PRB反应介质修复地下水中硝酸盐的试验研究

以胶州前韩地下水为例,选用铁粉、活性炭、锯末及其混合物为反应介质,设计6种PRB反应器, 探讨了反应介质对硝酸盐降解速率及对环境的影响,以寻求一种廉价而高效的降解地下水中硝酸盐的材 料。结果表明,采用PRB技术降低地下水硝酸盐浓度是可行的。零价铁、活性炭、锯末均对硝酸盐有去除 作用,当PRB反应器中含有铁粉时能将硝酸盐氮去除90%以上。     

基于EK-PRB修复镉污染土壤的微生物优化技术

采用电动-可渗透反应墙(EK-PRB)联合微生物优化技术,研究其对Cd污染土壤修复效果的影响。利用固定化微生物技术,制备粉煤灰-酵母菌小球、壳聚糖-酵母菌小球和生物炭-酵母菌小球,并对比制备的PRB小球和单一的PRB材料(粉煤灰、生物炭、壳聚糖)对Cd去除效果的影响。结果表明,相对于单一的PRB材料,PRB小球可增加土壤中的电流和电导率,对Cd的去除率更高,但是对p H影响较小。通过对PRB材料进行表征分析,证实了其对Cd去除效果有一定影响。考虑到经济成本与修复效果,选择电压梯度为2.5 V·cm^-1,PRB材料为粉煤灰-酵母菌小球去除Cd,去除率可达53.70%。研究结果证实了固定化微生物结合EK-PRB技术的可行性以及修复优势。     

垃圾渗滤液危害及其处理工艺探讨

垃圾渗滤液是一种危害较大的高浓度有机废水,如不妥善处理,会对周围环境及地下水造成严重污染。介绍垃圾渗滤液的来源及影响因素、垃圾渗滤液的处理工艺、垃圾渗滤液的物化处理。     

南昌某垃圾填埋场渗滤液中高浓度氨氮的脱除研究

采用化学沉淀工艺,对垃圾填埋场渗滤液进行预处理,使氨氮等获得较好的去除效果,为后续处理奠定良好基础。通过单因素实验研究考察了不同反应pH值、药剂配比以及反应时间对氨氮去除率的影响,确定了实验的最佳条件。实验初步探索了反应生成的沉淀物-磷酸铵镁的产生量,其成分中含有大量的氮磷等营养元素,可作为一种复合肥进行回收利用。     

长春市某垃圾填埋场污染源带反应阻截方案设计研究

以充分的水文地质数据和准确的污染物扩散模型为前提,设计并运用渗透反应墙(PRB)技术进行污染场地修复。结合长春市某垃圾填埋场污染场地实例,在获得模拟区域整体水文地质数据之后,通过GMS地下水流场模拟软件对有机污染物(COD)在地下环境中的扩散分布进行模拟,进而合理确定了渗透反应墙安装位置、填充材料以及长度、宽度、埋深等参数,得出在垃圾填埋场Ⅲ区东部至车间以内安装渗透反应墙为适宜。     

渗滤液流失造成的MSW填埋气潜能减量

中国城市生活垃圾(MSW)中易生物降解的有机质能产生大量可造成有机污染的渗滤液,这些渗滤液的流失对填埋垃圾的产气能力会产生不利影响,为了确定损失的这部分渗滤液的产气能力,对模拟填埋100 d的处于酸化阶段的渗滤液实施了70d的厌氧消化试验.试验过程中对渗滤液的产气量、甲烷含量、产沼气潜能、pH变化规律及COD去除率做了监测研究.结果表明,渗滤液沼气累积产量为34.55 ml/ml,甲烷浓度为65.0%,渗滤液产甲烷潜能为22.46 ml/g;pH值在开始两天下降至6.7,并在产气阶段逐渐上升到8.3;渗滤液的COD去除率为83.8%.基于对模拟填埋渗滤液的沼气潜能研究,一个开始填埋100d后的中国MSW填埋场流失的填埋气潜能已达到11.5%.     

处理过的老龄垃圾渗滤液为阴极液的微生物燃料电池性能研究

处理过的老龄垃圾渗滤液与好氧污泥悬浊液的混合液按不同体积配比(0%、25%、50%、75%和100%),作为阴极液,构建生物阴极型微生物燃料电池(MFC),研究其产电特征以及对阳极底物和阴极液中污染物的处理效果。结果表明,处理过的老龄垃圾渗滤液作为阴极液时,MFC对化学需氧量(COD)和氨氮的去除率较其作为阳极液时分别提高2.27倍和42%。处理过的老龄垃圾渗滤液与好氧活性污泥悬浊液的混合液作为阴极液可提高MFC的产电性能和对污染物的去除效果。以体积比为75%的处理过的老龄垃圾渗滤液作为阴极液时,能显著提高MFC产电效果,输出电压和输出功率密度最大,分别为498 mV、295.2 mW/m~3,内阻最小为244Ω,阳极COD去除率最高为44.81%。     

