TREATMENT AND RESOURSE REUSE OF INDUSTRIAL WASTEWATER FROM PRODUCTION PROCESS OF PHENYL ACETIC ACID

The effluent from phenyl acetic acid (PhCH2COOH) production process can betreated with NDA-999 macroporous polymeric adsorbent with about 100% removalefficiency of PhCH2COOK benzyl alcohol (PhCH2OH)and benzaldehyde (PhCHO) aswell as the decrease in Total Organic Carbon (TOC)from 4691mg/l to <300mg/L. 3. 7kgPhCH2COOH and 120kg NaCl will be recovered from per m3 wastewater and theadsorbent can be reused after being regenerated by NaOH aqueous solution andmethanol. Good economic, social and environmental results can be achieved with thismethod.

Advances Treatment Technologies in Chemical Industry Wastewater

The main treatment methods of chemical wastewater were reviewed.Physical,chemical,and biochemical treatment technologies effective for removing those pollutants were presented with their applicability,effectiveness and advantages.The problems facing the wastewater treatment in the petroleum chemical industry and coal chemical industry were introduced.In the end,the new progress and trend of the processes were overviewed.

Comparative study of thermophilic and mesophilic anaerobic treatment of purified terephthalic acid (PTA) wastewater

The paper provides a critical comparison between mesophilic and thermophilic anaerobic treatment of PTA wastewater through diagnosis of a case study. Aspects covered are bioavailability, biodegradability, microbial population, thermodynamics, kinetics involved and bio-reactor design for PTA wastewater treatment. The results of the case study suggests that one- stage thermophilic anaerobic reactor coupled with coagulation-flocculation pre-treatment unit and an aerobic post treatment unit could be techno-economically viable for PTA wastewater treatment to ensure that the final effluent quality conforms to the international standard. The in-formation emanated from this study could be useful and thought provoking to the professionals and academia in the area of PTA wastewater treatment and can serve as impetus toward the development of research lines in similar problems like the treatment of other petrochemical wastewater such as phenol-con- taining wastewater, benzene/benzoic acid-con- taining wastewater or wastewater from other similar industrial settings.

Membrane bioreactor process of organic wastewater from brassylic acid manufacturing plant

The wastewater treatment from brassylic acid manufacturing plant using membrane bioreactor (MBR) was studied. The membrane bioreactor consisted of batch-operation biological aeration tank and ultrafiltration evaluation tank. The content of test included the affection of variation operation conditions on ultrafiltration separation, the general characteristics of MBR process, and the difference comparing with the conventional biological treatment. The results are as follows: (1) among the test membrane material, polyether sulphone (PES) membrane is more suitable for the wastewater treatment; (2) when the cutoff molecular weight is among 10000-50000, the higher the cutoff molecular weight, the bigger the water flux is in the test; (3) under the operation pressure, water flux increases accompanying with the increasing of operation pressure; (4) the paper filtered COD concentration has more affection on the water flux than the suspended solid concentration; ( 5) as they volume loading of MBR increases, the accumulation of high molecule organic substance and colloid increases, the membrane,permeate COD concentration and paper filtered COD concentration increase too, meanwhile the water flux reduces; (6) when the sludge retention time of activated sludge of MBR increases, the accumulation of high molecule organic substance and colloid reduces, the membrane permeate (:OD concentration and paper filtered COD concentration reduce too, and the water flux increases; (7) comparing with the conventional biological process, the microbial activity is higher, but the microbial species is less.

A binder-free electrode for efficient H_(2)O_(2) formation and Fe2+ regeneration and its application to an electro-Fenton process for removing organics in iron-laden acid wastewater

