厌氧除磷同步脱氮及影响因素研究

采用鸡粪污泥为种泥,在厌氧混合连续流反应装置内进行厌氧还原磷产生磷化氧功能菌的富集,进行硝酸盐、硫酸盐、不同碳源和氮源条件下厌氧除磷效率的研究,并考察磷化氧的生成与硝酸、总磷、氨氮去除的关系.结果表明,(1)SO_4~(2-)-S适宜的投加量为26 mg·L~(-1),不投加NO_3~--N.水中含有氧化态的无机物在厌氧条件下与磷争夺[H]导致厌氧除磷的效率下降.(2)合适的碳源为葡萄糖1 000 mg·L~(-1),纤维素不适合作为碳源,合适的氮源为蛋白胨500 mg·L~(-1),水中含有的还原糖和有机氮源促进磷化氧的生成.(3)pH值控制在6.5～7.0的范围,最适宜的生长温度在35℃左右.(4)氨氮的去除率随着总磷的去除率而增加,在厌氧条件下可达到同时脱氮除磷的效果.磷的去除由厌氧除磷菌还原磷生成磷化氧完成,氨氮由生成氮气或生成蛋白质来去除.     

猪场废水厌氧消化过程中的除磷效果

采用序批式半连续厌氧消化试验方法,研究猪场废水厌氧消化过程中磷的去除情况。结果表明,水力停留时间（HRT）为1、3、6和9 d的厌氧反应器平均除磷率分别为65.0%、81.1%、82.7%和83.0%,而COD平均去除率分别为54.5%、82.3%、87.0%和85.9%。厌氧反应器除磷能力随沼气产量的增加而增加,说明厌氧反应器中磷的去除与产甲烷过程密切相关。对厌氧消化前后的污泥进行浸提后发现,厌氧消化过程中,化学反应生成磷酸盐沉淀的除磷作用十分显著,污泥中正磷酸盐,与铁结合的磷化合物（Fe-RP）,还原可溶性磷,与钙、镁离子结合的磷化合物（Ca-RP、Mg-RP）以及无机或有机聚合磷增加量分别为0.027 8～0.101 5、0.013 5～0.081 0、0.2165～0.430 5、23.4～54.8和7.2～21.5 mg.g-1;且总体而言,HRT越长,污泥中与不同金属结合的磷增加量就越大。从HRT、磷和有机物的去除效果以及沼气产气速率3个方面综合考虑,猪场废水厌氧消化反应器的HRT控制在3 d为宜。     

厌氧颗粒污泥对五氯苯酚脱氯过程中的影响因素

在间歇培养血清瓶中,研究了厌氧颗粒污泥对五氯酚脱氯过程中的影响因素.结果表明,葡萄糖、酵母膏和蛋白胨显著提高了PCP的脱氯速率.添加甲酸、乙酸、乙醇对PCP脱氯速率有一定提高,丙酸和丁酸对脱氯速率没有影响.20%氢气的加入对PCP脱氯速率的影响显著.废水中硝酸盐和硫酸盐等电子受体的存在降低了PCP的脱氯速率.微生物抑制剂氯仿、青霉素降低了PCP脱氯速率,表明厌氧微生物尤其是甲烷菌对还原脱氯有重要影响.PCP最佳还原脱氯温度为38℃,最佳pH为7,低的氧化还原电位(<-200mV)有利于脱氯的进行.图5参13     

厌氧-好氧生物除磷影响因素的控制

采用厌氧-好氧生物除磷工艺,研究了两个关键因子--化学需氧量与磷的比值和污泥负荷对系统除磷效果的影响及其控制.结果表明,原污水中化学需氧量与磷的比值越高,厌氧放磷越多,越有利于除磷;厌氧放磷与厌氧吸收碳源呈正相关;并且,进水化学需氧量与磷的比值的变化对整个系统碳源污染物的去除效果不会产生明显的影响.试验发现,厌氧条件下聚磷菌贮存碳源的多寡并不完全依赖于高能磷酸键水解提供的能量,原污水中化学需氧量越多,越有利于厌氧碳源的贮存.若要达到好的除磷效果,系统的污泥负荷必须控制在0.21～0.5 kg/(kg·d)之间,且污泥负荷越高,除磷效果越佳.     

