锌精炼铅塔燃烧系统烟气温度模糊控制研究

针对锌精馏铅塔动态过程中的非线性、非最小相位特征、不稳定性、时滞和负荷干扰,基于模糊控制策略下给出了锌精馏铅塔燃烧系统新的控制方法.运用模糊控制系统对锌精馏铅塔的烟气温度进行仿真研究和实时控制结果表明,该研究所设计的模糊控制器能够克服许多干扰因素,产生了良好的控制效果.     

污水厂污泥一体化竖式强化渗滤浓缩自然干化与消化研究

针对目前国内污泥处理处置存在的问题,为实现污泥浓缩消化一体化,开发了污泥一体化强化渗滤浓缩自然干化与消化新工艺反应器,并进行了城市水厂污泥处理试验.结果表明,在有机负荷为0.8 kg VSS/(m3·d)、平均水力停留时间为8.3 d、污泥停留时间为120 d的条件下,污泥有机物去除率可达到44.4%,排泥含水率达到79.1%,污泥消化与浓缩过程起到了相互促进的作用.渗滤液须抽回至污水处理厂处理.     

Non-microcystin producing Microcystis wesenbergii (Komárek) Komárek (Cyanobacteria) representing a main waterbloom-forming species in Chinese waters

It is well known that several morphospecies of Microcystis, such as Microcystis aeruginosa (Kützing) Lemmermann and Microcystis viridis (A. Brown) Lemmermann can produce hepatotoxic microcystins. However, previous studies gave contradictory conclusions about microcystin production of Microcystis wesenbergii (Komárek) Komárek. In the present study, ten Microcystis morphospecies were identified in waterblooms of seven Chinese waterbodies, and Microcystis wesenbergii was shown as the dominant species in these waters. More than 250 single colonies of M. wesenbergii were chosen, under morphological identification, to examine whether M. wesenbergii produce hepatotoxic microcystin by using multiplex PCR for molecular detection of a region (mcyA) of microcystin synthesis genes, and chemical analyses of microcystin content by ELISA and HPLC for 21 isolated strains of M. wesenbergii from these waters were also performed. Both molecular and chemical methods demonstrated that M. wesenbergii from Chinese waters did not produce microcystin.     

Fenton法氧化处理水中土霉素的研究

为了评价Fenton法预处理抗生素生产废水中残留的高浓度土霉素的可行性,对Fenton试剂(Fe2 -H2O2)法催化氧化降解水溶液中的土霉素进行了研究.探讨了H2O2与Fe2 投加比例、投加量以及起始pH值对降解效果的影响,同时考察了土霉素废水中大量共存的草酸根离子对氧化过程的影响.结果表明,当H2O2与Fe2 按照5:1的比例投加时降解效率最高,最佳初始pH值在3.0-4.0之间.在最佳投加比例下,H2O2投加量为0.9 mmol/L,100 mg/L的土霉素可在10 min内得到完全降解.最佳反应条件下经过处理后土霉素水溶液TOC的去除率达40%左右,可生化性(BOD5/COD)也得到明显的改善.水中共存的草酸根离子对氧化效率具有明显的影响,但通过增加亚铁离子的量可以消除草酸的影响.     

Rhodobacter sp. NP25b菌株缺氧降解壬基酚聚氧乙烯醚的研究

从城市污水处理厂活性污泥中分离得到一株能够在缺氧条件下以壬基酚聚氧乙烯醚(NPEOs)为惟一碳源和能源生长的菌株NP25b.经生理生化鉴定和16S rRNA基因序列分析,该菌株属于红细菌属(Rhodobacter sp.),对该菌株降解NPEOs的特性进行了研究.结果表明,在缺氧条件下,菌株NP25b在7 d内对初始底物浓度为400 mg/L NPEOs的降解率可达84%.利用液相色谱-质谱(LC-MS)和气相色谱-质谱(GC-MS)对NPEOs降解中间产物进行了分析,结果表明,主要降解产物为短链NPEOs和壬基酚聚氧乙烯醚乙酸(NPECs),其中包括具有较强内分泌干扰效应的NP1EO.该菌株能够代谢含有疏水基团的聚氧乙烯醚类表面活性剂,例如辛基酚聚氧乙烯醚和脂肪醇聚氧乙烯醚.推测菌株NP25b降解NPEOs是通过乙氧基(EO)链末端氧化后逐步切割完成的.     

