Abstract ：

Stable partial nitrification (PN) in low-ammonia wastewater has been a critical challenge, but comammox Nitrospira shows great potential in PN systems due to unique physiological characteristics. Polyvinyl alcohol/sodium alginate electrospinning nanofiber (PVA/SA-EN) and polyvinylidene fluoride EN (PVDF-EN) were used to construct EN hydrogel beads (ENHB) with sandwich and core–shell structures, respectively. Comammox HB (cHB) and three types of comammox ENHB (cENHB) were assembled by immobilizing comammox sludge and operated for 60 days in low-ammonia wastewater. Results showed a significant correlation between PN performance, HB pore structure, and comammox Nitrospira abundance. With superior pore structure and mechanical strength, PVA/SA-PVDF-cENHB achieved a nitrite accumulation rate of 55.08 %, indicating enhanced PN performance. The contribution of comammox Nitrospira to PN was 73.19 %. Its abundance in PVA/SA-PVDF-cENHB was 5.56 × 10⁶ copies/(g sludge), 1.16–1.95-fold higher than the other three HB. Nanofiber composite-enhanced hydrogel immobilizes comammox Nitrospira provides new ideas for achieving robust PN in low-ammonia wastewater. © 2025 Elsevier Ltd

Keyword ：

Ammonia Nanofibers Sodium alginate

Cite：

Copy from the list or Export to your reference management。

Abstract ：

Partial nitrification activated sludge immobilized with polyvinyl alcohol-sodium alginate (Polyving Akohol-Sodium Alginate, PVA-SA) was used to treat domestic wastewater and achieve stable partial nitrification in a continuous flow AO (Anaerobic/Oxic) reactor. Using the response surface method, the effects of hydraulic retention time (HRT), internal recirculation ratio and filling rate on nitrite accumulation ratio (NAR) and total nitrogen removal nitrogen removal efficiency (NRE) were investigated, and a quadratic regression model was successfully established. The results showed that the system had the best performance in nitrogen removal with NAR and NRE reaching 86.22% and 86.56% when HRT, internal recirculation ratio and filling rate of aerobic section were controlled as 6.43h, 2.93, and 25%, respectively. In addition, it was observed by live and dead bacteria and Fluorescence In Situ Hybridization (FISH) that the live cells were mainly distributed in the range of 0~500µm on the surface of the particles, while the dead bacteria were distributed in the range of 0~300µm. FISH fluorescence was gradually decreased in intensity with the increase of depth. Finally, 16S rRNA sequencing results showed that the relative abundance of Nitrosomonas increased from 0.013% to 5.02% and Nitrospira increased from 0.055% to 1.99% in the immobilized particles of the long-term run compared with that of the partial nitrification activated sludge. The proportion of NOB in the nitrifying bacteria was reduced, while the proportion of AOB was increased, which contributed to the stabilization of nitrogen removal effect of partial nitrification. This study provides a promising technology for the engineering application of partial nitrification in municipal wastewater plants. © 2024 Chinese Society for Environmental Sciences. All rights reserved.

Keyword ：

microbial community structure partial nitrification response surface methodology PVA-SA biological nitrogen removal

Cite：

Copy from the list or Export to your reference management。

Abstract ：

采用聚乙烯醇-海藻酸钠(PVA-SA)包埋材料固定短程硝化活性污泥在连续流AO(Anaerobic/Oxic)反应器中处理生活污水并实现稳定的短程硝化.利用响应曲面法,对水力停留时间(HRT)、内循环比以及填充率等参数进行研究,探讨了对亚硝酸盐积累率(NAR)和总氮去除率(NRE)的影响,并成功建立了二次回归模型.结果表明,控制参数HRT为 6.43h,内循环比为 2.93,好氧段填充率为 25%,此时NAR和NRE效果最佳,分别达到 86.22%和 86.56%,表明该工艺具有良好的脱氮性能.此外,还通过活死细菌及原位荧光杂交(FISH)发现,活菌主要分布在颗粒表面0～500μm范围内,死菌分布在0～300μm范围内,并随着深度增加荧光强度逐渐降低.最后,16S rRNA 测序结果表明,长期运行的包埋颗粒相比于短程硝化活性污泥中 Nitrosomonas 的相对丰度由0.013%增加到 5.02%,Nitrospira由 0.055%增加到 1.99%,硝化细菌中亚硝酸氧化细菌(NOB)的比例被降低,而氨氧化细菌(AOB)的比例升高,促进了短程硝化脱氮效果的稳定.

