Operation of three parallel AN/AO processes to enrich denitrifying phosphorus removing bacteria for low strength wastewater treatment

Three parallel anaerobic-anoxic/anaerobic-aerobic （AN/AO） processes were developed to enrich denitrifying phosphorus removal bacteria （DPB） for low strength wastewater treatment. The main body of the parallel AN/AO process consists of an AN （anaerobic-anoxic） process and an AO （anaerobic-aerobic） process. In the AO process, the common phosphorus accumulating organisms （PAOs） was dominate, while in the AN process, DPB was dominate, The volume of anaerobic zone（Vana）：anoxie zone（Vano） ： aerobic zone （Vaer） for the parallel AN/AO process is 1：1：1 in contrast with a Vana：Vaer and Vano：Vaer of 1：2 and 1：4 for a traditional biological nutrient removal process （BNR）. Process 3 excels in the 3 processes on the basis of COD, TN and TP removal. For 4 month operation, the effluent COD concentration of process 3 did not exceed 60 mg/L; the effluent TN concentration of process 3 was lower than 15 mg/L; and the effluent TP concentration of process 3 was lower than 1 mg/L.

Biological Nutrient Removal in a Full Scale Anoxic/Anaerobic/Aerobic/ Pre-anoxic-MBR Plant for Low C/N Ratio Municipal Wastewater Treatment

A novel full scale modified A2O （anoxic/anaerobic/aerobic/pre-anoxic）-membrane bioreactor （MBR） plant combined with the step feed strategy was operated to improve the biological nutrient removal （BNR） from low C/N ratio municipal wastewater in Southern China. Transformation of organic carbon, nitrogen and phosphorus, and membrane fouling were investigated. Experimental results for over four months demonstrated good efficiencies for chemical oxygen demand （COD） and NH4^＋-N removal, with average values higher than 84.5%and 98.1%, re-spectively. A relatively higher total nitrogen （TN） removal efficiency （52.1%） was also obtained at low C/N ratio of 3.82, contributed by the configuration modification （anoxic zone before anaerobic zone） and the step feed with a distribution ratio of 1：1. Addition of sodium acetate into the anoxic zone as the external carbon source, with a theoretical amount of 31.3 mg COD per liter in influent, enhanced denitrification and the TN removal efficiency in-creased to 74.9%. Moreover, the total phosphate （TP） removal efficiency increased by 18.0%. It is suggested that the external carbon source is needed to improve the BNR performance in treating low C/N ratio municipal waste-water in the modified A^2O-MBR process.

Wastewater treatment performance and microbial community structure in the constructed wetland under double-pressure of low temperature and Ag NPs exposure

To investigate the effects of silver nanoparticles(Ag NPs)and low temperature double-pressure on the wastewater treatment efficacy and the microbial community structure of constructed wetlands,a pilot-scale vertical flow constructed wetland was set up to treat synthetic wastewater under laboratory conditions.By measuring the effluent concentration of ammonia nitrogen(NH_(4)^(+)-N),total nitrogen(TN),total phosphorus(TP),chemical oxygen demand(COD),and the diversity,richness,and community structure of microorganisms of the upper and lower soil layers in the wetland,the nutrient removal effect of the constructed wetland and the changes in the microflora of the soil layer were studied.The results reveal that the correlation coefficients between the removal rates of TN and NH_(4)^(+)-N and the temperature are 0.463 and 0.692,respectively,indicating a significant positive correlation.From the warm to the cold season,both the diversity and richness of microorganisms in the lower soil layer of wetlands are inhibited under the double-pressure of Ag NPs and low temperature,and the abundances of the denitrogenation functional bacteria such as Candidatus nitrososphaera,Sulfuritalea,Anaeromyxobacter,Candidatus solibacter,Nitrospira,and Zoogloea are altered.Low temperature and Ag NPs exposure can thus affect the wastewater treatment performance of constructed wetlands,possibly because of the seasonal changes of the microflora.

Simulation of Low TDS and Biological Units of Fajr Industrial Wastewater Treatment Plant Using Artificial Neural Network and Principal Component Analysis Hybrid Method

