处理BPA模拟废水的SBR工况参数对污泥有机毒性的影响研究

在处理双酚A(BPA)模拟废水的序批式活性污泥系统(SBR)反应器中,保持进水COD含量均为300 mg·L-1左右,通过改变水力停留时间HRT从12~8 h,污泥龄SRT从20~10 d,考察污泥有机毒性和其他水质指标的变化.试验分析了空白组和40 mg·L-1初始浓度BPA对照组在不同工况条件下周期末出水COD值、污泥有机毒性分布规律以及稳定期单周期内COD值和污泥有机毒性的变化趋势.结果表明,缩短水力停留时间和污泥龄有利于活性污泥降解BPA,并消减稳定期污泥的有机毒性;出水COD稳定在50 mg·L-1左右,且水相和泥相均无BPA残留.在应用PCR-DGGE技术分析SBR系统内微生物菌群多样性和不同样品间的相似性过程中,得出污泥总毒性抑制率与微生物多样性呈负相关性关系,进水成分的不同和运行参数改变是导致污泥总毒性差异的主要原因.     

Removal of veterinary antibiotics from anaerobically digested swine wastewater using an intermittently aerated sequencing batch reactor

A lab-scale intermittently aerated sequencing batch reactor(IASBR)was applied to treat anaerobically digested swine wastewater(ADSW)to explore the removal characteristics of veterinary antibiotics.The removal rates of 11 veterinary antibiotics in the reactor were investigated under different chemical organic demand(COD)volumetric loadings,solid retention times(SRT)and ratios of COD to total nitrogen(TN)or COD/TN.Both sludge sorption and biodegradation were found to be the major contributors to the removal of veterinary antibiotics.Mass balance analysis revealed that greater than 60%of antibiotics in the influent were biodegraded in the IASBR,whereas averagely 24%were adsorbed by sludge under the condition that sludge sorption gradually reached its equilibrium.Results showed that the removal of antibiotics was greatly influenced by chemical oxygen demand(COD)volumetric loadings,which could achieve up to 85.1%±1.4%at 0.17±0.041 kg COD/m-3/day,while dropped to 75.9%±1.3%and 49.3%±12.1%when COD volumetric loading increased to 0.65±0.032 and1.07±0.073 kg COD/m-3/day,respectively.Tetracyclines,the dominant antibiotics in ADSW,were removed by 87.9%in total at the lowest COD loading,of which 30.4%were contributed by sludge sorption and 57.5%by biodegradation,respectively.In contrast,sulfonamides were removed about 96.2%,almost by biodegradation.Long SRT seemed to have little obvious impact on antibiotics removal,while a shorter SRT of 30–40 day could reduce the accumulated amount of antibiotics and the balanced antibiotics sorption capacity of sludge.Influent COD/TN ratio was found not a key impact factor for veterinary antibiotics removal in this work.     

进水底物浓度对蔗糖废水产酸合成PHA影响研究

混合菌群合成生物可降解塑料(PHA)成为目前研究的热点,三段式PHA合成工艺(水解产酸、产PHA菌富集、PHA合成)被广泛应用.在三段式工艺中,产PHA菌的富集非常关键,只有稳定产生PHA菌才能保障PHA合成的产量.针对产PHA菌富集系统容易出现污泥膨胀的问题,本研究考察了进水底物浓度对产PHA菌富集效率及运行稳定性的影响.在560mg·L-1、1 120 mg·L-1、1 680 mg·L-1这3组不同进水底物浓度的对比实验中,证实了COD 1 120 mg·L-1条件下富集反应器能够在较短污泥龄下稳定富集具有较高污泥浓度的高效产PHA菌,且不会发生污泥膨胀.在94 d的富集期后其批次实验最大PHA含量、PHA转化率(COD/COD)及PHA比合成速率能分别达到50%、0.714 5及0.191 2 mg·(mg·h)-1.研究还同时证实细胞内糖原水平高低与其PHA合成能力密切相关,可采用其作为富集效果的重要检测指标之一.     