The electro-Fenton process,with its capacity for in-situ H_(2)O_(2)formation and Fe^(2+)regeneration,is a strik-ing alternative to the traditional chemical-Fenton process.However,the frequent requirement of extra binders for electrode fabrication leads to low catalyst utilization,a complex fabrication process,and weak conductivity.Herein,a three-dimensional(3D)porous electrode was fabricated in-situ on a Ni foam(NF)substrate integrated with nitrogen-doped carbon nanotubes(N@C)derived from carbonization of zeolitic imidazolate framework-8(ZIF-8)without any binder.The resulting 900/N@C-NF cathode(synthesized at 900℃)was high in surface area,N content,and degree of graphitization,achieved high performance of H_(2)O_(2)production(2.58 mg L^(−1)h^(−1)H_(2)O_(2)/mg catalyst)at-0.7 V(vs.SCE),and enabled prompt regeneration of Fe^(2+).The electro-Fenton system equipped with the 900/N@C-NF cathode was effective in removing a diverse range of organic pollutants,including rhodamine B(Rh B),phenol,bisphenol A(BPA),nitroben-zene(NB),and Cu-ethylenediaminetetraacetic acid(EDTA),and significantly attenuating the concentration of chemical oxygen demand(COD)in the real acid wastewater,exhibiting superior activity and stability.This binder-free and self-supporting electro-Fenton cathode was thus shown to be an attractive candidate for application to wastewater treatment,particularly those rich in organics,acids,and Fe^(3+)/Fe^(2+).

A two-stage anaerobic system for biodegrading wastewater containing terephthalic acid and high strength easily degradable pollutants

The high strength easily biodegradable pollutants (represented by COD E) are strong inhibitors of terephthalic acid (TA) anaerobic biodegradation. At the same time, TA can inhibit easily biodegradable pollutants removal under anaerobic conditions to a limited extent. This mutual inhibition could happen and cause a low removal efficiency of both TA and COD E, when the effluent from TA workshops containing TA and easily biodegradable pollutants are treated by a single anaerobic reactor system. Based upon the treatment kinetics analysis of both TA degradation and COD E removal, a two stage up flow anaerobic sludge blanket and up flow fixed film reactor(UASB UAFF) system for dealing with this kind of wastewater was developed and run successfully at laboratory scale. An UASB reactor with the methanogenic consortium as the first stage removes the easily biodegradable pollutants(COD E). An UAFF reactor as the second stage is mainly in charge of TA degradation. At a COD E loading of 15.3 g/(L\5d) and a TA loading of 1.4 g/(L\5d), HRT 18.5h, the COD E and TA removal rate of the system reached 89.2% and 71.6%, respectively.

Biodegradability of terephthalic acid in terylene artificial silk printing and dyeing wastewater

As the characteristic pollutant, terephthalic acid(TA)was in charge of 40%—78% of the total COD of terylene artificial silk printing and dyeing wastewater(TPW-water). The studies on biodegradability of TA were conducted in a serial of activated sludge reactors with TPW-water. TA appeared to be readily biodegradable with removal efficiency over 96.5% under aerobic conditions, hardly biodegradable with removal efficiency below 10% under anoxic conditions and slowly biodegradable with a turnover between 31.4% and 56.0% under anaerobic conditions. TA also accounted for the majority of BOD in TPW-water. The process combined by anoxic, anaerobic and aerobic activated sludge reactor was suitable for TA degradation and TPW-water treatment. Further, the aerobic process was essentially much more effective than the anaerobic or anoxic one to degrade TA in TPW-water.

Hydrodynamics research of wastewater treatment bioreactors

To optimize the design and improve the performance of wastewater treatment bioreactors,the review concerning the hydrodynamics explored by theoretical equations,process experiments,modeling of the hydrodynamics and flow field measurement is presented. Results of different kinds of experiments show that the hydrodynamic characteristics can affect sludge characteristics,mass transfer and reactor performance significantly. Along with the development of theoretical equations,turbulence models including large eddy simulation models and Reynolds-averaged Navier-Stokes (RANS) models are widely used at present. Standard and modified k-ε models are the most widely used eddy viscosity turbulence models for simulating flows in bioreactors. Numerical simulation of hydrodynamics is proved to be efficient for optimizing design and operation. The development of measurement techniques with high accuracy and low intrusion enables the flow filed in the bioreactors to be transparent. Integration of both numerical simulation and experimental measurement can describe the hydrodynamics very well.