火灾高温下CFRP加固钢筋混凝土梁温度场分析

综合国外CFRP加固混凝土结构抗火试验相关研究,总结了CFRP的高温热工性能参数。用ANSYS软件对火灾高温下不同情况(无防火保护层和有防火保护层)和不同工况(防火涂料涂抹形式)下CFRP加固后的钢筋混凝土梁进行了温度场数值模拟研究。结果表明,防火涂料厚40 mm时,梁耐火极限可达2.5小时以上,且底面和两侧面全面涂抹防火涂料的防火效果最好。本文研究有助于进一步深入认识CFRP加固钢筋混凝土结构在高温下的力学性能和耐火极限,且对CFRP加固后的结构防火设计具有一定的指导意义。     

Effects of ecological factors on the diurnal activity rhythm of Yakutian black-capped marmots (Marmota camtschatica bungei) in the arctic

It is established that the activity of marmots (the genusMarmota) on the surface is timed to the daylight period. In the Arctic, under conditions of continuous illumination (the polar day), the diurnal rhythm of black-capped marmotsMarmota camtschatica bungei on the surface has a “daylight” pattern. The main external regulator of the diurnal rhythm is the altitude of the sun above the horizon. In the cold period, however, the effect of air temperature on animal activity becomes stronger.     

Bioavailability to grains of rice of aged and fresh DDD and DDE in soils

DDT had been widely used around the world before 1980s and is still under production and use for non-agricultural purposes in China. Because of their special physicochemical properties, p,p'-DDT and its main metabolites, p,p'-DDD and p,p'-DDE, accumulated and persisted in the environment, presenting potential menace on biota. A green-house study was conducted to determine the bioavailability of p,p'-DDD and p,p'-DDE to grains of rice and the influences of traditional Chinese farming practices on their bioaccumulation. Paddy rice and dry rice were grown in submerged paddy soils and non-submerged upland soils, respectively. Two types of soil, Hydragric Anthrosols (An) and Hydragric Acrisols (Ac), were employed. Bioaccumulation factors (BAFs) of DDE ranged from 0.67 for rice grown in non-submerged An to 0.84 in submerged An in the control group, whilst BAFs were all below 0.04 in experimental groups. BAFs of DDD varied from 1.39 for submerged An to 2.26 for submerged Ac in original soils. In contrast, BAFs were between 0.05 for non-submerged Ac and 0.08 for submerged An in DDD-contaminated soils. Flooding seemed to have two contradictory effects on the DDE/DDD accumulation by rice: on one hand, it made the pollutants more mobile and bioavailable; while on the other hand, it enhanced the degradation and binding of POPs. Adding rice straw to the soils protected DDE from being taken up yet promoted DDD accumulation by rice. Furthermore, the distinct inorganic component of the soils might also play an important role in the environmental activities of POPs.     

Biohydrogen production through fermentation using liquid swine manure as substrate

In this paper, continuous production of hydrogen through fermentation with liquid swine manure as substrate was researched using a semi-continuously fed fermenter (8 L in total volume and 4 L in working volume). The pH and temperature for the fermenter were controlled at 5.3 +/- 0.1 and 35 +/- 1 degrees C, respectively, throughout the experiment. Three hydraulic retention times (16, 20, and 24 h) were investigated for their impact on the efficiency and performance of the fermenter in terms of hydrogen yields. The results indicate that hydraulic retention time (HRT) has a strong influence on the fermenter performance. An increasing HRT would increase the variation in hydrogen concentration in the offgas. To produce hydrogen with a fairly consistent concentration, the HRT of the fermenter should not exceed 16 h, which, however, did not appear to be short enough to control methanogenesis because the offgas still contained about 5% methane. When methane content in the offgas exceeded 2%, an inverse linear relationship between hydrogen and methane was observed with a correlation coefficient of 0.9699. To increase hydrogen content in the offgas, methane production has to be limited to below 2%. Also, keeping oxygen content in the fermenter below 1.5% would increase the hydrogen concentration to over 15%. The product to substrate ratio was found to be around 50% for the fermenter system studied, evidenced by the observation that for every 6 liters of manure fermented, 3 liters of pure hydrogen were produced, which was significant and encouraging.     

Phosphorus Load Reduction Goals for Feitsui Reservoir Watershed, Taiwan

The present paper describes an effort for developing the total maximum daily load (TMDL) for phosphorus and a load reduction strategy for the Feitsui Reservoir in Northern Taiwan. BASINS model was employed to estimate watershed pollutant loads from nonpoint sources (NPS) in the Feitsui Reservoir watershed. The BASINS model was calibrated using field data collected during a 2-year sampling period and then used to compute watershed pollutant loadings into the Feitsui Reservoir. The simulated results indicate that the average annual total phosphorus (TP) loading into the reservoir is 18,910 kg/year, which consists of non-point source loading of 16,003 kg/year, and point source loading of 2,907 kg/year. The Vollenweider mass balance model was used next to determine the degree of eutrophication under current pollutant loading and the load reduction needed to keep the reservoir from being eutrophic. It was estimated that Feitsui Reservoir can becoming of the oligotrophic state if the average annual TP loading is reduced by 37% or more. The results provide the basis on which an integrated control action plan for both point and nonpoint sources of pollution in the watershed can be developed.