浅谈混凝剂在气田水处理中的应用

在重庆气矿气田水处理中加入了聚合氯化铝和聚丙烯酰胺,其应结果表明,这两种絮凝剂配合使用的效果较好,能达到石油企业废水回注指标(pH值为6～9,SS小于30mg/L,石油类物质少于10mg/L)。分析了两者单独使用的处理结果,针对目前使用中存在的问题,指出应注意的事项,并对今后重庆气矿气田水处理运行中混凝剂的使用提出了建议。     

川西北气矿中坝须二气田水处理方法

介绍了川西北气矿中坝气田须二气藏水质情况,论述了气田水四种处理方法的特点和适用性。为了维持生产和减少环境污染,在该气藏中引入了预处理装置,对气田水进行处理后再进行异层回注。介绍了该工艺的流程,处理后气田水中SS和石油类含量分别为15mg/L和5.3mg/L,达到了设计要求。对处理成本及四种地层水处理方案的经济效益进行了对比,分析了该技术的经济可行性,并根据其应用情况提出了建议,供生产决策部门参考。     

A Bird’s Eye View of the Malheur Wildlife Refuge Occupation: Nonhuman Agency and Entangled Species

In January 2016, armed militants occupied the Malheur National Wildlife Refuge, demanding an end to government control of the Refuge and other similarly protected public lands. Public discourse about the occupation highlights ongoing tensions around land use, property rights, and government overreach. The discourse foregrounds human animal concerns and all but erases nonhuman animal agency. This essay considers nonhuman animal agency and the entanglement of humans, nonhumans, and the land as seen in the occupation and surrounding discourse. We draw from critical animal studies and feminist posthuman theory to examine how discourses of the occupation produce and reinforce a sense of human exceptionalism that elides a more useful and nuanced understanding of human–nonhuman–land relatedness and agency. The analysis shows how, in the case of the Malheur occupation, occupiers and critics alike rely on discourses of “othering” towards both nonhuman animals and other humans. We take a “birding” perspective on the occupation to show how the webs of relationality that connect humans, nonhumans, and the land might be activated as an antidote to destructive discourses of human exceptionalism.     

厦门酸雨的区域分布及降雨过程分析

测定了厦门市几个代表点1993年3月至7月间雨样的pH值,并用ICP－AES方法测定了S、Ca、Mg等元素的浓度,实验结果表明,各区域雨样的pH值不仅与致酸污染物的排放(主要表现在S元素浓度上)有关,而且受到该区域的地理条件的影响,体现出酸雨的形成是致酸因素与致碱因素互相平衡制约的结果的一般规律。根据单场雨的分段分析数据,总结出pH值随降雨过程变化的几种模式,并分析了其成因。      

Calibration and Validation of Far Field Dilution Models for Outfall at Worli, Mumbai

The city of Mumbai, India with a population of 15 million discharges about 2225 MLD of domestic wastewater after partial treatment to adjoining marine water body. Under the Mumbai Sewage Disposal Project Scheme, sewage is being disposed to the west coast at Worli and Bandra through 3.4 kms long submarine outfalls. A field study was conducted at recently commissioned outfall diffuser location at Worli, at the onset of neap flood tide to study the dispersion patterns and measure the far field dilutions using radio and dye tracers. Estimated dilutions using different tracers were compared with outputs from an empirical model (Brooks) and a 2D numerical model (DIVAST). Validation using parameters such as BOD and FC, indicated a good match for BOD in near field compared to FC. The radiotracer ⁸²Br and Rhodamine WT generally gave good correlation with Brooks' and DIVAST models for nearfield, however at further distances predictions were not accurate.     

A field experiment with variable-suction multi-compartment samplers to measure the spatio-temporal distribution of solute leaching in an agricultural soil