填埋场项目地下水环境影响评价

填埋场分为垃圾填埋和安全填埋两种,而这两种填埋都会产生渗滤液对地下水造成影响。主要研究安全填埋项目,以样品检测与模拟为方法研究影响机制识别、不确定性分析等方面。     

不同阴极催化剂对城市垃圾渗滤液微生物燃料电池处理的影响

以城市垃圾渗滤液为阳极液基质,比较以MnO_2和TiO_2为阴极催化剂时,对MFC电池性能以及渗滤液中有机污染物去除率的影响。结果表明,MnO_2和TiO_2作为阴极催化剂,可催化氧化阴极最终电子受体(O_2)、提高电子传递速率,最终提高电池性能。阴极负载MnO_2后,电池性能显著提高,稳定输出电压和最大功率密度分别增大到0.43 V和0.89 W/m~3。与未负载阴极催化剂的MFC相比,经MFC运行7 d后,渗滤液中的生物需氧量(BOD)和NH_4~+-N去除率分别提高8.1%和5.0%,达72.9%和91.6%。但由于缺少光照,阴极负载TiO_2后电池性能无明显改善,稳定输出电压仅为0.23 V,最大功率密度仅0.12 W/m~3,且渗滤液中有机污染物的BOD和NH_4~+-N去除率比负载MnO_2催化剂的MFC低8.8%和5.7%。     

存量垃圾填埋场对地下水的污染评价

某地区存在着数量众多的存量垃圾填埋场,其中一些由于缺少防渗系统,造成渗滤液对地下水的污染。结合某地区某存量垃圾填埋场的基本情况,通过调查、勘探、实验室分析等一系列工作,分析垃圾场所处的地质环境、地层对垃圾污染物的防护能力,并采用综合污染指数法和内梅罗指数法,评价该垃圾场渗滤液对下伏第一层地下水的污染情况及对地下水水质的影响情况。结果表明填埋场下游地下水均有不同程度污染,且污染程度与距离垃圾场的远近正态相关,说明地下水污染与垃圾场的存在有密切联系。统计结果表明,砷的污染指数最高,约为24倍,其次为高锰酸钾指数,最高为2.4;地下水综合污染指数为标准值的5倍,内梅罗污染指数为标准值的17倍之多。该垃圾场对地下水的污染具有一定的普遍性,反映了某地区已存的部分存量垃圾填埋场对地下水的污染情况,为某地区地下水资源的治理、开发利用提供依据,同时也为全国开展该项工作提供大量的借鉴经验。     

Studies on porous radiant burners for LPG (liquefied petroleum gas) cooking applications

This paper deals with the performance tests of a PRB (porous radiant burner) used for LPG (liquefied petroleum gas) domestic cooking stoves. The burner consists of a two-layer porous media. The combustion zone is made up of silicon carbide, and alumina balls forms the preheating zone. For a given burner diameter, the performances of the burner, in terms of thermal efficiency and emission characteristics, are analysed for different equivalence ratios and thermal loads (wattages). The water boiling test as prescribed in the BIS (Bureau of Indian Standard): 4246:2002 was used to calculate the thermal efficiency of both the conventional LPG cooking stoves and the PRB. The maximum thermal efficiency of the LPG cooking stoves with a PRB was found to be 68% which is 3% higher than that of the maximum thermal efficiency of the conventional domestic LPG cooking stoves. Unlike the conventional LPG stoves, for which the CO and NO_X emissions were found in the ranges 400–1050 mg/m³ and 162–216 mg/m³, respectively, for the one with PRB, the same were in the ranges of 25–350 mg/m³ and 12–25 mg/m³. The axial temperature distribution in the burner showed that the reaction zone was close to the interface of the two zones and at a higher thermal load, it shifted towards the downstream. The surface temperature of the PRB was found to be uniform.     

醋酸乙酯车间废水的预处理研究

在国内主要采用酯化法生产醋酸乙酯,当采用间歇操作时,会导致反应釜需要定时清理,产生高浓度有机酸性废水即车间废水。介绍了处理类似废水的各种方法,并通过试验考察了投加不同碱剂,在不同搅拌速度、pH值下对COD去除率的影响。试验结果表明,调节车间废水pH值的最佳碱剂为Ca(OH)2,最佳pH值为9.0,最佳搅拌强度为60r/min,COD去除率最高为30.77%。     

Advanced wastewater treatment using filamentous algae in raceway ponds with underwater light

The current study evaluated nutrient removal efficiency, algae productivity, and economic feasibility related to cultivation of the filamentous algae, Hydrodictyon reticulatum, in a pilot plant-scale raceway pond with underwater light. Following the installation of an underwater light device, removal efficiencies of T-N and T-P increased by 11.0% and 12.3%, respectively. The productivity of algae also increased by 133.8% to 5.81 g/m²?d. Installation of the underwater light device increased the wastewater treatment capacity by over 3 times in the same area and enabled the removal of nutrients by over 3.5 times and removal of carbon dioxide by an additional 39 tons/yr. Estimates indicated that the cost of wastewater treatment and nutrient removal was reduced by more than 67%, while the production cost of H. reticulatum was reduced by 18% or more. Therefore, underwater light may solve issues related to the need for large sites in existing raceway ponds and enhance the economic efficiency by improving nutrient removal efficiency and productivity.     

