The removal of nitrogen from farmland drainage is challenging due to the typically low carbon-to-nitrogen (C/N) ratio. In this study, an algal-bacterial symbiosis system was developed to treat low C/N farmland drainage. The investigation focused on the nutrient removal rates, microbial growth characteristics, extracellular polymeric substances (EPS) content, and microbial community species composition under varied disturbance frequencies and light conditions (intensity and duration). Results demonstrated that the optimal operating conditions were three disturbances per 24 h, a light intensity of 20,000 lux, and a 16-hour lighting duration. Under these conditions, the average removal rates of soluble chemical oxygen demand, total nitrogen, total phosphorus, nitrate nitrogen, and ammonia nitrogen reached 45.1 %, 73.3 %, 98.1 %, 63.1 %, and 97.3 %, respectively. Compared to continuous disturbance, intermittent disturbance reduced energy consumption by over 90 % and promoted higher biomass accumulation, with an average dry weight of 508.7 mg L- 1 and chlorophyll-a concentration of 521.0 mu g L- 1. Meanwhile, a robust microbial community and a balanced bacterial-to-algal gene copy ratio (exceeding 25:1) were critical for nutrient removal. The optimized system facilitated symbiote secretion of bound polysaccharides (45.2 mu g L- 1, double that of other reactors), promoting the formation of robust biofilms and enhancing nutrient removal. This work provides a technical reference for improving nutrient removal in low C/N wastewater treatment processes.

城镇污水处理厂尾水排入水体后,尾水中的氮、磷仍易引起受纳水体富营养化问题,开展尾水深度处理以进一步去除氮、磷营养物质具有现实意义.通过试验研究了不同菌藻共培养对氮、磷的去除效果,筛选出优势菌藻组合,采用响应面法研究了通气量、光波长、细菌接种量对氮、磷去除效果的交互影响,提出最优参数组合,并建立菌藻共生系统,进行验证试验.结果表明:不同菌藻组合中,蛋白核小球藻-地衣芽胞杆菌-恶臭假单胞菌共培养组对TN、TP的去除效果较好;此菌藻共生系统在蓝光、通气量为1.8 L/min及细菌接种量为20％(体积比)条件下,TN去除率最大可达93.7％,1 d后TP基本上完全被去除;在蓝光、通气量为2.0 L/min及细菌接种量为5％条件下,2 d后氮去除率可达98.4％;在红光、通气量为2.0～3.0 L/min及细菌接种量为10％～20％条件下,2 d后氨氮可完全被去除.菌藻共生系统对氮、磷去除效果的最优参数组合为蓝光、通气量为1.8 L/min及细菌接种量为20％,最优参数组合验证的结果与预测值相符,系统出水符合GB 3838—2002《地表水环境质量标准》Ⅴ类水质标准,可为菌藻共生系统的实际应用提供理论基础.

Effective removal of phosphate from aqueous solution is of great significance in environmental protection. In this paper, the concept of developing a hierarchical and cost-effective aluminum functionalized melamine foam (MF) as phosphate adsorbent is presented. The material with 3D interconnected network, flexibility and ultralow density was fabricated via a simple adsorbing method based on hydrate aluminum and commercially available MF sponge. For use as an adsorbent, performance of the as-prepared MF-HA sponge was assessed with various pH, temperatures, adsorption time, initial P concentrations, ionic strengths and co-existing ions. The experimental results demonstrated that MF-HA performed well in a wide pH range of 4-10 and in the presence of foreign anions, with high maximum uptake capacity of 36.21 mg P/g. Furthermore, for the as-prepared material, the phosphate removal performance at different temperatures established the endothermic nature of the adsorption process. Moreover, MF-HA sponge could be directly separated from the solution and showed a satisfactory recyclability. The adsorbing strategy to design and fabricate the novel sponge with resultant high adsorption efficiency, cost-effectiveness, preferable selectivity, environmental friendliness, and easy separation from water may promote sponge functionalization for applications in extensive wastewater treatment areas.

针对社会学习粒子群算法存在的收敛速度慢及进化后期种群多样性缺失等问题,提出了一种基于分层学习的改进粒子群算法.首先,引入分层学习策略,并将其加入社会学习粒子群算法中,实现对种群中不同状态粒子的差别对待,从而增强算法中粒子的探索与开发能力;其次,对个体设定贡献值度量,在贡献值的基础通过减少种群数量,减少计算资源的浪费.最后,使用CEC2010测试函数集对所提算法进行测试,并与5种典型算法进行对比,验证了所提算法的有效性.

