Life cycle assessment of high concentration organic wastewater treatment by catalytic wet air oxidation

There have been many studies on life cycle assessment in sewage treatment,but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology,especially in catalytic wet air oxidation(CWAO).There are no cases of using actual industrialized data onto life cycle assessment.This paper uses Simapro 9.0 software to establish a life cycle assessment model for the treatment of high-concentration organic wastewater by CWAO,and comprehensively explains the impact on the environment from three aspects:the construction phase,the operation phase and the demolition phase.In addition,sensitivity analysis and uncertainty analysis were performed.The results showed that the key factors affecting the environment were marine ecotoxicity,mineral resource consumption and global warming,the operation stage had the greatest impact on the environment,which was related to high power consumption during operation and emissions from the treatment process.Sensitivity analysis showed that electricity consumption has the greatest impact on abiotic depletion and freshwater aquatic ecotoxicity,and it also proved that global warming is mainly caused by pollutant emissions during operation phase.Monte Carlo simulations found slightly higher uncertainty for abiotic depletion and toxicity-related impact categories.

Treatment of desizing wastewater from the textile industry by wet air oxidation

This paper describes the application of wet air oxidation to the treatment of desizing wastewater from two textile companies. A two\|liter high temperature, high pressure autoclave reactor was used in the study. The range of operating temperatures examined was between 150 and 290℃, and the partial pressure of oxygen ranged from 0.375 to 2.25 MPa. Variations in pH, COD Cr and TOD content were monitored during each experiment and used to assess the extent of conversion of the process. The effects of temperature, pressure and reaction time were explored extensively. More than 90% COD Cr reduction and 80% TOC removal have been obtained. The results have also been demonstrated that WAO is a suitable pre\|treatment methods due to improvement of the BOD\-5/COD\-\{Cr\} ratio of desizing wastewater. The reaction kinetics of wet air oxidation of desizing wastewater has been proved to be two steps, a fast reaction followed by a slow reaction stage.

Kinetics of Wet Air Oxidation of Wastewater from Natural Fiber Web Desizing

This work described the application of wet air oxidation (WAO) to the treatment of desizing wastewater from natural fiber processing. A two-liter autoclave batch reactor was used for the experiments. The range of operating temperature examined was between 150 and 290℃, and partial pressure of oxygen ranged from 0.375 to 2.25 MPa standardized at 25℃. Variations in Chemical Oxygen Demand(COD) and Total Organic Carbon(TOC) were monitored during each experiment and used to assess the performance of the process. Experimental results showed that WAO can be an efficient method for the treatment of desizing wastewater. Furthermore, Catalytic Wet Air Oxidation (CWAO) was applied to reduce the reaction temperature and pressure in WAO process. A higher COD removal ratio was achieved under more mild reaction condition with the aid of CWAO. A mathematical model was also proposed to simulate the WAO process of desizing wastewater, in which three distinct kinetics steps were considered to describe the degradation of starch. The model simulations were in well agreement with the experimental data.

LPWCO method for the treatment of high concentrated organic wastewater

Based on wet air oxidation (WAO) and Fenton reagent, this paper raised a new low pressure wet catalytic oxidation (LPWCO) which requires low pressure for the treatment of highly concentrated and refractory organic wastewater. Compared with general wet air oxidation, the pressure of the treatment(0 1—0 6MPa) is only one of tens to percentage of latter (3 5—10MPa). In addition, its temperature is no more than 180℃. Compared with Fenton reagent, while H 2O 2/COD(weight ratio) is less than 1 2, the removal of COD in the treatment is over twenty percents more than Fenton's even the value of COD is more than 14000mg/L. In this paper, the effect factor of COD removal and the mechanism of this treatment were studied. The existence of synergistic effect (catalytic oxidation and carbonization) for COD removal in H 2SO 4 Fenton reagent system under the condition of applied pressure and heating (0 1—0 6MPa, 104—165℃) was verified. The best condition of this disposal are as follows: H 2O 2/COD (weight ratio)=0 2—1 0, Fe 2+ 0 6×10 -3 mol, H 2SO 4 0 5mol, COD>1×10 4mg/L, the operating pressure is 0 1—0 6MPa and temperature is 104—165℃. This method suits to dispose the high concentrated refractory wastewater, especially to the wastewater containing H 2SO 4 produced in the manufacture of pesticide, dyestuff and petrochemical works.

Catalytic wet air oxidation of phenol over RuO_2/γ-Al_2O_3 catalyst

A kind of CWAO catalyst, RuO_2/γ-Al_2O_3, was prepared by dipping Al_2O_3into the aqueous solution of RuCl_3·3H_2O. XRD, SEM and TEM were used to determine the catalyticstructure. Influences of the calcination temperature, the initial pH of the feed solution anddegradation temperature on the activity of the RuO_2/γ-Al_2O_3 catalyst were investigated and thereaction mechanism was preliminarily studied. Results showed that uniform dispersion of RuO_2crystallites was observed on the surface of the catalyst. The activity of the catalyst was higher atcalcination temperature of 300℃ for 3 h and the particle reunion occurred and some large RuO_2crystallites were abundant at high calcination temperature of 500℃ The activity of the catalyst wasbetter in the acid solution than in the alkaline solution. Increasing degradation temperature andusing the catalyst could shorten the induction periods so that the phenol and COD removal wereincreased. For RuO_2/γ-Al_2O_3 catalyst, the phenol and COD removal were respectively 98% and 80%in a temperature of 150℃, pH of 5.6 and pressure of 3 MPa after a 2 h reaction. This indicated thatRu/γ-Al_2O_3 catalyst had good activity.