Keyword ：

响应曲面法 生物脱氮 微生物群落结构 PVA-SA 短程硝化

Cite：

Copy from the list or Export to your reference management。

Abstract ：

Partial nitrification activated sludge immobilized with polyvinyl alcohol-sodium alginate (Polyving Akohol-Sodium Alginate, PVA-SA) was used to treat domestic wastewater and achieve stable partial nitrification in a continuous flow AO (Anaerobic/Oxic) reactor. Using the response surface method, the effects of hydraulic retention time (HRT), internal recirculation ratio and filling rate on nitrite accumulation ratio (NAR) and total nitrogen removal nitrogen removal efficiency (NRE) were investigated, and a quadratic regression model was successfully established. The results showed that the system had the best performance in nitrogen removal with NAR and NRE reaching 86.22% and 86.56% when HRT, internal recirculation ratio and filling rate of aerobic section were controlled as 6.43h, 2.93, and 25%, respectively. In addition, it was observed by live and dead bacteria and Fluorescence In Situ Hybridization (FISH) that the live cells were mainly distributed in the range of 0~500µm on the surface of the particles, while the dead bacteria were distributed in the range of 0~300µm. FISH fluorescence was gradually decreased in intensity with the increase of depth. Finally, 16S rRNA sequencing results showed that the relative abundance of Nitrosomonas increased from 0.013% to 5.02% and Nitrospira increased from 0.055% to 1.99% in the immobilized particles of the long-term run compared with that of the partial nitrification activated sludge. The proportion of NOB in the nitrifying bacteria was reduced, while the proportion of AOB was increased, which contributed to the stabilization of nitrogen removal effect of partial nitrification. This study provides a promising technology for the engineering application of partial nitrification in municipal wastewater plants. © 2024 Chinese Society for Environmental Sciences. All rights reserved.

Keyword ：

Cell engineering Sodium alginate Bioremediation Effluent treatment Biological water treatment Nitrogen removal Wastewater treatment Nitrification Aerobic bacteria

Cite：

Copy from the list or Export to your reference management。

Abstract ：

In the activated sludge process, ammonia-oxidizing bacteria (AOB) grow slowly and have poor adaptability to adverse environments. Immobilization technology is an important means to improve AOB retention capacity. In this study, the strength, stability, and biological activity of different immobilized particles (PVA-SA (B), PVA-SA (S), PVA-SA (P), and PVA-SA (N)) were studied. In the short-term experiments, PVA-SA (S) and PVA-SA (N) particles exhibited good performance. The chemical oxygen demands (COD) (48 h) of PVA-SA (B), PVA-SA (S), PVA-SA (P), and PVA-SA (N) particles were 69.8, 52.6, 54.2, and 48.4 mg COD/g particles, respectively. Moreover, the specific oxygen uptake rate (SOUR) values were 11.1, 9.6, 3.5, and 8.0 mg O-2/(g MLSS h), respectively. In the long-term experiment, the PVA-SA (S) and PVA-SA (N) nitrification reactors were operated. The influent NH4+-N concentration gradually increased from 10 to 80 mg L-1. After 40 days, the NH4+-N removal efficiencies of PVA-SA (S) and PVA-SA (N) reactors reached 95%. Meanwhile, the intact ratios of PVA-SA (S) and PVA-SA (N) particles were 100% and 67.1%, respectively. The PVA-SA (S) particles were considered as the most promising immobilized particles in engineering applications.

Cite：

Copy from the list or Export to your reference management。

Abstract ：

以硅藻土(DE)为骨架,聚乙烯醇(PVA)、海藻酸钠(SA)为固定化材料,采用微生物固定化技术制备出一种包含高效降解菌和具有营养缓释功能的复合填料.探究了装填复合填料生物滴滤塔(BTF)净化二甲苯的性能.复合填料比表面积为4.53m2/g,具有良好的持水能力,且复合填料的重复使用性较好,连续处理8批污染物后,去除效率保持在95%以上.负载复合填料的BTF经过11d运行,出口浓度低于GB 16297-1996中规定的排放限值[ρ(二甲苯)=70mg/m3],结果表明此时BTF完成启动;进气浓度为1200mg/m3,空床停留时间(EBRT)分别为53s、38s、28s时,去除效率为98%、86%、78%;在EBRT为28s,进气浓度为700mg/m3、250mg/m3时,去除效率分别为91%、99%;在9天内外界不提供养分时,去除效率无明显下降.系统停运2天和7天,分别可在运行9.5h和1天内恢复原来的净化性能.实验结果表明复合填料具有较好理化性质,对二甲苯去除性能好,抗冲击负荷及停滞能力强,可为其应用提供一定参考价值.