In this research, water and sediment of Erhai Lake were studied to reveal occurrence characteristics and evaluate ecological risk of BPA and steroid estrogens. The detected concentrations of BPA, E2 alpha. E1, E2 beta, EE2 and E3 in lake water were 4.02 similar to 10.51ng/L, 0.73 similar to 24.53ng/L, 2.40 similar to 6.52ng/L, 9.17 similar to 20.65ng/L, 7.83 similar to 26.63 ng/L and 0.85 similar to 57.44ng/L during the dry season, respectively, while the EEQs ranged 25.94 similar to 74.84ng/L. Compared with dry season, under the influence of initial rain, the EEQs increased by 57%. PNEC-based ecological risk assessment results showed that except BPA was at moderate risk, steroid EDCs were almost at high risk whether in dry or rainy season. EDCs content in sediments ranges were 3.66 similar to 59.33 mu g/kg, nd similar to 17.65 mu g/kg, 22.21 similar to 181.40 mu g/kg, 8.11 similar to 79.30 mu g/kg, nd similar to 26.33 mu g/kg nd similar to 12.28 mu g/kg for BPA, E2 alpha, E1, E2 beta, EE2 and E3, respectively. The highest concentration section was located near the outlet of the Erhai Lake as the result of the deep lake water and the long process of EDCs deposition. By comparing the distribution characteristics of EDCs with COD, nitrogen and phosphorus, we found that E2 alpha, E2 beta, E3 and EE2 were closely related to soluble total nitrogen, probably mainly from agricultural non-point source pollution during dry season. However, in rainy season, EDCs in Erhai Lake were more affected by runoff.

过氧化二异丙苯生产过程中,会产生大量的强碱性、高盐、高COD的污水,这种污水是一种具有代表性的高含盐难处理的有机化工污水.介绍了洛阳技术研发中心开发的一种过氧化二异丙苯污水的好氧流化床生物膜反应器处理工艺,采用好氧流化床生物膜反应器及其工艺,对某化工厂过氧化二异丙苯生产装置排放的污水进行了侧线试验研究.试验结果显示,污水盐含量对微生物繁殖有抑制作用,SFBBR对TDS浓度小于35000mg/L的DCP污水处理效果较好,用两级SFBBR工艺,在不脱盐、不稀释直接进行生物处理的条件下,在进水COD为1200～2800mg/L,pH值为7左右,反应温度为20～40C,TDS为15000～40000mg/L,进气量为3m3/h的操作条件下,经一级好氧SFBBR处理后,污水COD为200～600mg/L,经二级SFBBR处理后,污水COD小于200mg/L,COD总去除率达91％,生化反应时间由180h缩短至61h,COD平均容积负荷提高约2倍,处理效率明显优于现有处理工艺,处理后污水可满足预处理要求.

On-site sampling analysis and laboratory-scale experiments were conducted to study the pollution status and release potential of EDCs in Erhai Lake. We found that nitrogen and phosphorus pollution in Erhai Lake sediment were both at a high level, as well as EDCs pollution. The concentrations of BPA, E2α, E1, E2β, EE2, and E3 were 36.84 ng/g(DW), 13.04 ng/g(DW), 128.97 ng/g(DW), 52.57 ng/g(DW), 18.48 ng/g(DW) and 5.36 ng/g(DW), respectively. The concentrations of E2α, E1, E2β and EE2 in the bottom water were higher than the surface water due to the impact of sediment release. The results of the 20 days release test indicated that BPA release from the sediment had a greater correlation with the original concentration and the particle size of sediment, while the steroid EDCs had no obvious correlation with these two factors, probably due to the difference in hydrophobicity between them. Under hydraulic disturbance and aerobic conditions, the release process of EDCs was accompanied by a large amount of microbial degradation, and degradation amount > released amount. BPA was released quickly, 9.56% was released in 20 days, but only 3.37% of steroid EDCs released. In comparison, the release process of steroids was longer and posed a greater threat to aquatic ecology.

