溶解氧对长距离输水管道水质影响

为保证长距离输水管道输送水水质,采用管道模拟反应器考察了溶解氧（DO）对输水管道水质影响以及曝气充氧后水质恢复情况。结果表明：DO降低影响氨氮（NH₄⁺-N）的去除,DO浓度越低越不利于NH₄⁺-N的去除,且曝气充氧后恢复越缓慢,DO=0.5 mg·L^-1和DO=1.5 mg·L^-1的反应器在运行95 h后,NH₄⁺-N去除率分别由90%降到21%和85%,曝气充氧54 h和3 h后恢复;DO浓度降低导致亚硝酸氮（NO₂^--N）积累明显增加,DO浓度越低,NO₂^--N的积累越严重,且曝气充氧后恢复越缓慢,DO=0.5 mg·L^-1的反应器在运行95 h后,出水NO₂^--N由0.02 mg·L^-1增加到0.354 mg·L^-1,曝气充氧54 h后恢复,DO=1.5 mg·L^-1的反应器在运行32 h后,出水NO₂^--N达到最大值0.112 mg·L^-1,曝气充氧4 h后恢复;DO浓度降低使水中UV₂₅₄升高,DO=0.5 mg·L^-1和DO=1.5 mg·L^-1的反应器在运行2 h后,出水UV₂₅₄分别增加了70.8%和20.8%,均在运行32 h后恢复,且曝气充氧后保持稳定。因此,DO对长距离输水管道水质具有重要影响,可采用DO实现对水质的调控。     

双膜耦合系统（MBR-MBfR）处理低碳氮比污水实验研究

为解决实际低碳氮比废水高效脱氮问题，以MBR-MBfR双膜耦合系统为研究对象，探究不同C/N双膜系统的脱氮效果。结果表明，当C/N=2时，其对NO₃^--N、NH₄⁺-N、TN及COD的协同去除效果最好，COD、NO₃^--N、NO₂^--N、NH₄⁺-N、TN的去除率分别达到79.16%、78.40%、88.41%、77.04%和77.31%，是适合MBR-MBfR双膜耦合系统的最佳碳氮比。用于处理实际废水经过20 d的运行，结果表明，COD、NO₃^--N、NH₄⁺-N、TN去除率分别达到75.88%、80.02%、76.42%和80.92%。达到较好的双膜耦合效果，为反应器高效脱氮以及去除含有有机碳的低C/N废水提供参考和技术支持。高通量测序结果表明：1)作为氨氧化菌(AOB)的亚硝基...     

曝气量对移动床生物膜反应器中微生物硝化活性的影响

移动床生物膜反应器(Moving Bed Biofilm Reactor,MBBR)兼具活性污泥和生物膜两者的优点,硝化和反硝化能同步进行。为研究曝气量对MBBR运行效果的影响,分别设置曝气量为0.3 L/min、0.4 L/min和0.5 L/min,培养5 d后测定反应器中NH₄⁺-N、NO₂^--N、NO₃^--N浓度变化,分析不同曝气量下反应器生物膜中微生物的硝化活性差异。结果表明,在COD浓度为350 mg/L、NH₄⁺-N浓度为45 mg/L时,曝气量为0.4 L/min的微生物硝化活性最佳,结果为以后高效运行MBBR提供依据。     

人工快渗系统短程硝化反硝化的协同启动及脱氮性能

为提高人工快渗(CRI)系统的脱氮性能,构建了好氧(O)/缺氧(A)两段式CRI系统处理模拟生活污水,采用NaCl-pH协同调控的方式启动短程硝化反硝化,考察了其对NH₄⁺-N、TN去除的强化效果。结果表明,进水中投加质量浓度为6 000 mg/L的NaCl运行13 d后,O-CRI反应柱的NO₂^--N积累率可达到71.7%,此时提高进水pH至8.8,NO₂^--N积累率可增高至95.5%,NaCl-pH协同调控可成功启动短程硝化。O/A-CRI系统稳定运行期间NH₄⁺-N、TN去除率均值分别达到97.6%、87.5%,比对照组分别提高了2.9、41.3个百分点。O-CRI反应柱内的脱氮功能菌以氨氧化菌(AOB)为主,其中相对丰度较高的菌属为Nitrosomonas、Nitrosospira,而以Nitrospira为代表的亚硝酸盐氧化菌(NOB)的活性由于被选择性抑制而致使其相对丰度大幅减小,从而保障了NO     

