混凝工艺去除合流污水中有机物及营养元素

通过系列杯罐试验混凝处理合流污水,采用硫酸铝（Al₂(SO₄)₃）、硫酸铁（Fe₂(SO₄)₃）、聚合氯化铝（PAC）和聚合氯化铝铁（PAFC）4种混凝剂均能有效去除污水中的 TP、PO^3-₄-P、SS和COD。聚合金属盐（PAC和PAFC）混凝处理效果优于金属盐（Al₂(SO₄)₃和Fe₂(SO₄)₃）,达到相同的处理效果的投加量明显低于后者。助凝剂采用聚丙烯酰胺（PAM）、聚乙烯醇（PVA）、自制的高分子聚合物（AN）和活化硅酸（AS）,在保持较低混凝剂投加量的条件下可明显提高污水处理效果;添加助凝剂对强化PO^3-₄-P的去除作用不明显,PO^3-₄-P的去除仅与混凝剂的投加量相关。混凝剂和助凝剂对污水中NH₃-N的去除作用相对不显著。SS去除率随混凝剂投加量的变化趋势说明混凝的机理较为复杂,可能存在多种混凝机理共同作用。     

污泥回流分离工艺（RSSP）除磷脱氮试验研究

介绍了一种新型的脱氮除磷工艺——回流污泥分离工艺（return sludge separate process）,及其运行情况。该工艺在传统的厌氧缺氧好氧（A²/O）的模式下,针对硝酸盐对厌氧释磷的抑制问题进行改进,提出回流污泥的气浮浓缩分离方案,以提高系统的脱氮除磷效果。研究结果表明,在进水COD为250～400 mg/L,NH⁺₄-N为30～45 mg/L,PO^3-₄-P为8～10 mg/L左右时,该工艺对NH⁺₄-N和PO^3-₄-P的去除率分别可达79.3%和95%。该系统与A²/O的平行比较数据表明,该系统能够提高氮磷综合处理效率,解决A²/O处理工艺中存在无效释磷和硝酸根抑制问题。     

MB(A2/O)处理城市污水富磷上清液的化学除磷研究

为开发新型除磷脱氮工艺,研制了将MBR和A²/O工艺相结合的新型MB(A²/O)反应器。研究了MB(A²/O)反应器处理城市污水厌氧富磷上清液的化学除磷,并分析了过程机理及特性。结果表明：对于TP在30～45 mg/L的富磷上清液,采用含20% Ca(OH)₂的工业石灰与P的最佳投加质量比为22.5;纯Ca(OH)₂与P的最佳投加质量比为5.6（摩尔比为2.5）;FeSO₄·7H₂O与P的最佳投加质量比为10.7（Fe^2＋与P的摩尔比为1.3）;Al₂(SO₄)₃·12H₂O与P的最佳投加质量比为12（Al^3＋与P的摩尔比为1.3）时,均可使出水TP稳定在0.3 mg/L以下;以石灰、NaOH的联合投加方式可大幅减少石灰投加量。     

催化铁与生物法耦合除磷工艺特性简

为了研究催化铁与生物耦合后对生物除磷特性的影响,实验采用人工配水用厌氧/好氧间歇流式富集培养聚磷微生物。对比发现,催化铁与生物耦合组中厌氧末段ORP降低了约60 mV,pH值小幅度的上升（≤0.3）,整个培养过程中铁离子的浓度开始快速增加,之后趋于稳定（约40 mg Fe/g MLSS）。对好氧末段污泥SVI值比较发现,耦合工艺污泥沉降性能得到改善。除磷曲线比较发现,耦合组中厌氧末段磷的释放量下降,而好氧阶段磷的吸收速率增加;胞内聚合物提取表明,耦合组厌氧末段聚磷菌细胞内PHA含量有提高,好氧末段糖原含量有下降。磷形态提取分析表明,耦合组好氧末段污泥中无机态PO^3-₄-P含量更高。低浓度铁离子可以起到与生物耦合同步除磷的目的,本工艺长期运行未发现耦合体系中催化铁对除磷的抑制作用。     