针对大规模多目标优化问题,提出了一种基于分解的改进粒子群算法.该方法将分解策略与社会学习粒子群优化算法相结合引入到个体的学习过程中,针对每个个体及其邻域个体,计算其沿权重向量方向与参考点之间的距离以及与权重向量之间的距离并对它们进行排序,个体通过学习离参考点近的任意个体以及离权重向量近的所有个体实现位置的更新.在5个ZDT测试函数上进行了500维和1000维的测试对比,结果表明本文所提的算法具有较好的收敛性以及分布均匀性.

Many evolutionary algorithms have been proposed for multi-/many-objective optimization problems; however, the tradeoff of convergence and diversity is still the challenge for optimization algorithms. In this paper, we propose a modified particle swarm optimization based on decomposition framework with different ideal points on each reference vector, called MPSO/DD, for many-objective optimization problems. In the MPSO/DD algorithm, the decomposition strategy is used to ensure the diversity of the population, and the ideal point on each reference vector can draw the population converge faster to the optimal front. The position of each individual will be updated by learning the demonstrators in its neighborhood that have less distance to the ideal point along the reference vector. Eight state-of-the-art evolutionary multi-/many-objective optimization algorithms are adopted to compare the performance with MPSO/DD for solving many-objective optimization problems. The experimental results on seven DTLZ test problems with 3, 5, 8, 10, 15 and 20 objectives, respectively, show the efficiency of our proposed method on solving problems with high-dimensional objective space.

In the rhizosphere, plant root exudates can mediate the toxicity of antibiotics on microorganisms, yet the mechanisms are poorly understood. To simulate the antibiotic contamination of global rivers and lakes, the current study investigated the effects of two antibiotics (ofloxacin at 8.69 × 104 ng L-1 and tetracycline at 8.62 × 104 ng L-1) and their binary combination (8.24 × 104 ng L-1 ofloxacin and 7.11 × 104 ng L-1 tetracycline) on bacterial communities in micro-polluted constructed wetlands with and without artificial root exudates. The two antibiotics had no significant effects on the removal of excess carbon and nitrogen from the microcosms treated with and without exudates. Furthermore, with regard to bacterial community structure, antibiotic exposure increased the bacterial richness of bulk and exudate treated microcosms (P < 0.05). However, a significant increase (P < 0.05) in bacterial diversity elicited by ofloxacin and antibiotic mixture exposure was only observed in microcosms with exudates. In exudate treated microcosms, ofloxacin promoted the relative abundance of Arthrobacter spp., which are ofloxacin-resistant bacterial species, which significantly varied from what was observed in microcosms free of exudates. Moreover, tetracycline, ofloxacin and their combination all significantly increased the relative abundance of nitrogen cycling bacteria Rhizobacter spp. and Rhizobium spp., and decreased the relative abundance of antibiotic-resistant bacteria Pseudomonas spp. Simultaneously, with regard to bacterial community functions, the functional profiles (Kyoto Encyclopedia of Genes and Genomes) showed that the pathways of amino acid and carbohydrate metabolism were enhanced by antibiotics in microcosms with exudates. The findings illustrate that antibiotics not only alter the bacterial structure and composition but also change their functional properties in constructed wetlands, and these interruption effects could be affected by root exudates of plants, which may further reveal the ecological implication of plants in constructed wetlands.

针对社会学习粒子群算法在求解大规模优化问题时存在的收敛速度慢以及种群多样性缺失等问题,提出一种基于决策变量分组的粒子群算法.根据决策变量间的相关性对决策变量分组,提高算法的收敛速度.采用反向学习策略,通过生成反向解,提高算法的全局寻优能力.采用CEC2010测试函数集对本文算法进行测试,仿真结果与已有典型算法进行对比,验证了本文算法的有效性.

To investigate the effects of antibiotics on nitrogen removal and uptake by wetland plants, four typical macrophyte species, Cyperus alternifolius L., Typha angustifolia L., Lythrum salicaria L., and Acorus calamus L., were grown in hydroponic cultivation systems and fed wastewater polluted with 10 μg L−1 Ofloxacin (OFL) and Tetracycline (TET). Biomass production, nitrogen mass concentration, chlorophyll content, root exudates, and nitrogen removal efficiency of hydroponic cultivation were investigated. The results indicated that in all hydroponic systems, NH4+–N was entirely removed from the hydroponic substrate within 1 day and plant nitrogen accumulation was the main role of the removed NO3−. OFL and TET stimulated the accumulation of biomass and nitrogen of A. calamus but significantly inhibited the NO3−–N removal ability of L. salicaria (98.6 to 76.2%) and T. augustifolia (84.3 to 40.2%). This indicates that A. calamus may be a good choice for nitrogen uptake in wetlands contaminated with antibiotics. OFL and TET improved the concentrations of total organic carbon (TOC), total nitrogen (TN), organic acid, and soluble sugars in root exudates, especially for oxalic acid. Considering the significant correlation between TOC of root exudates and nitrogen removal efficiency, the TOC of root exudates may be an important index for choosing macrophytes to maintain nitrogen removal ability in wetlands contaminated with antibiotics.