磷酸盐改性方解石去除水中磷酸盐研究

使用磷酸盐溶液和方解石之间的反应得到方解石去除水中磷酸盐后的产物,即磷酸盐改性方解石,通过实验对比分析了方解石和磷酸盐改性方解石对水中磷酸盐的去除动力学,并考察了磷酸盐改性方解石去除水中磷酸盐的各种影响因素。磷酸盐改性方解石对水中磷酸盐的去除能力明显优于方解石。当反应时间为2h时,实验条件下磷酸盐改性方解石对水中磷的去除率达到72%,而方解石对磷的去除率仅为35%。当pH为5~7时,磷酸盐改性方解石对水中磷酸盐的去除能力较高;当pH由7增加到10 h,对磷酸盐的去除能力略微下降;当pH由10增加到12 h,对磷酸盐的去除能力急剧下降。磷酸盐改性方解石对水中磷酸盐的单位去除量随初始磷质量浓度的增加而增加。过高的初始磷质量浓度会导致磷酸盐改性方解石对水中磷酸盐的去除率过低。磷酸盐改性方解石对水中磷酸盐的去除能力随反应温度的升高而增加。磷酸盐改性方解石对水中磷酸盐的去除动力学可以较好地采用准二级动力学模型加以描述。水中共存的钙离子有利于磷酸盐改性方解石对磷酸盐的去除,而水中共存的碳酸氢根离子抑制了磷酸盐改性方解石对磷酸盐的去除。磷酸盐改性方解石去除水中磷酸盐的主要机制是磷酸钙沉淀作用。磷酸盐改性方解石不仅会为磷酸钙沉淀反应的异质成核提供核心,促进磷酸钙沉淀的形成,而且当水处于对方解石不饱和状态时会溶解释放出可溶性钙,为磷酸钙沉淀的形成提供钙源。上述结果表明,方解石去除水中磷酸盐后的产物可以被再次用于水中磷酸盐的去除,并且对磷酸盐的去除效果优于原始的方解石。     

固定化菌-藻/铝污泥的脱氮除磷效果及机理研究

针对粉末状吸附剂易于流失、难以固液分离的现状,模拟研究了铝污泥、固定化菌、固定化藻/铝污泥、固定化菌-藻/铝污泥对污水的脱氮除磷效果。结果表明,藻粉与铝污泥的复合使吸附剂比表面积增加,可为氮磷提供更多的吸附点位;藻/铝污泥(体积比1∶10)、藻/铝污泥(1∶5)和藻/铝污泥(1∶2)吸附剂对磷最大的吸附量分别为8.45、10.06和6.68 mg·g^-1,是普通铝污泥的2.41、2.87和1.91倍。固定化菌-藻/铝污泥(1∶5)对污水的处理效果优于铝污泥、固定化菌和固定化藻/铝污泥(1∶5),对COD_Cr、TP、NH₃-N和TN的去除率分别为80.35%、91.88%、90.92%和92.51%。固定化菌-藻/铝污泥(1∶5)吸附剂对磷的去除主要取决于铝污泥与磷酸盐之间的离子交换作用与静电作用,固定化胶球的传质性可为细菌同步硝化反硝化提供优良条件。     

Diaphorobacter sp.J5-51降解酚类污染物的特性

为强化酚污染的生物治理,提高酚类污染物的去除效率,采用单因素实验方法研究1株Diaphorobacter细菌(命名为J5-51)降解酚类物质的特性.结果显示,菌株J5-51在pH为6.0-9.0、温度为25-35℃的情况下均能较好地降解对氯酚;添加0.2 mmol/L的Ca~(2+)能够促进、而添加相同浓度的Co~(2+)和Ni~(2+)则抑制对氯酚的降解;菌株降解对氯酚的速度与对氯酚的初始浓度呈负相关关系;除对氯酚外,菌株还能降解吡啶、苯酚、2-甲酚、3-甲酚和4-甲酚.在优化的条件下,菌株可在72 h内完全降解焦化废水中约400 m g/L的苯酚和100 mg/L的甲酚;同时,对菌株J5-51进行固定化有利于其降解酚类化合物.综上认为,菌株J5-51在处理酚类化合物共污染环境的生物修复中具有一定的应用潜力.(图6参13)     