Being familiar with characteristics of industrial town effluents from various wastewater treatment units, which have high qualitative and quantitative variations and more uncertainties compared to urban wastewaters, plays very effective role in governing them. With regard to environmental issues, proper operation of wastewater treatment plants is of par- ticular importance that in the case of inappropriate utilization, they will cause serious problems. Processes that exist in environmental systems mostly have two major characteristics: they are dependent on many variables;and there are complex relationships between its components which make them very difficult to analyze. In order to achieve a better and efficient control over the operation of an industrial wastewater treatment plant (WWTP), powerful mathematical tool can be used that is based on recorded data from some basic parameters of wastewater during a period of treatment plant operation. In this study, the treatment plant was divided into two main subsystems including: Low TDS (Total Dissolved Solids) treatment unit and Biological unit (extended aeration). The multilayer perceptron feed forward neural network with a hidden layer and stop training method was used to predict quality parameters of the industrial effluent. Data of this study are related to the Fajr Industrial Wastewater Treatment Plant, located in Mahshahr—Iran that qualita- tive and quantitative characteristics of its units were used for training, calibration and validation of the neural model. Also, Principal Component Analysis (PCA) technique was applied to improve performance of generated models of neural networks. The results of L-TDS unit showed good accuracy of the models in estimating qualitative profile of wastewater but results of biological unit did not have sufficient accuracy to being used. This model facilitates evaluating the performance of each treatment plant units through comparing the results of prediction model with the standard amount of outputs.

Study on Treatment Technology of Methanol in the Low-concentration Methanol-containing Wastewater of a Gas Field

The low-concentration methanol-containing wastewater of a gas field mainly consists of the dehydrated water from natural gas,the water at the bottom of a rectifying tower,and the water used to clear tanks and pipes. The concentration of methanol as its characteristic component is mostly lower than 3%. Its production and water quality change seasonally. It is mainly produced in late autumn,winter,and early spring when temperature is low. In the low-concentration methanol-containing wastewater,the content of organic matter,suspended solids and salts and COD value are high,and it is acidic. According to the physical and chemical properties of methanol such as easily dissolving in water,dissolving in most organic solvents,and having strong molecular polarity,laboratory experiments were made to study the difficulties of using high-temperature rectification,biodegradation,membrane filtration and organic oxidation technology to treat low-concentration methanol in the wastewater as well as the feasibility of industrial application. Ultraviolet catalytic oxidation technology has the advantages of high treatment efficiency,no secondary pollution,and no addition of treatment agent. After the low-concentration methanol-containing wastewater was treated by ultraviolet catalytic oxidation for 90 min,methanol concentration in the wastewater reduced from about 3% to around 0. 1%,thereby rapidly and efficiently degrading methanol in the wastewater. Based on the experimental parameters,a pilot device of ultraviolet catalytic oxidation was developed and used in the continuous treatment of the wastewater. When the flow rate of inflow was 500 L/h,the intensity of UV light was 2 k W,and hydraulic retention time was 60 min,methanol could be removed completely from the wastewater with the methanol concentration of about 0. 3%. This study provides a method for the treatment of low-concentration methanol-containing wastewater of a gas field,and also provides an experimental basis for the efficient degradation of organic wastewater.

Reductive recovery of manganese from low-grade manganese dioxide ore using toxic nitrocellulose acid wastewater as reductant

The hydrometallurgical strategy of extracting Mn from low-grade Mn ores has attracted attention for the production of electrolytic manganese metal(EMM). In this work, the reductive dissolution of low-grade Mn O2 ores using toxic nitrocellulose acidic wastewater(NAW) as a reductant was investigated for the first time. Under the optimized conditions of an Mn O2 ore dosage of 100 g·L-1, an ore particle size of-200 mesh, concentrated H2 SO4-to-NAW volume ratio of 0.12, reaction temperature of 90°C, stirring speed at 160 r·min-1, and a contact time of 120 min, the reductive leaching efficiency of Mn and the total organic carbon(TOC) removal efficiency of NAW reached 97.4% and 98.5%, respectively. The residual TOC of 31.6 mg·L-1 did not adversely affect the preparation of EMM. The current process offers a feasible route for the concurrent realization of the reductive leaching of Mn and the treatment of toxic wastewater via a simple one-step process.

Advanced Treatment of Wastewater Treatment Plant Effluent by Using Biofilms on Filamentous Bamboo

[ Objective ] The study aimed at treating wastewater treatment plant （WWTP） effluent by using bio-film reactor with filamentous bamboo as bio-carrier. [ Method] With the aid of a continuous flow reactor, a bio-film reactor using filamentous bamboo as bio-carrier was used to treat WWTP effluent with low C/N ratio, and the removal effects of CODc,, TN （total nitrogen）, and NO3--N in the wastewater were analyzed.[ Result ] The average removal rates of CODcr, TN, and NO3- -N reached 47.7%, 23.6% and 34.5% when the C/N ratio of influent was around 2. In addi- tion, a stable bio-film was formed very well in the secondary effluent with low C/N ratio and hardly degradable organic pollutants. The pollutants could be removed effectively because of the excellent surface characteristics and compositions of filamentous bamboo. [ Conclusion] The research provides a new method to treat WWTP effluent with low C/N ratio.

