基于厌氧氨氧化的含氨废气原位处理

采用部分亚硝化-厌氧氨氧化一体化反应器研究了含氨废气原位脱氮处理的可行性.结果表明,在控制低溶解氧(0.2~1 mg·L~(-1)),pH为7.9~8.2,中温(30~35℃)条件下,经过60 d的运行,成功地实现部分亚硝化-厌氧氨氧化一体化反应器的启动,总氮去除率达到88%,氮去除速率由0.05 kg·(m~3·d)~(-1)上升并稳定在0.7 kg·(m~3·d)~(-1).在含氨废气处理研究中,当含氨废气浓度低于2.59%,废气中原有的氧过量,导致硝态氮大量累积;当含氨废气体积分数为2.59%~4.2%时,废气中氧满足反应器脱氮的需求;当含氨废气体积分数高于4.2%,需要额外通入空气,补充反应器内的氧需求.经过60 d的运行,氨气的去除率达100%,总氮去除率达90.06%,总氮去除负荷为0.51 kg·(m~3·d)~(-1).说明基于厌氧氨氧化反应的一体化反应器可实现含氨废气稳定去除.     

Decolorization of Methyl Orange by a new clay-supported nanoscale zero-valent iron: Synergetic effect, efficiency optimization and mechanism

In this study, a novel nanoscale zero-valent iron (nZVI) composite material was successfully synthesized using a low-cost natural clay, “Hangjin 2^# clay” (HJ clay) as the support and tested for the decolorization of the azo dye Methyl Orange (MO) in aqueous solution by nZVI particles. According to the characterization and MO decolorization experiments, the sample with 5:1 HJ clay-supported nZVI (HJ/nZVI) mass ratio (HJ-nZVI5) showed the best dispersion and reactivity and the highest MO decolorization efficiency. With the same equivalent Fe⁰ dosage, the HJ-nZVI1 and HJ-nZVI5 samples demonstrated a synergetic effect for the decolorization of MO: their decolorization efficiencies were much higher than that achieved by physical mixing of HJ clay and nZVIs, or the sum of HJ clay and nZVIs alone. The synergetic effect was primarily due to the improved dispersion and more effective utilization of the nZVI particles on/in the composite materials. Higher decolorization efficiency of MO was obtained at larger HJ-nZVI dosage, higher temperature and under N₂ atmosphere, while the MO initial concentration and pH were negatively correlated to the efficiency. HJ clay not only works as a carrier for nZVI nanoparticles, but also contributes to the decolorization through an “adsorption-enhanced reduction” mechanism. The high efficiency of HJ-nZVI for decontamination gives it great potential for use in a variety of remediation applications.     

Novel cationic polyamidine: Synthesis, characterization, and sludge dewatering performance

In this study, a new and facile route was employed for synthesis of polyamidine with abundant cations and attractive five-membered ringlike structural unit. N-vinylformamide and acrylonitrile copolymerized firstly to form intermediates, and the intermediates were processed with hydrochloric acid to produce polyamidine. A series of polymerization conditions (e.g. polymerization time, temperature and dosage of initiator) were optimized through productivity, viscosity and cationic degree as evaluation. SEM analysis illustrated that the amidinization process could reduce the size of spaces between molecular and created compact structure, which would contribute to good flocculation performance and high viscosity. FT-IR, XPS and NMR spectra presented a rather clear structure of polyamidine. 34.3% of sludge was sedimentated through the flocculation of polyamidine in the early stages. In contrast, only 6.8% of sludge was sedimentated by polyacrylamide. The moisture content in dehydrated floc could be reduced to 77.7% when 60 mg/L polyamidine was added. These results demonstrated that the polyamidine showed a great potential in the practical application of sludge dewatering.     

天津分公司加氢裂化装置HAZOP分析

通过对180×10~4t/a加氢裂化装置的HAZOP分析实例,详细阐述了HAZOP分析方法的实际应用,找出装置需要改进的针对性建议措施,总结了HAZOP分析过程中常见的问题以及经验。     

淀山湖沉积物-水界面氮磷通量及其生态环境效应研究

底泥营养盐释放对淀山湖湖区造成的内源污染不容忽视.采用室外采样和室内模拟实验方法,对春夏两季淀山湖沉积物-水界面氮磷释放速率进行了研究.结果表明春季氨氮、硝态氮、可溶磷的的通量变化范围分别为-692.79~315.82 mg/(m2?h)、-19.04~5.29 mg/(m2?h)和-1.35~2.31 mg/(m2?h),平均值分别为76.65 mg/(m2?h)、-3.29 mg/(m2?h)和0.64 mg/(m2?h).夏季三者变化范围分别为-74.15~91.91 mg/(m2?h)、-70.71 mg/(m2?h)~8.65 mg/(m2?h)和-10.02~18.86 mg/(m2?h),平均值为4.85 mg/(m2?h)、-42.16 mg/(m2?h)和9.47 mg/(m2?h).淀山湖区春夏两季总氮(TN)、总磷(TP)的交换总量分别为-1769.22 t,1539.40 t,淀山湖底泥可以有效去除上覆水体氮负荷,但却是水体磷的释放源.     

