克劳氏芽孢杆菌(Bacillus clausii S-4)吸附Zn2+的研究

为了验证生物吸附剂去除废水中重金属离子Zn²⁺的可行性，筛选了一株高效吸附Zn²⁺的微生物菌株克劳氏芽孢杆菌Bacillus clausii S-4。采用火焰原子吸收、红外光谱和扫描电镜能谱分析，对这种新型生物吸附剂在水相中吸附Zn²⁺的性能和机理进行了研究。结果表明，B. clausii S-4菌体在20 ℃、30 ℃、40 ℃条件下，吸附Zn²⁺的最佳pH为4.5，吸附容量为57.5 mg/g，吸附容量随温度的升高而增加，吸附过程是吸热反应，吸附平衡时间约30 min。吸附前后，B. clausii S-4菌体表面上的化学官能团和金属离子发生了明显的变化，—OH、—NH⁺₄、—COOH、（—CO—NH—）、—C₆H₅等官能团可能参与了吸附过程。0.1 mol/L HNO₃、HCl和EDTA对锌的解吸附效果较好。在矿山废水中，B. clausii S-4菌体对Zn²⁺的吸附效果也比较理想，显示出其潜在的应用价值。     

活性污泥体系中聚糖菌的富集与鉴定

活性污泥体系中，聚糖菌(GAOs)在厌氧环境下与聚磷菌(PAOs)形成对底物的竞争关系，对聚糖菌的研究对于优化生物除磷工艺有重要意义。以葡萄糖为惟一碳源，在磷限制条件下，利用特殊运行方式对活性污泥进行驯化培养出了稳定的聚糖菌颗粒污泥，厌氧阶段磷释放量与有机物吸收量浓度(mg/L)比从7.4%下降为0.25%。从培养好的活性污泥反应器中分离获得2株聚糖菌，经菌落PCR和16S rRNA序列分析确定了所得聚糖菌菌株G1和菌株G2分别是枯草芽孢杆菌(Bacillus subtilis)和解鸟氨酸克雷伯氏菌(Klebsiella ornithinolytica)。     

一株降解纤维素梭形芽胞杆菌的筛选与鉴定

从肥沃的土壤中经过分离获得14株降解纤维素的细菌，以菌株在纤维素刚果红平板中溶菌圈直径与菌落直径的比值为依据进行筛选，获得一株比值为4.5的菌株，编号为X62。采用DNS法对影响该菌产生纤维素酶活力的单因素进行了分析，并通过对其进行形态特征、生理生化特征测定以及16S rDNA序列分析，确定X62为梭形芽胞杆菌（Lysinibacillus fusiformis），将其命名为Lysinibacillus fusiformis X62。X62的16S rRNA序列GenBank登录号为JX198550。     

一株异养脱氮菌的脱氮性能及其影响因素研究

研究异养硝化过程中分离得到一株具有异养脱氮性能的菌株，经16S rRNA鉴定后为Providencia rettgeri菌属，命名为Providencia rettgeri strain YL。在实验室条件下，初步探讨了不同碳氮源、温度、pH值、摇床转速和微量元素对Providencia rettgeri strain YL菌株脱氮作用的影响，研究结果显示，Providencia rettgeri strain YL菌株在葡萄糖和氯化铵为碳氮源的培养基中生长最好，温度为30℃、pH值为7、摇床转速为120 r/min时具有最佳的脱氮效果，微量元素Mg²⁺最有利于Providencia rettgeri strain YL菌株的生长和脱氮。     

