旋转填料床中硝酸吸收NO_x的实验研究(英文)

Absorption of NOx into nitric acid solutions was studied in the presence of ozone by using a rotating packed bed (RPB) contactor. The influences of operating parameters, such as high gravity number, amount of ozone, gas velocity, liquid spray density and inlet concentration of NOx, on the removal efficiency of NOx were investigated, among which the high gravity number and ozone amount are more important. Ozone was introduced to oxidize HNO2 to HNO3 to prevent the decomposition of HNO2 in the liquid phase. The high gravity number presents the effective external force for enhancing the mass transfer of ozone from gas phase to liquid phase. Under the experimental condition, the removal efficiency of NOx is higher than 90% and the concentration of nitric acid product exceeds 45%.     

旋转填充床内高黏介质脱除有机挥发组分过程强化

The removal of a volatile organic compound (VOC) from high viscous liquid was carried out in a rotating packed bed (RPB) in this study. The mixed liquid of syrup and acetone was used as simulated high viscous polymer solution with acetone as the volatile compound. The influence of the rotating speed of RPB, liquid viscosity, liquid flow rate, vacuum degree, and initial acetone content in the liquid on acetone removal efficiency was investigated. The experimental results indicated that the removal efficiency increased with increasing rotating speed and initial acetone content in the viscous liquid and decreased with increasing liquid viscosity and flow rate. It was also observed that acetone removal efficiency increased with an increasing vacuum degree and reached 58% at a vacuum degree of 0.1 MPa. By the comparison with a flash tank devolatilizer, it was found that acetone removal ef-ficiency in RPB increased by about 67%.     

耦合内置缺氧区的氧化沟系统强化脱氮除磷的研究(英文)

A novel modified pilot scale anaerobic oxidation ditch with additional internal anoxic zones was operated experimentally, aiming to study the improvement of biological nitrogen and phosphorus removal and the effect of enhanced denitrifying phosphorus removal in the process. Under all experimental conditions, the anaerobic-oxidation ditch with additional internal anoxic zones and an internal recycle ratio of 200% had the highest nutrient removal efficiency. The effluent NH4+-N, total nitrogen (TN), PO43-P and total phosphorus (TP) contents were 1.2mg·L-1 , 13mg·L-1, 0.3mg·L-1 and 0.4mg·L-1, respectively, all met the discharge standards in China. The TN and TP removal efficiencies were remarkably improved from 37% and 50% to 65% and 88% with the presence of additional internal anoxic zones and internal recycle ratio of 200%. The results indicated that additional internal anoxic zones can optimize the utilization of available carbon source from the anaerobic outflow for denitrification. It was also found that phosphorus removal via the denitrification process was stimulated in the additional internal anoxic zones, which was beneficial for biological nitrogen and phosphorus removal when treating wastewater with a limited carbon source. However, an excess internal recycle would cause nitrite to accumulate in the system. This seems to be harmful to biological phosphorus removal.     

剩余活性污泥碱性发酵液用于厌氧交替好氧-缺氧序批式反应器生物除磷脱氮的碳源的研究(英文)

Activated sludge process has been widely used to remove phosphorus and nitrogen from wastewater. However, the nitrogen and phosphorus removal is sometimes unsatisfactory due to the low influent COD. Another problem with the activated sludge process is that large amount of waste activated sludge is produced, which needs further treatment. In this study, the waste activated sludge alkaline fermentation liquid was used as the main carbon source for phosphorus and nitrogen removal under anaerobic followed by alternating aerobic-anoxic conditions, and the results were compared with those using acetic acid as the carbon source. The use of alkaline fermentation liquid not only affected the transformations of phosphorus, nitrogen, intracellular polyhydroxyalkanoates and glycogen, but also led to higher removal efficiencies for phosphorus and nitrogen compared with acetic acid. It was observed that ammonium was completely removed with either alkaline fermentation liquid or acetic acid as the carbon source. However, the former resulted in higher removal efficiencies for phosphorus (95%) and nitrogen (82%), while the latter showed lower ones (87% and 74%, respectively). The presence of a large amount of propionic acid in the alkaline fermentation liquid was one possible reason for its higher phosphorus removal efficiency. Exogenous instead of endogenous denitrification was the main pathway for nitrogen removal with the alkaline fermentation liquid as the carbon source, which was responsible for its higher nitrogen removal efficiency. It seems that the alkaline fermentation liquid can replace acetic acid as the carbon source for phosphorus and nitrogen removal in anaerobic followed by alternating aerobic-anoxic sequencing batch reactor.     