Fe~(3+)除磷对缺氧好氧膜生物反应器工艺运行性能及生物除磷的影响

针对膜生物反应器(MBR)较长的污泥龄导致磷的处理效果差的问题,采用铁盐强化除磷,向反应器中投加n(Fe)/n(P)=2.0的Fe Cl3·6H2O,系统考察膜生物反应器对氮、有机物及磷的去除效果,重点考察膜生物反应器投加铁盐前后运行性能、活性污泥菌群及膜污染速率变化情况.结果显示,在氮、有机物去除方面,投加前后没有发生明显的变化,去除率始终保持在90%左右.在磷去除方面,投加前磷的平均去除率为52%,投加后去除率提高了近40%,去除效果显著提升.实验进一步研究了加入三价铁盐前后对活性污泥优势菌群和生物除磷的影响.铁盐的投加降低了活性污泥菌群多样性及部分已知聚磷菌的相对丰度,对生物除磷造成一定的负面影响.在膜污染方面,通过跨膜压差(TMP)记录分析此浓度的铁盐并没有导致膜生物反应器膜组件膜污染的加剧.本研究表明,该浓度(n(Fe)/n(P)=2.0)的铁盐进入膜生物反应器会对体系内活性污泥聚磷菌的相对丰度及生物除磷效率造成一定程度上的降低,但对膜污染没有明显影响,可以使出水各项指标尤其是磷的尾水排放浓度达标.     

硅藻土基复合除磷剂的制备及其吸附性能

以硅藻土为原料,通过引入钢渣复合的方法制备硅藻土基复合除磷剂,采用傅里叶变换红外光谱(FTIR)、X-射线衍射(XRD)和扫描电镜(SEM)对复合除磷剂进行表征,并研究投加浓度、吸附时间、pH值和温度对复合除磷剂吸附效果的影响.结果表明,与钢渣复合后,复合除磷剂中部分基团可能发生变化,晶体结构可能发生改变,出现新的晶相.静态除磷试验表明复合除磷剂的最佳反应条件:投加质量浓度2g·L-1,吸附时间1h,水样pH值为5,温度25℃.硅藻土基复合除磷剂对磷的吸附动力学行为符合准二级动力学模型;Freundlich、Langmuir和Redlich-Peterson吸附等温方程均能较好地描述复合除磷剂对磷的等温吸附特征.硅藻土基复合除磷剂对磷的理论饱和吸附量为1 428 mg·kg-1,是一种潜在的高效环保型吸附材料.     

序批式活性污泥(SBR)转移工艺的除磷机制

以城市污水为水源,进行了污泥转移SBR工艺的除磷机制研究.实验结果表明,通过污泥转移方式实现在生物选择器中强化对聚磷菌的筛选,从而显著提升了传统SBR工艺的除磷性能.污泥转移量对系统释磷性能影响显著,污泥转移量为30%条件下活性污泥PHB(poly-β-hydroxybutyric acid)含量达到细胞干重的24.3%,生物选择器中厌氧释磷与污泥中PHB合成呈现良好的正相关性.污泥转移量分别为15%、30%和40%下生物选择器中的平均释磷速率分别为7.00、11.17、8.83 mg TP·(g MLSS·h)-1.通过物料衡算表明,系统中传统PAO除磷机制起主要作用,并存在较弱的反硝化除磷过程.在污泥转移量30%、泥龄10 d条件下,传统PAO(Phosphorus accumulating organisms)代谢模式除磷量占76.81%,同化除磷量占15.43%,反硝化除磷量占7.76%.     

Effect of iron addition on the performance of anoxic-oxic membrane process and biological phosphorus removal北大核心CSCD

In order to solve the problem of poor treatment of phosphorus in membrane bioreactor (MBR) with long sludge retention time (SRT), a ferric salt was added to enhance phosphorus removal; FeCl36H2O (Fe/P = 2.0) was added to the reactor. The removal efficiency of nitrogen, organic matters, and phosphorus in the MBR was investigated systematically. Moreover, this study focused on the membrane performance, the change of active sludge flora, and the effect of adding a ferric salt on membrane fouling before and after the addition. It was seen that adding the ferric salt could not affect the removal of COD and NH4 +-N and the removal rate of COD and NH4 +-N reached over 90%. However, the average removal rate of phosphorus was 52%, while the removal rate increased by nearly 40% after adding the ferric salt. The effects of adding ferric salts on the dominant bacteria and biological phosphorus removal of activated sludge were further studied. The results showed that the addition of ferric salt (Fe/P = 2.0) decreased the diversity of active sludge flora and relative abundance of some phosphorusaccumulating organisms and had a negative effect on biological phosphorus removal. The analysis of transmembrane pressure difference (TMP) recording revealed that the concentration of iron salts did not exacerbate membrane fouling. The results showed that the concentration of iron salts entering the membrane bioreactor would reduce the relative abundance and phosphorus removal efficiency of the activated sludge in the system to a certain extent, but it had no obvious effect on membrane fouling. It allowed the effluent to attain acceptable standards, especially with respect to phosphorus removal efficiency. © 2018 Science Press. All rights reserved.     