Wastewater Decontamination from Microorganisms by Electrospraying Corona Discharge

A novel water treatment technique, based on a combination of electrospraying and pulsed corona discharge, has been used for bio-decontamination of wastewater. The electrospraying process has been found to increase the surface area of the treated wastewater, and hence increases the efficiency of the corona treatment process. The phase diagram of the discharge, which characterizes the discharge regimes, has been identified experimentally. The survival ratio of the microorganisms has been investigated experimentally as a function of the applied voltage and the numbers of treatment runs using air and oxygen as working gases. Microorganism surface has been examined using scanning electron microscope (SEM), which enabled in understanding the decontamination mechanisms of the treated microorganism. A complete decontamination has been achieved after only one run for an applied voltage higher than 16 kV when the discharge system was operated in oxygen gas. Optical emission spectrum of the electrosprayed water confirmed the existence of OH-radicals responsible for decontamination process.

酿酒污水资源化应用性能及风险分析

酿酒污水因其有机物浓度高而难以高效处理,但城镇污水处理厂面临着因有机物不足而导致的低碳氮比(C/N)污水反硝化效果差的问题。因此,该实验考察了以酿酒污水作为碳源强化低C/N污水的亚硝酸盐氮(NO3--N)去除效果,对水力停留时间(HRT)进行了优化,并对关键微生物和技术风险进行了分析。结果表明,在HRT为12~36 h、酿酒污水和低C/N污水体积比500∶1、进水总氮(TN)19.7 mg/L的条件下,处理后化学需氧量(COD)、TN、NO3--N浓度可以满足污水处理厂尾水排放标准。HRT优化过程造成了菌群差异,其中食酸菌属(Acidovorax)是同步去除COD和NO3--N的主要异养反硝化菌属。此外,致病和移动元件表型富集表明,在HRT为12 h时微生物致病和传播综合风险最低。综上,酿酒污水的资源化利用技术是可行的,并且HRT为12 h是最高效、安全的技术参数。研究可为酿酒污水处理提供理论指导和参考。

单级电渗析低成本浓缩高盐废水

高盐废水“零排放”是近年来工业废水处理研究的热点之一。电渗析因具有高电流效率和低成本的特点,已成为高盐废水“零排放”最有前途的技术之一。操作参数和进水水质在电渗析浓缩过程中起着重要作用,通过探究初始浓度、浓、淡室体积比和电流密度对浓缩效果的影响规律,确定单级电渗析低成本浓缩的运行条件,为电渗析处理高盐废水提供了参考。实验结果表明:增大进水初始浓度、淡室体积和电流密度有利于提升高盐废水的处理效果。

基于气泡雾化喷嘴的低能耗含油污水处理实验研究

微气泡气浮技术在低能耗下对含油污水的高效处理是目前的研究热点。利用气泡雾化喷嘴作为微气泡发生器,搭建了低能耗微气泡射流气浮处理含油污水的实验系统,系统研究了气液质量流量比(ALR)和工作压力(p)对微气泡群尺度分布特征和除油效果的影响,并计算了气泡雾化喷嘴的能耗。实验结果表明,利用气泡雾化喷嘴形成液下射流可以产生大量微气泡,其中尺度小于150μm的气泡数量占比在55%以上、小于600μm的气泡数量占比在98%以上;随着ALR的增加,微气泡数量整体呈现先增后减的变化趋势,最佳ALR=0.15;当p=0.2 MPa、ALR=0.15时,微气泡群的索特尔平均直径可降低至238μm,出水含油质量浓度为29.73 mg/L,微气泡射流气浮装置处理1 kg含油污水时能耗仅为6.53×10^(-4) kW·h,较溶气气浮能耗降低35%以上。

