微生物固定高浓度CO2技术的研究进展

大气中的CO2浓度升高主要是化石燃料燃烧造成的，CO2浓度升高引发的温室效应已经成为一个重大的环境问题．从微生物固定CO2机理及高浓度CO2对微生物的影响、固定高浓度CO2的微生物和生物反应器的优化等方面分析目前国内外微生物固定高浓度CO2的研究状况．     

全淹没低压CO2灭火系统设计计算

二氧化碳(CO2)是一种能够用于扑救多种类型火灾的灭火剂,对绝大多数被保护的物质没有破坏作用,灭火后能很快散逸,不留痕迹,排入大气又没有毒害。相对在国内正在试用的“FM-200”、“烟烙尽”而言,CO2在国内不但储量丰富,价格也很便宜,而且在世界先进国家成功地运用CO2灭火系统已有60多年的经验。《二氧化碳灭火系统设计规范》GB50193-93,1999年局部修订条文已于1999年11月17日批准并于2000年3月1日起执行。其中,增加了有关低压CO2的条文等,为在我国推广使用CO2灭火系统铺平了道路。在建筑消防设施的设计中,全淹没CO2灭火系统应用尤为…     

关于《全淹没低压CO2灭火系统设计计算》的讨论

《消防技术与产品信息》今年第 8期刊登了北京城乡建筑设计院王文科同志的《全淹没低压 CO2 灭火系统设计计算》(以下简称“计算”)一文。这篇文章比较系统地详尽说明了全淹没低压 CO2 灭火系统的设计计算方法和计算过程 ,并提供了一系列数据和表格。这就充分说明了作者在此方面进行了相当深入的研究 ,提出的设计步骤也相当清楚。毫无疑问 ,此文必定会对低压CO2 灭火系统的设计者有很大影响。由于 CO2 灭火系统的设计是两相流管网计算 ,所以其计算方法相当复杂且烦琐。手工计算一项工程一般都需要几天时间 ,且计算过程中很容易发生错误…     

厌氧—生物接触氧化—滤布滤池深度处理校园污水

西北干旱地区某校园污水先采用水解酸化阶段-产甲烷阶段分离的厌氧生物处理及两级生物接触氧化处理,出水再进行滤布滤池深度处理。结果表明,该工艺能有效地将高有机物浓度、高氨氮的校园生活污水处理后达到城市污水再生利用杂用水的水质标准。该工程利用厌氧污泥回流到产甲烷阶段前,腐殖污泥回流到水解酸化池并加大污泥回流率的方法,基本无剩余污泥排放。     

微藻固定高浓度CO2技术的研究进展

自工业革命以来,不断增长的燃料消耗导致大气中CO2浓度日益升高,由此所产生的温室效应已经受到全世界的普遍关注.近年来,国际上已经开展了生物固碳技术的相关研究.详细介绍了目前国内外利用微藻固定高浓度CO2技术的研究现状.     

厌氧同时反硝化产甲烷工艺的应用及进展

厌氧同时反硝化产甲烷工艺能够充分利用废水中的有机碳源,在实现生物脱氮的同时产生甲烷,其关键是如何减小或消除硝态氮（NO^- -N）对产甲烷茵的抑制作用。目前,解决该问题的主要手段有培养同时反硝化产甲烷颗粒污泥和生物膜等方法。研究表明,厌氧同时反硝化产甲烷反应器串联好氧硝化反应器（SDMR—ANR）系统,适于处理早期的垃圾渗滤液、屠宰废水等含高浓度有机物和高NH4＋ -N的废水,其中进水COD／N03- -N和好氧反应器出水回流比是影响其运行效果的关键因素。此外,还介绍了厌氧同时反硝化产甲烷工艺的微生物种群结构及进一步的功能扩展。     

不同污泥处理与处置工艺的碳排放分析

对我国现行的主流污泥处理与处置技术路线:生物干化/土地利用工艺和热干化/焚烧工艺的碳排放进行了计算和收支分析。结果表明,生物干化工艺的CO2直接排放量和碳足迹量均较低,而热干化/焚烧工艺的CO2排放量和碳足迹量分别为生物干化的5.33和4.94倍。将干化污泥用作草坪基质具有一定的碳减排和碳汇增加功能,CO2减排量和吸收量分别达到68.7和648kg/t。从碳净排放量看,热干化/焚烧工艺表现为高碳排放特征(372.9 kg/t),而生物干化/土地利用工艺具有碳减排效应(-643.6 kg/t),符合当前的政策背景与产业导向。     