气化熔融处理生活垃圾时灰渣的熔融特性

弄清垃圾灰渣的熔融特性对于保证生活垃圾的气化熔融与液态出渣具有重要作用。针对重庆生活垃圾灰与无烟煤灰形成的灰渣,实验研究了在不同的燃料添加量及添加剂条件下灰渣的熔点与粘度,并结合炉温的变化,分析了不同条件对灰渣熔融及液态出渣的影响。结果表明,灰渣的熔点与粘度均随燃料添加量的增加而升高;向燃料比为10%的灰渣中加入添加剂后,灰渣的熔点降低幅度较小,其粘度却随碱度的增加而增大以至熔渣流动性变差;燃料比为40%时,灰渣熔点与粘度均随添加剂的加入而显著降低,且向渣中加入CaO使得灰渣碱度为1.2时灰渣熔点较低且粘度较小,有利于其熔融与液态出渣。     

序批式生物膜法同步除磷脱氮特性研究

对淹没序批式生物膜法去除有机物和磷及同步部分脱氮的特性进行了研究。其适合的载体装填密度为30％，水力停留时间为9h，其中厌氧3h，好氧6h，进水COD负荷从0．27kg/(m^3.d)到1．32kg/(m^3.d)均可使除磷率达90％以上，脱氮率达50％－60％。淹没式生物膜法除磷脱氮工艺中的优势菌属为假单胞菌属，其次依顺序为气单胞菌属，芽孢杆菌属，微球菌属，硝化矸菌属，生物膜具有生物量大（MLVSS达5531．7mg/L)，脱落污泥含磷量高（达5．67％），沉降性好（SVI为101．7）的特点，污泥产率为0．1996kg干泥／kgCOD。     

Characteristics of the stabilized/solidified municipal solid wastes incineration fly ash and the leaching behavior of Cr and Pb

Fly ash is a hazardous byproduct of municipal solid wastes incineration (MSWI). An alkali activated blast furnace slag-based cementitious material was used to stabilize/solidify the fly ash at experimental level. The characteristics of the stabilized/solidified fly ash, including metal leachability, mineralogical characteristics and the distributions of metals in matrices, were tested by toxic characteristic leaching procedure (TCLP), X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) respectively. Continuous acid extraction was utilized to extract metal ions and characterize their leaching behavior. The stabilization/solidification procedure for MSWI fly ash demonstrates a strong fixing capacity for the metals by the formation of C-S-H phase, hydrated calcium aluminosilicate and ettringite. The stabilized/solidified fly ash shows a dense and homogeneous microstructure. Cr is mainly solidified in hydrated calcium aluminosilicate, C-S-H and ettringite phase through physical encapsulation, precipitation, adsorption or substitution mechanisms, and Pb is mainly solidified in C-S-H phase and absorbed in the Si-O structure.     

焚烧炉飞灰熔融处理组成特性分析

将焚烧飞灰在不同温度下进行熔融实验，用扫描电镜对熔融前后试样的微观结构和形貌变化进行比较，结果显示：熔融体表观结构平整光滑，有较高的硬度，其断面有光泽产生且无明显气孔，试样已达到完全熔融；用X射线衍射分析仪对试样熔融前后成分的变化进行分析，未经熔融处理的试样主要晶相为：NaCl，KCl，SiO2，CaCO3，CaSO4，Ca2SiO4以及Ca12Al14O33，CaS和钙黄长石为熔融后试样的主要晶相．其次还有CaO和透灰石；浸出实验结果显示熔融处理后飞灰的毒性得到降解．     

Levels and patterns of polychlorinated biphenyls in residues from incineration of established source-classified MSW in China