用于磷吸附的载铁(β-FeOOH)沸石制备及特性简

以天然沸石为载体,采用FeCl₃水解法制备用于磷吸附的载铁沸石（β-FeOOH-Z）,优化β-FeOOH-Z的制备条件,包括FeCl₃溶液浓度、负载pH值、负载时间、负载温度和烘干温度,并利用X射线衍射（XRD）和傅里叶变换红外光谱（FTIR）对β-FeOOH-Z及其磷吸附特性进行分析。结果表明,β-FeOOH-Z的优化制备条件为：FeCl₃溶液浓度1 mol/L、负载pH值6、负载时间24 h、负载温度25℃和烘干温度60℃。优化制备条件下,100~120目沸石的载铁量为100.2 mg/g,铁的负载率为18%,其磷吸附量为7.68 mg/g,比天然沸石提高79.6%。XRD分析结果表明,β-FeOOH-Z中的杂质元素较天然沸石减少,并有效负载β-FeOOH;制备条件对β-FeOOH-Z的成分有较大影响,FeCl₃溶液浓度较低、负载温度和烘干温度过高均使β-FeOOH-Z中含有α-Fe₂O₃,并导致其磷吸附效率降低。FTIR分析结果表明,β-FeOOH-Z的表面羟基在其吸附磷过程中起重要作用,羟基与磷酸根离子的配位交换是β-FeOOH-Z吸附磷的主要作用机制。     

原位水解生成的羟基氧化铁凝聚吸附除磷效能与机制简

将不同摩尔比Fe³⁺与OH^-（[Fe³⁺]：[OH^-]=1：0、1：1、1：2和1：3）反应获得原位水解生成的羟基氧化铁（in situ FeO_xH_y）,研究了具有不同水解程度的羟基氧化铁对凝聚吸附除磷效能与机制。研究显示,In situ FeO_xH_y对磷的去除率随铁投量增大而升高,且均在中性pH范围内具有最佳除磷效果;在相同铁投量条件下,磷去除率随着[OH^-]：[Fe³⁺]的升高而降低;当体系碱度较低时（pH<6）,引入OH^-可促进Fe³⁺水解而提高除磷效果。4种羟基氧化铁均可在15 s内可快速吸附磷,且吸附过程符合准二级动力学模型;Freundlich模型均可很好地描述磷在4种羟基氧化铁表面的吸附行为。磷酸盐吸附后,In situ FeO_xH_y表面Zeta电位明显降低,且[Fe³⁺]：[OH^-]为1：0的羟基氧化铁降低最为显著。结合MINITEQ计算软件磷酸盐、铁盐形态分析结果显示,对于碱度较低的体系,通过投加一定量OH^-可促进Fe³⁺水解,进而使得其更易与水中H₂PO₄^-与HPO₄^2-结合,生成具有多核羟基的磷酸铁络合物,进而提高除磷效果。     

重金属锌胁迫下湿地植物对磷的吸收能力变化研究

选择4种常见的湿地植物,研究了重金属锌胁迫下,湿地植物对磷的吸收能力的变化。结果表明,当加入0.5 g ZnSO₄/kg 土壤时,4种湿地植物根表铁氧化物胶膜对锌的吸附量增加,而对磷的吸附量显著降低（p<0.05）;湿地植物根表铁氧化物胶膜上吸附的磷是湿地植物吸收的磷源,并影响湿地植物地上部分磷含量;在高浓度锌的胁迫下,灯心草地上部分铁含量增加,而导致地上部分磷含量显著降低（p<0.05）。湿地植物根表铁氧化物胶膜上的锌和地上部分铁含量都影响了湿地植物对磷的吸收。     

改良型A2/O-MBR工艺的反硝化除磷性能研究简

重点考察了一种改良型膜生物反应器（A²/O-MBR）的脱氮除磷性能。该工艺主要特点在于对膜池硝化回流液进行了固液分离,并将上清液和浓缩污泥分别回流至缺氧池和厌氧池,这种改进提高了系统对氮、磷的同步去除效率。实验结果表明,在水力停留时间（HRT）为12 h,污泥龄（SRT）为30 d,混合液回流比为200%的运行条件下,进水COD、NH₄⁺-N、TN和TP平均浓度分别为（225±38）、（24.8±3.9）、（26.7±2.9）和（2.90±0.53）mg/L时,增加膜池硝化回流液固液分离装置前后,系统对COD和NH₄⁺-N的去除都维持在较高水平,而系统对TN和TP的去除效果显著提高,出水TN和TP平均浓度分别由（14.9±3.3）mg/L和（1.95±0.72）mg/L下降到（9.4± 1.9）mg/L和（0.91±0.38）mg/L,表明增加膜池硝化回流液固液分离装置显著改善了A²/O-MBR系统的脱氮除磷效果。反硝化除磷活性实验结果进一步表明,改进后系统中反硝化除磷活性占总除磷活性的比例由51.5%上升至61.7%,说明增加膜池硝化回流液固液分离装置强化了系统的反硝化除磷性能。     

