Mass-based and phosphorus-based settling curves are presented. The median settling velocity on a mass-basis for the settleable solids was 1.7 cm s−1. The median settling velocity for the settleable phosphorus was 1.15 cm s−1. Manually stripping fecal material from rainbow trout resulted in settleable solids with a median settling velocity of 0.7 cm s−1. Examination of the settling velocity curves show that halving the overflow rate (OFR) from 2 to 1 cm s−1 changes the removal efficiency from 0.61 to 0.73, an increase of about 20%. Halving the OFR again to 0.5 cm s−1 increases the removal efficiency to 0.81, an improvement of about 11%. Settling characteristics of aquacultural solids will vary from facility to facility. The methods described in this paper can be used to perform a similar type of analysis at other aquacultural sites, which may be growing other species under different management regimes. 相似文献
7.
Moshood N. Tijani 《Agricultural Water Management》2009,96(3):437-444
This study focuses on experimental pilot assessment of contamination of shallow groundwater systems and soil-plant transfer of trace metals under amended irrigated fields. The study approach involved a pilot experimental (greenhouse) set-up of organo-mineral amended test plots/troughs (40 cm × 47 cm × 46 cm) planted with two common vegetable crops (Amaranthus hybridus and Abelmoschus esculentus) and irrigated with wastewater. In addition to the geochemical analyses of the primary un-amended and amended soils before planting as well as residual soils after harvesting, measurements of the physico-chemical parameters and chemical analyses of trace metals concentrations in irrigation leachates and harvested vegetable tissues were also undertaken following appropriate standard sample preparation and analytical methods.The results of the geochemical analyses carried out on irrigation leachate samples collected during the sprouting stage revealed that most of the analyzed trace metals in the collected leachates exhibited 2-10 folds depletion (except for Cu and Co with enrichment of about 1.5-3 folds) compared to the initial wastewater used for irrigation. A situation attributed to uptake/bioaccumulation of these metals and selective enrichment in the residual soils as well as to leaching by infiltrating irrigation water. Nonetheless, the observed higher trace elements concentrations in the second sets of leachates collected during harvesting stage compared to the first sets of leachates collected during the sprouting/vegetative stage is an indication of higher plant uptake during sprouting/vegetative stage or initial sorption/complexation of biosolids amendment before later vertical re-mobilization by infiltrating irrigation water.Although, virtually all of the analyzed metals exhibited elevated concentrations (2-173 ppm) in both A. hybridus and A. esculentus, a closer evaluation revealed 1.2-8.2 folds enrichment of Cr, Co, Ni, Cd, Cu, and Pb in A. esculentus compared to that of A. hybridus, an indication of the fact that phyto-accumulation of trace metal is plant-specific and dependent on physiological set-up. The overall evaluation had clearly demonstrated the potential danger of bioaccumulation of toxic trace metals under biosolid amended soils as well as impacts of irrigation-induced leaching on the shallow groundwater quality, while the need to evolve a sustainable agricultural practices is also highlighted.
Capsule
Organo-mineral amendment can lead to trace metal bioaccumulation (in plants) and irrigation-induced leaching to shallow groundwater system. 相似文献8.
Sodicity and salinity in a Brazilian Oxisol cultivated with sugarcane irrigated with wastewater 总被引:2,自引:0,他引:2
Rafael Marques Pereira Leal Uwe Herpin Lilian Pittol Firme Célia Regina Montes Adolpho José Melfi 《Agricultural Water Management》2009,96(2):307-316
Changes in soil sodicity-salinity parameters are one of the most characteristic alterations after treated sewage effluent (TSE) irrigation in agro-systems. Considering the importance of these parameters for agricultural management, as well as the economical value of sugarcane for Brazil, the present study aimed at evaluating effects on soil sodicity and salinity under tropical conditions over 16 months of TSE irrigation in a sugarcane plantation at Lins, São Paulo State, Brazil. Soil samplings were carried out in February 2005 (before planting), December 2005 (after 8 months of TSE irrigation) and September 2006 (after 16 months of TSE irrigation) following a complete block design with four treatments and four replicates. Treatments consisted of: (i) control, without TSE irrigation; (ii) T100, T150 and T200, with TSE irrigation supplying 100% (0% surplus, total of 2524 mm), 150% (50% surplus, total of 3832 mm) and 200% (100% surplus, total of 5092 mm) of crop water demand, respectively. Compared to initial soil conditions, at the end of the experiment increases of exchangeable sodium (from 2.4 to 5.9 mmolc kg−1), exchangeable sodium percentage (ESP) (from 8 to 18%), soluble Na (from 1.4 to 4.7 mmol L−1) and sodium adsorption ratio (SAR) of soil solution (from 3.6 to 12.6 (mmol L−1)0.5) were found in the soil profile (0-100 cm) as an average for the irrigated plots due to high SAR of TSE. Associated with the increments were mostly significant increases in clay dispersion rates at depths 0-10, 10-20 and 20-40 cm. Electrical conductivity (EC) of soil solution increased during the TSE irrigation period whereas at the end of the experiment, after short term discontinuation of irrigation and harvest, EC in the topsoil (0-10 and 10-20 cm) decreased compared to the previous samplings. Moreover, despite increasing sodicity over time mainly insignificant differences within the different irrigated treatments were found in December 2005 and September 2006. This suggests that independent of varying irrigation amounts the increasing soil sodicity over time were rather caused by the continuous use of TSE than by its quantity applied. Moreover, also plant productivity showed no significant differences within the TSE irrigated plots. The study indicates that monitoring as well as remediation of soil after TSE irrigation is required for a sustainable TSE use in order to maintain agricultural quality parameters. 相似文献
9.
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