混合碳源浓度对单级好氧生物脱氮除磷的影响

以乙酸钠和丙酸钠1:2混合作为碳源,进水COD浓度分别为200,400,600,800mg/L,研究混合碳源浓度对单级好氧生物脱氮除磷的影响,并通过比较微生物体内储能物质的变化,探讨混合碳源浓度对生物脱氮除磷性能影响的机理.结果表明,当进水磷和氨氮浓度分别为12,30mg/L时,随着进水COD由200增加至800mg/L,磷去除率由39.9%提升至86.4%(氮去除率从13.5%提升至96.4%).进水COD为400mg/L时单位挥发性悬浮固体(VSS)的磷和氮去除量达到最高[分别为(4.31±0.08)和(6.15±0.22)mg/g].当进水COD由200增加至400mg/L时生物除磷活性增强,而COD继续增加会使污泥沉降性能变差,脱氮除磷生物活性降低.好氧吸磷和同步硝化反硝化主要由微生物体内储能物质多β羟基烷酸盐(PHA)驱动,当进水COD为400mg/L时单位VSS消耗的PHA最多.混合碳源浓度通过影响碳源的好氧代谢,使微生物体内储能物质的积累/转化量不同,进而影响系统的脱氮除磷性能.     

Investigation on removal pathways of Di 2-ethyl hexyl phthalate from synthetic municipal wastewater using a submerged membrane bioreactor

Highly hydrophobic Di 2-ethyl hexyl phthalate (DEHP) is one of the most prevalent plasticizers in wastewaters. Since its half-life in biological treatment is around 25 days, it can be used as an efficiency indicator of wastewater treatment plant for the removal of hydrophobic emerging contaminants. In this study, the performance of submerged membrane bioreactor was monitored to understand the effect of DEHP on the growth of aerobic microorganisms. The data showed that the chemical oxygen demand (COD) and ammonia concentration were detected below 10 and 1.0 mg/L, respectively for operating conditions of hydraulic retention time (HRT) = 4 and 6 hr, sludge retention time (SRT) = 140 day and sludge concentration between 11.5 and 15.8 g volatile solid (VS)/L. The removal efficiency of DEHP under these conditions was higher and ranged between 91% and 98%. Results also showed that the removal efficiency of DEHP in biological treatment depended on the concentration of sludge, as adsorption is the main mechanism of its removal. For the submerged membrane bioreactor, the pore size is the pivotal factor for DEHP removal, since it determines the amount of soluble microbial products coming out of the process. Highly assimilated microorganisms increase the biodegradation rate, as 74% of inlet DEHP was biodegraded; however, the concentration of DEHP inside sludge was beyond the discharge limit. Understanding the fate of DEHP in membrane bioreactor, which is one of the most promising and futuristic treatment process could provide replacement for conventional processes to satisfy the future stricter regulations on emerging contaminants.     

污泥龄对低氧丝状菌活性污泥微膨胀系统的影响

为了研究污泥龄(SRT)对低氧丝状菌活性污泥微膨胀系统的影响,采用序批式间歇反应器(SBR)进行试验,分别按照厌氧/好氧和单级好氧的方式运行,考察了不同SRT下丝状菌污泥微膨胀系统的沉降性、脱氮除磷过程以及污泥特性的变化.结果表明,在好氧水力停留时间充分的条件下,低氧环境不但不会影响丝状菌微膨胀污泥的硝化进程,而且还有助于同步硝化反硝化(SND)、单级好氧除磷的发生.厌氧/好氧运行时,SRT与活性污泥的比硝化速率、比释磷速率和比吸磷速率成反比,与SND率和污泥的含磷量成正比.单级好氧运行时,减小SRT对硝化过程影响不大,但是有助于改善除磷效果.活性污泥的比耗氧速率(SOUR)、胞外聚合物(EPS)中多糖与蛋白质含量的比值、以及粘度都与SRT成反比.适当地减小SRT可以改善丝状菌微膨胀污泥的沉降性.厌氧/好氧运行时,厌氧段微氧环境易引发过度丝状菌污泥膨胀;单级好氧运行时,SRT过低会造成污泥黏性骤增而引发黏性污泥膨胀.     

Simultaneous nitrification and denitrification in activated sludge system under low oxygen concentration

Simultaneous nitrification and denitrification (SND), which is more economical compared with the traditional method for nitrogen removal, is studied in this paper. In order to find the suitable conditions of this process, a mixed flow activated sludge system under low oxygen concentration is investigated, and some key control parameters are examined for nitrogen removal from synthetic wastewater. The results show that SND is accessible when oxygen concentration is 0.3–0.8 mg/L. The nitrogen removal rate can be obtained up to 66.7% with solids retention time (SRT) of 45 d, C/N value of 10, and F/M ratio of 0.1 g COD/(g MLSS·d). Theoretical analysis indicates that SND is a physical phenomenon and governed by oxygen diffusion in flocs. Translated from Environmental Pollution and Control, 2004, 26(1): 11–13 [译自: 环境污染与防治]     

Effect of sludge retention time on sludge characteristics and membrane fouling of membrane bioreactor

