近30年来鄱阳湖环湖区土地利用与景观格局变化研究

以1988—2018年7期Landsat遥感卫星影像为数据源,采用土地利用转移矩阵、景观格局指数等方法探究了鄱阳湖环湖区近30年来土地利用与景观格局变化特征.结果表明：(1)近30年来鄱阳湖环湖区建设用地和林地面积显著增加,耕地、草地、水域和未利用地面积减少.(2)建设用地的转入类型以耕地为主,30年间共侵占耕地面积1243.66 km²,占建设用地面积增加量的71.19%.林地的转入类型主要为耕地和草地,其中,耕地转入占比56.95%.耕地的转出类型以建设用地、草地和林地为主,且1999年以后随着城镇化的发展耕地主要转向建设用地.(3)近30年来鄱阳湖环湖区景观总体破碎程度逐渐增大,景观斑块个数共增加63492个,增幅为11.68%.景观连通性降低,各类型土地呈均衡化趋势分布,景观异质性增加.研究结果可为推动鄱阳湖环湖区土地资源保护、生态环境保护和经济协同发展提供参考依据.     

长庆油田伴生气回收及综合利用

根据原油生产过程中伴生气的性质和特点,归纳出目前长庆油田伴生气回收技术及其适应性。通过应用"燃料加热"、"轻烃回收"、"燃气发电"三种方式,达到节能减排的目的。针对长庆油田伴生气回收及利用提出了下一步展望:完善混输工艺,优化集气管网,合理调配气量,从而消除伴生气排放污染,达到环保要求。     

胺液脱硫系统再生性能下降原因分析及对策

中国石化茂名分公司两套胺液集中再生装置出现异常,再生后贫液中ρ(H_2S)达到2.0~3.0 g/L,远高于1.2g/L的工艺设计值。通过在实验室模拟装置上考察新鲜脱硫剂的吸收和再生性能、分析工厂胺液脱硫系统贫液的杂质组成和来源、对比实验室净化前后的效果,查明胺液脱硫系统脱硫剂再生性能下降的原因。据此对工厂胺液脱硫系统提出相应的操作建议,包括采取胺液净化技术将系统热稳盐含量(w)从2.35%降至0.95%、规范操作以降低Na~+含量等措施,使得胺液脱硫系统在整改后的两个月运行中,贫液中ρ(H_2S)从原来的最高1.68 g/L降至0.66 g/L以下,达到胺液脱硫系统稳定运行的目的。     

海南火山岩滤料曝气生物滤池工艺优化研究

本研究基于上向流曝气生物滤池污水处理系统,研究了该工艺不同气水比、不同水力停留时间、不同滤料高度层、反冲洗强度对污染物的处理效能的影响。结果表明,气水比为4∶1、水力停留时间2 h时,BAF出水中COD、NH+4-N和SS指标达到最佳;沿程污染物去除率随着滤料层高度的增加逐渐增大,当滤料高度大于1.6 m时趋于稳定,COD、NH+4-N和SS平均去除率分别达到80%、99%和80.3%。建议曝气生物滤池的反冲洗推荐程序为:先气冲(18 L/(m2·s)),单独气洗2~3 min;再气冲(18 L/(m2·s))加水冲(5 L/(m2·s)),联合反冲洗3~5 min;最后水冲(5 L/(m2·s)),漂洗5~8 min。     

Pulsed discharge plasma induced Fenton-like reactions for the enhancement of the degradation of 4-chlorophenol in water

To sufficiently utilize chemically active species and enhance the degradation rate and removal efficiency of toxic and biorefractory organic pollutant para-chlorophenol (para-CP), the introductions of iron metal ions (Fe²⁺/Fe³⁺) into either pulsed discharge plasma (PDP) process or the PDP process with TiO₂ photo-catalyst were tentatively performed. The experimental results showed that under the same experimental condition, the degradation rate and removal efficiency of para-CP were greatly enhanced by the introduction of iron ions (Fe²⁺/Fe³⁺) into the PDP process. Moreover, when iron ions and TiO₂ were added together in the PDP process, the degradation rate and removal energy of para-CP further improved. The possible mechanism was discussed that the obvious promoting effects were attributed to ferrous ions via plasma induced Fenton-like reactions by UV light irradiation excited and hydrogen peroxide formed in pulsed electrical discharge, resulting in a larger amount of hydroxyl radicals produced from the residual hydrogen peroxide. In addition, the regeneration of ferric ions to ferrous ions facilitates the progress of plasma induced Fenton-like reactions by photo-catalytic reduction of UV light, photo-catalytic reduction on TiO₂ surface and electron transfer of quinone intermediates, i.e. 1,4-hydroquinone and 1,4-benzoquinone.     

