常压塔塔顶腐蚀关键参量相关性分析与预测

预测常压塔顶回流罐切水的关键离子浓度可以为常压塔顶系统工艺防腐提供技术指导。收集了某炼厂2014-2016年常压装置的生产实时工艺参数、原料及产品采样数据、水质分析化验参数,采用线性插值方法对不同时间尺度的数据进行补全。通过线性相关性分析获得了影响常压塔顶回流罐切水总铁离子浓度、pH的主要因素,并基于深度学习、支持向量机回归、粒子群优化方法建立了腐蚀关键参量预测模型。结果表明,pH值和总铁离子浓度的相关因素大部分重叠,与原料性质及产品馏出温度较强相关;建立的回归模型预测精度高,在训练集和预测集上,总铁离子浓度预测值与测量值最大偏差分别为4. 4%和9. 8%,pH值预测值与测量值最大偏差分别为0. 9%和1. 1%。     

梯级混凝技术在造纸废水处理中的应用

选取聚合氯化铝(PAC)和聚丙烯酰胺(PAM)作混凝剂对速生材造纸中段废水进行了梯级混凝(即混凝及其污泥回流)处理,考查了pH值、PAC投加量、污泥回流量等因素对处理效果的影响。结果表明,当废水pH值为6.5～8.2、PAC用量3 mL/L、污泥回流量为40%～60%时,实验效果明显优于传统混凝方式,COD由400 mg/L降至100 mg/L左右,去除率达75%。出水pH值为7.5～8.2,符合国家排放标准,并满足造纸回用水要求。     

酸化污泥回流的生物淋滤技术处理制革污泥

采用回流——即在原始污泥中添加淋滤结束的生物酸化污泥继续进行淋滤的方法,研究了回流比、混合污泥起始pH值、酸化污泥pH值对生物淋滤技术去除制革污泥中重金属铬的影响.结果表明,采用回流的方法能够同步完成原污泥的预酸化和接种,当控制回流后混合污泥的起始pH值在4.00左右时,经过3d的淋滤,污泥的pH值下降到1.95以下,污泥中铬的溶出率达到95%以上.     

生物流化床法处理污泥回流液的影响因素研究

将生物流化床工艺与活性污泥工艺相结合,以市政污水处理厂污泥回流液为研究对像。以0.3～0.45mm活性炭颗粒为载体对生物流化床中微生物进行培养、驯化,挂膜成功后,分别对生物流化床厌氧段和好氧段进行了单因素试验,得出进水的最佳pH值介于7.0～7.5,生物流化床厌氧段的最佳水力停留时间4.4h、最佳碳源为蔗糖,;缺氧段及好氧段的最佳水力停留时间2.69h、8.06h,曝气量0.5mL/min。在最佳工艺参数条件下进行污泥回流液脱氮除磷试验得出,此工艺可使总氮浓度为150.0mg/L,总磷浓度为59.0mg/L的污泥回流液的总氮浓度降低至65.19mg/L,此时的总氮去除率为56.54%;总磷的去除率较低。试验结果表明,该工艺对处理污泥回流液中氮磷具有一定的效果。     

微电解-Fenton联合工艺处理酸化压裂废水

采用微电解-Fenton氧化法对酸化压裂模拟废水进行处理,有效地降低了废水的COD,试验中考察了微电解反应进水pH值、铁碳质量比、反应时间以及联合Fenton工艺中废水的pH值、H2O2加入量、反应时间对COD去除率的影响。结果表明,微电解法工艺的优化条件:pH2.5左右,反应停留时间120min,铁碳质量比5∶1;Fenton反应的优化条件:微电解出水调pH4.0左右,反应时间75min,H2O(2质量分数为10%)加入量7.5ml/L,最终处理的出水COD去除率达64.8%,联合工艺的COD去除率比单一的微电解法提高了26.3%,为后续的处理创造了有利的条件。     