Municipal solid waste (MSW) source-classified collection represents an advancement in resource cycling and secondary pollution control in China. Comparative experiments were performed to assess the levels and patterns of polychlorinated biphenyls in bottom ash, fly ash from boiler, and fly ash from bag filter from an MSW incineration plant with source-classified collection of MSW. Polychlorinated biphenyls were concentrated in the bag filter fly ash and in the bottom ash. The total amount of polychlorinated biphenyls was much lower than in fly ashes and bottom ash from traditional mixed waste incineration. Total concentration of coplanar polychlorinated biphenyls and toxic equivalent quantities were also reduced. Due to variations of feed waste, complete combustion, including continuously high incineration temperature, low CO concentrations and high air excess ratio were observed. Incineration temperature showed a negative correlation, while CO concentration showed a positive correlation with total and coplanar polychlorinated biphenyls, indicating that the latter can be reduced by controlling combustion conditions related to properties of feed waste.     

铝矿赤泥强化聚合氯化铝混凝除磷试验研究

对聚合氯化铝(PAC)投加赤泥前后的除磷效果及絮体进行了研究.结果表明,赤泥对PO3-4有吸附作用;投加一定量赤泥,提高了实验室模拟废水和实际污水中磷的去除率;与单用PAC相比,赤泥的加入增强了絮体的持磷性,增加了絮体的密实度,缩小了底泥的体积,强化了PAC的除磷性能.     

Practical consideration for design and optimization of the step feed process

Based on the anoxic/oxic (A/O) step feed process, a modified University of Cape Town (UCT) step feed process was developed by adding an anaerobic zone and adjusting sludge return pipeline. Performance evaluation of these two types of processes was investigated by optimizing operational parameters, such as the anaerobic/anoxic/oxic volumes, internal recycle ratios, and sludge retention times, for removal of chemical oxygen demanding (COD), nitrogen, and phosphorus. Results showed high removal efficiencies of COD of (85.0±1.7)%, ammonium of (99.7±0.2)%, total nitrogen (TN) of (85.5±1.7)%, phosphorus of (95.1±3.3)%, as well as excellent sludge settleability with average sludge volume index of (83.7±9.5) L·mg^-1 in the modified UCT process. Moreover, (61.5±6.0)% of influent COD was efficiently involved in denitrification or phosphorus release process. As much as 35.3% of TN was eliminated through simultaneous nitrification and denitrification process in aerobic zones. In addition, the presence of denitrifying phosphorus accumulating organisms (DNPAOs), accounting for approximately 39.2% of PAOs, was also greatly beneficial to the nitrogen and phosphorus removal. Consequently, the modified UCT step feed process was more attractive for the wastewater treatment plant, because it had extremely competitive advantages such as higher nutrient removal efficiencies, lower energy and dosages consumption, excellent settling sludge and operational assurance.     

Acidogenic sludge fermentation to recover soluble organics as the carbon source for denitrification in wastewater treatment: Comparison of sludge types

For biological nitrogen (N) removal from wastewater, a sufficient organic carbon source is requested for denitrification. However, the organic carbon/nitrogen ratio in municipal wastewater is becoming lower in recent years, which increases the demand for the addition of external organic carbon, e.g. methanol, in wastewater treatment. The volatile fatty acids (VFAs) produced by acidogenic fermentation of sewage sludge can be an attractive alternative for methanol. Chemically enhanced primary sedimentation (CEPS) is an effective process that applies chemical coagulants to enhance the removal of organic pollutants and phosphorus from wastewater by sedimentation. In terms of the chemical and biological characteristics, the CEPS sludge is considerably different from the conventional primary and secondary sludge. In the present study, FeCl₃ and PACl (polyaluminum chloride) were used as the coagulants for CEPS treatment of raw sewage. The derived CEPS sludge (Fe-sludge and Al-sludge) was then processed with mesophilic acidogenic fermentation to hydrolyse the solid organics and produce VFAs for organic carbon recovery, and the sludge acidogenesis efficiency was compared with that of the conventional primary sludge and secondary sludge. The results showed that the Fe-sludge exhibited the highest hydrolysis and acidogenesis efficiency, while the Al-sludge and secondary sludge had lower hydrolysis efficiency than that of primary sludge. Utilizing the Fe-sludge fermentation liquid as the carbon source for denitrification, more than 99% of nitrate removal was achieved in the main-stream wastewater treatment without any external carbon addition, instead of 35% obtained from the conventional process of primary sedimentation followed by the oxic/anoxic (O/A) treatment.

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