CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jianguo Li,Wanli Yan,Shikan Zheng,Chengsong Ye,Yangying Zhao,Xin Yu
Membrane types are known to have a decisive effect on the operational efficiency of membrane-bound reactors. The gas-permeable membrane, serving as the biofilm growth and oxygen transfer medium, plays a vital role in the membrane-aerated biofilm reactor (MABR). However, few studies have thoroughly investigated how membrane types affect MABR performance. Four parallel MABRs were equipped with different membrane types: microporous PTFE (R1), dense silicone (R2), composite A (R3), and composite B (R4) membranes. Results showed that the R3 and R4 exhibited comparable and superior COD and nitrogen removal efficiency relative to R1, maintaining stable transmembrane pressure. XDLVO theory was used to assess the interfacial interaction energy between sludge flocs and membrane surfaces. Polar forces were crucial for sludge adhesion, affecting biofilm formation and growth. Composite B exhibited the lowest energy barrier (2529 KT), leading to the fastest biofilm formation and thicker biofilms, which enhance nitrogen removal. PTFE exhibited the highest energy barrier (9655 KT), resulting in the most extended biofilm cultivation period and the thinnest biofilm. Based on fluorescent in-situ hybridization (FISH), membrane types significantly affect the distribution of nitrogen-removing microbial communities. As the biofilm thickened, the stratification of the nitrifying bacterial population became increasingly pronounced, forming distinct layers within the biofilm. Nitrosomonas and Nitrobacter dominated the biofilm near the membrane, while Nitrospira was most abundant in the outer biofilm. The outermost biofilm layer was predominantly composed of heterotrophic denitrifying bacteria (HDB). The research has shown that different biofilm types exhibit heterogeneity stratification in nitrifying bacteria and HDB. 16S rRNA genes sequencing revealed that Nitrospira was the predominant nitrifying genus within the heterotrophic/autotrophic biofilm.
研究领域:
环境工程
·
微生物学
✓ 已验证
DOI
高影响因子
Journal of Material Cycles and Waste Management
·
2023
·Vol. 25
·期 4
·2485-2497
·
IF 3.1
Wei Jie,Liu Zhanwei,Yan Hengwei,Yang Wanzhang
Herein, fluorine fixation, nitrogen removal, and the alkaline solution recovery of alumina were studied using calcium-based high-temperature soda roasting. In addition, the effects of roasting conditions, dissolution conditions, and additives (carbon alkali and calcium salt) on fluorine fixation and alumina recovery were studied. The results show that when the roasting temperature was 1100 ℃ and the roasting time was 2 h, the dissolution temperature was 80 °C, while the dissolution time was 20 min. The ratio of soda to dross was 1.0, and 30 wt% CaCO 3 had been added as a fluorine fixing agent. The Al extraction rate from aluminum dross (AD) reached 86.21%, the denitrification rate reached 99.54%, the concentration of soluble fluoride ion was reduced to 0.111 g·L −1 , and the fluoride fixation rate was 75.04 wt%. CaF 2 is the main component of the leaching residue, which can be added as an insulation material for electrolysis. Alkaline oxidation roasting and calcium-based fluoride fixation are effective methods to separate aluminum, fluoride, and nitrogen. This study provides a new method for the safe and efficient utilization of AD.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Mengxiang Geng,Ting Zeng,Xiangyi Deng,Zhenyue Zhang,Chunqiao Xiao,Ru'an Chi
Residual ammonium salt in closed rare earth mining sites leads to elevated levels of ammonia nitrogen in the surrounding environment. To mitigate ammonia nitrogen pollution at its source, a cost-effective and environmentally friendly recycling process was proposed. This process involves leaching residual ammonia nitrogen using a magnesium sulfate solution, followed by chemical precipitation for ammonia nitrogen removal. Additionally, nitrogen can be recovered as ammonia gas through the thermal decomposition of precipitates, allowing for further ammonia nitrogen adsorption from the leachate. The residual ammonium salts leaching rate reached 96.38 % with a 0.1 mol/L magnesium sulfate solution at a flow rate of 0.6 mL/min. The chemical precipitation method achieved a maximum nitrogen removal rate of 86.87 %, with an activation energy of 2.6 kJ/mol, indicating a relatively rapid process. At 190 °C, the ammonia nitrogen release rate of precipitates was 82.5 % after 2 h of thermal decomposition. The adsorption process was consistent with pseudo-second-order kinetics models using thermal decomposition products. Overall, the comprehensive removal rate of residual ammonium salts from the closed rare earth mining site was approximately 83.3 % in recycling process, optimizing the utilization of phosphorus, magnesium, and nitrogen and achieving efficient and environmentally friendly nitrogen removal.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 47
