高原地区MBR一体化曝气优化与脱氮除磷研究

针对高原地区MBR一体化技术脱氮除磷效果不佳与系统运行关键参数方面存在的问题,以贵州草海一座采用MBR技术的污水站为对象,探究运行优化曝气量以及运行4个月的脱氮除磷效果。结果表明,缺氧区、好氧区的优化曝气量分别为20、120 m~3/h,该曝气量工况下COD、NH_4~+-N、TN、TP去除率分别为93.72%、95.87%、69.32%、88.57%。在优化曝气工况运行下,3-6月份出水COD和NH_4~+-N、TN、TP的质量浓度平均分别为10.96 mg/L和1.76、10.51、0.36 mg/L。出水TN含量在3月份出现2次超标,TP含量在3月份出现3次超标,其余指标均可达到GB18918-2002的一级A标准。可为采用MBR工艺的污水处理厂在低温低压低氧环境运行提供参考。     

A~2/O生化法+物化法污水处理厂运行效果分析

介绍了采用A2/O生化法+物化法工艺的污水处理厂的工艺流程、主要构筑物参数,对COD、TP、TN、NH3-N等测定数据进行分析,评价污水处理厂运行效果。结果表明,污水经过处理后,COD、TP、TN、NH3-N平均去除率分别达到88.9%、89.0%、49.7%、98.4%,出水COD为17 mg/L,TP、TN、NH3-N的质量浓度分别为0.145、9.15、0.23 mg/L,满足GB 18918-2002的一级A标准要求。在进水COD低于设计条件的情况下,出水污染物含量不易受进水量增加的影响。     

多种物化生化组合工艺处理印染电镀混合废水

通过"混凝+预处理曝气+预处理沉淀+A2/O生化法+物化"组合工艺对污水处理厂废水进行处理,对COD、TP、TN、NH3-N等测定数据进行分析,评价污水处理厂运行效果.结果表明:COD、TP、TN、NH3-N的平均去除率分别为97％、96％、70％、97％,出水各项指标的平均值分别为:COD浓度为46 mg/L、TP浓度为0.06 mg/L、TN浓度为8 mg/L、NH3-N浓度为0.6 mg/L,出水满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)中的一级A标准要求,在进水浓度低于设计值的情况下,出水污染物浓度不易受进水量增加的影响.     

连续流间歇曝气工艺处理生活污水规律探究

采用连续流间歇曝气工艺处理生活污水,探究不同间歇曝气方式对连续流反应器中COD、NH_4~+-N、TN、TP去除效果的影响。结果表明,间歇曝气的运行方式有利于抑制污泥膨胀问题;所有工况COD去除率均高于82%,且随着曝气时间的增加而增加,最高可达到92%;出水TP的质量浓度在1.8~5.5 mg/L,平均去除率约为30%,缺氧阶段NO_x~--N(x=2、3)、好氧缺氧交替频率、温度均是影响TP去除效果的因素;进水TN主要以NH_4~+-N的形式存在,出水TN的质量浓度浓度在51~53 mg/L,去除率23.2%~55.8%,反硝化阶段碳源不足是造成TN去除率低的主要因素;NH_4~+-N平均去除率在78%左右,间歇曝气NH_4~+-N的去除效率均高于连续曝气工况。     

土壤净化床系统处理巢湖农村生活污水应用研究

针对巢湖流域农村社区生活污水产生特点和水质特性,研究了土壤净化床对分散厌氧处理后的生活污水的处理效果。结果表明,土壤净化床能有效去除COD、TN、NH4+-N、TP,COD去除率一般在70%以上,最高能达90%;TN去除率一般在50%以上,最高达到80%;NH4+-N去除率一般稳定在50%～70%;TP去除率一般稳定在60%。由于温度对COD、TN、NH4+-N、TP的去除为正效应影响,而春节期间温度较低,外出务工人员集中返乡,以及居民饮食结构变化导致进水COD、TN、NH4+-N、TP较其他时期高出1倍,导致该期间出水未能达到GB 18918-2002一级B标准。从近2年的监测结果分析,要使该工艺技术在巢湖流域农村区域进行推广应用,还须进一步研究该区域春节期间污水水质特征和负荷对土壤净化床运行的影响。     