复合生物反应器亚硝酸型同步硝化反硝化脱氮

Sequence hybrid biological reactor （SHBR） was proposed, and some key control parameters were investigated for nitrogen removal from wastewater by simultaneous nitrification and denitrification （SND） via nitrite. SND via nitrite was achieved in SHBR by controlling demand oxygen （DO） concentration. There was a programmed decrease of the DO from 2.50 mg·L^-1 to 0.30 mg·L^-1, and the average nitrite accumulation rate （NAR） was increased from 16.5% to 95.5% in 3 weeks. Subsequently, further increase in DO concentration to 1.50 mg·L^-1 did not destroy the partial nitrification to nitrite. The results showed that limited air flow rate to cause oxygen deficiency in the reactor would eventually induce only nitrification to nitrite and not further to nitrate. Nitrogen removal efficiency was increased with the increase in NAR, that is, NAR was increased from 60% to 90%, and total nitrogen removal efficiency was increased from 68% to 85%. The SHBR could tolerate high organic loading rate （OLR）, COD and ammonia-nitrogen removal efficiency were greater than 92% and 93.5%, respectively,, and it even operated under low DO concentration （0.5 mg·L^-1） and maintained high OLR （4.0 kg COD·m^-3·d^-1）. The presence of biofilm positively affected the activated sludge settling capability, and sludge volume index （SVI） of activated sludge in SHBR never hit more than 90 ml·L^-1 throughout the experiments.     

Enhanced biological nutrient removal in modified carbon source division anaerobic anoxic oxic process with return activated sludge pre-concentration☆

A pilot-scale modified carbon source division anaerobic anoxic oxic (AAO) process with pre-concentration of returned activated sludge (RAS) was proposed in this study for the enhanced biological nutrient removal (BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60%and 50%, respectively, with an inner recycling ratio of 100%under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L?1 with a removal efficiency of 63%and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.     

回流污泥预浓缩强化新型氧化沟系统生物除磷的研究(英文)

A pilot-scale,pre-anoxic-anaerobic oxidation ditch was used in this study to treat municipal wastewater with limited carbon source.A novel return activated sludge(RAS) pre-concentration tank was adopted for improv-ing the phosphorus removal efficiency and the effects of RAS pre-concentration ratio were studied.Under the opti-mal operational condition,the suspended total phosphorus(STP) and the total phosphorus(TP) removal efficiencies were around 58.9% and 63.9% respectively and the effluent-P was lower than 0.8 mg·L-1.The reason is that with the optimal RAS pre-concentration ratio,nitrate is completely removed with endogenous carbon source and the secondary phosphorus release is strictly restrained in the pre-anoxic tank.Therefore,the anaerobic phosphorus release and the carbon source uptake by phosphorus accumulation organisms(PAOs) in the sludge,which are ex-tremely important to the phosphorus removal process,can be fully satisfied.Furthermore,the oxidation-reduction potential is proved to be suitable for controlling the RAS pre-concentration ratio due to influent fluctuation and varied conditions.The novel modified system is also beneficial for PAO accumulation.     

Continuous flow removal of acid fuchsine by dielectric barrier discharge plasma water bed enhanced by activated carbon adsorption

Continuous processes which allow for large amount of wastewater to be treated to meet drainage standards while reducing treatment time and energy consumption are urgently needed. In this study, a dielectric barrier discharge plasma water bed system was designed and then coupled with granular activated carbon (GAC) adsorption to rapidly remove acid fuchsine (AF) with high efficiency. Effects of feeding gases, treatment time and initial concentration of AF on removal efficiency were investigated. Results showed that compared to the N2 and air plasmas treatments, O2 plasma processing was most effective for AF degradation due to the strong oxidation ability of generated activated species, especially the OH radicals. The addition of GAC significantly enhanced the removal efficiency of AF in aqueous solution and shorten the required time by 50%. The effect was attributed to the ability of porous carbon to trap and concentrate the dye, increasing the time dye molecules were exposed to the plasma discharge zone, and to enhance the production of OH radicals on/in GAC to boost the degradation of dyes by plasma as well as in situ regenerate the exhausted GAC. The study offers a new opportunity for continuous effective remediation of wastewater contaminated with organic dyes using plasma technologies.     

