In a given sample in order to reduce nitrate nitrogen pollution in water, nitrate nitrogen removal methods based on iron–carbon micro-electrolysis have become a key research focus.

The effect of stormwater runoff on dissolved organic matter (DOM) in rivers is one of the central topics in water environment research. Jiujiang is one of the first cities established in the green development demonstration zone of the Yangtze River Economic Belt (Jiangxi Province, China). Three-dimensional excitation-emission matrix fluorescence with parallel factor analysis (3DEEM-PARAFAC) and ultraviolet-visible (UV-Vis) spectroscopy were used to explore the effects of runoff on organic matter in Shili River (Jiujiang, Jiangxi Province, China). The results show that the runoff led to an increase of some critical pollutants and DOM concentrations, especially in the middle reaches of the river. The concentration and relative molecular weight of DOM in water increased as a result of runoff. Three humic-like (C1-C3) and two protein-like (C4 and C5) components of DOM were identified using the PARAFAC model. The sources of the three humic-like components (C1, C2, C3) were consistent, unlike those of the protein-like component C4. Compared with the pre-rainfall period, the content of humus compounds flowing into the river through the early rainwater runoff was lower, which caused the relative content and proportion of humic substances little change and protein-like species increasing. The DOM mainly derived from autochthonous sources, and runoff had limited effect on its characteristics. Jiujiang is a key demonstration city for Yangtze River conservation. Rainwater runoff is one of the pollution sources of urban rivers, which leads to the deterioration of water quality and influences the distribution characteristics of DOM in water bodies. The PARAFAC components could adequately represent different indicators and sources of DOM in urban rivers, providing an important reference for urban river management.

Algal blooms that occur periodically in rivers, lakes, and reservoirs are associated with the cumulative effects of excess nutrients from industrial and agricultural development. Algicidal bacteria can be used as environmentally friendly biocontrol agents to manage harmful algal blooms in eutrophic water. However, there is still a dearth of studies on the effects of mixed algicidal agents, the persistence of algae removal efficiency, and the impacts on native aquatic microbial communities. Two strains of algicidal bacteria, Cellvibrio sp. G1 and Chitinimonas sp. G2, were previously isolated and purified from reservoir sediment. Herein, G1 and G2 broth cultures, alone and in combination (1:1, V/V), were added to eutrophic water collected from a park at the volume ratio of 5 %. Eutrophic water remediation efficiency under different treatments was monitored for 30 days, and microbial community dynamics in water were analyzed by full-length sequencing of the 16S rRNA genes. The best algae removal efficiency was observed in the water treated with G1 alone, as indicated by the highest algae removal rate of 41.3 %. The total nitrogen removal rates of G1, G2, and their combination were 33.47 %, 23.65 %, and 28.88 %, respectively; ammonia-nitrogen removal rates were 24.11 %, 25.02 %, and 19.63 %, respectively; total phosphorus removal rates were 24.11 %, 25.02 %, and 19.63 %, respectively; and orthophosphate removal rates were 46.11 %, 44.37 %, and 27.92 %, respectively. In the water treated with G1 and/or G2, the major genera with algicidal capacity (i.e., Cellvibrio and Chitinimonas) were outcompeted by the well adapted genera (e.g., Pseudomonas). At the late stages of treatment, the algicidal genera decreased in relative abundance, leading to decline in algae removal efficiency and increase in chlorophyll concentration. Based on both eutrophic water remediation efficiency and environmental adaptability, G1 alone was superior to G2 alone or in combination with G1, thus having potential practical implications.

It is imperative to solve the problem of endogenous phosphorus (P) release from sediments in the governance of natural water bodies. Deciphering P migration and transformation patterns that are coupled to iron (Fe) and sulfur (S) cycling at the sediment-water interface (SWI) is the key to understanding the mechanisms underlying endogenous P release. In the present study, we deployed diffusive gradients in thin films (DGT) probes in situ at the SWI in Fuyang River, Hebei Province, China. When the probes were retrieved, the surrounding sediments were synchronously sampled. We analyzed the longitudinal spatiotemporal distribution of Fe, S, and P at the SWI. We also explored how functional bacterial community diversity was associated with the coupling reactions of Fe, S, and P as well as endogenous P release from sediments at the functional gene level. The results showed that labile Fe, S, and P occurred at low concentrations in sediments 0-2 cm below the SWI, while they were enriched in sediments at depths of 4-8 cm. The longitudinal distribution of different labile elements exhibited greater differences between October and February than regional differences, with higher concentrations at downstream locations than upstream locations. In February, Fe/Al-bound P and sulfide (S2-) concentrations increased in sediments compared with those in October owing to an increase in the relative abundances of dominant genera among P-mineralizing bacteria and sulfate-reducing bacteria. As a result, Fe in Fe-bound P precipitated as FeS2, which induced P remobilization and release into the overlying water. The spatiotemporal distribution patterns of functional genes related to P (phoD and ppk) and S (aprA) transformation were consistent with those of labile P and S, which strongly suggests that microorganisms played a role in driving and regulating the coupled cycling of P and S at the SWI.