Preparation and characterization of Fe_2O_3-CeO_2-TiO_2/γ-Al_2O_3 catalyst for degradation dye wastewater

In order to develop a catalyst with high activity for catalytic wet oxidation （CWO） process at room temperature and atmospheric pressure, Fe2O3-CeO2-TiO2/γ-Al2O3 catalyst was prepared by consecutive impregnation method and the prepared parameters were optimized. The structure of the catalyst was characterized by BET, XRF, SEM and XPS technologies, and the actual wastewater was used to investigate the catalytic activity of Fe2O3-CeO2-TiO2/γ-Al2O3 in CWO process. The experimental results showed that the prepared catalyst exhibited good catalytic activity when the doping amount of Ti was 1.0 wt% （the weight ratio of Ti to carriers）, and the middle product, Fe2O3-CeO2-TiO2/γ-Al2O3, was calcined in 450℃ for 2 h. The CWO experiment for treating actual dye wastewater indicated that the COD, color and TOC of actual wastewater were decreased by 62.23%, 50.12% and 41.26% in 3 h, respectively, and the ratio of BOD5/COD was increased from 0.19 to 0.30.

Degradation analysis of A^2/O combined with AgNO3 + K2FeO4 on coking wastewater

In this work, a coking wastewater was selected and a biochemical Az/O treatment device for fractional degradation was designed and employed. After each stage of the treatment, the products were analyzed through gas chromatography-mass spectroscopy （GC-MS） to determine their composition. Finally, AgNO3 ＋ K2FeO4 was used as an advanced deep catalytic oxidation treatment. It was concluded from the analysis that cyclic organics could be degraded and the chemical oxygen demand （COD） was controlled within 50 mg. L-1, in line with the target value, Meanwhile, the spectra obtained from the GC-MS were in accordance with the conclusions reached based on the COD. The research results showed that all hard-degradable organics in coking wastewater could be eliminated through the A2/O bio-membrane treatment and the advanced treatment of making use of K2FeO4 as an oxidant and Ag＋ as a catalyst, the catalytic efficiency with Ag＋ as a catalyst of K2FeO4 was very high. Ag＋ could evidently improve the oxidation capacity of K2FeO4 to wastewater in its short stability time, and this is an important innovation.

高级氧化技术强化皮革废水生化处理效果的研究

皮革废水是一类成分较为复杂,含有较多有毒、有害物质的工业废水,直接排放可能对水体和生态环境带来较为严重的危害。为了高效处理皮革废水,本文简述了皮革废水的来源和特点,介绍了三种高级氧化技术,并以实验的方式重点分析了高级氧化技术在强化皮革废水生化处理效果中的应用。

丙烯酸行业废水处理技术的研究与应用

丙烯酸行业废水是一种COD浓度高,有毒有害物质多,有机组成复杂的含盐废水。目前对该行业的废水处理主要采用热力焚烧法、湿式催化氧化法以及生化组合法等,本文对此类技术的研发与应用现状进行了简要介绍。同时评估了诸如实用超临界水氧化、树脂吸附、Fenton氧化、光电子波等其他潜在处理法最后指出了废水处理技术的发展方向和未来前景。

催化湿式氧化处理霜脲氰生产废水工艺研究

针对霜脲氰生产废水有机物浓度高、色度高、盐分高等特点,研究了以催化湿式氧化为核心的处理工艺。实验结果表明:Fe系催化剂较其他催化剂具有较好的去除效果,最佳的Fe催化剂加入量为1.5‰(质量分数);进水pH越低,COD去除率越高,确定最佳进水pH值为2.5;确定了最佳空速为1 h-1;在最佳进水及反应条件下,采用催化湿式氧化工艺连续处理霜脲氰废水,COD去除率达到80%,脱色效果十分明显。

有机硅生产废水的综合处理工艺设计

有机硅生产废水成分复杂,化学需氧量(COD)、铜离子和锌离子含量高,含盐量大,单一的处理方法难以实现达标排放。本文以某有机硅单体生产企业为例,结合有机硅生产废水的特点,从源头分质分流,分别采用混凝+气浮预处理、隔油+机械式蒸汽再压缩蒸发器(MVR)预处理、芬顿/紫外线高级氧化和生化处理,实现废水达标排放。

湿式催化氧化技术的研究与发展概况

湿式空气氧化技术是在高温、高压下处理高浓度、有毒、有害、生物难降解有机污染物的一种有效的高级氧化技术 .概述了湿式空气氧化技术的发展、机理和动力学 ,并讨论了湿式催化氧化技术中催化剂的组成、分类、特点和失活原因以及它在废水处理中的研究和应用现状 ,指出湿式催化氧化技术是较有发展前景的技术 .

