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关键词： Woodchip bioreactor   Preferential flow   Denitrification   In situ monitoring   Water quality   High frequency  

摘要： Woodchip bioreactors are a practical, low-cost technology for reducing nitrate (NO3) loads discharged from agriculture. Traditional methods of quantifying their performance in the field mostly rely on low-frequency, time-based (weekly to monthly sampling interval) or flow-weighted sample collection at the inlet and outlet, creating uncertainty in their performance and design by providing incomplete information on flow and water chemistry. To address this uncertainty, two field bioreactors were monitored in the US and New Zealand using high-frequency, multipoint sampling for in situ monitoring of NO3-N concentrations. High-frequency monitoring (sub hourly interval) at the inlet and outlet of both bioreactors revealed significant variability in volumetric removal rates and percent reduction, with percent reduction varying by up to 25 percentage points within a single flow event. Time series of inlet and outlet NO3 showed significant lag in peak concentrations of 1-3 days due to high hydraulic residence time, where calculations from instantaneous measurements produced erroneous estimates of performance and misleading relationships between residence time and removal. Internal porewater sampling wells showed differences in NO3 concentration between shallow and deep zones, and "hot spot" zones where peak NO3 removal co-occurred with dissolved oxygen depletion and dissolved organic carbon production. Tracking NO3 movement through the profile showed preferential flow occurring with slower flow in deeper woodchips, and slower flow further from the most direct flowpath from inlet to outlet. High-frequency, in situ data on inlet and outlet time series and internal porewater solute profiles of this initial work highlight several key areas for future research.

关键词： Urine nitrification   Nutrient recovery   Membrane bioreactor   Membrane distillation   Urine fertiliser   Resource recovery  

摘要： Source separation and recovery of human urine have often been proposed as an effective way to achieve a more sustainable waste-to-resource cycle. Its high density of available macronutrients (N-P-K) in urine makes it an ideal raw material for the production of fertiliser. However, to improve the safety and public acceptance of urine-based fertilisers, odour and pathogens must be removed. In this work, low-temperature DCMD was investigated a mean to produce a non-odorous high-concentration liquid fertiliser. The effectiveness of urine-fertiliser in hydroponically growing leafy vegetables was benchmarked with a commercial solution. Also, prior to the DCMD, urine was biologically oxidised through an MBR which removed over 95% of the DOC and converted almost 50% of the NH3 into NO3-. The results showed that, despite the high salinity and high LMW organics in human urine, MD was still able to achieve a final product with TDS concentration up to 280 g.L-1. A sharp flux decline was measured after 80% water recovery, but alkaline cleaning effectively removed the thick fouling layer and fully recovered the initial flux. When used to grow lettuce and Pak Choi hydroponically, the produced urine fertiliser achieved promising performances as the biomass from the aerial part of the plants was often similar to the one obtained with commercial fertilisers. Overall, this article investigates the whole urine-to-biomass cycle, from collection to treatment to plant growth tests. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Anions   Liquids   Ammonia   Nitrogen   Biotechnology  

摘要： An integrated biotrickling filter-anammox bioreactor system for the complete treatment of ammonia in air with conversion to nitrogen gas without the supply of an extraneous electron donor for denitrification was established. Partial nitritation (i.e., conversion of ammonium to nitrite) was successfully achieved in the biotrickling filter (BTF) through free ammonia (FA) and free nitrous acid (FNA) inhibition on nitrite-oxidizing bacteria (NOB). During transients, while increasing nitrogen loading, FA was the main inhibitor of ammonia-oxidizing bacteria (AOB) and NOB, while during a steady state, it was mainly FNA, which was responsible for inhibitory effects due to the accumulation of nitrite. Ammonia removal by the BTF reached 50 gN m(-3) h(-1) with 100% removal at an inlet concentration of 404 ppm(v) and a gas residence time of 21 s. Average removal of ammonia during stable operation was 95%. The anammox bioreactor was slightly undersized compared to the BTF and could remove 75% of total nitrogen discharged by the BTF when the two reactors were connected and liquid was in one-pass mode. This undersizing caused accumulation of nitrite in the system when liquid was circled in a quasi-closed loop, which gradually inhibited the activity of anammox bacteria. Overall, this study demonstrates that ammonia in air can be effectively treated and converted to harmless nitrogen gas without an external electron donor supply using a biotrickling filter combined with an anammox bioreactor.

