间歇曝气下高浓度硝酸氮的反硝化实验研究

用甲醇、醋酸钠和消化污泥上清液作碳源 ,在序批式模式下进行高浓度硝酸盐的反硝化。实验发现 ,间歇曝气有助于提高反硝化污泥的沉降性能 ,而厌氧条件下 ,污泥的沉降性能差。污泥浓度 4～ 5 g VSS/ L下 ,3种碳源都能有效地进行反硝化。最大硝酸盐去除率为 0 .4 86 g NO3- N/ (g VSS·d)。开始阶段亚硝酸盐浓度增加 ,但用醋酸盐和消化污泥上清液作碳源 ,其浓度最终下降为零。     

可生物降解塑料与沸石载体体系对硝酸盐氮污染地下水的生物修复研究

生物反硝化是修复地下水硝酸盐氮污染的一种有效途径。为进一步确定异养反硝化碳源与载体投加量的配比,取用污水处理厂活性污泥为微生物来源,以可生物降解塑料为新型固相碳源,沸石为微生物载体,设计了9组固相碳源与载体不同配比的柱实验,旨在遴选出可生物降解塑料和沸石的最优配比。同时考察在最优配比时,不同进水硝酸盐氮浓度下的硝酸盐氮去除率、填料降解率、生物膜附着量、生物膜附着效率、反硝化效率等反应特性。结果表明,可生物降解塑料∶沸石(质量比)=2∶1为最优配比。在最优配比下,进水硝酸盐氮质量浓度为40~100mg/L时,异养反硝化对硝酸盐氮具有很好的去除效果(最终去除率均在99%以上),且能够保持较高的反硝化效率,同时载体负载微生物的性能稳定。     

高氨氮污泥脱水液短程硝化反硝化的启动及稳定

采用A/O-CSTR工艺处理高氨氮污泥脱水液。进水氨氮浓度浓度约为375 mg/L,C/N比小于1.0,反硝化碳源明显不足。A/O反应器完成短程硝化反应,CSTR定期投加初沉污泥作为碳源进行反硝化。两者联合达到总氮去除的目的。实验研究短程硝化反应的启动过程,以及CSTR出水回流对短程硝化和系统脱氮效果的影响。实验结果表明系统具有良好的硝化反硝化效果。A/O反应器亚硝酸盐积累率迅速提高并稳定在90%以上。CSTR有效利用初沉污泥实现了稳定的反硝化。出水回流有利于提高总氮去除率,在回流比为200%时,系统平均总氮去除率达到85%以上。     

不同碳源和泥龄对反硝化聚磷的影响

在4个SBR装置(1#~4#)中,对4种不同比例的丙酸/乙酸合成废水采用厌氧/缺氧方式驯化富集反硝化聚磷菌(DPB),研究了碳源浓度和污泥龄对除磷的影响。实验结果表明:(1)厌氧段碳源COD浓度越高,释磷越充分,溶解性正磷酸盐(SOP)去除率越高;但当碳源COD浓度超过某个浓度值时,未反应完全的有机物残留于后续缺氧段对缺氧吸磷产生抑制作用。(2)污泥龄SRT=15 d时,活性污泥的性能较好,达到了较好的除磷效果。(3)在相同碳源浓度和相同的污泥龄下,随着丙酸/乙酸比例的提高,SOP的去除率逐渐的降低。说明在厌氧/缺氧环境下,碳源中丙酸比例的提高不利于系统中磷的去除。高乙酸含量的碳源更适合反硝化除磷系统。     

以吡啶、喹啉和吲哚为单一碳源时反硝化过程中亚硝酸盐积累及动力学研究

以吡啶、喹啉和吲哚为单一碳源,通过摇床实验进行反硝化过程动力学研究。实验结果表明,以吡啶和喹啉为单一碳源的反硝化过程中,NO-2-N的积累率分别达到了53.4%和16.4%;以吲哚为单一碳源的反硝化过程中,NO-2-N的积累现象不明显,最高不超过4%。以NO-3-N+0.6 NO-2-N作为反硝化电子受体,采用基于Monod方程的动态模型进行拟合,拟合曲线与实验测定值相关性良好。其次,采用基于Monod方程的微分方程组模型,也能够很好地拟合3种碳源条件下反硝化过程硝酸盐、亚硝酸盐质量浓度的变化,得到相应的动力学参数。     

硝酸盐反硝化颗粒污泥的快速培养与理化特性

以甲醇为碳源,在USB反应器内接种活性污泥,50 d内培养出优质的反硝化颗粒污泥。颗粒污泥的形成历经3个阶段:启动运行期,颗粒污泥出现期以及颗粒污泥成熟期。颗粒污泥床底层反硝化效率最高可达总量的78%,中部颗粒污泥湿密度与沉降速率较大,分别为1.077 g/m L和194 m/h。成熟的颗粒污泥具有湿密度大,沉降速率高等特点,颗粒表面丝状体互相缠绕,有明显的孔隙结构。     