不同回用用途下典型城市污水再生处理工艺的生命周期评价分析

对3种典型城市污水再生处理工艺(微絮凝+砂滤+消毒(MSD)、混凝+转盘过滤+消毒(CRD)和混凝沉淀+超滤+消毒(CUD))进行生命周期环境影响定量评价,探讨了不同工艺在不同回用用途下的环境表现。结果表明:MSD工艺在富营养化(EP)方面的影响略高,归一化结果为9.32E-15,其他方面环境影响均小于CRD和CUD工艺;不同回用用途的污水再生可在某些方面抵消原需水产生的环境影响,有一定环境效益,不同出水用途的替代抵消作用可影响环境表现。以砂滤为主的典型城市污水再生处理工艺在出水用于工业冷却水时,归一化加权结果为其他两种工艺的25%和7.5%,具有较好的应用前景。     

污泥膨胀原因及控制措施研究

以排水集团运行的几座污水处理厂为研究对象,对工艺设计参数及运行条件等进行对比分析,找出影响污泥膨胀的关键因素。采用微生物形态学和分子生物学方法对丝状菌种类进行辨别,确定研究的污水厂污泥膨胀的丝状菌主要为微丝(Microthrix parvicella)菌。通过分析微丝菌的特性,结合倒置A~2/O工艺的运行特点,在不进行任何改造的情况下,提出冬季运行将倒置A~2/O工艺调整为A/O工艺的运行措施。并将这一措施用于实际水厂,连续3年未发生污泥膨胀,污泥沉降性能较好,出水水质稳定。通过小试研究和实际水厂分析,证明厌氧选择器在控制污泥膨胀中可发挥一定作用,为活性污泥工艺设计提供参考。     

不同TOC/NH4+-N对厌氧氨氧化脱氮效能的影响

采用SBR厌氧氨氧化反应器,研究了不同TOC与NH_4~+-N比值对厌氧氨氧化反应器的脱氮效能的长短期影响.结果表明,在有机物短期影响时,反应器所能承受的最大TOC/NH_4~+-N为1.4,总氮去除速率可达0.26 kg·(m~3·d)~(-1).长期影响下,在TOC/NH_4~+-N小于0.4时,反应器可获得最高脱氮效能,总氮去除率为0.34 kg·(m~3·d)~(-1),TOC/NH_4~+-N大于0.4后,反应器脱氮效能持续降低,并且短期内厌氧氨氧化菌难以迅速恢复活性.利用q PCR(定量PCR)技术对长期影响前后反应器内菌种群落变化做定量分析,结果表明随着有机物的增加,反应器中的ANAMMOX菌数量从2.9×10~(11)copies·mL~(-1)减少至3.15×10~(10)copies·mL~(-1),在TOC/NH_4~+-N大于1.6的环境中,NH_4~+-N未能由厌氧氨氧化菌去除,厌氧氨氧化菌不能表现出生物活性.此时测得反硝化菌数量为3.0×10~9copies·mL~(-1),反应器中的NO_2~--N绝大部分由反硝化去除,虽然反硝化菌数量远少于ANAMMOX菌,但能表现出远超ANAMMOX菌的活性.     

活性污泥厌氧Fe(Ⅲ)还原氨氧化现象初探

采用常规化学分析和微生物群落变性梯度凝胶电泳(DGGE)监测技术,探究了厌氧条件下活性污泥中Fe(Ⅲ)还原氨氧化(Feammox)反应的存在及微生物群落动态响应.结果表明,当反应器运行至第24 d时NH_4~+发生转化,同时检测到NO_3~-和Fe(Ⅱ)的生成,表明活性污泥中存在着Fe(Ⅲ)还原NH_4~+氧化反应,产物主要为NO_3~-和Fe(Ⅱ),并伴随少量N_2生成.经过84d培养,氨氮最大转化量达29.85 mg·L~(-1),转化率为59.7%,出水NO_3~-最高值达24.56 mg·L~(-1).活性污泥中Feammox为产酸过程,体系中p H值下降.整个培养过程中微生物群落条带分布发生变化,参与活性污泥中Feammox反应的部分群落在培养过程获得保留,部分优势菌群获得富集.     

Preparation of amphiphilic composite and removal of oil and hexavalent chromium from wastewater

A new composite for water treatment was prepared by melt blend for oil and hexavalent chromium absorption. Ethylene Propylene Diene Monomer (EPDM) was the matrix, calcinatory Fe₂O₃ and anion-exchange resin 201×7 were the fillers. This composite can suspend in water–oil contact (WOC) and absorb oils and hexavalent chromium in wastewater simultaneously. The absorbencies of composites changed greatly with various ratios of calcinatory Fe₂O₃ and anion-exchange resin 201×7. The results showed that the oil absorbencies increased continuously and hexavalent chromium absorbencies were step-down as calcinatory Fe₂O₃ loadings from 13 to 19%. The composite can adsorb oils and hexavalent chromium simultaneously. The optimized proportion of calcinatory Fe₂O₃ and anion-exchange resin 201×7 in composite was found when the absorbencies of oils and hexavalent chromium reaching the maximum simultaneously. This composite is an inexpensive, convenient and high efficiency material for removing oils and hexavalent chromium from wastewater.