铝基MOF负载纳米零价铁去除硝酸盐的研究

采用液相还原法制得的纳米零价铁(nZVI),负载于铝基金属有机框架上制成复合材料(nZVI@Al-MOF),用于去除水中的NO₃^--N。考察初始pH、nZVI@Al-MOF投加量、温度和共存离子等因素对去除NO₃^--N的影响。结果表明,在pH为3.0～11.0的研究范围内,nZVI@Al-MOF去除NO₃^--N几乎不受pH的影响。NO₃^--N初始质量浓度20 mg/L、温度298 K,nZVI@Al-MOF投加量2.0 g/L时,反应180 min,初始pH为3.0、5.0、7.0、9.0、11.0时,NO₃^--N去除率分别可达96.8%、97.1%、97.8%、99.8%、98.1%,几乎所有的NO₃^--N被还原为NH₄⁺-N,去除效果极佳且表现稳定。伪二级吸附动力学模型极好描述了...     

外源磷缺乏对厌氧氨氧化脱氮效能影响

通过批次实验和UASB反应的连续实验考察了在不同缺乏外源磷的程度时,厌氧氨氧化颗粒污泥对基质氮的去除情况以及出水磷含量的变化。结果表明,批次实验中,PO₄^3--P的质量浓度在2.3~0 mg/L对厌氧氨氧化颗粒污泥的脱氮效能没有明显的消极影响,而当PO₄^3--P的质量浓度为1.0 mg/L时基质去除率93.160%比进水PO₄^3--P的质量浓度2.3 mg/L的实验组的高3.93百分点。在连续实验中,外源PO₄^3--P的质量浓度在2.3~0 mg/L时,对NH(4)⁺-N和NO₂^--N的去除没有消极影响,NH(4)⁺-N和NO₂^--N去除率始终保持在99.68%和99.69%左右;当进水PO₄^3--P的质量浓度为0时,出水NO₃^--N含量稍有减少,PO₄^3--P的质量浓度约为0.222 mg/L。     

生物脱氮新工艺研究进展

厌氧氨氧化技术利用NO₂^--N氧化NH₄⁺-N来实现污水中氮素的高效去除,其中NO₂^-N的产生是实现厌氧氨氧化应用的难点,而短程硝化是获取NO₂^-N的重要途径之一。针对目前在实际工程中通过短程硝化难以实现长期稳定的亚硝酸盐累积的问题,介绍了厌氧氨氧化、短程反硝化工艺影响因素及工程应用的研究进展;分析了短程反硝化工艺累积NO₂^-N的过程,从而去除污水中的氮素污染物。对短程反硝化与厌氧氨氧化工艺耦合方式在处理实际废水时的可行性与应用前景进行展望。     

改性纳米零价铁去除地下水硝酸盐的研究

采用提纯凹凸棒土(ATP)负载纳米零价铁(nZVI)制备得到改性材料ATP-nZVI,将其用于对地下水硝酸盐的去除研究。通过静水实验考察了溶液中共存阴离子和反应温度对ATP-nZVI去除NO₃^--N的影响,通过模拟可渗透反应墙(PRB)考察了溶液初始pH、初始NO₃^--N浓度、材料装填方式、流速对ATP-nZVI去除NO₃^--N的影响,并通过更换PRB装填材料将ATP-nZVI与石英砂、ATP、铁粉、nZVI等材料对NO₃^--N的去除效果进行了比较。结果表明：共存阴离子对ATP-nZVI去除NO₃^--N具有抑制作用,其抑制作用的顺序为PO₄^3->CO₃^2->SO₄^2->Cl^-;ATP-nZVI对NO<...     

Co3O4-钛基纳米电极去除工业废水中硝酸盐的研究

工业废水中过量的硝酸盐(NO₃^-)可导致严重的环境污染和人类健康问题,通过电化学还原法去除工业废水中的NO₃^-具有重要意义。采用阳极氧化和溶胶-凝胶两步法制备了Co₃O₄-钛基纳米电极(Co₃O₄-TNE),并研究了其电化学还原NO₃^-的性能。结果表明,Co₃O₄的负载有利于暴露更多的反应活性位点,Co₃O₄-TNE电极比TNE表现出更强的电化学活性和更高的NO₃^--N去除率。电流密度的增加有利于提高NO₃^--N去除率,Cl^-浓度的增加有利于降低NH₄⁺-N生成率且对NO₃^--N去除率几乎...     