厌氧／缺氧SBR反硝化除磷过程的研究

Removal of denitrifying phosphorus was verified in a laboratory anaerobic/anoxic sequencing batch reactor (A/A SBR). The results obtained demonstrated that the anaerobic/anoxic strategy can enrich the growth of denitrifying phosphorus removing bacteria (DPB) and take up phosphate under anoxic condition by using nitrate as the electron acceptor. The phosphorus removal efficiency was higher than 90% and the effluent phosphate concentration was lower than 1mg·L^-1 after the A/A SBR was operated in a steady-state. When the chemical oxygen demand(COD) of influent was lower than 180mg·L^-1, the more COD in the influent was, the higher efficiency of phosphorus removal could be attained under anoxic condition. However, simultaneous presence of carbon and nitrate would be detrimental to denitrifying phosphorus removal. Result of influence of sludge retention time (SRT) on denitrifying phosphorus removal suggested that the decrease of SRT caused a washout of DPB and consequently the enhanced biological phosphorus removal decreased with 8 days SRT. When the SRT was restored to 16 days, however, the efficiency of phosphorus removal was higher than 90%.     

Denitrification and Dephosphatation by Anaerobic/Anoxic Sequencing Batch Reactor

Removal of denitrifying phosphorus was verified in a laboratory anaerobic/anoxic sequencing batch reactor (A/A SBR). The results obtained demonstrated that the anaerobic/anoxic strategy can enrich the growth of denitrifying phosphorus removing bacteria (DPB) and take up phosphate under anoxic condition by using nitrate as the electron acceptor. The phosphorus removal efficiency was higher than 90% and the effluent phosphate concentration was lower than lmg·L-1 after the A/A SBR was operated in a steady-state. When the chemical oxygen demand(COD) of influent was lower than 180mg·L-1, the more COD in the influent was, the higher efficiency of phosphorus removal could be attained under anoxic condition. However, simultaneous presence of carbon and nitrate would be detrimental to denitrifying phosphorus removal. Result of influence of sludge retention time (SRT) on denitrifying phosphorus removal suggested that the decrease of SRT caused a washout of DPB and consequently the enhanced biological phosphorus     

生物过滤法处理炼油污水厂恶臭废气

为了考察生物过滤法处理炼油污水厂恶臭气体的可行性,本试验采用两个串联的填充堆肥、树皮和火山岩混合物的三段式生物过滤反应器连续处理某炼油污水厂浮选池的恶臭废气。考察了主要污染物的去除、冲击负荷影响和填料中营养物质的变化。试验结果表明：空床停留时间66 s时, 非甲烷总烃、苯、甲苯及二甲苯的进口浓度范围分别为5. 1～1081. 8、0. 1～328. 8、0. 2～91. 8、0. 2～48. 2 mg·m-3时,平均去除率分别为79. 7%、98. 9%、98. 8%、99. 6%;对废气浓度变化的适应性好;反应器的渗沥液应通过喷淋返回填料层。应用该生物过滤器能成功地去除炼油污水厂浮选池排放的恶臭废气。     

生物滤池处理微污染水效能的试验研究

以微污染江水为试验水样,通过中试考察了石英砂滤池和GAC-石英砂滤池的运行效能,探讨生物滤池处理此类水体的可行性.结果表明,生物滤池处理微污染水可获得良好的出水水质.二者对浊度有很好的去除效果;石英砂滤池对NH3-N、CODMn及UV254平均去除率分别为72.4%、19.6%及22.9%;GAC-石英砂滤池运行效果更好,平均去除率分别达84.5%、39.6%和42.5%;稳定运行期间,二者对NO-2-N的去除率接近100%,但在运行周期及应对水质突变方面,GAC-石英砂滤池的性能明显优于石英砂滤池,因此,采用GAC-石英砂滤池可以更好地提高出水水质.本研究为给水厂普通滤池改造成生物滤池的可行性和有效性提供了试验依据.     

Removal of Xylene from Waste Gases using Biotrickling Filters

Two identical laboratory‐scale biotrickling filters, filled with different ceramic materials, were operated in order to investigate the removal of xylene from a waste gas stream. The biotrickling filter columns were seeded with pure bacteria identified as Bacillus firmus, which can utilize xylene as the sole carbon and energy source. The purification performance of the biotrickling filters was examined for xylene inlet concentrations C_g ≤ 3000 mg/m³ at different gas flow rates of 0.2 m³/h, 0.6 m³/h, and 1 m³/h, which correspond to gas empty bed residence times (EBRTs) of 84.8 s, 28.3 s, and 17.0 s, respectively. Both biofilters displayed a removal efficiency of no less than 95 % with the inlet xylene less than 3000 mg/m³ at the EBRTs of 84.8 and 28.3 s. When EBRT decreased to 17.0 s, the biofilter filled with ceramic particle type 2 had a better performance. The flow rate of trickling liquid has little effect on the removal efficiencies of the two filters. In the case of uneven distribution of trickling liquid in the packing materials, the performance of the biofilter can be improved by increasing the nitrogen nutrient supplement. Biomass quantity decreases as the depth of packing material increases in both biofilters, but the biofilter filled with ceramic particle type 1 had more alive bacteria per unit mass of packing material than the other.     