水环境中典型抗抑郁药物的分布与去除现状

抗抑郁药物是一类具有生物毒性的新型环境污染物,近年来在水环境中频繁检出,已引起水处理界的广泛关注。介绍了典型抗抑郁药物的来源及分布现状,并以检出频率较高的西酞普兰和文拉法辛为例,综述了其在污水处理厂中的去除现状,以及高级氧化技术对其的降解效果。由于我国对水环境中的抗抑郁类药物的研究尚处于起步阶段,因此在今后的研究中有必要关注典型抗抑郁药物在污水处理过程中的降解机制,探究污水成分对降解过程的影响。     

改性蛋壳材料对重金属离子的去除机理研究

以废弃蛋壳为主要原料,通过微波法和铁改性法分别合成吸附材料ME和FE,采用扫描电镜、X射线衍射以及比表面积分析仪进行表征,并考察材料对废水中Cu~(2+)、Cd~(2+)、Pb~(2+)的吸附性能及其影响因子(反应时间、吸附剂投加量、重金属离子初始质量浓度以及溶液pH)。结果表明:ME对Cu~(2+)、Cd~(2+)的吸附效果较好,当废水中Cu~(2+)、Cd~(2+)的初始质量浓度为50 mg·L~(-1)、ME的投加量为0.6 g·L~(-1)、pH=4时,反应20 min后,ME对Cu~(2+)、Cd~(2+)的去除率均高达100%,其饱和吸附量分别为179.2、183.6 mg·g~(-1);FE对Pb~(2+)的吸附效果较好,当废水中Pb~(2+)的初始质量浓度为50 mg·L~(-1)、pH=6时,FE对Pb~(2+)的饱和吸附量可达87.23 mg·g~(-1),Langmuir吸附等温方程可较好地描述该吸附过程。     

酸性NaClO_2溶液同时脱硫、脱硝的试验研究

以NaClO2溶液为吸收剂,在自行设计的小型鼓泡反应器中进行了烟气同时脱硫、脱硝的实验研究,分析了影响脱除效率的各种因素及规律.试验发现,NaClO2初始浓度、吸收溶液初始pH值、吸收液温度、SO2和NO初始浓度等对脱除效率影响较大;在确定的最佳试验条件下,脱硫、脱硝效率分别达到100%和95.2%.另外还利用光化学方法分析了脱硫、脱硝产物,结果表明:脱硫产物主要为SO24-,脱硝产物主要为NO3;在此基础上,提出了酸性NaClO2溶液脱硫、脱硝的反应机理.     

Kinetics and mechanism of CO2 gasification of coal catalyzed by Na2CO3, FeCO3 and Na2CO3–FeCO3

The purpose is to develop a mild catalytic CO₂-gasification technology that can promote CO₂ utilization and reduce cost in air separation systems with improving system efficiency and obtaining desirable gaseous products. In this study, the influence of Na, Fe and their composite catalysts on the structure and gasification reactivity of chars derived from pyrolysis of Powder River Basin (PRB) coal was investigated. The results showed that a strong positive synergistic effect between Na and Fe catalyst in the gasification process was observed, the catalytic activity of the added catalysts was in order of: 4% Na > 3% Na–1%Fe > 2% Na-2% Fe > 1% Na-3% Fe > 1% Na-2% Fe > 4% Fe > raw coal. The catalysts inhibited the growth of the aromatic ring structure and enriched the generation of O-containing functional groups. Compared to Fe, the Na-based catalyst could easily diffuse into inner pores of coal char, forming C–O–Na structure and thus increasing the gasification reactivity of chars. In addition, due to the formation of inert material between SiO₂ and Na, the catalytic activity of Na catalysts was significantly decrease at the late stage of char conversion. Comparatively, the Fe-based catalysts showed better stability life. Moreover, it was found that the activation energy for CO₂-gasification of PRB coal can be decreased by 50% due to the addition of Na catalyst.     

Characterization of ionic liquid pretreatment and the bioconversion of pretreated mixed softwood biomass

In this study, mixed softwoods were pretreated with an ionic liquid, 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), and the bioconversion efficiencies to fermentable sugars were estimated through the enzymatic hydrolysis. The cellulose crystallinity, surface morphology, structures and compositions of softwood were significantly changed after the ionic liquid pretreatment was carried out under a wide range of temperatures and reaction times. And, biomass digestibility significantly increased with increasing pretreatment temperature and reaction time. The enzymatic degradation of pretreated softwoods was remarkably improved at the pretreatment of high temperatures via the modification of crystalline cellulose I to a mixture of easily digestable cellulose II and amorphous structure, and partial removal of hemicellulose. The conversion of cellulose to glucose reached more than 90% at relevant conditions and the highest glucose yield was measured to about 78%. Through the study, it was clearly shown that ionic liquid pretreatment is one of the effective methods to produce high fermentable sugars without lignin dissolution from lignocellulosic biomass.