包埋型单宁酸铁制备及吸附催化脱氮性能研究

单宁酸铁(TA-Fe)具有吸附催化脱氮性能,包埋型TA-Fe可解决其固液分离问题。采用海藻酸钠(SA)制备包埋型SA/TA-Fe,并对其特性进行表征,同时评价SA/TA-Fe的吸附催化脱氮性能,以及制备条件对SA/TA-Fe的吸附催化脱氮性能的影响。结果表明,SA/TA-Fe具有明显孔隙结构且TA-Fe存在于孔隙表面,但比表面积明显下降。SA/TA-Fe对NH4⁺-N和NO₂^--N均具有吸附能力,但吸附能力低于TA-Fe,同时对NH4⁺-N的吸附能力大于NO₂^--N。包埋后TA-Fe对吸附NO₂^--N的影响更为显著。SA/TA-Fe对NH4⁺-N和NO₂^--N具有吸附催化能力,可同步提高NH4⁺-N和NO₂^--N的去除量。采用20 g/L的SA溶液,按照TA-Fe和SA质量比为2:1,交联时间为12 h,制得的SA/TA-Fe对NH4⁺-N和NO₂^--N的吸附催化去除效果最佳。     

一株异养硝化菌的分离鉴定及其最佳亚硝化条件

采用传统微生物分离纯化方法,从焦化废水活性污泥中筛选到一株高效去除氨氮并显著积累亚硝酸盐氮的异养硝化细菌C16.该菌株为G-,短杆状;菌落为白色、半透明.经形态、生理生化特性以及16S rRNA基因序列分析,初步鉴定该菌属于产碱杆菌属(命名为Alcaligenes sp.C16).对该菌的异养硝化功能进行了研究,结果表...     

Performance and sludge characteristics of anammox process at moderate and low temperatures

A sequencing batch reactor (SBR) was used to investigate the performance and sludge characteristics of anammox process at moderate and low temperatures. The initial pH was 7.5 and hydraulic retention time (HRT) was 3 h. When temperature was 25-35 °C, nitrogen removal rate (NRR) fluctuated from 1.67 to 1.82 kg/m³·d. However, when temperature dropped to 15 °C, NRR suddenly decreased by 0.48 kg/m³·d. Larger activation energy was acquired at lower temperature, and it was difficult to achieve efficient nitrogen removal under low temperature. When temperature declined to 10 °C, ΔNO ₂ ^? -N/ΔNH ₄ ⁺ -N and ΔNO ₃ ^? -N/ΔNH ₄ ⁺ -N reached 1.02 and 0.27, respectively. Inhibition resulting from low temperature on anammox activity was recoverable, and the modified Boltzmann model was appropriate to analyze recovery feature of anammox process. Low temperature not only led to poor nitrogen removal, but also affected sludge size and feature.     

AAO-BAF反硝化除磷系统的二次启动特性

利用厌氧/缺氧/好氧工艺与曝气生物滤池组成的双污泥强化反硝化除磷系统（AAO-BAF）处理生活污水,通过对比污染物的去除性能,分析了该系统除污染物性能的恢复情况。试验用反硝化除磷污泥在室温下放置了1个月。试验期间比较了两种启动方式,AAO反应器中厌氧、缺氧和好氧区的容积比（V_r）分别为2：5：2和2：6：1,记为1^#和2^#。试验结果表明,系统去除有机物和氨氮的性能基本没有恶化。第17 d,两种启动方式得到的TN和PO₄^3--P的去除率分别达到了约75%和92%;去除单位NO^-₃-N吸收的PO₄^3--P量也由试验初的0.5 mg PO₄^3--P·（mg NO^-₃^-N）^-1增加到了1.5 mg PO₄^3--P·（mg NO^-₃-N）^-1 左右。试验结果显示,AAO-BAF系统更适宜采用有利于除磷性能和污泥沉降性能快速恢复的方式1（1^#）进行二次启动。     