·71766-71773
·
IF 5.19
Huo Junyu,Li Chaoyu,Hu Xiaojin,Xie Huijun,Hu Zhen,Wu Haiming,Liang Shuang,Zhang Jian
Iron ore and manganese ore were used as substrate of constructed wetlands (CWs) to enhance nitrogen (N) removal. However, the N purification performance in CWs filled with iron or manganese ore under antibiotics stress needs further study. In this study, three groups of CWs filled with river sand, limonite (a kind of iron ore), and manganese ore sand were constructed, which were named as C-CWs, Fe-CWs, and Mn-CWs, respectively. The effect and mechanism of the composite antibiotics sulfamethoxazole (SMX) and trimethoprim (TMP) on N removal in CWs were investigated. While the addition of SMX and TMP inhibited about 40% nitrification and promoted about 25% denitrification in all CWs, Fe-CWs and Mn-CWs always had better N removal performance than C-CWs. Changes in microbial community structure in CWs indicated that the better N removal performance in Fe-CWs and Mn-CWs was attributed to the presence of more abundant and diverse N-associated bacteria, especially Fe- and Mn-driven autotrophic denitrifying bacteria. What’s more, the addition of iron ore or manganese ore contributed to the better N removal performance with highest relative abundance of N-transferring bacteria under antibiotics stress.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Environmental Chemistry Letters
·
2022
·Vol. 20
·期 4
·2243-2251
·
IF 13.615
Zhu Guocheng,Chen Junming,Zhang Shanshan,Zhao Zilong,Luo Huihao,Hursthouse Andrew S.,Wan Peng,Fan Gongduan
Black-odorous waters are an increasingly common phenomenon characterized by excessive levels of nutrients, the formation of metal sufide precipitates, volatile sulfurous compounds, low dissolved oxygen and high chemical oxygen demand. Black-odorous waters frequently occur in lake and river systems where inputs have restricted circulation. The key remediation issue is the removal of nitrogen and phosphorus. Here, we present a novel aeration-adsorption system using fiber balls and we study treatment parameters and removal mechanism. Kinetics and changes of the solid phase were followed using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Results show complete removal of ammonia N, initially at 31 mg/L, and 92.8% removal of total nitrogen, initially at 29 mg/L, after a 24 h reaction time at pH 9.67. At pH 5.67 and 9.67, total phosphorus and phosphate could be significantly reduced by 90–92% at 3.2–5.2 mg/L after 24 h. Treatment met China’s integrated wastewater discharge standards, demonstrating an effective and robust treatment capability. First-order and second-order kinetic models provided a good fit to the treatment data, indicating physical and chemical adsorption were involved in the treatment reactions. The reaction mechanism involved hydrogen substitution and binding to oxygen. These results present a cost effective and robust approach for the removal of N and P from black, odorous water, providing opportunity to abate environmental contamination.
研究领域:
环境工程
·
水污染治理
·
生态修复
·
环境化学
✓ 已验证
DOI
高影响因子
Water Science and Engineering
·
2024
·
IF 3.7
Shan-Shan Gao,Xing Yin,Rui Huang,Jia-Yu Tian
Simultaneous nitrification and denitrification (SND) is an efficient method to remove nitrogen in municipal wastewater treatment. However, low dissolved oxygen (DO) concentrations are generally required, leading to serious membrane fouling in membrane bioreactors (MBRs). This study aimed to clarify the synergistic effect of biomass and DO on nitrogen removal and membrane fouling. To achieve this goal, four submerged MBRs equipped with ceramic membranes were operated with different biomass (mixed liquor suspended solids (MLSS)) concentrations (3 000 mg/L, 5 000 mg/L, 7 500 mg/L, and 12 000 mg/L) under various DO concentrations (2.0 mg/L, 1.0 mg/L, and 0.5 mg/L). As a result, increasing biomass in the MBRs enhanced total nitrogen (TN) removal via SND, and excellent TN removal efficiencies of 60.7% and 75.8% were obtained using the MBR with an MLSS concentration of 12 000 mg/L and DO concentrations of 2.0 mg/L and 1.0 mg/L. However, a further decrease in DO deteriorated TN removal due to the inhibition of nitrification. Moreover, high MLSS concentrations were beneficial to membrane fouling control for ceramic membranes in MBRs. The lowest transmembrane pressure development rate was observed for the MBR with an MLSS concentration of 12 000 mg/L. High biomass offset the adverse effect of DO decrease on membrane fouling to some extent, and improved the stability of the reactor. Therefore, biomass might be an important parameter for membrane fouling reduction in ceramic MBRs. Overall, optimal biomass and DO concentrations for TN removal were identified, providing useful information for the successful operation of MBRs with efficient TN removal and membrane fouling control.