曝气生物滤池处理含硝态氮废水的研究

将优选后的好氧反硝化菌用于曝气生物滤池处理含硝态氮工业废水,研究了曝气生物滤池挂膜与启动阶段的脱氮效率,并对运行参数进行优化。结果表明,系统启动16 d后,达到稳定阶段,脱氮效率达到92.3%以上,且基本无NO2--N积累,此时可认为挂膜成功;当pH为7、水力负荷低于0.671 m3.m-2.h-1、NO3--N负荷低于1.93 kg.m-3.d-1、气水体积比为8:1时,系统获得最好的脱氮效果,NO3--N的去除率最高达到96.1%,且出水中基本无NO2--N积累。     

Biofiltration of xylene emissions: bioreactor response to variations in the pollutant inlet concentration and gas flow rate

In order to remove xylene vapors from an air stream, an upflow laboratory scale biofilter was operated for a period of 2 months. The experimental study consisted of two different phases: in the first phase, the biofilter was operated at various gas flow rates and the xylene inlet concentration was maintained at 1.39 g m⁻³. In the second phase, various inlet concentrations of the contaminant were tested at a constant gas flow rate of 0.4 m³ h⁻¹ corresponding to an empty bed residence time of 150 s. The biofilter response to steep and abrupt variations in the xylene inlet concentration and gas flow rate was examined. The results obtained revealed that the removal efficiency of the biofilter regained its high values (above 96%) in less than 24 h following the change to low concentrations and gas flow rate. Temperature measurements showed that the biofilter temperature strongly depends on the intensity of the microbial activity in the filter bed. The experimental mass ratio of carbon dioxide produced to the xylene removed was equal to 2.72 indicating that the contaminant was eliminated exclusively by aerobic biodegradation. These findings suggest that a follow up of the amount of carbon dioxide produced in the filter bed can be very helpful in monitoring the performance of the biofilter. For relatively small inlet loads of xylene, the contributions of the different sections of the biofilter to the removal efficiency of the contaminant and the carbon dioxide production were unevenly balanced but became more uniformly distributed for relatively high inlet loads.     

水平潜流人工湿地沿程脱氮效率

为探讨不同水生植物砾石水平潜流人工湿地的沿程脱氮效率,选择了花叶芦竹、旱伞草、再力花、香蒲、芦苇5种挺水植物,均匀种植于长13 m、宽4.5 m的砾石水平潜流湿地,测定了不同植物湿地系统对低污染水的沿程脱氮效率。结果表明,处理两种浓度(总氮10 mg/L和20 mg/L)低污染水时,总氮和氨氮的去除率表现为芦苇>再力花、旱伞草>香蒲>花叶芦竹>未种植,硝态氮和亚硝态氮的去除率表现为花叶芦竹、香蒲、芦苇>再力花>旱伞草、未种植。处理总氮10 mg/L的低污染水时,未种植、花叶芦竹、芦苇、再力花和香蒲湿地对总氮、氨氮、硝态氮和亚硝态氮沿程去除率总体呈下降趋势,尤其是芦苇湿地在1/3段即达到了77.95%的去除效率;砾石填料潜流湿地中芦苇、香蒲的种植长度5 m左右为宜,花叶芦竹、旱伞草、再力花的种植长度9 m左右为宜。处理总氮20 mg/L的低污水时,不同植物湿地系统的总氮、氨氮、硝态氮和亚硝态氮沿程去除率基本呈现前端去除效率高,中部略有降低,后部又有所上升;芦苇、香蒲、旱伞草和再力花至少种植13 m以上,可使湿地出水达到一级A标准,芦苇为最佳选择。因此,应根据不同污染负荷下挺水植物的生长和沿程脱氮效率来设置砾石填料湿地床的规模。     