诱导结晶法去除地下水中氟离子简

针对现行高氟地下水处理工艺中存在的工艺复杂、运行管理困难等问题,提出采用诱导结晶法除氟。其技术核心是在高氟水中投加氟磷灰石作为晶种,并投加磷酸盐和钙盐使水中氟离子在晶种表面生成氟磷酸钙（Ca₁₀（PO₄） ₆F₂）结晶。通过单因素实验得出最佳工艺条件：投加8g/L氟磷灰石,并投加NaH₂PO₄和CaCl₂,使钙离子、磷酸根离子和氟离子的摩尔比为10：5：1,搅拌速度为100 r/min,反应时间1 h。反应中磷酸根离子和钙离子的利用率分别达到98%和25%以上。电子扫描显微镜（SEM）表征晶种在参与反应后,表面有结晶生成。研究表明,采用诱导结晶法可将水中氟离子浓度从5~10 mg/L降至1 mg/L以下,达到饮用水水质标准。     

反硝化除磷颗粒污泥培养方式的对比实验研究

采用两完全相同的气升式间歇反应器（SBAR）进行反硝化除磷颗粒污泥培养方式的对比实验研究。R1始终以厌氧/好氧/缺氧（A/O/A）模式运行,在颗粒化的同时富集反硝化除磷菌（DPAOs）;R2以厌氧/好氧（A/O）模式培养颗粒,待颗粒形成后加入缺氧段,形成A/O/A模式,强化富集DPAOs。结果表明,R2中颗粒化时间较短,但所形成颗粒的沉降速率和比重分别为30.4 m/h和1.022 g/cm³,低于R1培养颗粒的35.9 m/h和1.061 g/cm³;R1中颗粒对于COD、NH⁺₄-N、TN和TP的平均去除率分别是86%、98%、82%和91%,高于R2中的86%、99%、74%和66%;反应器运行至183 d时,DPAOs所占比例分别为44.7%和20.9%。     

Simultaneous nitrification and denitrification in an aerobic reactor with granular sludge originating from an upflow anaerobic sludge bed reactor.

Anaerobic granular sludge, obtained from an upflow anaerobic sludge bed reactor at a brewery waste treatment station, was cultured for 3 months under aeration conditions until the diameter of sludge was in the range 1.8 to 2.6 mm. The aerobic granular sludge gathered acquired the ability of catalyzing simultaneous nitrification and denitrification (SND) and was applied in the study of the process of nitrogen removal in a bioreactor. The ratio between chemical oxygen demand (COD) and ammonium-nitrogen (NH4(+)-N) concentration in the influent was found to be an important factor influencing the process of SND. The final percentage removal of NH4(+)-N reached 100% under the optimal condition of 500 mg/L COD and 0.39 NH4(+)-N/COD. Intermediate products, such as nitrite-nitrogen and nitrate-nitrogen, were also analyzed to clarify the SND process with the aerobic granular sludge.     

PAH removal from spiked municipal wastewater sewage sludge using biological, chemical and electrochemical treatments

Polycyclic aromatic hydrocarbons (PAHs) have been widely studied due to their presence in all the environmental media and toxicity to life. These molecules are strongly adsorbed on the particulate matters of soils, sludges or sediments because of their strong hydrophobicity which makes them less bioavailability, thus limiting their bioremediation. Different sludge treatment processes were tested to evaluate their performances for PAH removal from sludge prealably doped with 11 PAHs (5.5mg each PAH kg(-1) of dry matter (DM)): two biological processes (mesophilic aerobic digestion (MAD) and simultaneous sewage sludge digestion and metal leaching (METIX-BS)) were tested to evaluate PAH biodegradation in sewage sludge. In parallel, two chemical processes (quite similar Fenton processes: chemical metal leaching (METIX-AC) and chemical stabilization (STABIOX)) and one electrochemical process (electrochemical stabilization (ELECSTAB)) were tested to measure PAH removal by these oxidative processes. Moreover, PAH solubilisation from sludge by addition of a nonionic surfactant Tween 80 (Tw80) was also tested. The best yields of PAH removal were obtained by MAD and METIX-BS with more than 95% 3-ring PAH removal after a 21-day treatment period. Tw80 addition during MAD treatment increased 4-ring PAHs removal rate. In addition, more than 45% of 3-ring PAHs were removed from sludge by METIX-AC and during ELECSTAB process were quiet good with approximately 62% of 3-ring PAHs removal. However, little weaker removal of 3-ring PAHs (<35%) by STABIOX. None of the tested processes were efficient for the elimination of high molecular weight (> or = 5-ring) PAHs from sludge.     

