负荷交替法快速培养好氧硝化颗粒污泥的研究

在3个SBR(R1、R2、R3)中分别培养好氧硝化颗粒污泥,R1和R2分别采用进水氮负荷交替变化和进水碳氮负荷同步交替变化这2种新的培养方式,R3采用传统的逐步提高氮负荷法.对R1、R2和R3培养得到的硝化颗粒污泥在物理性状、污染物去除效能等方面进行对比分析.结果表明,R1和R2的培养方式明显缩短了培养时间,70 d左右成功培养出完全意义上的硝化颗粒(硝化菌的活性超过异养菌的活性),而R3需147 d.采用进水碳氮负荷同步交替变化法快速培养出的颗粒外形更规则、硝化菌活性更高、脱氮性能更优,稳定运行时氨氮和总氮去除率分别为95%和70%左右,在理化性状和脱氮性能上明显优于其他2种.对比发现,在硝化颗粒污泥培养初期,适当提高进水有机负荷,能加快颗粒的形成及生长.     

高碳氮负荷下同时脱氮除碳好氧颗粒污泥研究

在4 L反应器中,以补加葡萄糖和硫酸铵的猪场废水为基质,不接种活性污泥,加入粉末状活性炭对废水土著微生物进行预固定.通过批次进水并控制运行条件（逐渐提高COD、NH 4＋-N负荷、缩短沉降时间、提高曝气量）培养同时脱氮除碳好氧颗粒污泥,研究了该好氧颗粒污泥的脱氮除碳功能及对高碳氮负荷冲击的响应.结果表明,成熟好氧颗粒污泥为土黄色不规则球状,粒径为0.5～3.5 mm.COD和NH 4＋-N负荷分别在4.80～12.6 kg.（m3.d）-1和0.217～0.503 kg.（m3.d）-1时,好氧颗粒污泥对COD的去除率〉94%,对NH 4＋-N的去除率〉98%.当COD和NH 4＋-N负荷分别提高至15.70 kg.（m3.d）-1和0.723kg.（m3.d）-1并运行4 d后,反应器内絮体激增,颗粒沉降变差并开始破碎,NH 4＋-N去除率下降至81.6%.排出部分污泥并降低负荷继续运行,颗粒污泥的NH 4＋-N去除率可迅速恢复至98%以上.本研究培养的好氧颗粒污泥具有良好的同时脱氮除碳功能,可以耐受高COD和NH 4＋-N负荷的双重冲击.     

内循环活性炭生物流化床处理农药生产废水的试验研究

采用内循环活性炭生物流化床反应器处理某农药厂生产废水,通过试验研究了该反应器在室温条件下处理农药生产废水的性能.结果表明:当进水pH值控制在7.0～7.5、水力停留时间为6h、曝气量控制在使活性炭处于流化状态时,CODcr的去除率为50％,总氮的去除率为32.33％,同时可生化性明显提高,生物毒性有所降低.     

非离子表面活性剂对污泥调理脱水效果的影响

现有污泥脱水技术仅使污泥含水率降到80%左右,难以满足日益严格的污泥处置要求.以污泥比阻（SRF）、脱水率为考察指标,比较了两大类非离子型表面活性剂（辛基酚聚氧乙烯醚OPEO型和烷基糖苷APG）对剩余污泥的脱水效果,并对原泥及调理后污泥进行了显微观察.结果表明,非离子表面活性剂可使污泥絮体粒径变小,不规则程度降低,改善了污泥的脱水性能,而且烷基糖苷APG脱水效果优于OPEO型.APG投加量为0.05%干固体时,污泥比阻即可降低到原泥的42%,脱水率可达到93%.以烷基糖苷APG为调理剂进行板框脱水实验,结果表明,当APG投加量为0.05%干固体时,脱水泥饼含水率比原泥脱水泥饼含水率低约10%,脱水率可达到97%.本研究为APG应用于污泥脱水,改善污泥脱水性能提供一些参考.     

采用体积信息熵表征颗粒污泥系统稳定性及其稳定机制

SBR反应器中培养自养硝化颗粒污泥,在絮体转化为颗粒过程中,颗粒的体积信息熵从2.05(27 d,初见颗粒)降低为1.85(95 d),熵值降低的主要动力来自于松散的絮体在较快沉速选择压条件下被淘洗出系统.当絮体被淘洗出系统即完成颗粒化过程,在129 d时测得系统中颗粒沉速分布的中位数为6.27 m.h-1,因此颗粒体积熵值的变化不再受沉速选择压(6m.h-1)的控制.颗粒的粒径、沉速及体积熵值分布均呈现周期性变化,其中信息熵的均值为2.16,最小值为1.79,最大值为2.63.在这种周期性变化过程中,系统总是表现为粒径均值先增大后减小.熵值的波动的驱动力来自于颗粒的破碎与破碎体的成长,体积分布信息熵的大小可以很好地表征系统的稳定性及其稳定机制.     