生物除铁除锰滤池的曝气溶氧研究

从理论计算和试验两方面探讨了生物除铁除锰滤池中的曝气溶氧问题。结果表明,生物滤层除铁除锰不需要高溶解氧,也不需要通过散除CO2来提高原水的pH值,相反CO2可作为微生物繁殖代谢的碳源。认为简单的曝气充氧方式与生物滤池的结合可大大简化传统的处理流程。     

两相厌氧/膜生物反应器工艺的快速启动

为了实现两相厌氧/膜生物反应器(TPAD/MBR)工艺处理制药废水的快速启动,采用混合污泥接种,对产酸相、产甲烷相和MBR进行分步启动。结果表明:产酸相的启动时间为42d,对COD的平均去除率为41.7%;产甲烷相的启动时间为20 d,对COD的平均去除率为86.7%;MBR的启动时间为12 d,对COD的平均去除率为95.2%,出水COD80 mg/L。废水经产酸相处理后挥发酸平均含量为2 569 mg/L,其中乙酸和乙醇的平均含量分别为873 mg/L和1 127 mg/L,这证明经过产酸相后废水的可生化性大大提高,为产甲烷相的进一步处理提供了有利条件。产酸相的最佳pH值为4.8~5.2,产甲烷相的最佳pH值为6.5~7.0。接种混合污泥及分步启动缩短了产酸相、产甲烷相和MBR的启动时间,实现了TPAD/MBR工艺的快速启动。     

生活污水生物处理领域中的CDM机会探讨

近年来,清洁发展机制(CDM)随着全球气候变化的加剧而迅速发展起来.以污水生物处理产生的重要温室气体(CO2,、CH4、N2O)为研究对象,从物质流(碳素流、氮素流、硫素流及磷素流)角度对污水生物处理中的CDM机会进行了探讨.结果表明:在污水生物处理领域中存在着较多的CDM机会.主要表现为:①好氧处理中高效节能充氧设备的选用及开发;②厌氧处理中光合细菌的光合作用固定CO2、强化厌氧过程中的H:产生及强化厌氧过程中的CH4产生以发展碳化工;③厌氧氨氧化及亚硝酸型硝化反硝化两种新型脱氮技术中存在着较多的CO2减量机会;④体系运行工况的优化及微生物种群的优化与调控,可有效地减少生物脱氮中产生的N2O;⑤优势微生物(聚磷菌)形成条件的优化.     

A case study on the methane explosion in the excavation chamber of an EPB-TBM and lessons learnt including some recent accidents

This study is related to a case concerning a methane explosion occurred inside the excavation chamber of an EPB-TBM in Silivri-Istanbul on the 20th of May in 2010. The authors of the paper were nominated as official inspectors of the court. A literature survey is first carried out in order to review similar accidents happened worldwide. Causes and effects of the explosion are analyzed later in detail. Precautions against methane emission are also summarized. It is concluded that a methane explosion inside the excavation chamber of an EPB-TBM is a very rare case and was not reported in the literature as the authors’ best knowledge. Oxygen necessary for methane explosion came from the foam used in the excavation chamber. Explosion occurred probably due to sparking caused by friction between screw conveyor and its casing. It is recommended that further research studies should focus on producing more secure foams being functional without oxygen, a methane detector should also placed inside the chamber with a power cut-off system.     