污泥减量过程中臭氧氧化对硝化和反硝化影响的试验研究

采用AO工艺,考察了在污泥减量过程中臭氧(O3)氧化对生物系统硝化和反硝化能力的影响.结果表明,在每克SS中O3投量为0.05 g时,氧化后污泥中的CODcr由37.5 mg/L增至700mg/L,TN由4.86 mg/L增至36.6 mg/L,NH4 -N由0.353mg/L增至7.49 mg/L,NO3--N由2.19 mg/L增至5.15 mg/L.虽然氧化系统出水NH4 -N浓度略高于对照系统,但氧化系统NH4 -N的去除率大于98%,硝化能力基本没有受到O3氧化的影响.O3氧化污泥后增加的有机物作为附加的碳源循环至缺氧段,提高了反硝化的效果,当污泥氧化比例分别为10%、20%、30%时,进入缺氧段的CODCr/TN分别平均增至11.21、11.56、11.88,氧化系统的反硝化效果也随之分别提高5%、25%、37%.     

厌氧氨氧化菌接种污泥的选择培养过程研究

厌氧氨氧化菌的2种不同接种污泥培养实验表明,厌氧消化污泥和好氧硝化污泥均可成功启动厌氧氨氧化过程.接种厌氧消化污泥比好氧硝化污泥培养的厌氧氨氧化菌启动快,但后者去除效果较好.接种好氧硝化污泥的反应器的厌氧氨氧化速率随着氨氮基质进水浓度的增加呈线性增加.进水氨氮浓度为280 mg/L时的氨氮平均去除率达91%;而接种厌氧消化污泥的相应氨氮平均去除率仅为52%.厌氧氨氧化过程以接种好氧硝化污泥来启动为宜.     

Pilot-plant study of wastewater sludge decontamination using a ferrous sulfate bioleaching process.

The objective of this research was to investigate the performance of the ferrous sulfate bioleaching (FSBL) process in a pilot plant for decontamination and stabilization of wastewater sludge. Batch and continuous experiments, conducted with two 4-m3 bioreactors using indigenous iron-oxidizing bacteria (20% v/v of inoculum) with addition of 4.0 g ferrous sulfate heptahydrate per liter of sludge initially acidified to pH 4.0, were sufficient for effective heavy metal (cadmium, copper, manganese, zinc, and lead) removal yields. The average metal removal yields during the FSBL process were as follows: cadmium (69 to 75%), copper (68 to 70%), manganese (72 to 73%), zinc (65 to 66%), and lead (16%). The FSBL process was also found to be effective in removing both fecal and total coliforms (abatement > 5 to 6 log units). The nutrients content (nitrogen, phosphorus, and magnesium) were also preserved in decontaminated sludge.     

摇动床生物膜反应器和活性污泥法组合技术处理高浓度有机废水的研究

利用摇动床生物膜反应器(简称摇动床)技术具有的容积负荷高与污泥产量低的优点,在普通活性污泥池的前部填充高性能丙烯酸树脂纤维(Biofringe)填料,研究了摇动床和活性污泥法组合技术处理高浓度有机废水的有效性。结果表明,该组合技术具有很强的有机物去除能力,当进水COD平均质量浓度由1500mg/L上升到2514mg/L时,出水COD的平均去除率基本保持在96%以上;整个运行阶段的出水COD浓度均满足《污水综合排放标准》(GB8978—1996)的二级标准;当进水NH4+-N浓度增加时,NH4+-N的去除率由99.7%降低到76.5%,但是在试验运行的整个阶段,摇动床和活性污泥法组合技术系统都表现出较强的硝化能力;活性污泥池中最高的混合液悬浮固体(MLSS)质量浓度为10625mg/L,最高MLSS约为普通活性污泥法的4倍;运行结束后的污泥产率为0.186,污泥产率仅为普通活性污泥法的50%左右。     

Fate of Terpene Compounds in Activated Sludge Wastewater Treatment Systems

ABSTRACT

Terpene-based cleaners are being widely used in industrial cleaning formulations because of their ability to replace suspected ozone-depleting chemicals such as 1,1,1-trichloroethane and 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113). Substitution of chlorinated solvents with ter-pene-based cleaners, however, is expected to result in increased discharges to wastewater from industrial operations. A pilot-scale study was conducted at the U.S. Environmental Protection Agency's (EPA) Test & Evaluation Facility in Cincinnati, OH, to quantify the fate of specific terpene compounds in the activated sludge wastewater treatment process. Biodegradation rates of terpenes were estimated from the difference between the influent terpene mass flow rates and the amounts volatilized to air, partitioned to waste sludge, and passed through the treatment process unchanged. Any chemical transformation of the terpene compounds studied was attributed to biodegradation.