Deep reservoirs vary in their hydrostatic pressure owing to artificial water level control. The potential migration of phosphorus (P) in reservoir sediments raises the risk of harmful algal blooms. To ascertain the mechanisms of endogenous P release in reservoirs, we characterised aquatic microbial communities associated with coupled iron (Fe), P and sulphur (S) cycling at the sediment-water interface. The responses of microbial communities to hydrostatic pressures of 0.2-0.7 mega pascals (MPa; that is, micro-pressures) were investigated through a 30-day simulation experiment. Our findings unravelled a potential mechanism that micro-pressure enhanced the solubilisation of Fe/aluminium (Al)-bound P caused by microbially-driven sulphate reduction, leading to endogenous P release in the deep reservoir. Although the vertical distribution of labile Fe was not affected by pressure changes, we did observe Fe resupply at sediment depths of 2-5 cm. Metagenomic analysis revealed increased abundances of functional genes for P mineralisation (phoD, phoA), P solubilisation (pqqC, ppx-gppA) and sulphate reduction (cysD, cysC) in sediments subjected to micro-pressure, which contrasted with the pattern of S oxidation gene (soxB). There was a tight connection between P and S cycling-related microbial communities, based on significant positive correlations between labile element (P and S) concentrations and functional gene (phoD, cysD) abundances. This provided strong support that Fe-P-S coupling processes were governed by micro-pressure through modulation of P and S cycling-related microbial functions. Key taxa involved in P and S cycling (for example, Bradyrhizobium, Methyloceanibacter) positively responded to micro-pressure and as such, indirectly drove P release from sediments by facilitating P mineralisation and solubilisation coupled with sulphate reduction.

Microcystis aeruginosa is a globally important cyanobacterial species that poses a threat to human health and development. The use of bacteria to control algal blooms has become an important research topic in recent years. In the present work, the algicidal strain G1 was isolated from sediments of a reservoir in Xi'an, China, identified by 16S ribosomal DNA (rDNA), and its algicidal effects were investigated. The rDNA sequence of G1 (GenBank accession number MW205793) is 99.86% similar to that of Chitinimonas sp., and the strain indirectly solubilised algae. Algae removal by G1 was optimal during the decay phase (algae solubilisation rate = 65.85%). Temperature (5-120 degrees C) did not significantly affect algae removal, pH 5-9 was tolerated, and pH 7 achieved the highest algae lysis rate (63.56%). Ultrasonic treatment of G1 destroyed the algae-solubilising effect. An injection ratio of 15% achieved the highest algae lysis rate (67.64%) under 12 h:12 h light:dark conditions, and full darkness achieved the highest algae lysis rate (68.21%). Thus, G1 can effectively inhibit the reproduction of M. aeruginosa, making it a promising biological agent for controlling algal growth.

The temperature/pH dual-responsive gel spheres were prepared by orthogonal experiments and response surface methodology, and finally, the optimal synthesis conditions were obtained by a composite score, including swelling, mechanical properties, mass transfer properties, and so forth. The results showed that a sodium alginate concentration of 3% (w/v), CaCl2 concentration of 2% (w/v), gelling time of 40 h, drop height of 14 cm, NaCl concentration of 0.6% (w/v), N-isopropylacrylamide concentration of 0.03% (w/v), and acrylic acid concentration of 4.06% (w/v) were optimal synthesis conditions. The environmental change tolerance experiments showed that the nitrogen removal of the dual-response nitrifying gel spheres was better than the domesticated sludge at low temperatures (4 °C) and in alkaline (pH 9 and 10) conditions. The as-obtained gel spheres can respond intelligently to the changes in ambient temperature and pH. It is hoped that this study will provide technical parameters for the development and application of microbial immobilization carriers.