Three identical membrane bioreactors (MBRs) were operated over 2 years at different sludge retention time (SRT) of 10 d, 40 d and no sludge withdrawal (NS), to elucidate and quantify the effect of SRT on the sludge characteristics and membrane fouling. The hydraulic retention times of these MBRs were controlled at 12 h. With increasing SRT, the sludge concentrations in the MBRs increased, whereas the ratio of volatile suspended solid to the total solid decreased, and the size of sludge granule diminished in the meantime. A higher sludge concentration at long SRT could maintain a better organic removal efficiency, and a longer SRT was propitious to the growth of nitrifiers. The performance of these MBRs for the removal of COD and NH₄⁺-N did not change much with different SRTs. However, the bioactivity decreased as SRT increase. The measurement of specific oxygen uptake rates (SOUR) and fluorescence in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes testified that SOUR and the proportion of the bacteria-specific probe EUB338 in all DAPI-stainable bacteria decreased with increasing SRT. The concentrations of total organic carbon, protein, polysaccharides and soluble extracellular polymeric substance (EPS) in the mixed liquor supernatant also decreased with increasing SRT. The membrane fouling rate was higher at shorter SRT, and the highest fouling rate appeared at a SRT of 10 d. Both the sludge cake layer and gel layer had contribution to the fouling resistance, but the relative contribution of the gel layer decreased as SRT increase.     

好氧段碳源浓度对同步去除和富集磷酸盐生物膜的影响

利用聚磷菌以循环交替O/A模式运行,对生活污水处理厂的主流工艺中实现磷酸盐的同步去除和富集,探究了好氧段碳源浓度对聚磷生物膜去除和富集磷酸盐性能以及生物膜中微生物种群结构的影响.结果表明,好氧COD质量浓度从200 mg·L~(-1)降低到0 mg·L~(-1),吸磷速率提升1. 29倍,出水磷质量浓度稳定在0. 5 mg·L~(-1)以下;释磷速率提升3. 56倍,富集液磷酸盐质量浓度从27. 125 mg·L~(-1)升高到55. 91 mg·L~(-1).微生物群落变化中,鉴定为聚磷菌的变形菌门(Proteobacteria)的含量增加约2倍,红环菌科(Rhodocyclaceae)和厌氧绳菌科(Anaerolineaceae)的富集效果分别提高了2. 28和5倍.降低好氧段碳源浓度,有利于聚磷菌的筛选和富集,强化了好氧段磷酸盐的去除以及厌氧段磷酸盐的释放,获得了更高的磷酸盐富集液,并且为以资源回收为目的的未来城市污水处理厂提供降低好氧段碳源需求的理论基础.     

富磷污泥厌氧发酵过程中乙酸浓度对磷释放的影响

以强化生物除磷(EBPR)污泥为研究对象,考察了不同初始乙酸浓度条件下富磷污泥厌氧发酵过程中磷及相关指标的变化,并探讨释磷机制.结果表明:初始乙酸浓度对污泥最大释磷量影响不大,(73.1±2.2)%的污泥总磷量(TP)以磷酸盐的形式释放到液相中,其主要来自聚磷的分解.聚磷的分解途径包括:1)聚磷菌(PAOs)通过吸收乙酸贮存聚β-羟基烷酸酯(PHA)的厌氧生物释磷机制释放磷酸盐;2)PAOs的维持作用导致的聚磷直接分解过程.当初始乙酸浓度不充足时,生物释磷过程受限制,聚磷以相对较慢的速率直接分解;随着乙酸浓度的增大,生物释磷速率增快,同时随之增加的PHA含量能促进污泥的水解酸化.上清液中PO43--P和Mg2+浓度在达到最大值后出现了下降的现象,其可能形成鸟粪石等沉淀.根据试验数据,本文提出了从富磷污泥中回收磷的策略,即可在厌氧消化开始前向污泥中投加一定量碳源,并在发酵24h内分离上清液进行磷回收,这样不仅可以快速大量地从上清液中回收磷并减少沉淀引起的管道堵塞等问题,还可消除高浓度磷酸盐对厌氧消化的影响.     

间歇曝气式膜生物反应器对养猪沼液中兽用抗生素的去除特性

研究了间歇式膜生物反应器在不同进水碳氮比和有机负荷下对养猪沼液中11种兽用抗生素的去除特性,以及污泥中抗生素的含量变化.结果表明,水力停留时间(HRT)≥5 d、化学需氧量(COD)/总氮(TN)=2.1时,该膜生物反应器对抗生素和COD的去除率均较高,分别达到(79.1±0.7)%和(88.4±1.4)%;当HRT缩短至3 d时,虽然COD去除率不受影响,但抗生素的去除率明显下降;COD/TN从2.1降至0.7后,抗生素去除效率不受影响,但COD去除率明显降低.长污泥龄(SRT)下污泥中出现四环素类和喹诺酮类抗生素的持续积累,积累量随污泥龄的缩短而降低.污泥中的抗生素含量与组成受进水影响较大.     