关键词： Biofilms   Genetics   Layers   Membranes   Biomass  

摘要： Anaerobic membrane bioreactors (AnMBRs) can significantly reduce the release of antibiotic resistance elements to the environment. The purpose of this study was to elucidate the role of membrane fouling layers (biofilms) in mitigating the release of intracellular and extracellular antibiotic resistance genes (iARGs and eARGs) from an AnMBR. The AnMBR was equipped with three membrane modules, each exhibiting a different level of fouling. Results showed that the absolute abundance of ARGs decreased gradually in the suspended biomass during operation of the AnMBR. Normalized abundances of targeted ARGs and intI1 were found to be significantly higher in the fouling layers compared to the suspended biomass, implying adsorption or an increased potential for horizontal gene transfer of ARGs in the biofilm. Effluent ARG data revealed that the highly fouled (HF) membrane significantly reduced the absolute abundance of eARGs. However, the HF membrane effluent concomitantly had the highest absolute abundance of iARGs. Nevertheless, total ARG abundance (sum of iARG and eARG) in the effluent of the AnMBR was not impacted by the extent of fouling. These results suggest a need for a combination of different treatment technologies to effectively prevent antibiotic resistance proliferation associated with these two ARG fractions.

关键词： Mature landfill leachate   Membrane bioreactor   Reverse osmosis   FT-ICR MS   Dissolved organic matter  

摘要： This study investigated the effectiveness of a combined membrane bioreactor (MBR) and reverse osmosis (RO) process for treating leachate produced by a large-scale anaerobic landfill. The MBR process had limited treatment efficiency for removing organic pollutants, but when combined with RO, the integrated system completely removed macromolecular compounds (i.e., humic- and fulvic-like substances) and produced effluent that satisfied the applicable discharge standard. The landfill leachate contained many types of DOM that had high molecular weight and were highly unsaturated. Although the MBR process removed some DOM that had a relatively low saturated degree (mainly aliphatic compounds (2.0 >= H/C >= 1.5) with relatively high bioa- vailability), many bio-refractory compounds were not removed. The RO system greatly reduced the content of residual DOM in MBR effluent and was effective for removing heteroatom DOM, especially polycyclic aromatics (AI > 0.66) and polyphenols (0.66 >= AI > 0.50). The effluent from the combined process of MBR and RO treatment mainly contained a small number of aliphatic compounds and phenolic compounds (AI <= 0.50 and H/C < 1.5) that had higher bioavailability than DOM in the raw leachate and posed little environmental risk.

关键词： Bioreactor   mechanical stimulation   construct   regeneration   tendon  

摘要： Objective: Although several different types of bioreactors are currently available with mechanical stimulation of constructs or prostheses for tendon regeneration, they are in many cases expensive and difficult to operate. This paper proposes a simple bioreactor to mechanically stimulate up to three constructs for tendon and ligament repair, composed of a stainless-steel frame and an electric motor. Methods: The deformation is produced by a cam wheel, whose eccentricity defines the maximum deformation. The test samples, braids of PLA seeded in surface with mouse fibroblasts, are immersed in the culture medium during mechanical stimulation. Results: Its advantages over existing similar bioreactor designs include: easy renewal of the culture medium and an external electric motor to avoid heating and contamination issues. After 14 days of stretching, the culture samples showed enhanced cellular proliferation and cell fiber alignment in addition to higher production of type I collagen. The cells initially seeded on the braid surface migrated to the inside of the braid. Conclusion: Although the results obtained have a poor statistical basis, they do suggest that the bioreactor could be usefully applied to stimulate constructs for tendon and ligament repair. Anyway, further experiments should be conducted in the future.

关键词： membrane bioreactor (MBR)   ozonation (O-3)   integrated process   sulfadiazine   modified polymeric membranes   Doehlert uniform array  

摘要： Ozonation can be used as a polishing treatment for degrading low-concentration pharmaceutical compounds recalcitrant to biological treatment, when large amounts of biodegradable organics have been previously removed by biological processes. Nevertheless, a systematic investigation has not yet been carried out for the coupled MBR + O-3 process through an experimental design approach. Thereby, the purpose of this study is to evaluate the performance of different processes (membrane bioreactor-MBR, ozonation;and integrated MBR + O-3) for removing the antibiotic sulfadiazine (SDZ) from a synthetic wastewater matrix of industrial interest. The MBR behavior was monitored over seven months for different parameters (pH, temperature, permeate flow, transmembrane pressure, biological oxygen demand-BOD5, chemical oxygen demand-COD, total organic carbon-TOC, solids, and SDZ concentration). Additionally, the amount of SDZ sorbed onto the sludge was characterized, an issue which is scarcely addressed in most research works. Ozonation experiments were conducted in batch mode in a 2-L glass reactor provided with openings for gas flow. For the MBR + O-3 process, the effects of gas flow rate (0.1-1.5 L min(-1)) and inlet ozone concentration (4-12 mg L-1) on SDZ removal from the MBR permeate were systematically assessed using a Doehlert experimental design and response surface methodology. The results indicated that the MBR system showed good performance regarding organic matter removal efficiency, evaluated in terms of BOD5 (91.5%), COD (93.1%) and TOC (96.3%). In contrast, SDZ was partially removed (33%) by the MBR;in that case, the results indicated that the antibiotic was moderately removed with the sludge and partially biodegraded. In turn, the MBR + O-3 system showed excellent performance for removing SDZ (100%), TOC (97%), BOD5 (94%) and COD (97%). The statistical analysis confirmed that the influence of ozone gas flow rate upon the SDZ removal rate was more important than that

