好氧颗粒污泥用于膜污染的控制

膜生物反应器在运行过程中容易引起严重的膜污染,从而限制了膜生物反应器在实际废水处理工程中的应用.从污泥特性角度分析了好氧颗粒污泥的特点和减缓膜污染的原因,并且与活性污泥比较,提出好氧颗粒污泥减缓膜污染的优势,为膜污染的控制提出了新的思路和方法.     

盐度对硝酸细菌活性的影响及动力学特性

为分析盐度对硝酸细菌（NOB）活性的影响及其动力学特性,本文采用高浓度亚硝态氮污水富集培养NOB.对NOB富集污泥进行荧光原位杂交技术（FISH）分析表明Nitrobacter占细菌总数的（81%±6%）.污泥的最大比亚硝态氮氧化速率为（42.5±0.9）mgN/（gVSS·h）.用此污泥考察了盐度对NOB活性的影响,并测定了盐度为10g/L时NOB的动力学参数（Ko、K_S）.结果表明,与盐度为0g/L时的NOB活性相比,盐度为15g/L时NOB活性降低了3.3%;盐度为10和20g/L时的NOB活性分别降低了11%.盐度为10g/L时,NOB的最大比亚硝态氮氧化速率为（37.9±0.7）mgN/（gVSS·h）,氧的半饱和常数K_o值为（1.51±0.06）mg/L,底物（亚硝态氮）半饱和常数K_S值为（6.06±0.15）mg/L,Ko、K_S测定值均高于ASM2模型中氨氧化细菌（AOB）推荐值.盐度对NOB的抑制降低了最大比亚硝态氮氧化速率,对氧传递和底物（亚硝态氮）传递均存在影响.     

黄河三角洲生物多样性分析

黄河三角洲是我国东部最年轻的陆地,保存着中国暖温带地区最广阔、最完整、最年轻的湿地生态系统。鉴于已有的研究工作对黄河三角洲地区生物多样性通过黄河与周边地区的联系方面的研究相对薄弱,以现有研究工作为基础,以黄河的廊道作用为主线,并结合2003年9月和2004年10月两次实地地面植被调查,主要对黄河三角洲自然保护区的植物区系组成状况进行统计分析,总结出黄河三角洲地区生物多样性状况、植物区系组成的特点及其与周边地区的相互关系。黄河三角洲地区生物多样性主要表现出如下特点:植被结构简单、覆盖度低、生态系统年轻性特点和湿地生态系统特点明显;植物种类少、常具有抗盐、抗旱特性;旱生、中旱生植物以及与内蒙古共有植物种类多,充分体现了黄河的生物廊道作用;主要保护动物种类多,生物多样性保护意义重大。这些特征既反映了黄河三角洲新生陆地的盐化生境特点,同时也深刻揭示了河流通道对区域生物多样性形成的重要作用。     

重铬酸钾法测定COD中的干扰及消除

化学需氧量（COD）是描述水质有机物污染程度、评价水质好坏和污水治理效果的重要指标之一。目前,COD的测定大都采用重铬酸钾硫酸回流法。当水体中存在Cl^-、NO2^-、S^2-、Fenton等物质时,会影响化学需氧量的测定结果。讨论了采用重铬酸钾法测定化学需氧量时,以上几种物质对测定结果的干扰情况。着重探讨各种影响因素在不同情况下的消除方法以及各种消除干扰方法的优缺点。     

Predicting the transportation tendency and potential reservoirs of dioxins by compartment distribution coefficient

We assessed the transportation tendency of dioxins and predict locations at high risk for dioxin pollution. A new parameter, the compartment distribution coefficient D_C, was created to account for the tendency of dioxins to preferentially accumulate in particular compartments. It was obtained by a model using levels of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in four countries: Japan, the United States, the United Kingdom, and Australia. The comparison with the temporal and spatial variation of D_C indicated whether the location release or long-range transportation caused the changes. This study showed that PCDD/Fs have the greatest tendency to remain in soil among studied media. A higher D_C value in Australia may indicate that this location is a potential future reservoir source of dioxins.     