Keyword ：

固定化 填料 结构表征 硅藻土 生物反应器

Cite：

Copy from the list or Export to your reference management。

Abstract ：

采用固定化技术，以聚乙烯醇（PVA）、海藻酸钠（SA）联合构筑凝胶骨架，引入活性炭（AC）、CaCO_3和复合菌粉制备一种固定化生物填料（BM填料），对添加到BM填料中的AC进行粒径优化；以乙苯作为目标污染物，考察装填该填料的生物滴滤塔（BTF）对其去除效果。结果表明：当添加的AC为100目时，BM填料的比表面积达到57.46 m~2/g，机械强度最高，对乙苯的去除效果最好。理化性质分析表明，该填料内部为致密的三维网状结构，具有较好的亲水性与吸附性，表面存在大量—OH、—COO~-等亲水基团，相同条件下对乙苯吸附量是聚氨酯海绵填料（PU填料）的2.9倍。同时该填料具有较好耐酸性，在pH降至1时依然保持高降解活性。装填BM填料的BTF可在6 d内完成挂膜；经过7 d停滞，去除率5 d可以恢复至100%；在进气乙苯浓度为800～900 mg/m~3，停留时间（EBRT）为33 s时，仍可将乙苯完全去除。相较于PU填料，以BM为填料的BTF性能更优。

Keyword ：

固定化 填料 活性炭 生物滴滤 降解 乙苯

Cite：

Copy from the list or Export to your reference management。

Abstract ：

Composite fillers containing efficient xylene-degrading bacteria with nutrient slow-release function were prepared by microbial immobilization technique, using diatomaceous earth (DE) as the backbone, and polyvinyl alcohol (PVA) and sodium alginate (SA) as immobilization materials. A biotrickling filter (BTF) was loaded with the composite fillers and the xylene purification performance was investigated. The specific surface area of the composite filler was 4.53m2/g, which had good water-holding capacity,and the composite filler showed good reusability with the removal efficiency maintaining above 95% after continuous treatment of 8 batches of pollutants. After 11 d of operation, the outlet concentration of the BTF loaded with composite filler was below the emission limit [ρ(xylene)=70mg/m3] specified in GB 16297—1996, which indicated that the start-up of the BTF was completed at this time. When the inlet concentration was 1200 mg/m3 and the empty bed residence time (EBRT) was 53s, 38s and 28s, the removal efficiency was 98%、 86% and 78%, respectively. When the EBRT was 28s and the inlet concentration was 700mg/m3and 250mg/m3, the removal efficiency was 91% and 99%, respectively. When no additional nutrients were provided for 9d, the removal efficiency did not decrease significantly. When the system was stagnated for 2d and 7d, the performance could be restored within 9.5h and 1d of operation, respectively. The results showed that the composite fillers had better physicochemical properties, good removal performance for xylene, and strong resistance to shock loading and stagnation, which can provide some reference value for its application. © 2023 Chemical Industry Press. All rights reserved.

Keyword ：

structural characterization diatomaceous earth fillers bioreactors immobilization

Cite：

Copy from the list or Export to your reference management。

Abstract ：

Cell immobilization was used to enrich and retain functional bacteria within partial denitrification-Anammox (PD/A) process to achieve its fast start-up for the first time. To do so, residue sludge and Anammox sludge were immobilized in poly (vinyl alcohol)/sodium alginate (PVA/SA) gel for PD cultivation and Anammox bacteria inoculation, respectively. Stable PD with NO3--N to NO2--N transformation ratio (NTR) of 72.0% was achieved within 13 days at 25 °C and successfully combined with Anammox on 14th day. The hydrous porous PVA/SA gel matrix played the role of extracellular polymeric substance (EPS) and thus protected the microbes against low temperature. Satisfactory nitrogen removal rate (NRR) (301.6 ± 6.1 g N/(m3·d)) was achieved even when temperature decreased to 13 °C. The contribution of nitrogen removal via Anammox was as high as 77.10%. Abundance of Thauera and Candidatus Kuenenia increased from 0.9% and 1.1% to 30.6% and 2.1%, respectively.

Keyword ：

Poly(vinyl alcohol)/sodium alginate Bio-carriers Cell immobilization Partial denitrification Anammox

Cite：

Copy from the list or Export to your reference management。

Abstract ：

采用近海污染物浒苔为原材料制备包埋水凝胶颗粒,研究浒苔包埋颗粒的机械稳定性、动力学特性,以及在污水处理过程中C/N比对浒苔包埋颗粒短程反硝化性能的影响。采用PVA、SA、PVA-SA及浒苔-WPU制作包埋颗粒,对比研究不同包埋颗粒的机械强度、膨胀系数和溶胀性能;采用乙酸钠为碳源,研究不同初始NO_3~--N浓度和COD条件下,C/N对浒苔包埋颗粒短程反硝化性能的影响;同时采用Monod方程和有效扩散系数方程对浒苔包埋颗粒的短程反硝化动力学特性进行了研究。结果表明:浒苔包埋颗粒具有良好的机械强度、膨胀系数及溶胀性能,能够在长期实验中保持稳定,同时价格低廉,适合在污水处理工艺中使用; C/N比对浒...

Keyword ：

包埋颗粒 厌氧氨氧化 浒苔 短程反硝化 反应动力学

Cite：

Copy from the list or Export to your reference management。