有机磷农药废水湿式空气氧化预处理的研究

以o,o-二甲氧基硫代磷酰氯生产废水为代表,在2L不锈钢高压釜中研究了有机磷农药废水湿式空气氧化预处理工艺,得到了实现有机磷、有机硫去除80—90％,COD去除60％的工艺条件及其优化组合。工艺条件相当缓和,废水处理后,其可生化降解性显著提高,BOT_5/COD由0.2增至0.4—0.5。工艺条件用于处理其它几种有机磷农药废水,取得同样好的效果。

催化湿式氧化法处理氨氮废水的研究

以过渡金属氧化物 Cu O为主活性组分通过对 Mn O2 的复合和掺入电子助剂 Ce O2 的考察 ,研制出适用于催化湿式氧化法处理氨氮废水的复合催化剂 .实验结果表明 ,新制备的复合催化剂氧化活性显著提高 ,并有效地抑制铜的溶出 .通过对氧气分压、反应温度和废水 p H等工艺条件的进行考察 ,由实验结果得出催化湿式氧化法处理氨氮废水的适宜工艺条件为 2 5 5℃ ,4.2 MPa和 p H=1 0 .8,在此条件下用自制催化剂处理初始浓度为 1 0 2 3mg/L氨氮废水 ,在 1 5 0 min内 ,NH3 - N的去除率达到 98% ,经处理后的废水达到国家二级 ( 5 0 mg/L)的排放标准 .

CeO_2掺杂RuO_2/γ-Al_2O_3催化剂结构与湿式氧化降解苯酚的活性研究

采用浸渍法制备了RuO2/γ-Al2O3和RuO2-CeO2/γ-Al2O3催化剂,利用XRD,XPS和ESR分析了催化剂的结构,并研究了湿式氧化降解苯酚的活性.结果表明,两种催化剂表面RuO2均有良好的分散性,并且催化剂表面存在氧空位和化学吸附氧,CeO2的掺杂使催化剂表面氧空位和化学吸附氧数量增加.两种催化剂对湿式氧化降解苯酚具有良好的催化活性,当苯酚质量浓度为4200mg/L,在150℃和3MPa下,RuO2/γ-Al2O3催化剂湿式氧化降解苯酚反应150min后,苯酚全部被去除,RuO2-CeO2/γ-Al2O3催化剂反应60min后,苯酚的去除率为96%.

焦化废水深度处理技术综述

焦化废水是煤焦化过程产生的废水,含有高浓度的酚类、苯系物、杂环化合物、多环化合物等有机污染物,并且高盐、高氨氮,是一类难处理的工业废水。随着国家对焦化废水的管理日趋严格,传统的"预处理+生化处理"工艺很难满足排放或回用要求,因此对焦化废水的深度处理势在必行。从物化法和生化法两个方面对目前焦化废水深度处理常用技术的研究和应用情况进行了介绍,并探索性地提出了焦化废水深度处理技术未来的研究和发展方向。

催化湿式氧化处理农药废水的研究

利用担载型双金属活性组分催化剂 ,考察了反应温度、压力、进料空速和V(空气 )∶V(H2 O) (体积比 )等反应条件对催化湿式氧化处理某农药废水效果的影响。对于该种废水 ,在 4 .2MPa ,2 4 5℃ ,空速为 2 .0h-1,V(空气 )∶V(H2 O) =30 0的反应条件下 ,废水的COD去除率可达到 91.3%。经处理后废水的BOD5/COD >0 .5 ,说明其可生化性能良好。

工业废水催化湿式氧化处理的研究

采用系列贵金属-半导体氧化物催化剂,在高压釜中250℃液相条件下对焦化厂等工业废水以及由氨、吡啶等组成的模拟废水进行液相氧化试验。结果发现几种催化剂对不同污染物有不同序列的催化氧化活性,其净化作用有各自的选择性。WT-501催化剂对氨和有机污染物均有高活性,焦化废水经WT-501催化氧化处理后’COD、NH_3分別从9302mg/L和5230mg/L降至619mg/L和47mg/L,去除率高达93.2％和99％。

废水处理催化湿式氧化法及其催化剂的研究进展

湿式氧化 法是为 处理高浓 度有毒有 害废物 或废水而 发展 起来 的行 之有 效的 方法， 在国 外已得到广 泛重视 和应用。 本文介绍 了湿式氧 化法的 基本概念 ，着重 阐述 了近 来催 化湿 式氧 化法 中有关催化 剂的研 究进展和

湿式氧化法处理苯酚、苯胺和硝基苯废水的研究

采用湿式氧化法分别处理含苯酚、苯胺和硝基苯的废水,研究了反应温度(160～220℃)对氧化反应的影响。苯酚的氧化经历两步,即诱导期和快反应期,而苯胺的氧化反应无诱导期。有机污染物的反应活性与其结构和氧化反应的模式有关,在一定的时间内,3种有机污染物的氧化去除率的次序为:苯酚>苯胺>硝基苯。