Solutes spread out in time and space as they move downwards from the soil surface with infiltrating water. Solute monitoring in the field is often limited to observations of resident concentrations, while flux concentrations govern the movement of solutes in soils. A recently developed multi-compartment sampler is capable of measuring fluxes at a high spatial resolution with minimal disturbance of the local pressure head field. The objective of this paper is to use this sampler to quantify the spatial and temporal variation of solute leaching below the root zone in an agricultural field under natural rainfall in winter and spring. We placed two samplers at 31 and 25 cm depth in an agricultural field, leaving the soil above undisturbed. Each sampler contained 100 separate cells of 31 × 31 mm. Water fluxes were measured every 5 min for each cell. We monitored leaching of a chloride pulse under natural rainfall by frequently extracting the collected leachate while leaving the samplers buried in situ. This experiment was followed by a dye tracer experiment. This setting yielded information that widely surpassed the information that can be provided by separate anionic and dye tracer trials, and solute transport monitoring by coring or suction cups. The detailed information provided by the samplers showed that percolation at the sampling depth started much faster (approximately 3 h after the start of rainfall) in initially wet soil (pressure head above − 65 cm) than in drier soil (more than 14 h at pressure heads below − 80 cm). At any time, 25% of the drainage passed through 5–6% of the sampled area, reflecting the effect of heterogeneity on the flow paths. The amount of solute carried by individual cells varied over four orders of magnitude. The lateral concentration differences were limited though. This suggests a convective–dispersive regime despite the short vertical travel distance. On the other hand, the dilution index indicates a slight tendency towards stochastic–convective transport at this depth. There was no evidence in the observed drainage patterns and dye stained profiles of significant disturbance of the flow field by the samplers.     

Growth, yield and elements content of wheat (Triticum aestivum) grown in composted municipal solid wastes amended soil

A commercial formulation of composted municipal solid wastes (MSW) was used for amending soil at 0, 50, 100, 150, 200 and 250 kg ha⁻¹ in which wheat had been grown (field experiments) and element residues of amended soil and plant parts were enumerated. MSW amendment caused a significant improvement in soil quality. Growth (shoot length, leaf number, leaf area, tiller number, plant dry weight and chlorophyll contents of leaves) and yield (length of panicle, number of panicles per plant and grain yield per plant) of wheat increased gradually up to the MSW-amendment level of 200 kg ha⁻¹. Elements, Ni, Zn, Cu, Cd, Cr, and Pb accumulated in plants from MSW amended soil, but the degree of metal accumulation was the least in seeds in comparison to other plant parts (root, stem and leaf). Moreover, Ni, Zn, Cd and Pb, were in high concentration in all plant parts. It is recorded that the level of 200 kg ha⁻¹ MSW amendment caused better growth and yield of wheat, but progressive levels of metal accumulation in plant parts were recorded due to increase in amendment levels. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Mapping nitrate leaching to upper groundwater in the sandy regions of The Netherlands, using conceptual knowledge

The European Community asks its Member States to provide a comprehensive and coherent overview of their groundwater chemical status. It is stated that simple conceptual models are necessary to allow assessments of the risks of failing to meet quality objectives. In The Netherlands two monitoring networks (one for agriculture and one for nature) are operational, providing results which can be used for an overview. Two regression models, based upon simple conceptual models, link measured nitrate concentrations to data from remote sensing images of land use, national forest inventory, national cattle inventory, fertiliser use statistics, atmospheric N deposition, soil maps and weather monitoring. The models are used to draw a nitrate leaching map and to estimate the size of the area exceeding the EU limit value in the early 1990s. The 95% confidence interval for the fraction nature and agricultural areas where the EU limit value for nitrate (50 mg/l) was exceeded amounted to 0.77–0.85 while the lower 97.5% confidence limit for the fraction agricultural area where the EU limit value was exceeded amounted to 0.94. Although the two conceptual models can be regarded as simple, the use of the models to give an overview was experienced as complex.     

Data integration across borders: a case study of the Abbotsford‐Sumas aquifer (British Columbia/Washington State)1

Abstract: Integrating spatial datasets from diverse sources is essential for cross‐border environmental investigations and decision‐making. This is a little investigated topic that has profound implications for the availability and reliability of spatial data. At present, ground‐water hydrostratigraphic models exist for both the Canadian or for the United States (U.S.) portion of the aquifer but few are integrated across the border. In this paper, we describe the challenges of integrating multiple source, large datasets for development of a ground‐water hydrostratigraphic model for the Abbotsford‐Sumas Aquifer. Growing concerns in Canada regarding excessive withdrawal south of the border and in the U.S. regarding nitrate contamination originating north of the border make this particular aquifer one of international interest. While much emphasis in GIScience is on theoretical solutions to data integration, such as current ontology research, this study addresses pragmatic ways of integrating data across borders. Numerous interoperability challenges including the availability of data, metadata, data formats and quality, database structure, semantics, policies, and cooperation are identified as inhibitors of data integration for cross‐border studies. The final section of the paper outlines two possible solutions for standardizing classification schemes for ground‐water models – once data heterogeneity has been addressed.