pH值对零价铁自养反硝化过程的影响

以零价铁和硝酸盐为基质,通过批量实验和连续流发酵罐实验中铁自养反硝化脱氮速率的测定,研究了铁自养反硝化过程pH值的变化以及pH值对零价铁自养反硝化污泥活性的影响.批量实验采用4个添加污泥的反应瓶,初始pH值分别为6.2、6.7、7.5、8.8和一个初始pH为6.7的未添加污泥瓶.结果表明初始pH值6.7时表现出最高氮素脱除速度,其中未添加污泥的批量瓶pH持续上升至10左右,4个不同初始pH添加污泥的批量瓶的pH值后续均集中在7.5~7.8之间,难以凸显不同pH值对反硝化菌的影响.利用能够控制pH值稳定的连续流发酵罐,通过设立6、6.5、7、7.5、8这5个恒定的pH梯度,对微生物不同pH值条件下的适应性和活性进行观察,结果表明在pH为6.5时污泥活性最大,其氮脱除速率达到1.35mg·(L·h)~(-1).     

锂电池生产中NMP凝液回收计算及“零排放”处理工艺

锂电池生产中,污染物主要为含NMP蒸汽废气。文中阐述了排出废气中的NMP蒸汽凝液回收计算,指出了现有的用冷凝加活性炭吸附方法净化处理NMP蒸汽废气工艺弊病,同时提出了废气封闭式循环冷凝,即零排放处理工艺。     

以磷酸钙盐的形式从污水处理厂回收磷的研究

磷是一种不可再生、难以替代的有限自然资源.磷的可持续利用问题越来越受到世界各国学者与政府的高度重视.近年来,从污水厂回收磷在世界各国逐渐兴起,而我国在这方面的研究还处于起步阶段,尤其是以磷酸钙盐的形式回收磷的相关研究还未见报道.以磷酸钙盐形式回收废水中的磷,优化磷回收过程相关工艺控制条件.结果表明,pH值和Ca2 浓度是磷酸钙盐回收的关键因素,最优值分别为10和6.68,磷回收率达到90%.     

污泥转移SBR工艺吸磷影响因素分析

新型SBR工艺是由SBR反应器和生物选择器构成,显著特点是通过污泥转移实现除磷优势菌种的筛选,强化除磷效果。以生活污水为处理对象,研究了转移量、温度、pH以及DO对吸磷的影响。试验研究表明:比吸磷速率与污泥转移量关系为y=e(1.49+4.95x-7.3x2),中值误差为1.93%,系统在34%的转移量下其最大比吸磷速率可达10.27 mg/(g·h);进水温度分别为5~15℃、15~25℃、25~35℃工况培养的污泥在(24±2)℃时的比吸磷速率为11.86,10.39,9.35 mg/(g·h);pH=6.5、7、7.5、8条件下比吸磷速率分别为8.8、9.9、10.39、10.58 mg/(g·h);DO分别为1~2,2~3,3~4,4~5 mg/L时比吸磷速率分别为8.8,9.96,10.39,10.44 mg/(g·h)。确定该工艺的最佳吸磷条件为污泥转移量为34%,进水温度为5~15℃,pH=7.5~8,ρ(DO)为3~4 mg/L。     

回流比水力负荷对前置反硝化生物滤池工艺处理污水的影响研究

前置反硝化生物滤池工艺具有良好的脱氮性能,其中回流比是影响其处理效果的一个重要因素.试验考察了回流比分别为50%、100%、200%、300%的条件下该工艺对COD、NH4+-N、TN的去除效果.研究表明,在回流比从50%提高至300%的过程中,该工艺对污染物的去除效果以200%为界呈先上升后下降的趋势,但对去除TN的影响较为显著,回流比为200%时,对应COD、NH4+-N和TN的平均去除率分别为92.67%、90.50%和80.50%.在保持回流比100%的条件下,随水力负荷从1.52m.h-1增加到2.82m.h-1的过程中,前置反硝化生物滤池工艺对污染物的去除效果以2.08m.h-1为界呈先上升后下降的趋势,水力负荷为2.08m.h-1时,对COD、NH4+-N和TN的平均去除率分别为91.72%、90.29%和74.45%.COD、NH4+-N和TN主要在BAF(DN)缺氧环境内得到去除,平均去除率分别为78.48%、68.02%和58.21%.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.