反硝化聚磷过程影响因素及数学模型研究

反硝化聚磷过程是反硝化除磷工艺的核心过程。采用静态实验的方法研究了比污泥厌氧释磷量、污泥浓度、硝酸盐浓度几个重要参数对反硝化聚磷过程的影响,实验污泥来自实验室双泥系统。研究表明,比污泥厌氧释磷量对反硝化聚磷过程有显著影响,在电子受体充足的情况下,比污泥反硝化聚磷速率及聚磷潜能随比污泥厌氧释磷量的提高而增加,但比污泥厌氧...     

广玉兰叶用于生活污水的反硝化处理

目前,固体碳源常被用于低碳氮比地表水和地下水的修复研究,关于生活污水的应用较少。研究首先选用广玉兰、梧桐和香樟3种落叶作为反硝化外加碳源,分析了3种落叶的释碳性能和动力学,筛选出广玉兰叶,考察温度和固液比对其反硝化过程的影响,并最终将广玉兰叶作为外加碳源投入生活污水中,考察其在实际废水中的反硝化效能。结果表明:Logistic模型能更好地模拟落叶的释碳过程;温度和固液比都会影响到落叶的反硝化效能,实验过程中3组温度系统的硝酸盐去除负荷为30℃最优,不同固液比条件下,单位质量落叶硝酸盐去除负荷最大为208.49 mg·g~(-1),对应的固液比为1∶250,表明落叶的投加量并非越多越好;落叶投加到生活污水反硝化实验结果显示,当污水中可快速利用碳源消耗殆尽,落叶溶出的碳源能快速弥补反硝化碳源的不足,维持较高的反硝化率。     

可降解餐盒去除地下水硝酸盐的砂槽模拟实验研究

采用室内砂槽实验装置,研究了以可降解餐盒(BMB)为反硝化碳源的生物反应器对于模拟污水中硝酸盐的去除效果及其影响因素。结果表明,以BMB为反硝化碳源的反应器启动时间短。当进水硝酸盐浓度为50 mg/L,水温为25℃,水力停留时间为1.15 d时,硝酸盐的去除率可达92.6%以上,实验过程中出现亚硝酸盐积累,出水TOC浓度上升,但反应稳定后亚硝酸盐浓度均低于0.1 mg/L,且TOC浓度有下降趋势;水力停留时间减小或者进水硝酸盐浓度增加均能使得脱氮效率降低,但当水力停留时间在0.57~1.15 d,进水硝酸盐浓度在50~80 mg/L范围变化时,反应器硝酸盐去除效率仍能达到80%以上;温度对反硝化作用影响较大,当温度为(20±1)℃时,硝酸盐的去除效率仅为62.0%、74.4%和97.5%。     

以聚己内酯作为生物反硝化固体碳源的研究

为解决水体因低碳氮比而导致脱氮效率差的问题,将颗粒聚己内酯(PCL)重新塑形为阶梯环状,研究其作为反硝化过程的生物膜载体与固相碳源的反硝化性能。结果表明,在静态实验中,平均反硝化速率为8.57 mg NO3-N/(L·h);反硝化过程为零级反应。连续填充床实验中,超过90%的硝酸盐可被去除,出水NO2-N质量浓度低于0.20 mg/L;出水NH3-N质量浓度略有上升;出水溶解性有机碳(DOC)先上升后降低至1 mg/L左右。电子扫描显微镜扫描显示,PCL阶梯环反应表面空隙率较高,表面生物膜以杆菌为主,反应后被明显腐蚀;液相色谱检测显示PCL阶梯环分子量反应前后略有下降,其结构未受到破坏;表明该材料适合作为反硝化反应的碳源的同时,又可以作为载体供微生物附着生长。     

The use of naturally generated volatile fatty acids for herbicide removal via denitrification

This research focuses on the removal of 2, 4-D via denitrification, with a particular emphasis on the effect of adding naturally generated volatile fatty acids (VFAs) as a carbon source. These VFAs had been produced from an acid-phase anaerobic digester (mean VFA concentration of 3153 ± 801 mg/L [as acetic acid]). The first step involved developing 2, 4-D degrading bacteria in a sequencing batch reactor (SBR) fed with both sewage and 2, 4-D (30–100 mg/L). Subsequent denitrification batch tests demonstrated that the specific denitrification rate increased from 0.0119 ± 0.0039 to 0.0192 ± 0.0079 g NO₃-N/g volatile suspended solids (VSS) per day, when using 2, 4-D alone versus 2, 4-D plus natural VFAs from the digester as a carbon source. Similarly, the specific 2, 4-D consumption rate increased from 0.0016 ± 0.0009 to 0.0055 ± 0.0021 g 2,4-D/g VSS per day, when using 2, 4-D alone as compared to using 2, 4-D plus natural VFAs. Finally, a parallel increase in the percent 2, 4-D removal was observed, rising from 28.33 ± 11.88 using 2, 4-D alone to 54.17 ± 21.89 using 2, 4-D plus natural VFAs.     

