长酸洗槽吹吸式酸雾捕集优化设计

吹吸式酸雾捕集经常用于蓄电池和较短的酸洗槽的酸雾捕集方面。在长酸洗槽(一般长度>10m)上运用吹吸式捕集酸雾。在此对目前常用酸洗槽设计方法进行了分析比较,并对一长酸洗槽(长14m)做了设计实例,经过实践检验,证明设计采用方法是恰当的,各设计参数是合理正确的。     

Long‐Term Water Quality and Biological Responses to Multiple Best Management Practices in Rock Creek,Idaho1

Abstract: Water quality and macroinvertebrate assemblage data from 1981 to 2005 were assessed to evaluate the water quality and biological responses of a western trout stream to the implementation of multiple best management practices (BMPs) on irrigated cropland. Data from Rock Creek near Twin Falls, Idaho, a long‐term monitoring site, were assembled from state and federal sources to provide the evaluation. Seasonal loads of the nonpoint source pollutants suspended sediment (SS), total phosphorus (TP), and nitrate‐nitrite (NN) were estimated using a regression model with time‐series streamflow data and constituent concentrations. Trends in the macroinvertebrate assemblages were evaluated using a number of biological metrics and nonmetric multidimensional scaling ordination. Regression analysis found significant annual decreases in TP and SS flow‐adjusted concentrations during the BMP implementation period from 1983 to 1990 of about 7 and 10%, respectively. These results are coincident with the implementation of multiple BMPs on about 75% of the irrigated cropland in the watershed. Macroinvertebrate assemblages during this time also responded with a change in taxa composition resulting in improved biotic index scores. Taxon specific TP and SS optima, empirically derived from a large national dataset, predicted a decrease in SS concentrations of about 37% (52 to 33 mg/l) and a decrease in TP concentrations of about 50% (0.20 to 0.10 mg/l) from 1981 to 1987. Decreasing trends in TP, SS, and NN pollutant loads were primarily the result of naturally low streamflow conditions during the BMP post‐implementation period from 1993 to 2005. Trends in macroinvertebrate responses during 1993 to 2005 were confounded by the introduction of the New Zealand mudsnail (Potamopyrgus  antipodarum), which approached densities of 100,000 per m² in riffle habitat. The occurrence of this invasive species appears to have caused a major shift in composition and function of the macroinvertebrate assemblages.     

Flood Effects on an Alaskan Stream Restoration Project: The Value of Long‐Term Monitoring1

Densmore, Roseann V. and Kenneth F. Karle, 2009. Flood Effects on an Alaskan Stream Restoration Project: The Value of Long‐Term Monitoring. Journal of the American Water Resources Association (JAWRA) 45(6):1424‐1433. Abstract: On a nationwide basis, few stream restoration projects have long‐term programs in place to monitor the effects of floods on channel and floodplain configuration and floodplain vegetation, but long‐term and event‐based monitoring is required to measure the effects of these stochastic events and to use the knowledge for adaptive management and the design of future projects. This paper describes a long‐term monitoring effort (15 years) on a stream restoration project in Glen Creek in Denali National Park and Preserve in Alaska. The stream channel and floodplain of Glen Creek had been severely degraded over a period of 80 years by placer mining for gold, which left many reaches with unstable and incised streambeds without functioning vegetated floodplains. The objectives of the original project, initiated in 1991, were to develop and test methods for the hydraulic design of channel and floodplain morphology and for floodplain stabilization and riparian habitat recovery, and to conduct research and monitoring to provide information for future projects in similar degraded watersheds. Monitoring methods included surveyed stream cross‐sections, vegetation plots, and aerial, ground, and satellite photos. In this paper we address the immediate and outlying effects of a 25‐year flood on the stream and floodplain geometry and riparian vegetation. The long‐term monitoring revealed that significant channel widening occurred following the flood, likely caused by excessive upstream sediment loading and the fairly slow development of floodplain vegetation in this climate. Our results illustrated design flaws, particularly in regard to identification and analysis of sediment sources and the dominant processes of channel adjustment.     

纵向岭谷区8月气温的年际变化及其影响因子

将地表温度和向外长波辐射拓展成为综合因子后，应用主分量-典型相关分析方法分析了纵向岭谷区76个测站8月气温与前期和同期地表温度和向外长波辐射因子间的关系。结果表明：7月及8月地表温度场和向外长波辐射场与云南纵向岭谷区8月温度场存在显著的相关关系，通过5％的显著性检验。前期及同期纵向岭谷区8月气温典型相关场的正、负值区分布情况大致相同，即纵向岭谷区北部怒江、澜沧江的上游流域和沿怒江、澜沧江、元江以西流域的8月气温与沿这3条河流以东的流域的同月气温为反向分布，其显著相关区位于3条河流以东和以西两个流域的德宏州、临沧市、思茅市、西双版纳州、大理州及楚雄州。菲律宾附近海域、中南半岛、南海及加里曼丹岛等区域是地表温度及向外长波辐射典型相关场中正、负值较大、较小的区域，也是影响纵向岭谷区8月气温的关键区域，同时印缅低压、西太平洋副热带高压是影响该区的关键系统。     