研究领域:
环境工程
·
污水处理
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yanda Qian,Peng Wan,Andrew S. Hursthouse,Guocheng Zhu
Nitrogen pollution poses a significant threat to aquatic ecosystems, necessitating the deployment of effective water treatment strategies to mitigate its levels. Given the scarcity of traditional nitrogen adsorbents in the water treatment sector, this study explored the potential of titanium tannate, a metal-phenolic network (MPN) material, as a carrier for nitrogen removal. Specifically, a novel composite material, zero-valent iron/titanium tannate (nZVI/Ti-TA), was synthesized through a liquid-phase reduction reaction method and subsequently assessed for its nitrogen removal efficacy in batch experiments. The results showed that nZVI/Ti-TA is a dual-functional composite, exhibiting both adsorption and reduction capabilities. The optimal preparation parameters were determined to be a mass ratio of Ti-TA to FeSO 4 •7H 2 O of 1:1.5 and a molar ratio of NaBH 4 to FeSO 4 •7H 2 O of 8. Furthermore, the composite exhibited a broad pH application range, maintaining stable performance across a pH range of 4 to 9. Additional parameters, such as nitrogen concentration, adsorbent dosage, and the presence of ions, also influenced the treatment outcomes. Specifically, higher nitrogen concentrations and lower adsorbent doses resulted in a higher adsorption capacity. Conversely, higher concentrations of ions like SiO 3 2− , CO 3 2− , and K + inhibited nitrogen separation. However, the composite demonstrated promising results in treating inorganic and organic nitrogen in real wastewater samples. In model solutions, inorganic nitrogen could be completely removed, while in field applications such as domestic wastewater, the total nitrogen removal rate exceeded 95 %. The primary mechanisms underlying nitrogen removal were the dual functions of adsorption by Ti-TA and reduction by nZVI. The adsorption process was primarily governed by hydrogen bonding and electrostatic interactions. Overall, this study introduces a novel composite material for effective removal of nitrogen, offering a promising solution to the pressing issue of nitrogen pollution in aquatic ecosystems.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Shuyin Zhang,Jing Zou,Lingxuan Chen,Chunhua Shen,Jian Lu,Jianlin Zhang,Hangyu Cui,Geng Huang,Jun Ma
Although thermal-activated peroxymonosulfate (PMS) system possesses good performance on the removal of organic pollutants, thermal/PMS system exhibited poor capacity to remove ammonia nitrogen (NH 4 + -N). This study demonstrated the huge enhancement on the removal of NH 4 + -N by thermal/PMS system with the commonly coexistent bromide ion (Br - ). The elimination of NH 4 + -N by thermal/PMS/Br - system fitted the pseudo -zero-order kinetics model well, while the corresponding k obs in the presence of 200 μM Br - was 5.76 times greater than that by thermal/PMS system. Bromine (HBrO) was confirmed as the dominant oxidant responsible for removing NH 4 + -N and TN, while the radicals of HO ⋅ , SO 4 ⋅- and Br ⋅ were also generated but made minor contribution to removing NH 4 + -N. HBrO was mostly produced by PMS reacting directly with Br - , while these radicals were produced from the cleavage of the O-O bond in PMS and the reaction between PMS and HBrO under high temperature. Thermal/PMS/Br - system exhibited superior performance on TN removal (up to 90 %) than that by thermal/PMS system (less than 5 %) and Cl - -enhanced system (about 80 %). The main removal product of NH 4 + -N was identified as the environmentally friendly gas of N 2 , although nitrate was also detected. Neutral pH condition was the optical pH for NH 4 + -N removal. Increasing reaction temperature, PMS dosage and Br - concentration were beneficial to accelerating the removal of NH 4 + -N. Cations of Cu 2+ and Fe 3+ , anions of SO 4 2- , CO 3 2 - and NO 3 - , humic acid and the actual water matrix of landfill leachate negligibly influenced the removal of NH 4 + -N, while Cl - exhibited strong enhancement on NH 4 + -N removal. In summary, this study provided an effective method to improve the oxidizing capacity of thermal/PMS system, especially for NH 4 + -N removal in wastewater containing Br - .
研究领域:
环境科学
·
污水处理
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Hongbo Chen,Yefeng Zhou,Xiayi Hu,Ke Tian,Junfeng Zhang
Due to the widespread use of antibiotics in healthcare and livestock production , antibiotic resistance genes and residual antimicrobials would enter environment and further discharge into the municipal sewage system. The objective of this work was to explore the potential effect of chlortetracycline (CTC) on biological nutrient removal from wastewater. Thus, the effects of CTC on biological phosphorus and nitrogen removal were investigated with respect to the viability of bacteria, the activities of key metabolic enzymes, and the transformations of intermediate metabolites. Results showed that the presence of 0.1 mg·L −1 CTC did not show any impact on biological phosphorus and nitrogen removal. Nevertheless, the long-term exposure to 1 and 10 mg·L −1 CTC decreased TN removal efficiency from 77.4% to 64.1% and 53.4%, respectively. Meanwhile, the presence of 10 mg·L −1 CTC decreased the SOP removal efficiency from 96.3% to 78.1%. Mechanism studies indicated that CTC could affect the activities of reductase and the transformations of polyhydroxyalkanoates and glycogen, resulting in inhibition of denitrification and phosphorus uptake, which may be the major reason for the high level of CTC showing adverse influence on wastewater biological nutrient removal.
