温度对ANAMMOX生物膜工艺的脱氮影响与菌群结构分析

针对厌氧氨氧化(anaerobic ammonium oxidation,ANAMMOX)工艺常低温运行问题,分别采用无纺布与改性聚氨酯泡沫塑料填料序批式生物膜反应器(sequence batch biofilm reactor,SBBR)处理含氮污水,考察了从35℃降至15℃过程的脱氮效果.结果表明,在进水氮容积负荷...     

Degradation of benzophenone in aqueous solution by Mn-Fe-K modified ceramic honeycomb-catalyzed ozonation

Comparative studies of ozonation alone, ceramic honeycomb-catalyzed and Mn-Fe-K modified ceramic honeycomb catalyzed ozonation processes have been undertaken with benzophenone as the model organic pollutant. The experimental results showed that the presence of Mn-Fe-K modified ceramic honeycombs significantly increased the removal rate of benzophenone and TOC compared with that achieved by ozonation alone or ceramic honeycomb-catalyzed ozonation. The electron paramagnetic resonance （EPR） experiments verified that higher benzophenone removal rate was attribute to more hydroxyl radicals generated in the Mn-Fe-K modified ceramic honeycomb-catalyzed ozonation. Under the conditions of this experiment, the degradation rate of all the three ozonation processes are increasing with the amount of catalyst, temperature and value of pH increased in the solution. We also investigated the effects of different process of ozone addition, the optimum conditions for preparing catalyst and influence of the Mn-Fe-K modified ceramic honeycomb after multiple-repeated use.     

改性沼渣生物质炭活化过硫酸盐降解酚类性能

通过高温热解+稀盐酸改性制备改性沼渣生物质炭(ZBC-800),研究了ZBC-800活化过硫酸盐(PS)的效能,考察了活化剂、PS投加量、初始pH值对苯酚降解效果的影响,并实际运用于含酚类焦化废水TOC去除.结果表明,ZBC-800活化PS对苯酚去除效果显著,120min去除率达到91.58%,体系中主要通过产生¹O₂的非自由基途径降解苯酚;苯酚的去除效率随着ZBC-800投加量增加而提升,但高浓度PS会起到一定的抑制;不同初始pH值(4.10、6.80、8.40、10.00)对苯酚的降解效果基本没有影响,最终去除效率范围为91.58%~93.10%;针对实际含酚焦化废水,在初始pH=3、8.94g/L ZBC-800和0.5g/L PS体系下,TOC去除率达86.09%.表明ZBC-800可高效活化PS降解苯酚,效果显著,并在实际废水中表现出较好的降解能力,具有一定的应用前景.     

Herbicide Resistant Sugar Beet – What Is the Problem?

Risk assessment studies of herbicide resistant sugarbeet have revealed no risks to human health or the environment.Indeed it appears that commercial growth of this crop mightsecure benefits such as decreased pesticide use and increasedbiodiversity. However, widespread resistance to GM crops such asherbicide resistant sugar beet still persists in Europe. It isargued that this is not just because people do not know therelevant facts. Rather it is because popular resistance to GMfood is driven in part by concerns other than the fear ofnarrowly defined risks to health and the environment. These otherconcerns include an aversion to commercial monopoly and anegative view of pesticide use in general. Herbicide resistantsugar beet may also be perceived as a ``Trojan horse,' i.e., acrop whose licensing would create a precedent and make it morelikely that other, less environmentally friendly, crops will beapproved within the current strictly technical and science-basedrisk assessment procedures. To meet these public concerns, a kindof technology assessment reflecting factors such as benefits andconsumer choice is called for.     

旋风分离器内流场的数值模拟及方法分析

基于交错网格的SIMPLE方法对切向入口旋风分离器内的流场进行了数值模拟 ,为了分析验证不同湍流模型的适用效果 ,分别选用了标准的k -ε模型、Smith修正的模型和Chen Kim修正的模型。通过对同一工况模拟结果与实验数据的比较 ,发现Smith修正的湍流模型更适合于预报像旋风分离器内这种具有返转流动的强旋流场     