Homoacetogenesis as the alternative pathway for H2 sink during thermophilic anaerobic degradation of butyrate under suppressed methanogenesis

Butyrate degradation for hydrogen production under conditions suppressing methanogenesis was evaluated in continuously fed-tank reactors operated at 55 degrees C and started up with digested manure as inoculum. This study shows that the reaction of butyrate degradation to acetate and hydrogen could happen when gas sparging was applied. Gas sparging was very important for reducing hydrogen partial pressure and made the reaction thermodynamically possible. Almost no hydrogen or methane (methane production was prevented by the addition of 2-bromoethane-sulfonic acid) was detected, indicating that the H2 produced from butyrate oxidation was consumed in a subsequent step. It was found by isotope experiments that hydrogen produced from butyrate degradation reacted immediately with CO2 to form acetate via homoacetogenesis. When CO2/HCO(3-) was not provided in the system, butyrate degradation was no longer possible and butyrate-degrading cultures were washed out. It was furthermore found that the microorganisms responsible for homoacetogenesis were likely present in normal anaerobic environments, such as biogas reactors.     

用于低温环境的CO_2热泵技术

CO_2热泵与采用传统工质的热泵相比,具有低温适用性、环境友好性、设备紧凑、能够制取高温度热水等诸多优势。但是随着环境温度的降低,系统会出现排气温度升高、制热量下降等问题。通过对改进型单级压缩循环、双级压缩循环、准二级压缩循环、双极耦合系统、其他辅助加热方式的国内外研究现状进行对比分析,总结了各种循环方式主要的技术特点及不足,并提出了相关建议。这对于促进寒冷地区CO_2热泵系统的发展具有重要参考价值。     

二氧化碳抑爆性能实验研究

实验研究纯氧环境中CO2对甲烷爆炸极限的影响.结果发现,CO2体积分数达到78%时,混和气体退出可爆范围,临界O2体积分数为14%.使用爆炸三角形分析得出CO2对甲烷爆炸具有抑制作用,且其抑爆效果好于N2;同时分析了CO2抑爆的原因,为可燃气体抑爆措施的制定提供参考.     

Determination of activated sludge biological activity using model corrected CO2 off-gas data

Carbon dioxide (CO(2)) online off-gas monitoring is useful to detect changes in biological activity for activated sludge systems especially under limited oxygen conditions like under simultaneous nitrification-denitrification (SND) where respirometric measurements are not applicable. So far, the influence of the bicarbonate system on the liquid-gas transfer of CO(2) prevented the wider use of off-gas CO(2) for monitoring purposes in wastewater treatment. The objective of the paper is to demonstrate a practical method to correct measured off-gas CO(2) as an indicator of biological activity by taking into account pH shifts (resulting in CO(2) release or retention) and changes in influent alkalinity. The simple model is based on the physicochemical system of the bicarbonate/CO(2) equilibrium and the liquid-gas mass transfer for aerated systems. Standard on-line measurements (pH, temperature, flow rates) and periodical alkalinity titration serve as input data to estimate the influence of the carbonate system on the CO(2) off-gas concentrations measured on-line. For a particular plant the CO(2) mass transfer coefficients are derived from measurements compared to the theoretical calculation from oxygen mass transfer. The model estimates the biological carbon dioxide production rate (CPR; heterotrophic activity) by the correction of the measured carbon dioxide transfer rate (CTR; C-flux by the off-gas) with the calculated inorganic carbon dioxide transfer rate (r(F)) considering bicarbonate consumption (autotrophic activity).     

Dynamic evaluation of airflow rates for a variable air volume system serving an open-plan office

In a typical air-conditioned office, the thermal comfort and indoor air quality are sustained by delivering the amount of supply air with the correct proportion of outdoor air to the breathing zone. However, in a real office, it is not easy to measure these airflow rates supplied to space, especially when the space is served by a variable air volume (VAV) system. The most accurate method depends on what is being measured, the details of the building and types of ventilation system. The constant concentration tracer gas method as a means to determine ventilation system performance, however, this method becomes more complicated when the air, including the tracer gas is allowed to recirculate. An accurate measurement requires significant resource support in terms of instrumentation set up and also professional interpretation. This method deters regular monitoring of the performance of an airside systems by building managers, and hence the indoor environmental quality, in terms of thermal comfort and indoor air quality, may never be satisfactory. This paper proposes a space zone model for the calculation of all the airflow parameters based on tracer gas measurements, including flow rates of outdoor air, VAV supply, return space, return and exfiltration. Sulphur hexafluoride (SF6) and carbon dioxide (CO2) are used as tracer gases. After using both SF6 and CO2, the corresponding results provide a reference to justify the acceptability of using CO2 as the tracer gas. The validity of using CO2 has the significance that metabolic carbon dioxide can be used as a means to evaluate real time airflow rates. This approach provides a practical protocol for building managers to evaluate the performance of airside systems.     