具有降解亚硝酸盐活性的解淀粉芽孢杆菌的分离与安全性分析

从养殖污泥中分离筛选了一株优良的亚硝酸盐降解菌YX01,经ARIS 2X细菌自动鉴定系统以及16SrRNA系统发育分析,该菌株被鉴定为解淀粉芽孢杆菌(Bacillus am yloliquefaciens,GenBank登录号为JX649949),其16S rRNA序列与基因库中 芽孢杆菌属菌株的16S rRNA序列有99％～100％的同源性,而且与解淀粉芽孢杆菌菌株LD5(GenBank登录号:GQ853414)的亲缘关系最近.该亚硝酸盐降解菌YX01在浓度为2.0×107～2.0×109cfu/L时对小球藻(Chlorella sp.)生长有促进作用；在浓度大于2.0×1011cfu/L时对小球藻生长具有显著抑制作用；亚硝酸盐降解菌YX01对小球藻的半数抑制浓度(IC50)大于2.0×1011cfu/L.亚硝酸盐降解菌YX01对大型蚤(Daphnia magna)的48h-半数致死浓度(LC50)大于2.0×1011cfu/L,对草鱼(Ctenopharyngodon idellus)的96h-LC50大于2.0×1011cfu/kg.经分析,亚硝酸盐降解菌YX01为无毒菌株.     

碳酸根对磷酸钙沉淀反应回收磷的影响简

以模拟的厌氧消化液为处理对象，通过小试实验，考察不同初始磷浓度C_P、Ca/P物质的量比、pH和温度下，碳酸根（CO₃^2-）对磷酸钙沉淀反应回收磷的影响；利用扫描电镜（SEM）、X射线衍射仪（XRD）和傅里叶变换红外光谱（FTIR）对沉淀产物进行表征。结果表明，高浓度的CO₃^2-对以磷酸钙沉淀反应去除和回收磷的效率影响较大；C_P相同时，CO₃^2-浓度（C_CO3^2-）越大，P的去除率越低，低C_P（20 mg/L）时尤为显著；当C_CO3^2-相同时，随着C_P的增大，反应速率加快，P的去除率逐渐升高，但升高幅度越来越小；增大Ca/P比和pH能提高P的去除率，降低CO₃^2-对磷酸钙沉淀反应的抑制作用，综合考虑实际效果，应选择Ca/P比为3.33，pH为9.0作为适宜的反应条件；升高温度对降低CO₃^2-对磷酸钙沉淀反应的抑制作用贡献不大。在C_P为60 mg/L，Ca/P比为1.67，pH为9.0，温度为20℃的条件下，当C _CO3^2-为0时，得到的沉淀产物主要为羟基磷灰石HAP；当C _CO3^2-为30 mmol/L时，得到的沉淀产物为磷酸钙和碳酸合磷灰石的混合物。     

活性污泥中高效除臭菌株的驯化和筛选

以复合生物滤池作为生物除臭反应器，活性污泥作为菌源，进行氧化S^2-和NH⁺₄的活性驯化，2周后驯化成功，去除率达80%以上。通过平板划线分离，共分离出5株菌，其中细菌、酵母菌平板上各2株，霉菌平板上1株。将分离出的5株菌分别接种至含S^2-、含NO^-₂和含NH⁺₄的3类液体培养基中进行摇床培养2周，通过对菌株氧化能力的实验研究，筛选出2株净化H₂S的高效菌株，2株净化NH₃的高效菌株，能利用恶臭气体作为基质，具有潜在的应用价值。     

黄菖蒲和狭叶香蒲根系对氮磷的吸收动力学

采用改进的常规耗竭法，研究了黄菖蒲（Iris pseudacorus L.）和狭叶香蒲（Typha angustifolia L.）根系对NH₄⁺、NO₃^-和H₂PO₄^-的吸收特征及差异。结果表明，这2种植物根系对NH₄⁺、NO₃^-和H₂PO₄^-的吸收动力学特征均可采用Michaelis-Menten方程描述。2种植物根系对NH₄⁺、NO₃^-和H₂PO₄^-的亲和力（Km）和最大吸收速率（Vmax）有显著差异。吸收H₂PO₄^-时，黄菖蒲根系具有较高的Vmax值和较低的Km值，说明黄菖蒲具有嗜磷特性，并能够适应广范围浓度的H₂PO₄^-环境，适宜用于污染水体磷的去除；吸收NO₃^-时，狭叶香蒲根系具有较高的Vmax值和较低的Km值，表明狭叶香蒲可用于广范围浓度NO₃^-污染的水体修复；吸收NH₄⁺时，黄菖蒲根系具有较低的Vmax值和Km值，而狭叶香蒲根系具有较高的Vmax值和Km值，说明黄菖蒲适宜用于NH₄⁺污染较轻水体的修复，而在NH₄⁺污染较重水体中宜选用狭叶香蒲作为先锋植物。     