镍对栅藻深度处理生活污水的影响研究

将栅藻包埋固定在海藻酸钙凝胶珠中,对人工污水进行深度净化,研究其在不同质量浓度Ni2+条件下对污水中氨氮和正磷酸盐的净化效率,以及净化过程中藻类叶绿素a质量浓度、过氧化物酶(POD)活性变化和去污过程中藻细胞富集Ni2+的情况。结果表明,低质量浓度Ni2+可引起藻细胞应激性反应,光合活性提高,解毒机制增强,未影响氨氮和正磷酸盐的净化效率;高质量浓度Ni2+会造成藻细胞伤害,光合活性减弱,POD活性下降,氨氮和正磷酸盐的净化效率减小。Ni2+对栅藻深度处理生活污水影响程度依据其在水体中的质量浓度。     

Complexation of iron by salicylic acid and its effect on atrazine photodegradation in aqueous solution

The photodegradation of atrazine and the photochemical formation of Fe(II) and H₂O₂ in aqueous solutions containing salicylic acid and Fe(III) were studied under simulated sunlight irradiation. Atrazine photolysis followed first-order reaction kinetics, and the rate constant (k) corresponding to the solution of Fe(III)-salicylic acid complex (Fe(III)-SA) was only 0.0153 h^?1, roughly one eighth of the k observed in the Fe(III) alone solution (0.115 h^?1). Compared with Fe(III) solution, the presence of salicylic acid significantly enhanced the formation of Fe(II) but greatly decreased H₂O₂ generation, and their subsequent product, hydroxyl radical (˙OH), was much less, accounting for the low rate of atrazine photodegradation in Fe(III)-SA solution. The interaction of Fe(III) with salicylic acid was analyzed using Fourier-transform infrared (FTIR) spectroscopy and UV-visible absorption, indicating that Fe(III)-salicylic acid complex could be formed by ligand exchange between the hydrogen ions in salicylic acid and Fe(III) ions.     

进水碳源对好氧颗粒污泥特性的影响

采用气升式内循环间歇反应器对好氧污泥颗粒化过程进行了研究,考察了反应器分别以蔗糖和乙酸钠为进水碳源时好氧颗粒污泥的特性.实验结果表明:好氧颗粒污泥的形成特性与进水碳源有很大的关系;以蔗糖为碳源时,好氧污泥颗粒化速度快,好氧颗粒污泥表面被丝状物包裹,颗粒中w(VSS)为92%;以乙酸钠为碳源时,污泥颗粒化速度慢,好氧颗粒污泥表面光滑,w(VSS)只有55%左右;不同碳源下形成的好氧颗粒污泥沉降性能差别不大,但好氧颗粒污泥胞外多聚物的含量有很大差别.结果表明,由于进水碳源不同,好氧颗粒污泥特性和废水处理能力有一定的差别.      

Circulating fluidized bed biological reactor for nutrients removal

A new biological nitrogen removal process, which is named herein “The circulating fluidized bed bioreactor (CFBBR)”, was developed for simultaneous removal of nitrogen and organic matter. This process was composed of an anaerobic bed (Riser), aerobic bed (Downer) and connecting device. Influent and nitrified liquid from the aerobic bed enters the anaerobic bed from the bottom of the anaerobic bed, completing the removal of nitrogen and organic matter. The system performance under the conditions of different inflow loadings and nitrified liquid recirculation rates ranging from 200% to 600% was examined. From a technical and economic point of view, the optimum nitrified liquid recirculation ratewas 400%. With a shortest total retention time of 2.5 h (0.8 h in the anaerobic bed and 1.5 h in the aerobic bed) and a nitrified liquid recirculation rate of 400% based on the influent flow rate, the average removal efficiencies of total nitrogen (TN) and soluble chemical oxygen demand (SCOD) were found to be 88% and 95%, respectively. The average effluent concentrations of TN and SCOD were 3.5 mg/L and 16 mg/L, respectively. The volatile suspended solid (VSS) concentration, nitrification rate and denitrification rate in the system were less than 1.0 g/L, 0.026-0.1 g NH₄ ⁺-N/g VSS·d, and 0.016–0.074 g NO_x ^?-N/g VSS·d, respectively.     

饱和砂土场地‑地铁车站地震响应参数敏感性分析∗

为进一步研究饱和砂土场地?地铁车站结构体系地震动响应的参数敏感性问题,以某单层双跨地铁车站为研究对象,采用 u-p 格式饱和两相介质有效应力动力求解方法,建立了饱和砂土场地?地铁车站结构体系耦合动力数值分析模型,选取土体剪切模量、渗透系数、内摩擦角和地震动强度作为敏感性影响参数,在基准值误差分析的基础上进一步开展灰色关联分析,得到了地震动响应影响因素的灰色关联度序列。计算分析结果表明：近场特征点动孔压比峰值对地震动强度和土体剪切模量的变化更为敏感,而加速度峰值对地震动强度和内摩擦角变化更为敏感,中柱上下端动剪力与动弯矩对内摩擦角和地震动强度的变化更为敏感。此参数敏感性分析流程方法,可为地铁车站抗震设计和减灾预测评估提供参考。