桦木硫酸盐木素的改性及树脂的合成研究

本文对桦木硫酸盐木素的改性及其在酚醛树脂中的应用进行了研究。结果发现,利用单因素法对木素硫改性进行分析时,其最佳条件为：硫用量５％,碱用量４％,最高温度２６０℃,保温时间１５ｍｉｎ。改性后木素甲氧基含量由原来的１８．８１％变为１１．８４％。利用改性及未改性木素取代苯酚合成木素酚醛树脂时,当两种木素分别取代６０％的苯酚,使用桦木为单板时,基胶合强度虽然低于同样条件下酚醛树脂在胶合强度,但仍能达到国标     

Electrocatalytic reduction of nitrate using Pd-Cu modified carbon nanotube membranes

● Pd-Cu modified CNT membranes were prepared successfully by electrodeposition method. ● The deposition voltage and deposition time were optimized for Pd-Cu co-deposition. ● NO₃⁻-N was removed efficiently from water by Pd-Cu modified CNT membranes. ● The presence of dissolved oxygen did not affect the nitrate reduction performance. ● Mass transfer rate was promoted significantly with the increase in membrane flux. Excessive nitrate in water is harmful to the ecological environment and human health. Electrocatalytic reduction is a promising technology for nitrate removal. Herein, a Pd-Cu modified carbon nanotube membrane was fabricated with an electrodeposition method and used to reduce nitrate in a flow-through electrochemical reactor. The optimal potential and duration for codeposition of Pd and Cu were −0.7 V and 5 min, respectively, according to linear scan voltammetry results. The membrane obtained with a Pd:Cu ratio of 1:1 exhibited a relatively high nitrate removal efficiency and N₂ selectivity. Nitrate was almost completely reduced (~99 %) by the membrane at potentials lower than −1.2 V. However, −0.8 V was the optimal potential for nitrate reduction in terms of both nitrate removal efficiency and product selectivity. The nitrate removal efficiency was 56.2 %, and the N₂ selectivity was 23.8 % for the Pd:Cu=1:1 membrane operated at −0.8 V. Nitrate removal was enhanced under acidic conditions, while N₂ selectivity was decreased. The concentrations of Cl⁻ ions and dissolved oxygen showed little effect on nitrate reduction. The mass transfer rate constant was greatly improved by 6.6 times from 1.14 × 10⁻³ m/h at a membrane flux of 1 L/(m²·h) to 8.71 × 10⁻³ m/h at a membrane flux of 15 L/(m²·h), which resulted in a significant increase in the nitrate removal rate from 13.6 to 133.5 mg/(m²·h). These findings show that the Pd-Cu modified CNT membrane is an efficient material for nitrate reduction.     

改性铁法处理印染废水

通过对铁屑进行改性,并辅以其它活性材料构成填料塔对印染废水进行处理。结果表明改性铁法与传统的铁屑固定氏法相比较,对可溶性染料的处理效果,二者相近;对不溶性染料本法的脱色率和COD去除率比传统铁屑法提高20％～30％,基本上解决了传统铁屑法不容易处理不溶性染料的难题。综合考虑COD去除率、脱色率两方面因素,选择pH值5～6,接触时间13～15min为最佳。     

Ammonium removal by modified zeolite from municipal wastewater

Ammonium removal by modified zeolite, H-form and Na-form zeolite, were examined by batch-type methods. The adsorption of ammonium on modified zeolite was exothermic process. The saturation adsorption capacity of ammonium on H-form and Na-form zeolite were 21.23 and 41.1.5 mg/g, respectively. After ten times adsorption-desorption-readsorption cycles the standard deviations of H-form and Na-form zeolite were 6.34% and 6.59%. The zeolite adsorption process has proved cost effective and practical in reducing ammonium by H-form and Na-form zeolite in municipal wastewater from concentration 27.68 mg/L to 2.80 mg/L and 5.91 mg/L.     

交替活性污泥工艺发展类型及研究方向

交替活性污泥工艺是在一个反应器或一组反应器中通过时间或空间的交替实现对污水的处理。从最初的SBR到各种改良形式,交替活性污泥工艺在控制系统、运行方式等方面迅速发展。传统的交替工艺只能适用于中小型污水处理,CAST、MSBR、UNITANK、多箱一体化工艺等通过运行方式组合,既提高了对处理规模的适应性,又能满足除磷脱氮要求。交替活性污泥工艺今后研究的重点是工艺组合优化,提高灵活性,特别是如何在单泥交替系统中解决除磷脱氮的矛盾,同时也要注意相应配套设备的开发,降低造价,提高可靠性。