低氨氮质量浓度废水DPR-SNAD脱氮除磷效能研究

针对低氨氮废水单级自养脱氮系统副产物硝氮残留,有机物耐受能力差,以及缺乏除磷功能等问题,提出反硝化除磷(Denitrifying Phosphorus Removal,DPR)-单级自养脱氮(Simultaneous Partial Nitrification,Anaerobic Ammonium Oxidation and Denitrification,SNAD)组合处理技术,重点考察氨氮负荷对单级自养脱氮工艺(Single-stage Nitrogen Removal Using Anammox And Partial Nitritation,SNAP)系统、泥龄对DPR系统构建的影响,以及低氨氮废水DPR-SNAD组合处理系统的脱氮除磷效能与微生物种群。研究结果显示:采用氨氮质量浓度梯度递减方式,氨氮负荷为0.20 kg N/(m^(3)·d)的低氨氮质量浓度的SNAP系统构建时间为63 d,较负荷为0.05 kg N/(m^(3)·d)的系统缩短了37 d。泥龄对构建的DPR系统效能影响显著,泥龄为35 d的系统除磷脱氮效能较高,PO_(4)^(3-)-P、NO_(3)^(-)-N、COD去除率分别为86.25%、98.00%、92.00%,系统释磷、吸磷、反硝化脱氮速率分别达4.60 mg/(L·h)、4.13 mg/(L·h)、5.53 mg/(L·h)。DPR-SNAD组合处理系统的氨氮(NH_(4)^(+)-N)、总氮(Total Nitrogen,TN)、总磷(Total Phosphorus,TP)、化学需氧量(Chemical Oxygen Demand,COD)去除率分别为100%、98.64%、86.00%、93.30%。TN、TP去除率较对照组SNAP分别提高了19.20百分点和86.00百分点。16S rRNA高通量测序结果显示,组合系统脱氮除磷功能菌属主要有Rhodobacter、Candidatus_Brocadia、Nitrosomonas、Gemmobacter,SNAD系统中厌氧氨氧化菌(Anaerobic Ammonia Oxidation,AnAOB)相对丰度显著高于对照组SNAP系统,DPR促进SNAD提高了系统脱氮效能。

黄铁矿基MFC-CW耦合系统反硝化动力学研究

研究比较了黄铁矿基双阳极MFC-CW在不同碳氮比(0和2.5)及初始硝酸盐浓度(7、14和28 mg/L)条件下上阳极和下阳极的反硝化速率,以及对不同阶段硝酸盐还原反应动力学的模拟,从动力学角度揭示系统自养-异养协同反硝化机理。结果显示:不同碳氮比下系统两阳极硝酸盐还原效果差异不大,而亚硝酸盐累积、硫酸盐生成的差别较大,两阳极处微生物群落组成相似,优势菌属的相对丰度受C/N、阳极位置影响较大;两阳极处的硝酸盐还原动力学均属于一级反应,且C/N=0时反硝化速率常数(0.0087、0.0045和0.0188/h)均小于C/N=2.5(0.0151、0.0071和0.0798/h;以上阳极为例);MFC-CW系统的反硝化动力学更符合Monod-CSTR模型,且在停留时间较长时取得更好的拟合效果,随着停留时间的增加,C/N=0时系统的反硝速率增加,C/N=2.5时系统的反硝化速率在一定范围内波动[0.6662—0.7744 g/(m^(2)·d)]。实验结果可为黄铁矿基MFC-CW的实际工程应用提供理论指导。

低温热泵蒸发-生化-RO工艺在废水回用中的应用研究

采用低温热泵蒸发-生化-反渗透(RO)组合工艺,对某企业清洗废水进行深度处理后回用。首先通过低温蒸发器去除大部分有机物和盐分,然后利用生化系统去除有机物和氨氮,最后利用RO系统去除剩余的有机物和盐分。运行结果表明,出水水质可满足企业生产工艺用水水质要求,具体水质指标:COD≤10 mg/L,氨氮≤1 mg/L,SS≤1 mg/L,LAS≤1 mg/L,电导率≤60μS/cm,pH为6~9。该项目实施后,经济效益显著。最后将低温热泵蒸发和其他传统蒸发技术作了经济和技术比较分析。

玉米芯与秸秆作为缓释碳源的改性研究

目的 为解决低C/N污水中碳源不足的问题,探究以玉米芯与秸秆作为固体缓释碳源的可能性。方法 分别使用NaOH溶液、H2O2溶液及NaOH与H2O2的混合液对玉米芯与秸秆进行改性,通过静态试验测定改性后固体碳源的质量变化,分析改性后固体碳源的浸出液中COD、NH_(4)^(+)-N、TN、TP的释放规律,对改性后固体碳源的可生化性能进行研究。结果 经过预处理后的固体碳源释碳能力均有不同程度的提升,经过碱处理组的质量减少最为明显,经过碱处理后的玉米芯具有良好、持久的释碳能力,氮磷的释放量几乎可忽略不计,经过碱处理后的玉米芯和秸秆的可生化性均有所提高,玉米芯的可生化性能增强更明显,更适合微生物的生长繁殖。结论 经过碱性溶液处理后的玉米芯更适于作为固体缓释碳源应用于低C/N污水的脱氮除磷。