Effects of phosphorus and nitrogen limitation on PHA production in activated sludge

The e ects of phosphorus and nitrogen limitation on polyhydroxyalkanoate (PHA) production and accumulation by activated sludge biomass with acetate as a carbon source were investigated. Pre-selected influent carbon-phosphorus (C:P, W/W) of 100, 160, 250, 500 and 750, and carbon-nitrogen (C:N, W/W) of 20, 60, 100, 125 and 180 were applied in the phosphorus limitation experiments and the nitrogen limitation experiments, respectively. The maximum PHA accumulation up to 59% of the cell dry weight with a PHA productivity of 1.61 mg PHA/mg COD consumed was observed at the C:N 125 in the nitrogen limitation experiment. This value was much higher than that obtained in previous studies with a normal substrate feeding. The study showed that activated sludge biomass would produce more polyhydroxybutyrate than polyhydroxyvalerate under the stress of nutrient limitation, especially under phosphorus limitation conditions. The experimental result also indicated that both phosphorus and nitrogen limitation may cause sludge bulking.     

Impact of ozone assisted ultrasonication pre-treatment on anaerobic digestibility of sewage sludge

Impact of ultrasonication(ULS) and ultrasonication–ozonation(ULS-Ozone) pre-treatment on the anaerobic digestibility of sewage sludge was investigated with semi-continuous anaerobic reactors at solid retention time(SRT) of 10 and 20 days. The control, ULS and ULS-Ozone reactors produced 256, 309 and 348 m L biogas/g CODfedand the volatile solid(VS) removals were 35.6%, 38.3% and 42.1%, respectively at SRT of 10 days. At SRT of20 days, the biogas yields reached 313, 337 and 393 m L biogas/g CODfedand the VS removal rates were 37.3%, 40.9% and 45.3% in the control, ULS and ULS-Ozone reactors, respectively.ULS-Ozone pre-treatment increased the residual organic amount in the digested sludge.These soluble residual organics were found to contain macromolecules with molecular weights(MW) larger than 500 k Da and smaller polymeric products with MW around 19.4and 7.7 k Da. These compounds were further characterized to be humic acid-like substances with fluorescent spectroscopy analysis.     

Nitrogen removal from wastewater and bacterial diversity in activated sludge at different COD/N ratios and dissolved oxygen concentrations

The impact of the organic carbon to nitrogen ratio (chemical oxygen demand (COD)/N) in wastewater and dissolved oxygen (DO) concentration on carbon and nitrogen removal efficiency, and total bacteria and ammonia-oxidizing bacteria (AOB) communities in activated sludge in constantly aerated sequencing batch reactors (SBRs) was determined. At DO of 0.5 and 1.5 mg O₂/L during the aeration phase, the efficiency of ammonia oxidation exceeded 90%, with nitrates as the main product. Nitrification and denitrification achieved under the same operating conditions suggested the simultaneous course of these processes. The most effective nitrogen elimination (above 50%) was obtained at the COD/N ratio of 6.8 and DO of 0.5 mg O₂/L. Total bacterial diversity was similar in all experimental series, however, for both COD/N ratios of 6.8 and 0.7, higher values were observed at DO of 0.5 mg O₂/L. The diversity and abundance of AOB were higher in the reactors with the COD/N ratio of 0.7 in comparison with the reactors with the COD/N of 6.8. For both COD/N ratios applied, the AOB population was not affected by oxygen concentration. Amplicons with sequences indicating membership of the genus Nitrosospira were the determinants of variable technological conditions.     

不同碳源种类对好氧颗粒污泥合成PHA的影响

影响好氧颗粒污泥稳定性的因素众多,其中碳源种类的不同会造成好氧颗粒污泥合成聚羟基烷酸酯(PHA)的不同,进而影响其稳定性能.采用混合碳源驯化培养的好氧颗粒污泥进行试验.考察了厌氧条件下,乙酸钠等八种碳源对好氧颗粒污泥合成PHA的影响.结果表明,颗粒污泥对乙酸钠和蔗糖具有较好的转化能力,合成PHA的量分别为102.19mgCOD/g·VSS和70.58mgCOD/g·VSS,显著高于其他碳源的PHA合成量(5~26mg/g×VSS).故以蔗糖和乙酸钠作碳源均有利于颗粒污泥稳定性能的维持,而当以甲醇作碳源时好氧颗粒污泥的贮存能力最差.     