人工神经网络结构对径流预报精度的影响分析

建立了基于径流形成机理的以时段降水量与前期径流量为预报因子的前向多层人工神经网络径流预报模型；分析了网络结构对月径流预报精度的影响，发现随网络结构的复杂化，网络训练误差减小，模型评定的确定性系数增大，并均趋于稳定，预报检验的确定性系数总趋势是减小；发现影响模型精度的决定因素是网络输入单元数，亦即径流影响因素；提出了以模型评定与预报检验共同高效或等效的模型选择的折衷方法，以及按模型适宜预报域进行多模型组合预报的最佳预报域组合法。     

基于长短时记忆网络的水质预测模型研究

在当前水质数据急剧增加的背景下,为了挖掘水质时间序列中的更多信息,提升水质预测的精度,构建了基于缺失值填补算法和长短时记忆网络(LSTM)相结合的水质预测模型。通过缺失值填补算法进行水质数据的缺失值处理,利用LSTM网络分别构建不同水质参数的预测模型,以太湖水质监测数据为样本,对模型进行检验。结果表明,基于缺失值填补算法-LSTM的水质预测模型适应性强,相较传统SVM、BP神经网络、RNN、LSTM模型预测精度更高,对水环境保护具有重要意义。     

Long-term thermophilic mono-digestion of rendering wastes and co-digestion with potato pulp

In this study, mono-digestion of rendering wastes and co-digestion of rendering wastes with potato pulp were studied for the first time in continuous stirred tank reactor (CSTR) experiments at 55 °C. Rendering wastes have high protein and lipid contents and are considered good substrates for methane production. However, accumulation of digestion intermediate products viz., volatile fatty acids (VFAs), long chain fatty acids (LCFAs) and ammonia nitrogen (NH₄-N and/or free NH₃) can cause process imbalance during the digestion. Mono-digestion of rendering wastes at an organic loading rate (OLR) of 1.5 kg volatile solids (VS)/m³ d and hydraulic retention time (HRT) of 50 d was unstable and resulted in methane yields of 450 dm³/kg VS_fed. On the other hand, co-digestion of rendering wastes with potato pulp (60% wet weight, WW) at the same OLR and HRT improved the process stability and increased methane yields (500–680 dm³/kg VS_fed). Thus, it can be concluded that co-digestion of rendering wastes with potato pulp could improve the process stability and methane yields from these difficult to treat industrial waste materials.     

Application of an early warning indicator and CaO to maximize the time–space-yield of an completely mixed waste digester using rape seed oil as co-substrate

In order to increase the organic loading rate (OLR) and hereby the performance of biogas plants an early warning indicator (EWI-VFA/Ca) was applied in a laboratory-scale biogas digester to control process stability and to steer additive dosing. As soon as the EWI-VFA/Ca indicated the change from stable to instable process conditions, calcium oxide was charged as a countermeasure to raise the pH and to bind long-chain fatty acids (LCFAs) by formation of aggregates. An interval of eight days between two increases of the OLR, which corresponded to 38% of the hydraulic residence time (HRT), was sufficient for process adaptation. An OLR increase by a factor of three within six weeks was successfully used for biogas production. The OLR was increased to 9.5 kg volatile solids (VS) m^?3 d^?1 with up to 87% of fat. The high loading rates affected neither the microbial community negatively nor the biogas production process. Despite the increase of the organic load to high rates, methane production yielded almost its optimum, amounting to 0.9 m³ (kg VS)^?1. Beneath several uncharacterized members of the phylum Firmicutes mostly belonging to the family Clostridiaceae, a Syntrophomonas-like organism was identified that is known to live in a syntrophic relationship to methanogenic archaea. Within the methanogenic group, microorganisms affiliated to Methanosarcina, Methanoculleus and Methanobacterium dominated the community.     

长期低温对絮状-颗粒耦合CANON脱氮及菌群影响

在SBR反应器中探究长期低温对等污泥浓度比例絮状-颗粒(1:1～1:1.5)耦合CANON系统的脱氮效能和微生物群落结构的影响.结果表明,在经历长期低温(10℃)条件下运行并回温(10→30℃)后,等比例污泥CANON系统NH₄⁺-N、TN去除率及TN去除负荷与温度变化呈正相关性,在回温30℃下运行30d后分别达到72.4%、63.0%和0.094kgN/(m³·d).氨氧化菌(AOB)和厌氧氨氧化菌(AAOB)活性与温度表现出正相关性,在回温后分别为0.025和0.049gN/(gVSS·d),分别为降温前(30℃)的83.3%和79.1%,NOB活性一直维持在较低水平(0.001gN/(gVSS·d)).高通量测序结果显示,长期低温对优势菌门无明显影响.回温后,颗粒和絮状污泥中的优势菌门分别为Ignavibacteriae和Proteobacteria;回温后系统颗粒污泥中功能菌Candidatus Brocadia、Candidatus Kuenenia(AAOB)相对丰度分别为6.017%、2.623%,其在絮状...     

试论环境空气质量自动监测系统的设计

目前 ,我国重点城市都在开展环境空气质量日报或预报工作 ,开展这一工作的基本条件之一是必须建立环境空气质量自动监测系统。由于我国目前的研制水平有限 ,空气质量自动监测系统基本上是靠引进国外技术及设备来完成的。而引进设备往往与我国的具体实际结合不够 ,尤其是在系统结构、数据采集、远程控制与诊断方面同我们的实际要求相去甚远。为此本文将围绕国内环境监测共同关注的环境空气质量自动监测系统及其设计的问题展开讨论 ,内容包括目前国内自动监测系统的现状 ;国外发展情况及趋势 ;自动监测系统结构与要求