悬浮填料氧化沟脱氮除磷的中试研究

通过正交实验研究了溶解氧(DO)含量、污泥回流比、污泥龄(SRT)对悬浮填料氧化沟系统脱氮除磷效果的影响,并对COD、NH4+-N、TN、TP去除率的极差和方差进行了分析。结果表明,DO含量对系统COD、NH4+-N、TN、TP的去除均有显著影响,污泥回流比对系统NH4+-N、TN、TP的去除有显著影响,SRT仅对TP的去除有显著影响。悬浮填料氧化沟系统脱氮除磷的优化运行工况为氧化沟DO的质量浓度0.8~1.2mg/L,污泥回流比75%~100%,SRT为10~15d。在此优化工况下运行,出水COD、NH4+-N、TN达到GB 18918-2002标准中的一级A标准,TP达到一级B标准。     

曝气方式及排水比对CASS稳定化运行的影响

针对南京某污水处理厂受冲击的循环活性污泥工艺(CASS),采取了稳定化运行措施,考察曝气量、曝气时间、进水曝气方式及排水比对工艺稳定化运行效率影响。结果表明,工艺历经非限制性、半限制性和限制性进水曝气方式后趋于稳定化运行,二级处理出水COD和TP、NH_4~+-N、TN的质量浓度平均分别为33.9 mg/L和0.335、1.85、12.41 mg/L,平均去除率分别为81%和80%、83%、31%,主要出水水质达到GB 18918-2002一级A标准。较低排水比运行处理效率较低,较高排水比运行利于TN去除,但出水COD、NH_4~+-N、TP有所增长,出水水质波动;排水体积比在26%～31%运行,处理效率较高,出水水质稳定。稳定运行下平均处理直接费用约0.47元/t。     

藻菌生物反应器处理油田污水的实验研究

利用实验室配置的模拟油田污水，考察了小球藻和藻菌生物反应器对污水净化处理效果和生物量积累的影响。实验数据显示：藻菌生物反应器运行25 d时，对模拟油田污水COD、TP、NH4+-N的去除率分别为44.23%、88.68%、85.01%,TN在反应器运行到53 d去除效果最高达到80.99%。小球藻生物反应器运行的第25天对污水COD、TP和NH4+-N的去除率分别为35.45%、81.17%、和80.10%,TN在反应器运行第53天时去除率最高为76.75%。结果表明，藻菌共生提高了微藻的光合速率、生长速率以及污染物的去除效率，其效果优于小球藻处理系统。     

SBR处理校园生活污水的试验研究

采用SBR工艺对校园生活污水进行试验研究,考察了系统对COD、TP、NH4^＋-N的去除效果。通过正交试验确定了最佳的运行工况为：瞬时进水,厌氧1h,曝气3h,沉淀1h。在最佳工况下运行时,COD、TP、NH4^＋-N的去除率分别达到89．15%、85．7%、68.1％左右,且通过20d稳定运行试验,处理效果一直保持良好,为校园生活污水的中水回用提供了重要的技术参数。     

A~2/O氧化沟—纤维转盘滤池工艺处理城市污水

以某污水厂为例,介绍了水解酸化—A2/O氧化沟—纤维转盘滤池组合工艺处理城市污水的效果。该工程处理水量7万m3/d,进水COD、BOD5、SS、NH4+-N、TN、TP分别为326.2、138.8、156.8、32、63、1.6 mg/L。采用该工艺处理后,COD、BOD5、SS、NH4+-N、TN、TP的去除率分别为90.1%、93.3%、94.4%、90.0%、77.3%、75%,出水达到了《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A排放标准。该工艺具有运行费用低、处理效果好、操作方便的优点。     

Compact Swelling in Bi1.4Pb0.6Sr2Ca2Cu3.6Oy During the Formation of High-Tc Superconducting Phase

Compact swelling in Pb-doped Bi-Sr-Ca-Cu-O superconductor has been studied by observing the effects of the size of calcined powders, volatilization of materials, and sintering of high- T _c (2223) powders. The bulk density increases at the early stage of sintering, for about 20 h, and then decreases. Densification occurs when the low- T _c (2212) phase and a liquid phase exist, whereas dedensification occurs with the formation of the 2223 phase regardless of the presence of the liquid. Gas evolution from specimens does not appear to be responsible for compact swelling. Compact swelling is explained by anisotropic growth of thin, platelike 2223 grains in random orientation. When 2223 grains grow in a preferred direction, compact swelling is suppressed.     

Synthetic routes to nanoscale BxCyNz architectures

B_xC_yN_z nanoscale materials, hybrids of h-BN and graphite, have been recently synthesised using various techniques. Here, we present the latest advances in the synthesis and characterisation of B-C-N nanotubes and nanofibres. In particular, we focus on layered BC₂N, BN, BC and CN_x systems, reviewing their production methods as well as their structural and electronic properties. These materials may find important applications in the fabrication of nanotransistors, robust nanocomposites, conducting polymers, storage components and field emission sources.     