两种填埋结构中氨氮的空间变化规律研究

依据准好氧填埋和厌氧填埋的原理,构建了准好氧和厌氧填埋的实验室模拟装置,研究了2种填埋结构渗滤液中氨氮的空间分布规律。结果表明,准好氧填埋结构3层渗滤液中氨氮浓度都呈不断稳定下降的趋势,29周时上层、中层和下层渗滤液中氨氮浓度分别从填埋初的931.8、1796和3019 mg/L下降到25.6、328.9和820.1 mg/L;厌氧填埋结构3层渗滤液中氨氮浓度下降趋势不明显且波动性较大。准好氧填埋与厌氧填埋结构渗滤液中氨氮浓度表现出明显的空间层次效应,为下层>中层>上层。     

膜法处理难降解石化废水的预处理工艺研究

采用混凝法分别以聚合氯化铁（PFC）、聚合氯化铝（PAC）和聚合硫酸铁（PFS）为混凝剂处理天津某石油化工厂二级氧化处理工艺出水,PFC对废水COD的去除效果最好,在PFC加入量为120mg／L时,废水的COD去除率最高,为22．35％。经正交实验确定了Fenton试剂氧化法处理废水的最佳实验条件为：Fe^2＋加入量290mg／L、H2O2加入量100mg／L、pH=6、反应时间30min,此时COD去除率为20．45％。活性炭吸附法对废水的处理效果随活性炭加入量增加而改善,活性炭的最佳加入量为2000mg／L,此时废水的COD去除率最高,为87．78％。     

Using enriched stable isotope technique to study Cu bioaccumulation and bioavailability in Corbicula fluminea from Taihu Lake,China

In this study, we measured trace metals (Cd, Cr, Cu, Ni, Pb, and Zn) in water and sediment from representative sites of Taihu Lake, with focus on the analysis of trace metal accumulation in Corbicula fluminea (bivalve). The results showed that the quality of water in Taihu Lake was generally good and the correlation was not found between Cu bioaccumulation in C. fluminea and the concentration in water and sediment. Thus, using the stable isotope tracer method, we studied Cu uptake from the water phase, the assimilation of Cu from the food phase, and the efflux of Cu in vivo by C. fluminea. The result revealed that this species exhibited a relatively lower efflux rate constant of Cu compared with other zoobenthos species. Using a simple bioenergetics-based kinetic model, Cu concentrations in the C. fluminea were calculated with the measured efflux rate. We put forward a novel method, which was taking the influence of biological kinetic on metal bioaccumulation into account to explain the field survey data.     

Recovery of elemental sulfur from zinc concentrate direct leaching residue using atmospheric distillation: A pilot-scale experimental study

Recovery of elemental sulfur from zinc concentrate direct leaching residue (DLR) using atmospheric distillation was systematically investigated on a pilot-scale system for the first time. Batch operating mode was suggested for recovery of elemental sulfur from water-rich DLR using atmospheric distillation. Elemental sulfur with purity higher than 99% was obtained under certain conditions in batch operating mode. With an appropriate feed amount of 1,200 kg, batch experiment conducted at 460°C resulted in sulfur purity of 96.22% and a recovery rate higher than 85%. Only 0.59 and 1.24 kWh power was needed to handle 1.0 kg DLR and produce 1.0 kg elemental sulfur, respectively. The results suggest that recovery of elemental sulfur from zinc concentrate DLR using atmospheric distillation is technologically and economically feasible. Moreover, other metal elements such as zinc were enriched in the distillation concentrate, which could be used for metal refining. Technologies could effectively lower the moisture content of DLR, and lowering the distillation temperature would be of great value for recovery of elemental sulfur from DLR using a distillation method.

Implications:

Distillation is a promising solution for recovery of elemental sulfur from DLRs. This work revealed the possibility of separation of elemental sulfur from zinc concentrate DLR using atmospheric distillation. Such knowledge is of fundamental importance in developing field-scale separation and purification technologies and devices in which simultaneous sulfur recovery and precious metal enrichment are possible. Important tasks for follow-up research are also suggested.