Microcystis aeruginosa can cause algal blooms, which has been a serious threat to the water environment. Microbial algae removal is a technology with good application prospects. In this study, we isolated a new algae-dissolving bacterium G2 from the reservoir substrate of Xi'an of Shaanxi Province, identified as Cellvibrio sp. according to 16S rDNA sequence analysis (GenBank accession No.: MW221316), and investigated the feasibility of G2's solubilizing M. aeruginosa. Results show that G2 solubilized algae by secreting extracellular substances indirectly, and it had the best removal effect on algae during the stabilization period. Increasing G2 dosing ratio (>10%) contributed to the effect of algae dissolution. G2 was sensitive to the change of temperature, and the algae removal rate reached (59.42±0.88)% and (63.10±1.42)% at 5 and 25 ℃, respectively. The removal efficiency was poor at temperatures higher than 75 ℃. The pH and light had no significant influences on the algae removal effect, and G2 had strong tolerance to acid and alkali (pH 3−11). In conclusion, G2 can inhibit the growth of M. aeruginosa efficiently, so it is a promising biocontrol agent to mitigate cyanobacterial blooms.

Although there have been many studies on the process conditions of Constructed Wetlands (CW) and Microbial Fuel Cells (MFC), there are few studies on the Constructed Wetlands coupled with Microbial Fuel Cells. Currently, low power production is the main problem faced by Constructed Wetlands-Microbial Fuel Cell systems (CW-MFCs). This experiment intends to research the effects of HRT, influent COD and electrode spacing on wastewater treatment and power generation performance. In this experiment, CW-MFCs with two different electrode spacings (18 cm for reactor A and 28 cm for reactor B) were set up under continuous flow conditions. The effects of HRT, influent COD and eletrode spacing on wastewater treatment and power generation performance were explored using a single-factor controlled variable method. Experiment results showed that the extension of HRT was beneficial for contaminants removal and the power generation of the CW-MFCs, but the excessive extension was ineffective for the electricity output. The optimal HRT of the CW-MFCs was 24 h when influent COD was 500 mg.l(-1). Improving influent COD within the appropriate range (500 similar to 1000 mg.l(-1)) facilitated the power generation and contaminant removal performance of the CW-MFCs. The maximum output voltage and power density were obtained in reactor A when influent COD was 1000 mg.l(-1) and HRT was 24 h, which were 548 mV and 120 mW.m(-3), respectively. Compared with reactor B, reactor with smaller electrode spacing achieved better electricity generation and contaminant degradation under the optimal condition. Its average output voltage could be improved by 5.1 similar to 46.1% and the removal rates of COD and NH4+-N could also be improved by 0.2 similar to 4.9 % and -0.9 similar to 13.7 %, respectively. This phenomenon indicates that there was a significant positive correlation between the number of Gram-negative bacteria and the electricity production performance of the CW-MFCs, which was due to the difference in electron transfer efficiency. This study can provide operation parameters for the CW-MFCs process.

针对活性污泥系统中硝酸盐异化还原为铵(DNRA)导致系统脱氮效率降低的问题,通过长期驯化培养试验、批式试验和高通量测序,考察水力停留时间(HRT)、硫离子(S2-)的投加和流态对活性污泥中DNRA氨化的影响.研究结果表明:间歇流条件下,当HRT由6 h延长至36 h时,DNRA氨化随着HRT的延长而增强,系统中生成氨氮质量浓度由0.43 mg/L逐渐增长至15.98 mg/L;连续流条件下,当HRT由6 h延长至48 h时,系统中生成氨氮质量浓度由2.03 mg/L逐渐增长至20.78 mg/L.投加S2-可有效促进硝酸盐氮转化成氨氮,当向系统投加20 mg/L的S2-时,间歇流和连续流系统出水氨氮质量浓度分别增加了11.58％和24.82％.且连续流下投加S2-后,DNRA功能菌总丰度比投加前提高了22.65％.在改变HRT和进水S2-质量浓度时,连续流系统中硝酸盐氮转化成氨氮比例均普遍高于间歇流系统.

In this study, homemade ceramsite- soil filler (system A) and a simple soil filler (system B) were applied in vertical upflow constructed wetlands, and their performance in the treatment of rural domestic wastewater were investigated under various HRTs and packing heights. Optimum performance was reached at a HRT of 6.4 d in both systems. The average removal rates of ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) in system A were as high as 90.78, 86.04, and 90.15%, respectively, which were 0.94, 2.21, and 10.62% higher than those in system B. The TN and NH4+-N removal efficiencies of both systems decreased with shorter HRTs, whereas the TP removal efficiency was almost not affected. Along the inlet direction, with increasing packing height, the pollutant removal capacity gradually decreased, and the NH4+-N removal efficiencies in the bottom layers (0-145 mm) of system A and B were 55.88 and 50.22%, respectively, with NH4+-N volumetric loads of 8.63 and 7.76 g/(m(3).d). System A contained more nitrifying genera at the genus level, mainly including Stenotrophomonas, Sphingomonas, and Acinetobacter. The addition of ceramsite resulted in a higher treatment efficiency and resistance to hydraulic shock loading.