论纺织印染废水低碳治理

纺织印染行业是废水及污染物排放量最大的工业行业之一,同时也是能源密集及碳排放高的行业;废水低碳治理已成为纺织印染行业可持续发展的重要路径。在分析印染废水处理工艺温室气体排放特征的基础上,提出依据染化料助剂推定的碳排放潜势概念;针对纺织印染废水处理工艺复杂及水质时变性大的问题,建立了基于碳氮物料平衡的废水处理工艺碳排放精准核算方法。面向废水低碳处理运行需求,总结了纺织印染废水低碳治理技术进展及发展方向。

化学团聚耦合低温省煤器强化除尘协同脱硫废水零排放试验研究

煤燃烧产生的细颗粒物和烟气脱硫产生的脱硫废水是燃煤电厂污染治理的难点。该文提出一种化学团聚耦合低温省煤器强化除尘协同脱硫废水零排放的处理工艺。将加入团聚剂的工艺水或脱硫废水通过双流体雾化喷入低温省煤器前烟道,细颗粒物在化学团聚剂液桥力的作用下发生团聚长大,沿程水分蒸发后,液桥力转化为固桥力形成大的团聚体,耦合低温省煤器促进静电除尘器对细颗粒物的脱除效率。示范试验结果表明,运行化学团聚可使粉尘排放浓度降低63.1%,168 h内平均粉尘排放浓度为2.66 mg/m^(3);基于运行数据优化了团聚剂喷量与低温省煤器循环水量;连续运行脱硫废水对强化除尘效果没有明显影响,实现了超低排放以及脱硫废水零排放。

CSTR处理低浓度豆腐废水的启动研究

为探究全混合式(CSTR)反应器处理豆腐废水的启动实验,在常温条件下对自行设计的CSTR反应器进行了相关实验。结果表明:在启动后的运行时间30 d后,进水COD为3500 mg·L^(-1),水力滞留时间为10 d,COD去除率达到了99.51%,池容产气率达到了0.46 L·L^(-1)d^(-1),甲烷的质量分数达到60.69%。所以,对CSTR高效厌氧反应器的低浓度废水启动方式是可行的,对原豆腐废料的降解方式也是可行的,为今后对CSTR高效厌氧反应器的设计应用提供了一种新型启动方式。

汞对低气压条件下污水处理系统脱氮性能的影响研究

汞(Hg)在低气压地区污水处理系统中的存在可能会降低污水处理效率。在实验室规模下以SBR为例,通过研究Hg对低气压条件下污水处理系统的影响发现,Hg显著降低了氨氮(NH_(4)^(+)-N)的去除率,尤其是高浓度Hg的影响更显著,NH_(4)^(+)-N去除率从89.73%下降至38.71%。Hg对SBR周期内的氮转化过程产生了负面影响,当进水Hg浓度为250μg/L时,活性污泥氨氧化速率(SAOR)和亚硝酸盐还原速率(SNIR)分别下降96.74%和96.91%,与之相关的功能酶活性分别降低100.00%和97.87%。此外,Hg改变了活性污泥的形态和结构,导致污泥整体结构的瓦解和表面特征的变化,同时对EPS的生成产生抑制作用,特别是蛋白质含量受到影响。在微生物群落方面,Hg的加入使活性污泥群落结构发生了显著变化,尤其是和硝化过程相关的功能菌属Nitrosomonas和Nitrospira。因此,低气压条件下需对污水处理系统中Hg存在带来的影响给予关注。

强化低温、低碳氮比污水脱氮的优势菌特性

低温、低碳氮比(BOD5/TN)污水的有效脱氮一直是北方城镇污水处理厂亟待解决的难题。对从哈尔滨地区低温(4~6℃)地下水中筛选获得的优势菌Y24-6进行研究,初步鉴定其为假单胞菌属(Pseudomonas),研究发现菌株Y24-6在自养条件下对硝酸盐去除率为(24.00±1.24)%。通过分析Pseudomonas sp.Y24-6对NO_(3)^(-)-N的去除过程,发现其在2 h内对硝酸盐的去除速率最高,为25.91 mg·L^(-1)·h^(-1)。基因组(序列号:JACBXG000000000)分析结果表明,菌株Y24-6通过CsrA、GlnL、GlnK和GlnA信号蛋白调控菌株的碳、氮代谢,且其中存在CO_(2)固定的关键酶基因(ppc和icd),在有机碳源不足时可通过固定环境中的CO_(2)来去除NO_(3)^(-)-N。将菌株Y24-6固定在S3型填料,24 h后每个填料可形成的菌量为(7.3±3.7)mg。用固定化的菌株Y24-6处理BOD5/TN<1、4℃的实际污水,TN的去除率平均为(34.55±0.09)%,对低温低碳氮比污水处理效果显著,本研究结果为寒区城镇污水冬季脱氮提供了参考依据。