超细粉煤灰基成型吸附剂的动态吸附实验

以粉煤灰为原料制备成型吸附剂，对水溶液中亚甲基蓝和Cr⁶⁺进行动态吸附研究，绘制穿透曲线，利用Origin软件对实验数据分析处理，得出穿透曲线的通式C_t=A₁－A₂〖〗1+(t/t₀)^p+A₁。结果表明，初始浓度C₀=25 mg/L，填料高度不同时，达到穿透点的时间随填料高度的增加而增加；填料高度h=200 mm，初始浓度不同时，达到穿透点的时间随初始浓度的增加而减小；该吸附剂对有机染料和重金属离子均有较好的吸附性能；穿透曲线通式的回归线性相关系数表明，该通式可很好地反映超细粉煤灰成型吸附剂的动态吸附过程。     

原位水解生成的羟基氧化铁凝聚吸附除磷效能与机制简

将不同摩尔比Fe³⁺与OH^-（[Fe³⁺]：[OH^-]=1：0、1：1、1：2和1：3）反应获得原位水解生成的羟基氧化铁（in situ FeO_xH_y），研究了具有不同水解程度的羟基氧化铁对凝聚吸附除磷效能与机制。研究显示，In situ FeO_xH_y对磷的去除率随铁投量增大而升高，且均在中性pH范围内具有最佳除磷效果；在相同铁投量条件下，磷去除率随着[OH^-]：[Fe³⁺]的升高而降低；当体系碱度较低时（pH<6），引入OH^-可促进Fe³⁺水解而提高除磷效果。4种羟基氧化铁均可在15 s内可快速吸附磷，且吸附过程符合准二级动力学模型；Freundlich模型均可很好地描述磷在4种羟基氧化铁表面的吸附行为。磷酸盐吸附后，In situ FeO_xH_y表面Zeta电位明显降低，且[Fe³⁺]：[OH^-]为1：0的羟基氧化铁降低最为显著。结合MINITEQ计算软件磷酸盐、铁盐形态分析结果显示，对于碱度较低的体系，通过投加一定量OH^-可促进Fe³⁺水解，进而使得其更易与水中H₂PO₄^-与HPO₄^2-结合，生成具有多核羟基的磷酸铁络合物，进而提高除磷效果。     

TS-1分子筛催化O_3/H_2O_2氧化乙酸

研究了酸性条件下TS-1分子筛催化O3/H2O2体系（O3/H2O2/TS-1）对降解水中乙酸效率的影响,优化了相关工艺参数,并对其作用机理进行了分析。结果表明,在pH为2.8时,TS-1的加入能显著提高臭氧化的降解效率。优化工艺参数表明,当过氧化氢投加量为3 g/L,TS-1投加量为5 g/L时,O3/H2O2/TS-1体系对乙酸具有较高的降解率,60 min后O3/H2 O2/TS-1体系对乙酸（初始浓度为100 mg/L）的去除率达到了58.7%。当pH为0.8时,O3/H2 O2/TS-1体系对乙酸的去除率仅为19.8%,降解效果较差。定量化计算表明,O3/H2O2和O3/H2O2/TS-1的Rct分别为1.62×10-8和8.67×10-7。通过测定乙酸降解过程水样中过氧化氢和液相臭氧的浓度变化,推测了具体反应机理。由于此体系在酸性条件下对乙酸有较好的降解效果,拓宽了现有O3/H2O2体系的应用范围。     

TS-1分子筛催化O3/H2O2氧化乙酸

研究了酸性条件下TS-1分子筛催化O3/H2O2体系(O3/H2O2/TS-1)对降解水中乙酸效率的影响,优化了相关工艺参数,并对其作用机理进行了分析。结果表明,在pH为2.8时,TS-1的加入能显著提高臭氧化的降解效率。优化工艺参数表明,当过氧化氢投加量为3 g/L,TS-1投加量为5 g/L时,O3/H2O2/TS-1体系对乙酸具有较高的降解率,60 min后O3/H2 O2/TS-1体系对乙酸(初始浓度为100 mg/L)的去除率达到了58.7%。当pH为0.8时,O3/H2 O2/TS-1体系对乙酸的去除率仅为19.8%,降解效果较差。定量化计算表明,O3/H2O2和O3/H2O2/TS-1的Rct分别为1.62×10-8和8.67×10-7。通过测定乙酸降解过程水样中过氧化氢和液相臭氧的浓度变化,推测了具体反应机理。由于此体系在酸性条件下对乙酸有较好的降解效果,拓宽了现有O3/H2O2体系的应用范围。     