Structure Evolution from Pb(Mg1/3Nb2/3)O3 to La(Mg2/3Nb1/3)O3

The crystal structure of lanthanum-modified lead magnesium niobates having composition (Pb_{1− x} La _x ) (Mg_{(1+ x )/3}-Nb_{(2− x )/3})O₃ with X = 0 to 1 was investigated by X-ray powder diffraction. It was found that the fundamental reflections from perovskite structure remain in the whole range of composition. The superlattice reflections from the A(B'_1/2-B"_1/2)O₃ ordered structure are also well preserved for La content greater than 50 at.%; however, a series of extra peaks of mixing indices appears, with intensities gradually enhanced with the increase of La content. For the complete substitution of Pb by La, a splitting of some reflections can be observed in the diffraction pattern. The results indicate that the crystal structure evolves continuously with the La content, from disordered cubic perovskite of space group Pm 3 m for X = 0, to ordered cubic perovskite of space group Fm 3 m for X = 0.5, distorted cubic perovskite of space group Pa 3 for 0.5 < X < 0.9, and finally to a rhombohedral perovskite, possibly belonging to the space group R 3 , for X ≥ 0.9. In the evolution of structure, a linear reduction of the lattice constant of the perovskite cell from 4.048 to 3.964 Å was observed.     

Dielectric-State Analysis in Solid-Solution Pb(Yb1/2Ta1/2)O3–Pb(Lu1/2Nb1/2)O3

The structure and temperature dependence of complex lead perovskite dielectrics were investigated for the system (1 − x )Pb(Yb_1/2Ta_1/2)O₃– x Pb(Lu_1/2Nb_1/2)O₃. Superlattice reflections for the compositions 0.8 < x < 1.0 were observed by X-ray diffractometry, and the temperature-composition dielectric-state diagram was determined. In the present study, the disordered middle composition, with 0.2 < x < 0.8, showed a diffuse paraelectric–ferroelectric phase transition, whereas the ordered end compositions, with 0 ≤ x < 0.2 and 0.8 < x ≤ 1.0, revealed successive sharp paraelectric–antiferroelectric and weak antiferroelectric–ferroelectric phase transitions. The dielectric state was confirmed by examining the variation of polarization ( P ) with electric field ( E ).     

(Bi1/2Na1/2)TiO3–Ba(Cu1/2W1/2)O3 Lead-Free Piezoelectric Ceramics

(Bi_1/2Na_1/2)TiO₃ with 0–6 mol% Ba(Cu_1/2W_1/2)O₃ (BNT-BCW), a new member of the BNT-based group, has been prepared following the conventional mixed oxide route. The compacted bodies were sintered at 1130°C for 2 h to get dense ceramics. The addition of BCW into BNT ceramics facilitated the poling process because of a reduction in leakage current. 0.995BNT·0.005BCW ceramics exhibit a relatively high piezoelectric constant ( d ₃₃= 80 × 10⁻¹² C/N) and a relatively low dielectric loss (tan δ= 1.5%). Increased amount of BCW was found to increase the dielectric constant and loss of BNT-BCW ceramics and to suppress the grain growth. During sintering, some BCW diffuses into the lattice of BNT to form a solid solution and some remains on the grain boundaries.     

炭黑/煤矸石/碳纳米管复合填料体系对天然橡胶性能的影响研究*

利用硝酸氧化法对碳纳米管(CNTs)进行纯化,并用环氧天然橡胶(ENR)进行改性处理。结合胶质量分数测定结果表明, ENR用量15%(质量)时效果最佳。采用胶乳凝聚法制备CNTs/天然橡胶(NR)母料。煤矸石粉(CG)经高温煅烧和表面改性处理。 将CNTs/天然橡胶(NR)母料、CG和炭黑(CB)通过机械混炼法与天然橡胶及配合剂混合,制备CB/CG/CNTs/NR复合材料,并对复合材料进行硫化特性及物理机械性能。结果表明： CNTs延迟硫化效应明显;相比炭黑,CG对硫化具有促进作用。硫化特性和甲苯溶胀法测定结果表明,在填料份数相同的条件下,单独由CB填充的NR有最大的交联密度,CNTs对交联密度影响不明显。物理机械性能测试结果表明,当CG：CB：CNTs=17.5:16.5:1(Phr)时,NR硫化胶的300%定伸应力和扯断伸长率明显高于单独由CB填充NR,而拉伸强度与之接近,复合填料样填充NR具有较好的综合性能。扫描电镜测试结果表明,复合填料在NR基体中分布均匀。