Troubleshooting and Optimization of High-Strength Inhibitory Chemical Wastewater Treatment Process

Wastewaters from the chemical industry are usually of high-strength and may contain minor inhibitory and recalcitrant organics that are at times not readily identifiable. This paper describes the experience of a biological waste water treatment plant （WWTP） processing a COD concentration of 43000 mg·L^-1 wastewater from an oxochemical manufacturing plant. Stage improvements of the plant process by dilution of the inhibitory influent using other chemical wastewater streams resulting in a synergistic process effect, and removal of inhibitory organics by phase separation via acidification, effectively achieved process optimization producing a high quality effluent. In particular, the COD removal efficiency of granular sludge based anaerobic reactors increased from 56% to 90%. The final effluent COD decreased from 250mg·L^-1 to 50mg·L^-1, consistently meeting the COD concentration of 100 mg·L^-1 regulatory discharge limit. The success of the process enhancements supports the hypothesis that long-chain quaternary carboxylic acids act as substrate inhibitors in the biological process.

ADSORPTION AND DESORPTION OF DSD ACID MANUFACTURING WASTEWATER ON MACROPOROUS RESIN

4,4’-diaminostilbene-2, 2’-disulfonic acid (DSD acid) manufacturing wastewater was treated by a macroporous resin in a fixed-bed column. The results showed that this method was suitable for removal of chemical oxygen demands (COD) and color. About 91% COD and 99.5% color removal were obtained under the optimum adsorption conditions, i.e. temperature 20℃, flow rate 1bed volume/hour (BV/hr) and pH1-2. The resin was efficiently regenerated with aqueous sodium hydroxide and water. Furthermore, 65.5% of 4,4’-dinitrostilbene-2, 2’-disulfonic acid (DNS) could be recovered from wastewater for possible recycling to the manufacturing process. The adsorption capacity of resin remained constant during the repetition process of adsorption and desorption.

Removal of manganese from waste water by complexation-ultrafiltration using copolymer of maleic acid and acrylic acid

Copolymer of maleic acid and acrylic acid （PMA-100）, combining with polyvinyl butyral （PVB） ultrafiltration membrane was used for the removal of Mn（II） from waste water by complexation-ultrafiltration. The carboxylic group content of PMA-100 and the rate of complexation reaction were measured. Effects of the mass ratio of PMA-100 to Mn（II） （n）, pH, background electrolyte, etc on the rejection rate （R） and permeate flux （J） were investigated. The results show that carboxylic group content of PMA-100 is 9.5 mmol/g. The complexation of Mn（II） with PMA-100 is rapid and completed within 5 min at pH 6.0. Both R and J increase with pH increasing in the range of 2.5-7.0, and R increases with the increase of n at pH 6.0 while J is little affected. The background electrolyte leads to the decrease of R, and CaCl2 has much greater effect on R than NaCl at the same ionic strength.

ADSORPTION OF PHENYLACETIC ACID ON MACROPOROUS POLYMERIC ADSORBENTS

Several macroporous polymeric adsorbents (NDA-999, XAD-8, X-5 and XAD-2) were employed in the study to adsorb phenylacetic acid from aqueous solution. Effect of salt and ambient temperature on adsorption was studied using NDA-999 adsorbent and the adsorption process conforms to Freundlich抯 model reasonably. Adsorption dynamics were conducted in batch experiments in order to make clear the mechanism of adsorption process. It is proved that the squared driving force mass transfer model can be adopted to elucidate the process. The treatment process of industrial wastewater containing high strength of phenylacetic acid was proposed for cleaner production of phenylacetic acid.

弱酸性蓝AS 染料排放的废盐制碳基吸附剂及利用

将染料弱酸性蓝AS(AS)生产排放的含盐废水喷雾干燥后制成废盐,再将其有机污染物煅烧制备成类活性炭吸附剂(LAC),用于AS染料生产过程中产生的洗涤废水的吸附脱色净化,同时回收粗盐NaCl可循环用于AS工业生产的盐析过程。对LAC进行吸附过程动力学、热力学研究,并研究AS染料废水溶液初始浓度、温度及pH对吸附性能的影响。在40 mg/L的AS染料废水中,温度为318 K的条件下,平衡吸附量为29.22 mg/g。在酸性及温度较高时吸附能力较强。Langmuir等温线方程能更好拟合吸附实验结果。另外,采用一锅混合法,添加四水合乙酸镁对LAC进行改性,改性后的吸附剂LACMg0.75比表面积较LAC提升了近5倍,饱和吸附量能够达到550.02 mg/g,较LAC提升了接近20倍。