Biological aerated filter was used to treat eutrophic river water at different filler mass ratio and temperature on the removal of contaminants. The filter contained a functional composite filler which was made of activated iron and ceramsite. The results showed that the reactor was stable after 30 days of start-up at room temperature and that the proportion of filler mass exerted little effect on COD removal. At different temperatures, the denitrification and phosphorus removal capacity of reactor #1 was better than that of reactor #2, in which the composite filler with an activated iron and ceramsite mass ratio was 1:1(reactor #1) and 1:3 (reactor #2). At 10 degrees C, both reactor #1 and # 2 had removed COD, TN and TP effectively. The relative abundance of species and the diversity of microorganisms in reactor #1 were higher than those in reactor #2. According to the analysis at the phylum and the genus level, bacteria with nitrification and denitrification functions in #1 and #2 were dominant and the proportion of activated iron affected the distribution of microbial population.

The release of endogenous phosphorus from sediments leads to the eutrophication of water bodies. Bacteria in sediments play a vital role in phosphorus cycling. A high hydrostatic pressure can alter the microecology and affect bacterial functions at the water–sediment interface. The aim of this study was to analyze the expression patterns of functional genes in bacteria associated with phosphorus transformation at the water–sediment interface of a deep reservoir under different hydrostatic pressures. Furthermore, the effects of hydrostatic pressure on phosphorus cycling pathways mediated by bacteria were explored. A device was designed to simulate the microecological environment in sediments from a reservoir in Xi’an, China, at atmospheric pressure, 0.2 MPa, 0.5 MPa, and 0.8 MPa. Phosphorus transformation genes, phoD, ppk, and pqqC, were quantified using real-time PCR. The bacterial community composition and diversity were analyzed using high-throughput sequencing of the ppk gene. The total phosphorus contents in the sediments were 724.72, 646.97, 630.92, and 682.88 mg kg–1 at the four respective hydrostatic pressures, respectively. Of this, inorganic phosphorus accounted for 68.8–79.0%, and Fe/Al-P accounted for 47.4–57.2%. The expression of phoD facilitated the transformation of organic to inorganic phosphorus and of Ca-P to Fe/Al-P, whereas the expression of ppk and pqqC regulated organic phosphorus hydrolysis by affecting phosphatase activity. The abundance and diversity of ppk-harboring bacteria were highest at 0.2 MPa, while the dominant genera did not change at the four pressures. The five most abundant genera were Pseudomonas, Bordetella, Cupriavidus, Achromobacter, and Rhizobium. High hydrostatic pressure facilitates the transformation of Fe/Al-P to Ca-P in, and phosphorus release from, reservoir sediments by regulating phoD, ppk, and pqqC expression in bacteria. Changing the hydrostatic pressure can alter the bacterial community structure at the genus level, but not the dominant populations harboring the ppk gene.

介绍了目前以煤矸石为原料制备沸石分子筛的主要方法及优缺点,总结了煤矸石制备的沸石分子筛在去除水中氨氮、磷、有机物、重金属离子和氟等方面应用,并对"煤矸石→沸石分子筛→去除水中污染物"这条"以废治废"路线进行了系统的分析与展望.相比于传统的沸石分子筛制备路径,煤矸石制备沸石分子筛的原材料极易获取、合成成本低,合成产物对水中各类污染物质去除效果好.在今后的研究中,还应在煤矸石沸石分子筛的绿色制备,改性沸石分子筛和沸石分子筛+X复合材料的研发等方面继续深入,并拓展其在水处理领域的应用范围和途径.

微电极是一种微型的电化学传感器,具有检测速度快、灵敏度高等特点,能够测定微观环境内物质浓度的细微变化.微电极能通过测定样品内浓度空间分布、计算反应速率的方式构建微观环境与宏观环境的联系.该文在微电极制备与应用的基础上,归纳总结了其在生物膜、颗粒污泥、沉积物中脱氮机制的研究现状.进一步分析了微电极与分子生物技术、数学模型联合使用探索生物脱氮机制的意义与前景.最后,展望了微电极未来的发展方向,并对其既有限制性因素提出了几点思考.