厌氧复合床处理模拟焦化废水的反硝化动力学

采用厌氧复合床(UBF)处理模拟焦化废水,进水中投加NaNO₃模拟硝化液回流,实现了同时反硝化/产甲烷,COD去除率达到94%,NO₃^--N去除率达到99%。取复合床下部污泥做反硝化动力学研究,在存在亚硝酸盐积累的情况下,以NO₃^--N+0.6NO₂^--N作为反硝化电子受体,采用双基质的Monod方程对实验数据进行拟合,拟合曲线与实验测定值相关性良好。其次,采用双基质的Monod微分方程组对NO₃^--N和NO₂^--N的浓度变化进行拟合,得到相关参数:硝态氮的最大比降解速率和半饱和常数分别为1.13 d^-1和2.0 mg·L^-1;亚硝态氮的最大比降解速率和半饱和常数分别为0.66 d^-1和2.5 mg·L^-1,基于硝态氮和亚硝态氮的有机物半饱和常数分别为90.8 mg·L^-1和96.8 mg·L^-1。     

自养脱氮工艺有机物去除段与硝化段精确分离的实现与实时控制

为了实现城市污水处理过程中的节能降耗,提出了三段式城市污水自养脱氮工艺,阐述了除有机物SBR在整套工艺中的重要地位,探讨了不同曝气量与污泥浓度条件下,除有机物SBR中有机物的去除特征与规律。结果表明,在不同的曝气量及污泥浓度条件下,COD降解结束前NO₂^--N与NO₃^--N的浓度均低于0.1 mg·L^-1,反应器进入COD难降解阶段后,NO₂^--N与NO₃^--N的浓度快速提高,可以认为在除有机物SBR内有机物的去除和硝化过程是分步进行的,即先进行有机物的去除,而后进行硝化过程。DO曲线与pH曲线的突越点与除有机物过程的终点始终保持一致,可将其作为实时控制参数监测有机物的去除终点,对好氧曝气过程进行实时控制。     

Land use impact on nitrogen discharge by stream: a case study in subtropical hilly region of China

As a crucial factor of water eutrophication, nitrogen (N) discharge by agricultural non-point sources (NPS) has become a worldwide concern, and so has its relationship to land use. This study was aimed at the quantitative relationships between N discharge by stream and land use. It was conducted in the Meicun watershed of Xuancheng County, Anhui Province, in the subtropical low hilly area of China. The study integrated dynamic monitoring of nutrient discharge by stream water and Geographic Information Systems (GIS) analysis of land use of the watershed. Results showed that NO₃⁻-N discharge ranged between 50 and 60% of the total nitrogen (T-N) and was 2.5–3.0 times as much as NH₄⁺-N. There was a significant difference between forested and mixed sub-watersheds for NH₄⁺-N, NO₃⁻-N and T-N concentrations. Significant correlations existed between NH₄⁺-N, NO₃⁻-N and T-N concentrations in stream water and the area percentages of forest and paddy fields. The study found that the discharges of NH₄⁺-N, NO₃⁻-N and T-N decreased exponentially with forest area increase, but a steep decline for NO₃⁻-N and T-N seemed to occur when the forest percentage surpassed 70% and then there was almost no change. Similarly, the discharges of NH₄⁺-N, NO₃⁻-N and T-N increased exponentially with the paddy fields increase, but a steep augmentation occurred for NO₃⁻-N and T-N when the paddy percentage surpassed 20% and then it remained at a plateau. The study showed that in the subtropical hilly region, paddy fields could increase N discharge due to farming management practices. Thus, primary measures to reduce N in the receiving water body would include a change in farming management and building an ecological interception system for paddy fields.     

CAST工艺改良对系统强化除磷性能的影响

传统CAST工艺广泛应用于国内各种规模城镇污水处理厂,单凭生物法难以达到城市污水排放一级A标准。采用改良的CAST工艺,在传统CAST工艺基础上引入主反应区独立的搅拌时序,并在实际规模的污水处理厂进行工程示范。通过两阶段的试验,逐步缩短曝气时间延长缺氧搅拌时间,优化聚磷菌的代谢环境,增强聚磷菌的竞争优势。经过改良后的CAST工艺TP去除率达到89.1%,较传统CAST工艺提高了22%,出水TP稳定达到一级A标准。静态试验结果表明改良后的工艺反硝化聚磷菌的比例有所增加, 吸收相似文献   