铁离子配位聚丙烯酸基芬顿催化纤维的制备及其性能

为改善聚丙烯酸(PAA)纤维的性能,在湿法纺丝过程中基于铁离子配位反应成功制备了可拉伸PAA初生纤维,利用后拉伸以及热定型工艺优化纤维性能,并探究其作为Fenton催化剂在染料废水处理领域的应用。结果表明:相较硫酸铁盐,氯化铁盐配位的PAA纤维具有更为优异的力学性能和尺寸稳定性;后拉伸和热定型工艺可显著提高PAA纤维的力学性能和催化活性,并抑制铁离子的流失,拉伸20倍且在130℃定型的纤维断裂强度为1.42 cN/dtex,与未拉伸纤维相比提高了914.3%,且可在3 min内脱色90%以上的亚甲基蓝(MB),循环使用40次未出现脱色率衰减现象。

赤泥用于酸性含锰废水中锰的净化研究

采用还原焙烧-磁选预处理赤泥,得到非磁性物;非磁性物经煅烧、盐酸溶出后加入饱和偏铝酸钠聚合剂聚合后过滤、熟化制备聚合氯化铝(PAC)基液;使用该PAC基液,在沉降时间5 h、PAC基液与废水体积比1∶120、搅拌转速140 r/min、pH值8、反应温度30℃、聚丙烯酰胺(PAM)投加量20 mg/L条件下处理含锰酸性废水,处理后液中锰质量浓度由325.3 mg/L降至1.5 mg/L,锰去除率达99.5%,净化后液中锰质量浓度达到国家一级排放标准。

F-53B胁迫下污水厌氧处理系统及微生物群落的响应

通过构建厌氧反应体系,评估低浓度(1mg/L)和高浓度(10mg/L)氯化多氟醚磺酸盐(F-53B)胁迫下,厌氧处理系统出水水质、污泥性状和细菌群落的响应特征.结果表明,在F-53B的胁迫下,COD、氮(TN、NH_(4)^(+)-N)和磷(TP、PO_(4)^(3-)-P)在出水中的含量会升高,而污泥相对生物量(MLVSS/MLSS)则出现下降,且F-53B的浓度越高影响越大.高通量测序分析发现,相较于对照组(0mg/L F-53B),仅高浓度F-53B胁迫下细菌群落的多样性(ACE、Chao1和PD指数)出现了显著下降.同时,研究还发现,随着高浓度F-53B暴露时间的延长,厚壁菌门的相对丰度逐渐增大,而变形菌门、拟杆菌门和硝化螺旋菌门的相对丰度逐渐降低.此外,基于FAPROTAX功能预测分析发现,F-53B胁迫下微生物表现出更低的氮(N)代谢潜力和更高的化能异养和发酵能力.冗余分析(RDA)表明,厚壁菌门主要受F-53B的正向影响,并与TN和NH_(4)^(+)-N呈正相关;而变形菌门受F-53B的负向影响,并与COD、TP和PO_(4)^(3-)-P呈正相关.揭示了新型氟化物—F-53B对污水厌氧处理系统的胁迫机制.

基于单宁酸-铁(Ⅲ)改性正渗透膜制备及抗污染性能

采用表面涂覆的方法对三醋酸纤维素(CTA)正渗透膜的活性层进行改性,首先利用单宁酸(TA)与铁离子(Fe^(3+))在膜表面以自组装的形式构建金属-多酚前体层,在此基础上进一步涂覆单宁酸/二乙烯三胺(TA/DETA)亲水功能层,最后借助TA的还原性在膜表面原位形成Ag/聚乙烯吡咯烷酮(PVP)抗菌功能层,制备了TA/Fe^(3+)-TA/DETA-Ag/PVP改性膜。利用错流式正渗透装置探究动态污染实验中膜通量的变化情况,通过扫描电子显微镜(SEM)和红外光谱(FTIR)分析膜污染前后表面形貌和组成,使用激光共聚焦显微镜(CLSM)对膜表面污染物微观分布进行表征,并对比CTA原膜和改性膜的清洗效能。结果表明:TA/Fe^(3+)-TA/DETA-Ag/PVP改性膜的水接触角由78.79°下降至33.05°,亲水性显著提升。在15天的动态污染实验结束后,CTA膜和TA/Fe^(3+)-TA/DETA-Ag/PVP改性膜的通量分别衰减为各自初始通量的52.14%和72.81%,且与CTA原膜相比,TA/Fe^(3+)-TA/DETA-Ag/PVP改性膜表面的活细菌数量和有机污染物量大幅减少。经过水力清洗和渗透反洗后,TA/Fe^(3+)-TA/DETA-Ag/PVP改性膜的通量恢复率可达80.37%,远高于CTA原膜的49.88%,具有较强的抗污染性。