Kinetics of chemoheterotrophic microbially mediated reduction of ferric EDTA and the nitrosyl adduct of ferrous EDTA for the treatment and regeneration of spent nitric oxide scrubber liquor.

Biomass from a prototype reactor was used to investigate the kinetics of chemoheterotrophic reduction of solutions of ferric ethylenediaminetetraacetic acid (EDTA) and solutions containing the nitrosyl adduct of ferrous EDTA using ethanol as the primary electron donor and carbon source. A series of batch experiments were conducted using biomass extracted from the scrubber solution treatment and regeneration stage of a prototype iron EDTA-based unit process for the absorption of nitric oxide with subsequent biological treatment. Using a linear-sweep voltammetric method for analysis of the ferric EDTA concentration, iron-reducing bacteria were found to behave according to the Monod kinetic model, at initial concentrations up to 2.16 g chemical oxygen demand (COD) as ethanol per liter, with a half-velocity constant of 0.532 g COD as ethanol/L and a maximum specific utilization rate of 0.127 mol/L of ferric ethylenediamine-tetraacetic acid [Fe(III)EDTA]*(g volatile suspended solids [VSS]/L)d(-1). Based on batch analyses, biomass yield and endogenous decay values of iron-reducing bacteria were estimated to be 0.055 g VSS/g COD and 0.017 L/d, respectively. An average of 1.64 times the theoretical (stoichiometric) demand of ethanol was used to complete reduction reactions. Kinetics of the reduction of the nitrosyl adduct of ferrous EDTA are summarized by the following kinetic constants: half-velocity constant (Ks) of 0.39 g COD/L, maximum specific utilization rate (k) of 0.2 mol/L [NO x Fe(II)EDTA(2-)](g VSS/L)d(-1), and inhibition constant (K(I)) of 0.33 g COD/L, as applied to the modified Monod kinetic expression described herein. Based on batch analyses, the biomass yield of nitrosyl-adduct-reducing bacteria was estimated to be 0.259 g VSS/g COD, endogenous decay was experimentally determined to be 0.0569 L/d, and an average of 1.26 times the stoichiometric demand of ethanol was used to complete reduction reactions.     

Estimation of the intrinsic maximum substrate utilization rate using batch reactors with denitrifying biofilm: a proposed methodology.

A method for estimation of the maximum substrate utilization rate (q(max)) using batch reactors with denitrification biofilm was introduced and compared with the traditional method of using batch reactors with suspended growth for q(max) estimation. The values of q(max) obtained from the suspended-growth reactors (0.69 to 0.71 g N/g volatile suspended solids [VSS] x d) and from the attached-biomass reactors (0.74 to 0.85 g N/g VSS x d) are similar and within the range of the values reported in the literature (0.23 to 2.88 g N/g VSS x d). Therefore, the intrinsic kinetic parameter, q(max), can be obtained using attached-growth batch reactors, if the effectiveness factor, eta, is approximately equal to 1 and the bulk concentration of the rate-limiting substrate, C, is much higher than the half-velocity constant, K(S). The attached-growth batch reactor method is unique, because the biomass used in the batch tests is the same as that present in the parent reactor under investigation.     

厌氧序批式反应器中丝状颗粒污泥的形成

以葡萄糖为基质,研究浮动盖式ASBR中颗粒污泥的形成。实验结果表明,污泥在120 d时完全颗粒化,颗粒污泥具有良好的沉降性能(25 m/h)及良好的产甲烷活性,甲酸、乙酸、丙酸及丁酸最大代谢活性分别达到0.216、0.825、0.237和0.796 g COD/(g VSS.d)。电镜扫描(SEM)发现,整个污泥结构均一,均由丝状菌构成。     

反硝化除磷的影响特性试验

采用SBR反应器(厌氧/缺氧/好氧工艺),分别研究了乙酸盐及硝酸盐浓度变化对反硝化除磷的影响特性。试验结果表明,当进水COD浓度>230mg/L时,乙酸盐浓度的变化对释磷、除磷速率等影响并不显著。在硝酸盐浓度<30mg/L时,硝酸盐浓度越高,缺氧段除磷速率也就越高。在C/P>23,C/N>5条件下,SBR系统对磷、氮去除率在90%以上。     

碳源对含盐废水短程硝化反硝化的影响

分别采用醋酸钠、甘油、乙醇和葡萄糖作为外加碳源,研究不同碳源对含盐废水短程硝化反硝化的影响.结果表明:(1)利用醋酸钠作为碳源,逐步增加NaCl盐度可以实现短程硝化反硝化,TN平均去除率高于95％.当NaCl盐度为14.2 g/L时,采用醋酸钠、甘油、乙醇和葡萄糖作为碳源时,NO2- -N的累积率分别为98.7％、86...     