氯氰菊酯降解真菌的筛选及其降解特性研究

用富集培养的方法从农药厂污水排放口的污泥中分离筛选到3株以氯氰菊酯为唯一碳源进行生长的真菌,分别命名为TS-203、TS-205和TS-306。经鉴定3株真菌分别属于土生曲霉组(Aspergillus terreus)、毛链孢属(M onilochaetes)和镰孢霉属(Fusarium)。分别测定了不同碳源、pH、培养温度及氯氰菊酯浓度对真菌生长量和降解能力的影响。结果表明,以氯氰菊酯为唯一碳源且浓度为50~150 mg/L,pH 6.0~8.0,培养温度30~40℃时,真菌的生长量较大,降解效果较好。本研究对氯氰菊酯农药残留的生物修复研究和应用具有十分重要的意义,可为今后治理氯氰菊酯残留污染提供参考。     

Combined toxicity of imidacloprid,acetochlor, and tebuconazole to zebrafish ( Danio rerio ): acute toxicity and hepatotoxicity assessment

Compound pollution refers to two or more kinds of pollutants with different properties, a pollutant from different sources, or the simultaneous existence of two or more different types of pollutants in the same environment. In this study, we aimed to investigate the individual and combined toxicity of the insecticide imidacloprid (IMI), the herbicide acetochlor (ACT), and the fungicide tebuconazole (TBZ) to zebrafish. The acute toxicity test results showed that the 96-h LC50 values of IMI, ACT, and TBZ were 276.84 (259.62–294.35) mg active ingredient (a.i.) L−1, 1.52 (1.34–1.74) mg a.i. L−1, and 8.16 (7.7–8.6) mg a.i. L−1, respectively. The combinations of IMI, ACT, and TBZ with toxicity ratios of 1:2:2, 1:4:4, 2:4:1, and 4:1:4 displayed synergistic toxic effects on zebrafish, while the toxicity ratios of 1:1:1, 1:1:2, 2:1:2, 2:2:1, and 4:2:1 of IMI, ACT, and TBZ, respectively, exhibited antagonistic toxic effects on zebrafish. The following experiments were performed with a toxicity ratio of 1:4:4 (IMI:ACT:TBZ). The activities of four enzyme biomarkers related to oxidative stress in the liver, catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and malondialdehyde (MDA) content were evaluated in each exposure group on days 7, 14, 21, and 28. Compared with those of the control group, the activities of CAT, SOD, and GST and the MDA content were significantly altered at different time points in the individual and combined exposure groups. Additionally, the activities of CAT, SOD, and GST and the MDA content were significantly altered in the combined group compared with those of the individual group after 14 days or 21 days of exposure. Therefore, it was confirmed that combined toxicity studies are indispensable in risk assessment.     

Concentration and dissipation of chlorantraniliprole and thiamethoxam residues in maize straw,maize, and soil