氟调酸在我国典型城市污水处理厂中的浓度分布及排放

氟调酸(fluorotelomer carboxylic acids,FTCAs)是全氟烷基羧酸(perfluoroalkyl carboxylates,PFCAs)的前体物,同时也是替代加工助剂.本研究应用固相萃取-液相色谱-三重四极杆质谱仪联用的检测分析方法,探究了中国5个城市9座城市污水处理厂进水、二沉池出水、三级处理出水和污泥中6种FTCAs和12种PFCAs的分布及排放特征.FTCAs在城市污水处理厂进水中的浓度为0.52—2.00×10^(3) ng·L^(-1),受纳工业废水的城市污水处理厂进水中FTCAs的浓度高于其他主要受纳生活污水的城市污水处理厂,表明工业废水的排放会影响城市污水处理厂中FTCAs的浓度水平.生物处理工艺对FTCAs和PFCAs的去除率分别为43%—93%和-40%—69%.∑FTCAs在三级处理出水及污泥中的总排放量为13.6 g·d^(-1),6:2 FTCA和8:2 FTCA为主要的组成物质.三级处理出水中FTCAs及PFCAs的风险商分析表明三级处理出水中6:2 FTCA、PFHxA、PFOA、PFNA和PFDA可能对鱼类存在潜在风险.本研究为我国城市污水处理厂中新污染物的管控提供了数据基础.

Mechanism and controlling strategy of the production and accumulation of propionic acid for anaerobic wastewater treatment

The production and accumulation of propionic acid affect significantly anaerobic wastewater treatment system, but the reasons are not approached until now. Based on the results of continuous-flow tests and the analysis of biochemistry and ecology, two mechanisms of producing propionic acid have been put forward. It is demonstrated that the reasons of propionic acid production and accumulation are not caused by higher hydrogen partial pressure. The combination of specific pH value and ORP is the ecological factor affecting propionic acid production, and the equilibrium regulation of NADH/NAD+ ratio in cells is the physiological factor. Meanwhile, it is put forward that using the two-phase anaerobic treatment process and the ethanol type fermentation in anaerobic reactor to avoid propionic acid accumulation are efficient methods.

不同负荷梯度对污水厂活性污泥的产酸性能分析

活性污泥发酵产酸有利于实现污泥资源化利用。文中以污水厂活性污泥为研究对象,在污水厂现场采用半连续碱性发酵方法,探究了先低梯度再高梯度长周期提负荷过程中污泥的产酸性能。结果表明:低梯度提负荷运行阶段,第112 d污泥的酸化率达到最大值,且乙酸占比为71.67%,游离氨(FA)质量浓度为(208±39)mg/L,低于250 mg/L,对微生物无抑制性。在高梯度提负荷阶段,第192 d污泥的水解率提高至41%,丁酸与戊酸的占比增加,FA质量浓度逐渐升高至450 mg/L时产酸性能下降。低梯度的优势菌Guggenheimella(24.88%)演变为高梯度的unclassified_Clostridiales(37.08%)。此外,当负荷为3250 mg TSS/(L·d)时,挥发性脂肪酸(VFAs)达到最大值(3339 mg COD_(Cr)/L)。经过50 d的稳定运行,污泥的产酸率为(606±30)mg COD_(Cr)/(g VSS)。合适的负荷梯度有助于污泥中有机物在碱性条件下(pH值=10.0±0.05)长期稳定连续生成VFAs。