关键词： 森林脑炎灭活疫苗   Vero细胞   生物反应器   免疫原性   安全性  

摘要： 目的评价生物反应器工艺制备森林脑炎灭活疫苗(Vero细胞)在动物体内的免疫原性及安全性。方法采用生物反应器培养Vero细胞,感染森林脑炎病毒(tick-borne encephalitis virus,TBEV),连续收获,经Sepharose 4FF柱层析纯化后,制备森林脑炎灭活疫苗,免疫昆明小鼠,检测疫苗在动物体内的免疫原性;通过疫苗接种豚鼠主动过敏性试验、ICR小鼠急性毒性试验、新西兰兔局部刺激性试验,评价疫苗在动物体内的安全性。结果制备的森林脑炎灭活疫苗(Vero细胞)对小鼠的免疫保护指数大于5.0×10^5,符合《中国药典》三部(2015版)标准。豚鼠主动过敏试验无豚鼠出现过敏性反应;急性毒性试验ICR小鼠未见明显毒性反应;局部刺激试验新西兰兔注射部位局部大体观察未见明显异常改变。结论生物反应器工艺制备的森林脑炎灭活疫苗(Vero细胞)具有良好的免疫原性和安全性。

关键词： 污水   絮凝   膜   膜生物反应器   奶牛场   污染  

摘要： 为探讨经济实用的高浓度奶牛场污水预处理方法,该研究开展了絮凝预处理对膜生物反应器(Membrane Bioreactor,MBR)膜污染的影响试验,试验采用高浓度奶牛场污水原水和絮凝出水作为MBR进水依次运行,对比分析了不同进水的膜污染规律及其原因。结果表明,絮凝出水作为MBR进水时膜污染速率较污水原水降低47%且膜组件的维护性清洗时间间隔由10 d延长至16 d;MBR处理污水原水的膜池混合液中胞外聚合物(Extracellular Polymeric Substances,EPS)和溶解性微生物产物(Soluble Microbial Products,SMP)浓度分别为4.76和3.94 g/L,而处理絮凝出水时的EPS和SMP浓度值分别为3.97和2.23 g/L。两阶段MBR膜池混合液各粒径值总体上均呈现先增大后减小的趋势,第1和第2阶段的最大粒径体积百分比分别出现在第16天和第23天,第1阶段EPS浓度和SMP浓度均随着颗粒粒径的增大而减小,第2阶段EPS浓度随着颗粒粒径的增大而增大但SMP浓度与颗粒物粒径之间无变化规律;MBR处理污水原水的膜池混合液颗粒粒径的峰值较分散,且16 d后峰值向小粒径方向移动,而处理絮凝出水的峰值粒径相对稳定,且峰值粒径对应的最大体积百分比从3.57%增加至5.95%。MBR对2种进水的化学需氧量(Chemical Oxygen Demand,COD)去除率均可达90%以上,氨氮(Ammonia Nitrogen,NH3-N)去除率均接近90%,对絮凝出水的总磷(Total Phosphorus,TP)处理效果高于污水原水。絮凝预处理使膜池混合液的EPS和SMP浓度降低且SMP蛋白质浓度显著降低(P<0.05)、膜池混合液颗粒粒径显著增加(P<0.05),有效减缓了MBR的膜污染,絮凝预处理与MBR组合可望为高浓度奶牛场污水处理提供可靠的技术途径。

关键词： Enzymatic membrane bioreactor (EMBR)   Laccase   Membrane properties   Redox-mediators   Trace organic contaminants (TrOCs)  

摘要： Performance of an enzymatic membrane bioreactor (EMBR) equipped with either an ultrafiltration (UF) or a nanofiltration (NF) membrane was explored for the degradation of a set of 29 chemically diverse trace organic contaminants (TrOCs). The NF membrane provided effective retention (90-99%) of TrOCs within the NF-EMBR. On the other hand, partial retention of charged and significantly hydrophobic (log >3) TrOCs was achieved by the UF membrane via charge repulsion and adsorption on the enzyme gel-layer formed on the membrane surface during UF-EMBR operation. Laccase achieved TrOC-specific degradation in both EMBRs. The extent of TrOC degradation was significantly (5 to 65%) better by NF-EMBR as compared to that achieved by UF-EMBR. Addition of a redox-mediator (violuric acid) at concentrations ranging from 10-100 mu M improved the degradation of non-phenolic TrOCs, but degradation efficiency reached a plateau when its concentration was increased beyond 25 mu M. Although the permeate flux of the UF/NF membranes dropped with time due to membrane fouling caused by enzyme gel-layer and/or concentration polarization, membrane flushing with water was effective in recovering the flux by up to 95%.