Analytical methods were developed to determine ter-pene concentrations in aqueous and gaseous media. The fate of two common terpene compounds (d-limonene and terpinolene) were evaluated in three identical pilot-scale systems: (1) a system with a high target spike range (2–10 mg/L), (2) a system with a low target spike range (0.5–2 mg/L), and (3) a control system (no spike).

The study showed that the primary removal mechanism for the terpene compounds in the activated sludge process is biodegradation. Typically, greater than 90% of the mass of terpenes entering the aeration basin of the activated sludge process biodegrades to other compounds; volatilization from the reaction basin accounts for less than 10%, while loss to waste activated sludge and the secondary clarifier effluent accounts for less than 1%.     

Electrokinetic enhancement removal of heavy metals from industrial wastewater sludge

An enhanced electrokinetic process for removal of metals (Cr, Cu, Fe, Ni, Pb, Zn) from an industrial wastewater sludge was performed. The electrokinetic experiments were conducted under a constant potential gradient (1.25 V cm(-1)) with processing fluids of tap water (TW), sodium dodecylsulfate (SDS) and citric acid (CA) for 5 days. Results showed that metal removal efficiency of heavy metals for EK-TW, EK-SDS and EK-CA systems are 11.2-60.0%, 37.2-76.5%, and 43.4-78.0%, respectively. A highest metal removal performance was found in EK-CA system. The removal priority of investigated metals from sludge by EK process was found as: Cu > Pb > Ni > Fe > Zn > Cr. The results of sequential extraction analysis revealed that the binding forms of heavy metals with sludge after electrokinetic process were highly depend upon the processing fluid operated. It was found that the binding forms of metals with sludge were changed from the more difficult extraction type (residual and sulfate fractions) to easier extraction types (exchangeable, sorbed, and organic fraction) after treatment by electrokinetic process. Results imply that if a proper treatment technology is followed by this EK process to remove metals more effectively, this treated sludge will be more beneficial for sludge utilization afterwards. Before it was reused, the risk associated with metals of more mobile forms to the environment need to be further investigated. The cost analysis was also evaluated for the investigated electrokinetic systems.     

Enhanced sludge granulation in upflow anaerobic sludge blanket (UASB) reactors by aluminum chloride.

Two upflow anaerobic sludge blanket (UASB) reactors were concurrently operated for 146 days to examine the effects of aluminum chloride (AlCl3) on the sludge granulation process during start-up. Sludge granulation (defined as that over 10% of granules were larger than 2.0 mm) was achieved in the control reactor (R1) in approximate three months. Introduction of Al3+ at a concentration of 300 mg/l reduced the sludge granulation time by approximate one month. Throughout the experiment the AlCl3-added reactor (R2) had a higher biomass concentration, e.g., 13.8 g-MLVSS/l versus 12.8 g-MLVSS/l on Day 146. Granules became visible earlier in R2 compared with R1 (35 days versus 65 days). The average size of granules from R2 was larger than that from R1. The results demonstrated that AlCl3 enhanced the sludge granulation process in the UASB reactors.     

Bacterial leaching of heavy metals from sewage sludge-bioreactors comparison

More than 50% of municipal sewage sludges cannot be used on agricultural land because of their heavy metals content. Therefore, microbial leaching of heavy metal from municipal sludge was studied in a continuously stirred tank reactor without recycling (CSTR) or with sludge recycling (CSTRWR) at residence times of 1, 2, 3 and 4 days. The reactor CSTRWR is supposed to be more efficient for bacterial process due to the recycling of active bacteria from the settling tank to the reactor. The CSTRWR and the CSTR with 1 g litre(-1) FeSO(4).7H(2)O addition were equally efficient because of copper reprecipitation or recomplexation in the settling tank of the CSTRWR. In the CSTR, about 62% of copper and about 77% of zinc were dissolved in 3 days residence time compared to 50% of copper and 64% of zinc in the CSTRWR, if 3 g litre(-1) FeSO(4).7H(2)O was added. Thus with larger amount of substrate, the CSTR was more efficient than the CSTRWR. Residence time and pH were the main factors for zinc solubilization while for copper, the redox potential was also a major factor. The effect of FeSO(4).7H(2)O concentration on bacterial activity to solubilize heavy metals was also studied, increased concentration of FeSO(4).7H(2)O yielded better copper solubilization while it had no effect or a negative effect on zinc. This supports the hypothesis of a direct mechanism for zinc solubilization and of an indirect mechanism for copper solubilization.