Evaluation of methods of measurement of nitrogen in poultry and animal manures

Kjeldahl nitrogen (N), total N and forms of inorganic N (ammoniacal (NH₄)-N, nitrate (NO₃)-N and nitrite (NO₂)-N) were measured in a range of animal manures. The manures include fresh samples of poultry manure, sheep manure, horse manure, dairy slurry and pig slurry and composted poultry manure. Kjeldahl N was measured by standard micro-Kjeldahl digestion. For total N measurements, NO₃-N and NO₂-N were recovered during Kjeldahl digestion by pretreatments with various oxidizing and reducing agents. Inorganic forms of N were measured by extraction with 2M KCl solution.Kjeldahl digestion alone allowed measurement only of organic N and NH₄-N. Amongst various modifications to the Kjeldahl, pretreatment with either acidified (H₂SO₄) Zn-CrK(SO₄)₂ or acidified (H₂SO₄) reduced Fe achieved complete recovery of NO₃-N. Nitrite N was only recovered by first oxidising the NO ₂ ^- to NO ₃ ^- with KMnO₄ followed by reduction to NH₄-N with acidified (H₂SO₄) reduced Fe.More than 95% of the total N in fresh animal manure was present as organic N and NH₄-N which were recovered by the standard Kjeldahl digestion. In the case of fresh manures there was no difference between the amount of total N measured by the Kjeldahl digestion and its modified methods. However composting of poultry manure or drying of poultry manure, pig slurry and dairy slurry resulted in an increase in NO₃-N which was not recovered during Kjeldahl digestion alone. Under these conditions the total N could be measured by pretreating the samples with KMnO₄ and reduced Fe prior to Kjeldahl digestion.Drying of animal manures caused a decrease in organic N and NH₄-N, especially in poultry, pig and dairy manures. There was a slight increase in NO₃-N; but most of the decrease in N content with drying was attributed to the volatilization loss of ammonia (NH₃). Amongst various drying methods examined air drying caused maximum loss of N as NH₃ whereas freeze drying caused minimum loss of N. This suggests that fresh animal manures can be freeze dried for analysis of N which causes minimum loss of N.     

短程硝化颗粒污泥SBR的快速启动与维持

为探究短程硝化污泥快速颗粒化的最佳条件,采用SBR反应器,在温度28℃,曝气量0.2m3.h-1,溶解氧(DO)2.0mg·mL-1,污泥龄(SRT)为15d的运行工况下,缩短沉降时间为2min,通过以pH作为氨氧化过程的控制参数,优化曝气时间,防止过曝气,经过80周期(19d)成功实现短程硝化絮状污泥的颗粒化,并维持稳定。形成的颗粒污泥粒径在1.5～2.0mm之间,对COD和氨氮的去除率分别达到80%和95%,亚硝酸盐积累率(NO2--N/NOx--N)平均达到95%。分子生物学FISH技术对颗粒污泥菌群结构的定量分析表明,AOB依旧是优势菌群,约占17.8%左右,NOB占0.6%。曝气初期FA的抑制和实时控制是启动和维持颗粒污泥短程硝化性能的主要原因。     

Achieving partial nitrification in a novel six basins alternately operating activated sludge process treating domestic wastewater

A novel technology was developed to achieve partial nitrification at moderately low DO and short HRT, which would save the aeration cost and have the capacity to treat a wide range of low-strength real wastewater. The process enables a relatively stable whereas nitrite accumulation rate (NO₂-AR) was stabilized over 94% in the last aerobic basin on average of each phase through a combination of short HRT and low DO level. Low DO did not produce sludge with poorer settleability. The morphology and internal structure of the granular sludge was observed by using a scanning electron microscope (SEM) analysis during a long-term operation. The images indicated that thick clusters of spherical cells and small rod-shaped cells (NOB and AOB are rod-shaped to spherical cells) were the dominant population structure, rather than filamentous and other bacteria under a combination of low DO and short HRT, which gives a good indication of nitrite accumulation achievement. MPN method was used to correlate AOB numbers with nutrient removal. It showed that an ammonia-oxidizing bacterium (AOB) was the dominant nitrifying bacteria, whereas high NO₂-AR was achieved at AOB number of 5.33×10⁸ cell/g MLSS. Higher pollutant removal efficiency of 86.2%, 98% and 96.1%, for TN, NH ₄ ⁺ -N, and TP, respectively, was achieved by a novel six basin activated sludge process (SBASP) at low DO level and low C/N ratio which were approximately equal to the complete nitrification-denitrification with the addition of sodium acetate (NaAc) at normal DO level of (1.5–2.5 mg/L).