美国和中国油气系统甲烷排放状况

（本刊讯）2012年3月6日,浙江省测绘与地理信息局副局长马建平一行4人在宁波市进行＂进村入企＂大走访活动,调研测绘与地理信息对经济社会发展的保障服务情况。调研组召集三家甲级测绘资质单位领导座谈,仔细听取了他们转变测绘发展方式,抓好地理信息产品生产,抓好海洋测绘工作,服务宁波经济建设情况和遇到的困难。     

Computational intelligence techniques for HVAC systems: A review

Buildings are responsible for 40% of global energy use and contribute towards 30% of the total CO2 emissions. The drive to reduce energy use and associated greenhouse gas emissions from buildings has acted as a catalyst in the development of advanced computational methods for energy efficient design, management and control of buildings and systems. Heating, ventilation and air-conditioning (HVAC) systems are the major source of energy consumption in buildings and ideal candidates for substantial reductions in energy demand. Significant advances have been made in the past decades on the application of computational intelligence (CI) techniques for HVAC design, control, management, optimization, and fault detection and diagnosis. This article presents a comprehensive and critical review on the theory and applications of CI techniques for prediction, optimization, control and diagnosis of HVAC systems. The analysis of trends reveals that the minimisation of energy consumption was the key optimization objective in the reviewed research, closely followed by the optimization of thermal comfort, indoor air quality and occupant preferences. Hardcoded Matlab program was the most widely used simulation tool, followed by TRNSYS, EnergyPlus, DOE-2, HVACSim+ and ESP-r. Metaheuristic algorithms were the preferred CI method for solving HVAC related problems and in particular genetic algorithms were applied in most of the studies. Despite the low number of studies focussing on multi-agent systems (MAS), as compared to the other CI techniques, interest in the technique is increasing due to their ability of dividing and conquering an HVAC optimization problem with enhanced overall performance. The paper also identifies prospective future advancements and research directions.     

Avenues into Food Planning: A Review of Scholarly Food System Research

This review summarizes several avenues of planning inquiry into food systems research, revealing gaps in the literature, allied fields of study and mismatches between scholarly disciplines and the food system life cycle. Planners and scholars in associated fields have identified and defined problems in the food system as ‘wicked’ problems, complex environmental issues that require systemic solutions at the community scale. While food justice scholars have contextualized problem areas, planning scholars have made a broad case for planning involvement in solving these wicked problems while ensuring that the functional and beneficial parts of the food system continue to thrive. This review maps the entry points of scholarly interest in food systems and planning's contributions to its study, charting a research agenda for the future.     

The ebullition of hydrogen, carbon monoxide, methane, carbon dioxide and total gaseous mercury from the Cornwall Area of Concern

This paper reports the first ebullitive fluxes of hydrogen (H2), carbon monoxide (CO), methane (CH4), carbon dioxide (CO2) and total gaseous mercury (TGM) from the Cornwall Area of Concern (CAC). Although sediments were contaminated with mercury, bubbling was a negligible source of mercury for the global atmosphere. Indeed, the average emission of TGM through ebullition was 0.04 pg m(-2) h(-1). Measurements of H2, CO, CH4 and CO2 trapped gas concentrations and fluxes were used as indicators of diagenesis processes. The CAC represented a significant regional source of CH4 since the estimated ebullitive fluxes (3.5 mg m(-2) h(-1)) were similar to the CH4 emissions measured above typical flooded freshwater wetlands. As molecular diffusion is known as the main pathway of CO2 transport from water to the atmosphere, CO2 ebullitive fluxes were weak (0.39 mg m(-2) h(-1)). Bubbling of CO (1.6 microg m(-2) h(-1)) was 10 folds less important than CO fluxes measured over flooded freshwater wetlands. Finally, H2 emissions (0.001 microg m(-2) h(-1)) were negligible since the level of this trace gas is tightly regulated by microorganisms in anaerobic environments.