洗浴废水处理工艺中混凝预处理的作用与效果研究

采用混凝沉淀—过滤—固定化生物活性炭—膜滤—UV 消毒工艺处理洗浴废水,整体试验结果比较理想,在物化处理过程中混凝环节至关重要。为此研究了混凝对浊度、LAS、COD_(Cr)、洗浴浴香的处理效果。研究结果表明：当投药量大于25mg/L 时,混凝沉淀可以把平均浊度为65NTU的原水降低到15NTU 以下,对 LAS、COD_(Cr)的去除率可达62%和50%以上,因此混凝是去除洗浴废水中悬浮物质、LAS 和有机污染物有效的物化处理单元;但是混凝不能有效地去除洗浴废水中的浴香。     

铁碳微电解工艺在含氟废水处理工程中的应用

根据某含氟废水的水质特点,采用废水综合调节池、铁碳微电解、混凝沉淀、砂滤及活性炭吸附工艺对含氟废水进行处理,经过一段时间运行后,污染物COD、氟化物的平均去除率达到90.7%和94.7%,出水水质完全符合排放标准并为光伏产业生产过程中排放的含氟废水处理提供参考,并提出了对铁碳微电解和混凝沉淀工艺进行优化的建议。     

不同预处理方式与微滤联用处理城市污水对比实验研究

采用微滤法处理模拟二沉池出水,以期达到城市污水回用的目的.进水采用人工配水,主要考察微滤膜对模拟二沉池出水中CODMn,氨氮(NH3-N)及UV254的去除效果,以及预处理方式对微滤膜处理工艺的影响.实验主要采用了两种预处理方式,即颗粒活性炭(GAC)吸附及聚合氯化铝(PAC)混凝.实验结果表明,单独采用微滤膜效果不明显,高锰酸钾指数的去除率仅为32.5%,氨氯去除率约为5%,且膜污染严重,通量下降很快.活性炭-微滤组合工艺对污水的CODMn去除效果较好,去除率达到88%;而混凝-徽滤工艺对UV254的去除效果较好,去除率达到87%;混凝-微滤及活性炭-微滤工艺对氨氮的去除率均不高.组合工艺比起单独使用微滤膜流量下降缓慢,混凝-徽滤工艺在4.5h内,流量没有下降,污染情况明显改善.     

高锰酸钾强化混凝—陶瓷微滤膜集成工艺处理水源水研究

采用高锰酸钾强化混凝—陶瓷微滤膜集成工艺处理水源水,主要考察了不同高锰酸钾投加量对集成工艺中膜污染状况和出水水质的影响。结果表明,在混凝过程中投加高锰酸钾进行预氧化,与单独的混凝—陶瓷微滤膜集成工艺相比,膜污染速率下降,降低了不可逆膜污染;出水水质得到一定程度的提高,其中UV254、CODMn、DOC、TN去除率分别提高了约3%、10%、5%、16%。另外,出水浊度<0.1 NTU,出水颗粒数水平也得到了很大改善。     

皮毛加工废水处理技术

采用混凝沉淀、水解酸化、百乐克生化池、两级曝气生物滤池处理皮毛加工废水。实际运行结果表明,该工艺运行出水水质稳定,处理效果好,出水水质可达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A排放标准的要求。     

CSBR-混凝沉淀组合工艺处理印染废水

印染废水色度大,有机物含量高,可生化性差,且水量和水质变化大,水质成分复杂,针对上述特点,采用了CSBR-混凝沉淀组合工艺处理印染废水,运行结果表明,在进水CODCr为1 200mg/L、BOD5为350 mg/L、SS为200 mg/L、色度为400倍、pH为11.5时,出水水质达到《纺织印染行业水污染物排放标准》(GB 42872-92)二级标准.该处理系统耐冲击负荷能力强,运行稳定,剩余污泥量少,基建和运行费用较低.     

PVDF微滤膜处理黄浦江微污染水的研究

试验采用聚偏氟乙烯(PVDF)微滤膜处理黄浦江微污染原水,进膜水经预氯化、混凝沉淀进行前处理.试验考察了影响膜压差(TMP)变化的相关因素及工艺的净水效果.中试研究结果表明,在膜通量不变的条件下,膜反冲洗加氯量、进膜水的pH以及预处理过程对膜压差(TMP)的增长有较大的影响.该工艺可获得良好的出水水质,且在实现膜长期稳定运行的工况下,经药剂清洗后微滤膜具有很高的通量恢复.     

混凝气浮-ABR-接触氧化工艺处理洗毛废水

洗毛废水是一种SS含量高、难生化降解的高浓度有机废水,处理难度大.针对重庆某纺织公司的洗毛废水,设计采用混凝气浮-ABR-接触氧化工艺处理,出水水质达到<污水综合排放标准>(GB 8978-1996)一级标准.在运行调试的过程中,根据洗毛废水的特点,对处理工艺进行了少量的改进.实践证明,在进水污染物含量远高于设计值时,出水水质仍然能够稳定达标.     

A/O2工艺处理焦化废水

邢台钢铁厂对蒸氨预处理工艺进行改造后,采用气浮-A/O2-混凝沉淀工艺处理焦化废水.工程实践表明,该工艺运行稳定、操作维护简单,出水各项指标均能达到《钢铁工业污染物排放标准》(GB 13456-92)二级排放标准.同时也可大幅减少运行费用.     

磁分离技术用于印染废水处理工程实例

针对废水处理厂周边7家印染企业排放的印染废水的特点,以及国标趋严、厂区储备用地有限的现状,在现有物化沉淀池后增设磁分离工艺,通过混凝加载磁粉,促进絮体快速沉淀。工程实际表明,出水水质能够满足《纺织染整工业水污染物排放标准》(GB 4287-2012)的间接排放标准,且系统运行稳定,处理成本低。     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.