Constructed wetlands (CWs) have emerged as a promising technology for the purification of micro-polluted water. However, their nitrogen removal performance can be significantly degraded by design, operational, and environmental factors. The present study investigates the effects of ofloxacin (OFL: 0.1, 10, and 1000 mu g L-1) and plants (Cyperus alternifolius L. and Typha angustifolia L.) on nitrogen removal in amicro-polluted CW system over a duration of 12 weeks. The effects were evaluated by investigating NH4-N and NO3-N removal efficiency, nitrification genes (amoA-AOA and amoA-AOB), denitrification genes (nirK and nirS), fungal 18S rRNA gene and microorganism community structure. The results showed that in unplanted CWs, OFL increased the NH4-N removal efficiency (from 72.6% to 80.7-82.1%), the abundances of amoA-AOA, nirS, nirK and fungal 18S rRNA gene, and the bacterial diversity but decreased the abundance of both amoA-AOB and bacterial richness. In contrast, both the nitrogen removal efficiency (83.4-89.5% for NH4-N and 33.8-38.5% for NO3-N) and bacterial diversity/richness were not significantly affected by OFL in planted CWs. In planted systems, OFL increased the relative abundance of Arthrobacter, Pseudomonas, and Enterococcus, which are proven antibiotic-resistant bacteria. This study showed that CWs are able to remove nitrogen from antibiotic-contaminated micro-polluted water, which might primarily be attributed to the presence of plants that protect the microorganism community. (C) 2018 Elsevier B.V. All rights reserved.

Denitrifiers play a dominant role in the earth's nitrogen cycle,the modem molecular ecology technology using the encoding gene of the enzyme has become the main method of the denitrifiers in the environment.The advantages and disadvantages of traditional sequencing technology and emerging high throughput sequencing technology are introduced in this paper.The research on the denitrifiers by molecular ecology technology is reviewed,and the future research on molecular ecology technology and its applications in denitrifiers are also discussed.

针对适应度计算复杂问题,提出了一种基于改进信赖域方法的代理模型的适应度计算方法.该方法采用差分计算过程来代替信赖域方法中搜索时的导数计算过程,从而避免了在计算中遇到的函数不可导使算法无法正常进行的问题.并采用此改进的信赖域方法与微粒群算法(PSO)相结合更新采样空间,提高采样效率.再结合径向基神经网络(RBF)代理模型,进一步提高算法的优化性能.在几类典型的测试函数中进行仿真实验,结果表明本文算法具有较好的寻优能力.

In micro-polluted constructed wetland (CW), the low pollutant concentrations and the low COD/N ratios (chemical oxygen demand: total nitrogen in influent), make the biological treatment more difficult. It is expected that root exudates drive microbial-based transformations within plant rhizosphere. In this research, the roles of root exudates of three aquatic plants (Phragmites australis, Typha angustifolia and Cyperus alternifolius) in improving the growth of heterotrophic denitrifying bacteria were determined in a micro-polluted CW. In studied root rhizospheres, the total organic carbon (TOC) released from the plant roots varied significantly among plant species and seasons; the average TOC ranged from 0.1715 to 0.9221 mg g(-1) root DM d(-1), which could fuel a denitrification rate of approximately 156-841 kg NO3--Nha(-1) year(-1) if all were used by the denitrifying bacteria; the abundances of nirK- and nirS-encoding bacteria were significantly influenced by the concentration of sucrose and glucose (0.869 <= r <= 0.933, p < 0.05), and microbial community richness and diversity had response to root exudates. The results revealed that root exudates can act as endogenous carbon sources for heterotrophic denitrifying bacteria and ultimately determine the microbe distribution patterns in micro-polluted CW. (C) 2017 Elsevier B.V. All rights reserved.