碱预处理污泥产酸效果及其生物群落研究

为了提高污泥水解酸化过程中的挥发酸产量,获取污水脱氮除磷所需的内碳源,以深圳市罗芳污水厂的二沉池污泥为研究对象,采用不同的碱量对其进行预处理。通过测定碱预处理污泥水解酸化过程中的挥发酸浓度,并采用聚合酶链式反应-变性梯度凝胶电泳(polymerase chain reaction denature gradient gel electrophoresis,PCR-DGGE)技术对参与碱预处理污泥水解酸化产酸过程的主要微生物种群进行分析,结果表明,当碱投加量为0.20 g NaOH/g VSS时,初始溶出的蛋白浓度为1 780 mg/L;水解酸化15 d时,挥发酸总量达到3 473 mg/L;参与产酸的主要细菌属于Firmicutes、Proteobacteria、Bacteroidetes三个门类。     

序批式反应器用于牛场污水的处理

对序批式反应器 (SBR)用于牛场污水的处理进行了试验研究 ,主要研究了三个水力停留时间 (HRT)和有机负荷率对污染物去除率、出水水质和污泥特性的影响。试验结果表明 ,对 10 0 0 0mg/LCOD牛场污水 ,使用 1dHRT ,相应有机负荷率为 10gCOD/L·d时 ,混合出水COD、TS、VS、TKN和TN的去除率分别为 45 %、2 1.4%、34 .2 %、5 3.2 %和 2 2 .2 % ,上清液出水的分别为 80 .2 %、6 3.4%、6 6 .2 %、75 %和 38.3% ;两种出水的SCOD和NH3 N去除率相同 ,分别为 5 0 .0 %和 76 .5 %。经SBR处理后 ,污泥的沉降浓缩性能也有了比较明显的改善。     

酸碱调控及底物浓度对木糖发酵产酸特性的影响

以木糖为碳源采用间歇培养方式,对木糖厌氧发酵产酸进行研究。考察木糖浓度和初始pH值对木糖厌氧产酸的影响。结果表明,随着木糖浓度的增加,总产酸量得到提高,但木糖利用率却呈现下降的趋势。当木糖浓度为5 g/L时,其利用率为100%,15 g/L时利用率为73.9%,此时挥发性脂肪酸(VFAs)为9.22 g/L。木糖的分批投加可有效促进产酸,尤其是促进乙酸浓度的提高。pH为5.0和6.0左右时,VFAs主要成分为乙酸和丁酸;而pH为7.0～9.0时,乙酸含量明显增高,在pH值为8.0的条件下乙酸含量占总VFAs的80.1%。在pH=8.0时经过8 d左右的发酵,VFAs浓度可达9.34 g/L。     

Removal of arsenic from groundwater by micellar-enhanced ultrafiltration (MEUF)

The removal characteristics of arsenate using micellar-enhanced ultrafiltration (MEUF) were investigated. Among four different cationic surfactants used, hexadecylpyridinium chloride (CPC) showed the highest removal efficiency of arsenic (96%), and the removal efficiency with hexadecyltrimethylammonium bromide (CTAB) was 94%. But the removal efficiency with benzalkonium chloride (BC) was the lowest (57%) due to higher critical micelle concentration (CMC) of BC than those of other surfactants. Over 80% of arsenic was removed with octadecylamine acetate (ODA). On the effect of solution pH on the arsenic removal, since the valance of arsenate decreases from trivalent to monovalent as pH decreases, the removal was reduced at lower pH. The presence of 0.45mM of nitrate and 0.01mM of phosphate reduced the removal efficiency by 5-8%. This decrease was because of the competition between the arsenate, nitrate and phosphate for the binding sites of the surfactant micelle. Similar decrease in the removal of arsenate was observed with CPC, CTAB and ODA in the presence of these anions. In cross-flow filtration, the removal efficiency of arsenic was similar to that in the dead-end system. However, the decline in flux was less than that in dead-end filtration. In order to lower the concentration of the surfactant in the effluent, the effluent was treated with powdered activated carbon (PAC) before discharging to the environment. Over 98% surfactant was removed with 1gl(-1) of PAC. In conclusions, the MEUF is considered as a feasible process using CPC or CTAB to remove the arsenate from groundwater compared with the other solid based adsorbent processes.