接种不同污泥启动厌氧氨氧化ASBR反应器研究

采用ASBR反应器,分别以好氧硝化污泥和厌氧颗粒污泥为种泥,通过对氨氮、亚硝酸盐氮等指标的监测和数据分析、污泥颜色的观察,研究2个厌氧氨氧化反应器启动的可行性及其差异.结果表明,2个厌氧氨氧化反应器均可成功启动;采用好氧硝化污泥启动厌氧氨氧化反应器耗时142 d,启动前后污泥颜色变化不大,亚硝酸盐氮浓度超过20 mmol/L会对厌氧氨氧化产生明显的抑制作用;采用厌氧颗粒污泥启动厌氧氨氧化反应器耗时249 d,启动前后污泥颜色变化很大,从黑色逐渐变为砖红色,亚硝酸盐氮浓度超过13.4 mmol/L会对厌氧氨氧化产生抑制作用;分别用以上2种污泥启动的厌氧氨氧化ASBR反应器中占优势地位的厌氧氨氧化菌不同.     

Transformations of particles, metal elements and natural organic matter in different water treatment processes

Characterizing natural organic matter （NOM）, particles and elements in different water treatment processes can give a useful information to optimize water treatment operations. In this article, transformations of particles, metal elements and NOM in a pilot-scale water treatment plant were investigated by laser light granularity system, particle counter, glass-fiber membrane filtration, inductively coupled plasma-optical emission spectroscopy, ultra filtration and resin absorbents fractionation. The results showed that particles, NOM and trihalomethane formation precursors were removed synergistically by sequential treatment of different processes. Preozonation markedly changed the polarity and molecular weight of NOM, and it could be conducive to the following coagulation process through destabilizing particles and colloids; mid-ozonation enhanced the subsequent granular activated carbon （GAC） filtration process by decreasing molecular weight of organic matters. Coagulation-flotation and GAC were more efficient in removing fixed suspended solids and larger particles; while sand-filtration was more efficient in removing volatile suspended solids and smaller particles. Flotation performed better than sedimentation in terms of particle and NOM removal. The type of coagulant could greatly affect the performance of coagulation-flotation. Pre-hydrolyzed composite coagulant （HPAC） was superior to FeCl3 concerning the removals of hydrophobic dissolved organic carbon and volatile suspended solids. The leakages of flocs from sand-filtration and microorganisms from GAC should be mitigated to ensure the reliability of the whole treatment system.     

Anaerobic tapered fluidized bed reactor for starch wastewater treatment and modeling using multilayer perceptron neural network

Anaerobic treatability of synthetic sago wastewater was investigated in a laboratory anaerobic tapered fluidized bed reactor(ATFBR) with a mesoporous granular activated carbon(GAC)as a support material.The experimental protocol was defined to examine the effect of the maximum organic loading rate(OLR),hydraulic retention time(HRT),the efficiency of the reactor and to report on its steady- state performance.The reactor was subjected to a steady-state operation over a range of OLR up to 85.44 kg COD/(m~3.d).The COD removal efficiency was found to be 92% in the reactor while the biogas produced in the digester reached 25.38 m~3/(m~3·d) of the reactor. With the increase of OLR from 83.7 kg COD/(m~3.d),the COD removal efficiency decreased.Also an artificial neural network(ANN) model using multilayer perceptron(MLP)has been developed for a system of two input variable and five output dependent variables. For the training of the input-output data,the experimental values obtained have been used.The output parameters predicted have been found to be much closer to the corresponding experimental ones and the model was validated for 30% of the untrained data.The mean square error(MSE)was found to be only 0.0146.     

Thermodynamics and kinetics of cadmium adsorption onto oxidized granular activated carbon

Cadmium sorption behavior of granular activated carbon oxidized with nitric acid was systematically studied by sets of the equilibrium and time-based experiments under various conditions.The cadmium adsorption capacity of oxidized granular activated carbon enlarged with an increase in pH,and reduced with an increase in ionic strength.Experimental data were evaluated to find out kinetic characteristics.Adsorption processes were found to follow pseudo-second order rate equation.Adsorption isotherms correlate well with the Langmuir isotherm model and the maximum sorption capacity of cadmium evaluated is 51.02μmol/g.Thermodynamic parameters were calculated based on Van't Hoff equation.Equilibrium constant Kd was evaluated from Freundlich isotherm model constants,Langmnir isotherm model constants,and isotherms,respectively.The average change of standard adsorption heatΔH~0 was -25.29 kJ/mol.NegativeΔH~0 andΔG~0 values indicate the adsorption process for cadmium onto the studied activated carbon is exothermic and spontaneous.The standard entropyΔS~0 was also negative,which suggests a decrease in the freedom of the system.     

利用紫外预处理加强氯苯的生物滴滤净化

试验采用主波长为185nm的低压汞灯为紫外光源、醚型聚氨酯海绵(PU-foam)为填料的紫外-生物滴滤塔联合装置净化氯苯废气.进气氯苯浓度为600mg·m-3、停留时间分别为92、69和46s时,联合装置的平均去除率分别达到99%、95%和80%;最大去除负荷达到59.6g·(m3·h)-1;联合装置和单独生物滴滤塔生物膜形成时间分别为20d和27d;联合装置的抗冲击能力较好,停留时间缩短至30s,联合装置去除效率可达75%以上,高于单独生物滴滤塔的去除效率(25%).对紫外-生物滴滤塔联合装置机制初步探讨表明,紫外氧化氯苯形成了水溶性较好的可生物降解的物质,降低生物滴滤塔氯苯的处理负荷,同时紫外辐照过程中产生的O3能有效地控制生物滴滤塔内微生物的过量生长,从而维持整个装置的最佳运行状态.