一株反硝化聚磷菌生长及脱氮除磷特性

为进一步探讨反硝化除磷机理,试验采用前期分离一株典型的反硝化聚磷菌,研究其生长及除磷脱氮特性。利用纯菌和反应器静态模拟试验考察了不同电子受体对脱氮除磷效率的影响。该反硝化聚磷菌的生长曲线比较典型,其潜伏期不足1h,对数生长期约为14h,菌株除磷过程中吸磷与硝氮去除呈良好的线性关系,对硝氮和亚硝氮两种电子受体都能利用,该菌株相对亚硝酸盐敏感性低,不同的电子受体并未对菌株除磷效果有明显的影响,吸磷率都达到60%以上。反应器静态模拟实验验证了在反应器内存在的主要优势DPB菌对两种不同电子受体都能利用,与菌株实验结果一致。     

Photo-reduction of NO by g-C3N4@foamed ceramic

G-C₃N₄ was supported on the surface of foamed ceramic, and the g-C₃N₄@foamed ceramic was packed in the photocatalytic reactor in a layered manner. Effects of urea and H₂O₂ concentration on NO conversion were investigated. Pulse experiments were carried out to investigate the change of NO conversion with time under different concentrations of H₂O₂. The contribution of each route that NO converted and the selectivities of products were calculated. Results showed that the photo-reduction of NO accounted for 2%, and the photo-oxidation of NO accounted for 14%, and the rest was absorbed by the humidifier. Products include ammonia (NH+ 4-N), nitrogen (N₂), nitrite (NO-2-N) and nitrate (NO-3-N), of which N₂ accounted for 9%.     

The treatment of waste-air containing mixed solvent using a biofilter: 1. Transient behavior of biofilter to treat waste-air containing ethanol

Transient behavior of a biofilter packed with mixed media (of granular activated carbon and compost) inoculated with a pure culture ofPseudomonas putida was observed at the height of each sampling port to treat wasteair containing ethanol. In addition, flooding effects of an excess supply of buffer solution was observed at each sampling port of the biofilter until it recovered the status prior to the flooding. Unlike previous investigations, various process conditions were applied to successive biofilter runs in order to monitor the corresponding unsteady behavior of the biofilter in this work. In early stage of biofilter run the removal efficiency of ethanol maintained almost 100%. However, it began to decrease when inlet load surpassed 100 g/m³/h consistent with maximum elimination capacity. At the end of biofilter-run removal efficiency was decreased and maintained at 40%. The results of this work were compared to those of such biofiltration studies as the work of Christen et al. from the point of view that pure cultures of microorganism were used in both works. Except for the period of flooding effect of the 2nd stage, the inlet load and removal efficiency continued at 105.5 g/m³/h and 95%, respectively, while they were 93.7 g/m³/h and 95%, respectively, according to the result of Christine et al. Removal efficiency remained at 90% for the beginning period of 3 days of the 3rd stage, and it gradually decreased to 60% for remaining 5 days of the stage with an inlet load of 158.26 g/m³/h, which may be interpreted as better than the result of Christine et al. Their result was that the removal efficiency on the inlet load of 154 g/m³/h of ethanol was continued to be 60% for 6 days of a separate biofilter run and decreased to 40% later. Thus, with similar inlet loads of ethanol, removal efficiency of this work was equivalent to or higher than that of Christine et al.     

城市生活垃圾晚期渗滤液氨氮的常温短程去除

试验用水为典型的晚期城市生活垃圾渗滤液。第一阶段试验采用“两级UASB+A/O”系统，在一级UASB中进行回流处理水反硝化，二级UASB进行产甲烷反应，A/O反应器进行NH4+-N硝化反应。第一阶段研究表明可生化有机物在一级UASB几乎全部降解，所以第二阶段试验取消第二级UASB形成“一级UASB+A/O”系统。系统的有机物去除率＝50~70％，系统出水COD＝1000~1500 mg•L-1。当运行温度为17~29℃时，实现了稳定的NO2--N累积率为90~99％的短程硝化。试验期间 NH4+-N负荷（ALR）=0.28~0.60 kgNH4+-N•m-3•d-1，NH4+-N硝化率=90~100%。当ALR <0.45 kgNH4+-N•m-3•d-1，硝化率>98％，出水NH4+-N<15mg•L-1。在进水COD/NH4+-N＝2~3时，无机氮TIN去除率＝70~80％。采用荧光原位杂交技术（FISH）对活性污泥进行检测，结果表明，A/O工艺活性污泥中的NH4+-N氧化菌（AOB）为细菌总数的4％左右，NO2--N 氧化菌（NOB）数量不足细菌总量的0.2％。