采用包埋法制备了粒径均匀的海藻酸钙(CA)硝化菌小球,并用不同浓度的NaC1溶液处理CA硝化菌小球来改善其扩散传质性能,以N-异丙基丙烯酰胺(NIPAAm)、丙烯酸(AA)为单体材料,形成温度/pH响应层,制得一种新型温度/pH双响应硝化菌凝胶小球.以NH4+-N为指示物考察不同制备条件下硝化菌凝胶小球的氨氮去除性能及对温度、pH的敏感特性,并将其应用于实际废水的脱氮处理.结果 表明,经浓度为0.3％的NaC1溶液改性后的CA硝化菌小球的扩散传质性能最佳;15mL温度响应溶液中NIPAAm为200 mg、 MBA为4 mg,10 mLpH响应溶液中AA为200 mg、 MBA为4 mg时双响应硝化菌小球的氨氮去除性能最好;当温度低至4℃时,氨氮去除率可达29.45％,当pH为9时,氨氮去除率仍可达35.48％.双响应硝化菌凝胶小球具有良好的温度、pH敏感特性,对实际废水中氨氮的去除也具有良好效果,有利于提高低温及碱性条件下硝化菌的硝化效果.

In the teaching of water pollution control theory, the design of sewage treatment plant engineering is a very important practical teaching link. This teaching practice project has a very important guiding role in cultivating students' engineering practice ability. This article first analyzes the current teaching status of sewage treatment plant engineering design, expounds some problems in the teaching process, and proposes targeted reform measures to improve sewage treatment plant engineering design teaching, aiming to improve the quality of sewage treatment plant engineering design teaching .

Filler plays an important role in biological sewage treatment technology. In the purification of urban sewage river, the single sponge iron filler is easy to harden. The combination of sponge iron and ceramsite can hinder the hardening and improve the removal efficiency. In this paper, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the fillers. The removal efficiency experiments were carried out through the self-designed biological aerated filter (BAF) reactor with sponge iron and ceramsite mixed fillers, and the microorganisms attached to the surface of the biological fillers were qualitatively and quantitatively identified through 16S rDNA. The results indicate that the presence of Fe3O4, Fe2O3, Fe3C, and Fe2CO3 in sponge iron determines that sponge iron has strong reducibility and provides electrons for efficient denitrification. NaAlSi3O8 in ceramsite filler plays a significant role in phosphorus adsorption. In #3, #4, and #5 reactors (the mass ratios of sponge iron and ceramsite were 1 : 1, 3 : 1, and 1 : 3, resp.), the removal efficiencies of mixed fillers are good on chemical oxygen demand (COD), total phosphorus (TP), and nitrogen (N), and the more the ceramsite fillers in the reactors are, the higher the microbial abundance and diversity are. The mixture of sponge iron and ceramsite can be used to purify urban sewage river. A scientific basis to purify the polluted water body of urban rivers in situ is thus provided.

Bacteria can use nitrate as a nutrient for growth, but the underlying mechanisms of this pathway have not yet been identified. We investigated the effects of changing the nitrogen source from ammonia to nitrate on the properties of heterotrophic bacterial growth in anoxic and anoxic/oxic (A/O) SBRs. Both SBR types were seeded with activated sludge cultivated with ammonia and were then fed with 1,400 mg.L-1 chemical oxygen demand (COD) and 250 mg.L-1 of nitrate nitrogen. Heterotrophic bacteria had a lag period of 8-9 d and 13-14 d in terms of growth and COD and nitrogen removal, respectively, in both reactors with nitrate as nutrient. Of the influent nitrate, 15% were converted to biomass nitrogen. Compared with ammonia or organic nitrogen as a nutrient source, with the use of nitrate more energy was needed for proteins synthesis, which resulted in a lower sludge yield (0.32-0.35) and lower amounts of proteins and phosphorus compounds. Furthermore, fewer extracellular polymer substances (EPS) and more soluble microbial products (SMP) were produced, both of which also had low proteins and high polysaccharide contents. The proteins in the cells were synthesized via dissimilatory nitrate reduction to ammonia (DNRA).

Although constructed wetlands (CWs) are widely used around the world with various substrates, the mechanisms of how these modified substrates affect wastewater treatment are still unknown. In this study, CW microcosms were established with and without ceramsite as a substrate, and the wastewater treatment efficiencies were evaluated during 71 days of incubation. Using the 16S rRNA high-through sequencing, the mechanisms of how CW substrate changed the microbial community was quantified. The results showed that compared to soil as substrate, the use of ceramsite as substrate material enhanced the removal of pollutants from CW systems, particularly under a short retention time (1.5-day) condition. There were more beneficial microorganism groups (nitrogen, sulfur, phosphate) in the ceramsite CW system than the non-ceramsite CW system, particularly in the bottom layers. Moreover, the CW with ceramsite substrate had more nitrification function. All of these results suggested that the ceramsite CW system enhanced the removal of pollutants because it increased the concentration of key microbes that are necessarily for nutrient cycles.