研究领域:
环境科学
·
微生物学
·
污水处理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Ying Chen,Fengyuan Zhang,Xiaoshuang Shi,Mingyi Lu,Kang Qin,Quan Feng,Rongbo Guo
This paper aims to improve the biological nitrogen removal performance by using magnetic polystyrene composite microparticles (PS@Fe 3 O 4 ). Three types of PS@Fe 3 O 4 with different surface morphologies were prepared by in-situ emulsion polymerization . Then, the optimum was creatively used as a biofilm carrier to form magnetic activated sludge (MAS) in lab-scale reactors. Compared to the conventional activated sludge , the utilization of PS@Fe 3 O 4 accelerated the sludge settling velocity to 0.76 m/h. In addition, the ammonium nitrogen removal, total nitrogen removal and simultaneous nitrification and denitrification improved by 7.08%, 24.27% and 19.53%, respectively. The dissolved oxygen concentration and pH were observed to reveal the effect of PS@Fe 3 O 4 on the nitrogen removal process. Based on microbial community analysis, there were more nitrifying and denitrifying bacteria in the MAS. Therefore, the novel developed PS@Fe 3 O 4 can be a promising utilization material as a biofilm carrier for biological wastewater treatment .
研究领域:
环境工程
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2022
·
IF 7.34
Ying Wang,Haoyu Chen,Chao Chen,Zikun Zhang,Yin Xu,Guangjiao Chen,Yanlong Zhang
The anammox-HAP coupling process can simultaneously achieve high-efficiency nitrogen removal and phosphorus recovery from sewage. The composition and physical properties of the byproducts (aHAP) collected in the anammox-HAP process were analyzed. In addition, the application potential and mechanisms for Cd(II) adsorption by aHAP in wastewater were investigated. The results show that aHAP is mainly composed of hydroxyapatite and calcium carbonate , having granular structure with honeycombs and pores. The aHAP shows an adsorption capacity of 21.10–34.80 mg/g for Cd(II) removal, and the adsorption behavior is consistent with pseudo-second-order and intra-particle diffusion models, showing that the rate-limiting step is controlled by the chemical reaction of surface complexation, ion exchange, and precipitation. In addition, the remaining anammox biomass in aHAP can bind Cd(II). The aHAP also shows a pH buffer capacity when the initial pH ranges between 4.10 and 8.46, and the final pH can be stabilized in the range of 6.3 to 8.3, which is suitable for anammox reactions. Collectively, the anammox-HAP coupling process can not only be used to achieve high-efficiency nitrogen and phosphorus removal, but its aHAP byproduct shows good adsorption properties and pH buffering capacity, which meets the requirements of green chemistry and has high economic and environmental benefits.
研究领域:
环境科学
·
污水处理
✓ 已验证
DOI
高影响因子
Environmental Technology & Innovation
·
2025
·
IF 7.1
Zhenxin Wang,Qilin Yu,Zhiqiang Zhao,Ruicheng Zhang,Hongbo Zhang,Yaobin Zhang
Anammox is limited in practical application due to the need to control the influent ratio of NO 2 - to NH 4 + . Fe(III) (hydr)oxides have been confirmed to serve as electron acceptors and induce a so-called Feammox to anaerobically oxidize ammonia in Anammox systems via extracellular electron transfer, which however is also restrained by the low activity of Fe(III) (hydr)oxides. Heme, a Fe-containing compound with high redox activity, was introduced into the Anammox system to improve NH 4 + oxidation in this study. A removal rate of 46.32 mg N/(L·d) was achieved for nitrogen through the addition of heme, which was 43.85% higher than the maximum Feammox efficiency in documents (32.20 mg N/(L·d)). Continuous experiments showed that the added heme participated in the intracellular and extracellular electron transfer of Anammox. The contribution of Feammox to nitrogen removal was affected by the influent NO 2 - -N/NH 4 + -N ratio. Under a high NO 2 - -N/NH 4 + -N ratio (1.25:1), the contribution of Feammox to NH 4 + -N removal was 8.29%. This ratio increased to 31.49% under a low NO 2 - -N/NH 4 + -N ratio (0.80). Besides increasing the nitrogen removal efficiency, heme addition may significantly lower the nitrite requirement in this biological process, leading to improved adaptability in its application.
研究领域:
环境微生物学
·
污水处理
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）