反硝化微生物在人工湿地脱氮过程中发挥着关键作用.利用荧光定量PCR技术检测沉积物中反硝化功能基因nirS和nirK的丰度,利用高通量测序技术分析反硝化微生物的多样性,并利用SPSS Pearson分析了pH、温度等环境因子对人工湿地沉积物中反硝化微生物丰度和多样性的影响.研究结果表明,人工湿地中nirS和nirK的丰度分别为1.01 ×107～4.18×108拷贝数/g干沉积物和2.99×105～6.77×106拷贝数/g干沉积物,其中nirS显著高于nirK丰度,nirS丰度与温度和NO3-N显著正相关,与pH显著负相关.nirS和nirK的Shannon指数分别介于3.54～4.76和2.97～4.45之间,nirS的多样性与温度显著负相关,与pH显著正相关.通过蒙特卡洛置换检验得出nirS的OTU组成与TOC显著相关.

Root exudates, particularly low molecular weight carbon (LMWC) substrates, are major drivers of bacterial diversity and activity in the rhizosphere environment. However, it is not well understood how specific LMWC compounds—such as organic acids, soluble sugars, and amino acids—influence the community structures of denitrifying bacteria or if there are specific functions of LMWC substrates that preferentially respond to nitrogen (N) removal in constructed wetlands (CWs). To address these knowledge gaps, we added mixtures of artificial exudates to CW microcosms containing N pollutant. N removal efficiency was observed over a 48-h experimental period, and at the end of the experiment, DNA was extracted from microbial samples for assessment of the bacterial community. The removal efficiencies of TN for the exudates treatments were higher than for control groups by 47.1–58.67%. Organic acid and soluble sugar treatments increased N removal, while amino acids were negative to N removal. The microbial community was changed when artificial exudates were added, but there were no significant relationships between LMWC compounds and bacterial community composition. These results indicate that although the responses of community structures of denitrifying bacteria to LMWC additions are still uncertain, there is evidence for N removal in response to exudate additions across LMWC types.

氮源污染在全球范围内的地下水、河流、海洋等水体中都是一个备受关注的环境问题,尤其是受人类活动影响较大的区域,其污染来源多样,因此,关于水体中氮污染来源识别是水体氮污染防治的有效手段.近几十年来,利用硝态氮中的氮、氧在不同来源同位素值的不同,作为识别水体中氮污染源的有效手段.通过总结利用硝酸盐氮氧双同位素识别氮源的基本原理和不同氮污染源中氮、氧同位素组成的特征变化区间,结合水体其他水质指标来定性判断水体中氮的来源,描述硝酸盐同位素测试预处理的4种方法.结合其他数学模型,定量识别水体中氮源的贡献比例,并对利用同位素技术研究氮源污染情况进行总结与展望.

A case study of the Yongan River, a major inflow of the Erhai Lake, was conducted to identify sources of ni?trate?N in the river water with the d15 N?NO3-and d18 O?NO3-double isotope technique. Along the river, 9 monitoring sites were set up, responsible for characterizing nitrate pollution of the water, and measuring nitrate d15 N?NO3-and d18 O?NO3-in the water samples after treatment with ion exchange resin. Results show that the nitrate sources along the Yongan River are responsible for about 50% of the total nitrogen pollution load in the water. Nitrate concentration in the water samples at the monitoring sites varied in the range of 0?07-5?22 mg·L-1, with mean being in the range of 1?00-2?39 mg·L-1. The isotope test reveals that the mean d15 N?NO3- of the water samples at the monitoring sites ranged from 6?12‰ to 13?88‰, and the mean d18 O?NO3-did from 8?24‰to 11?72‰. The findings demonstrate that the nitrate pollutant in the river comes mainly from chemical fertilization, livestock manure, domestic sewage, and nitrification of organic nitrogen in the soil in the valley. Quantification of contributions of the four sources with the IsoSource mixing model tells that 37?3%was attributed to chemical fertilization, 34?6% to disposal of livestock manure, 18.2% to discharge of rural domestic sew?age and 9?9% to nitrification of organic nitrogen in the soil. The experiment shows that the use of the IsoSource mixed model to quantify sources of nitrate pollutant in the river may provide future studies with a new train of thought and that ra?tio of the contributions of the sources to the total nitrate pollutant in the river is related to location of the villages the river runs through and type of land use therein.