Influence of microbial community structure of seed sludge on the properties of aerobic nitrifying granules

In order to evaluate the influence of microbial community structure of seed sludge on the properties of aerobic nitrifying granules, these granules were cultivated with different seed sludge, and the variation of microbial community and dominant bacterial groups that impact the nitrogen removal efficiency of the aerobic nitrifying granules were analyzed and identified using 16s rDNA sequence and denaturing gradient gel electrophoresis (DGGE) profiles. The results presented here demonstrated that the influence of the community structure of seed sludge on the properties of aerobic nitrifying granules was remarkable, and the granules cultivated by activated sludge from a beer wastewater treatment plant showed better performance, with a stable sludge volume index (SVI) value of 20 mL/g, high extracellular polymeric substance (EPS) content of 183.3 mg/L, high NH₄⁺-N removal rate of 89.42% and abundant microbial population with 10 dominant bacterial groups. This indicated that activated sludge with abundant communities is suitable for use as seed sludge in culturing aerobic nitrifying granules.     

Shifts in microbial community structure and diversity in a MBR combined with worm reactors treating synthetic wastewater

The chemical oxygen demand (COD) and NH₃-N removal, membrane fouling, sludge characteristics and microbial community structure in a membrane bioreactor (MBR) coupled with worm reactors (SSBWR) were evaluated for 210 days. The obtained results were compared to those from a conventional MBR (C-MBR) operated in parallel. The results indicated that the combined MBR (S-MBR) achieved higher COD and NH₃-N removal efficiency, slower increase in membrane fouling, better sludge settleability and higher activities of the related enzymes in the activated sludge. Denaturing gradient gel electrophoresis was used to analyze the microbial community structures in the C-MBR and the S-MBR. The microbial community structure in the S-MBR was more diverse than that in the C-MBR. Additionally, the slow-growing microbes such as Saprospiraceae, Actinomyces, Frankia, Clostridium, Comamonas, Pseudomonas, Dechloromonas and Flavobacterium were enriched in the S-MBR, further accounting for the sludge reduction, membrane fouling alleviation and wastewater treatment.     

短泥龄活性污泥系统碳磷污染物去除机制及微生物结构分析

在污泥停留时间（SRT）为3 d的条件下,探究了不同水力停留时间（HRT）条件下（4、6、8、12和16 h）的超短龄活性污泥系统碳、磷去除效果、机制,以及微生物群落结构特征.结果表明,在HRT=8 h及以上时短活性污泥系统才会有稳定的碳、磷去除效果,去除率分别能达到80%和90%以上;去除机理为吸附和生物作用,但COD和磷以吸附的方式去除比例随HRT的延长而减小,分别从47.2%和89.1%降低至35.9%和33.6%.微生物群落结构分析表明,短SRT系统中主要的优势微生物种类与传统活性污泥系统相似,除磷由传统聚磷菌（PAOs）和反硝化聚磷菌（DPAOs）共同完成,相对丰度随着HRT的延长而增加.     

Insights on the solubilization products after combined alkaline and ultrasonic pre-treatment of sewage sludge

This work provides insights on the solubilization products after a simultaneous combination of alkaline and ultrasonic (ALK + ULS) pre-treatment of sewage sludge. Soluble chemical oxygen demand (SCOD) increased from 1200 to 11,000 mg/L after such treatment. Organics with molecular weight around 5.6 kDa were solubilized because of the synergistic effect of ultrasound and alkali. Organics with molecular weight larger than 300 kDa increased from 7.8% to 60%, 16% and 42.3% after ULS, ALK and ALK + ULS treatment, respectively. Excitation emission matrix fluorescence spectroscopy analysis identified soluble microbial product-like and humic acid-like matters as the main solubilization products. Sludge anaerobic biodegradability was significantly enhanced with the simultaneous application of ALK + ULS pre-treatment. ALK + ULS pre-treatment resulted in 37.8% biodegradability increase compared to the untreated sludge. This value was higher compared to the biodegradability increase induced by individual ALK pre-treatment (5.7%) or individual ULS pre-treatment (20.7%) under the same conditions applied.     

利用活性污泥快速富集污水碳源的试验研究

通过小试研究了活性污泥对城市污水中有机物的吸附特征,分析了富碳污泥在静置沉降过程中对有机物的释放过程.结果表明,活性污泥能够快速吸附污水中的碳源,约10 min左右即可完成对不溶性有机物的吸附,对溶解性有机物的吸附过程较慢（约30 min）.富碳污泥在进行静置泥水分离过程中,存在有机物释放过程,在30～100 min的...