To study the dissipation rates and final residual levels of chlorantraniliprole and thiamethoxam in maize straw, maize, and soil, two independent field trials were conducted during the 2014 cropping season in Beijing and Anhui Provinces of China. A 40% wettable powder (20% chlorantraniliprole?+?20% thiamethoxam) was sprayed onto maize straw and soil at an application rate of 118 g of active ingredient per hectare (g a.i.ha^?1). The residual concentrations were determined by ultra-high-performance liquid chromatography–tandem mass spectrometry. The chlorantraniliprole half-lives in maize straw and soil were 9.0–10.8 and 9.5–21.7 days, respectively. The thiamethoxam half-lives in maize straw and soil were 8.4–9.8 and 4.3–11.7 days, respectively. The final residues of chlorantraniliprole and thiamethoxam in maize straw, maize, and soil were measured after the pesticides had been sprayed two and three times with an interval of 7 days using 1 and 1.5 times the recommended rate (72 g a.i. ha^?1 and 108 g a.i. ha^?1, respectively). Representative maize straw, maize, and soil samples were collected after the last treatment at pre-harvest intervals of 7, 14, and 28 days. The chlorantraniliprole residue was below 0.01 mg kg^?1 in maize, between 0.01 and 0.31 mg kg^?1 in maize straw, and between 0.03 and 1.91 mg kg^?1 in soil. The thiamethoxam residue concentrations in maize, maize straw, and soil were <0.01, <0.01, and 0.01–0.03 mg kg^?1, respectively. The final pesticide residues on maize were lower than the maximum residue limit (MRL) of 0.02 mg kg^?1 after a 14-day pre-harvest interval. Therefore, a dosage of 72 g a.i. ha^?1 was recommended, as it can be considered safe to human beings and animals.     

Dissipation,half-lives,and mass spectrometric identification of chlorpyrifos and its two metabolites on field-grown collard and kale

The persistence and fate of chlorpyrifos and its two metabolites, chlorpyrifos-oxon and the 3, 5, 6-trichloro-2-pyridinol (TCP) break-down product were investigated on kale and collard leaves under field conditions. A simultaneous extraction and quantification procedure was developed for chrorpyrifos and its two main metabolites. Residues of chlorpyrifos, chlorpyrifos oxon, and TCP were determined using a gas chromatograph (GC) equipped with an electron capture detector (GC/ECD). Chlorpyrifos metabolites were detectable up to 23 days following application. Residues were confirmed using a GC equipped with a mass selective detector (GC/MSD) in total ion mode. Initial residues of chlorpyrifos were greater on collard (14.5 µg g^?1) than kale (8.2 µg g^?1) corresponding to half-lives (T_1/2) values of 7.4 and 2.2 days, respectively. TCP, the hydrolysis product, was more persistent on collards with an estimated T_1/2 of 6.5 days compared to kale (T_1/2 of 1.9 days).     

Field studies of ethoprop movement and degradation in two Florida soils

Unsaturated- and saturated-zone field studies were conducted under two different agricultural conditions in Florida, U.S.A., to measure the movement and degradation of ethoprop.When ethoprop was applied to a sand soil in an orange grove located on the Florida central ridge, soil residues declined with a half-life of 13 days to near the limit of detection (0.01 μg g⁻¹ within 2 months. Ethoprop residues were generally contained in the upper 2 m of soil. Although low levels of ethoprop were found in four groundwater samples within the first 3 months after application, the cause of these isolated and transient residues could not be determined. The data show that there was no widespread plume of ethoprop residues beneath or downgradient from the treated area.On a flatwood soil on the west coast of Florida, ethoprop was incorporated into raised beds and protected by a plastic mulch in which tomatoes were grown. When the plastic mulch was present, ethoprop soil residues declined with a half-life of 40 days and were confined to the upper 0.3 m of soil. After the mulch was removed at crop harvest, the remaining ethoprop dissipated with a half-life of 12 days. Groundwater residues in excess of 1 μg L⁻¹ were confined to a single sample collected after the well had been damaged during a rototilling operation. Resides of < 1 μg L⁻¹ were present in three later samples from this well. At the sampling interval where the highest residues were detected in the damaged well, ethoprop residues of < 1 μg L⁻¹ were also found in three other wells but no residues were detected in these wells in later samples.     

Octyl and nonylphenol ethoxylates and carboxylates in wastewater and sediments by liquid chromatography/tandem mass spectrometry

This work presents an LC–MS–MS-based method for the quantitation of nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs) in water, sediment, and suspended particulate matter, and three of their carboxylated derivatives in water. The alkylphenol ethoxylates (APEOs) were analyzed using isotope dilution mass spectrometry with [¹³C₆]-labeled analogues, whereas the carboxylated derivatives were determined by external standard quantitation followed by confirmation using standard additions. The method was used to study APEO’s behavior in a wastewater treatment plant (WWTP), where total dissolved NP0-16EO concentration was reduced by approximately 99% from influent (390 μg l⁻¹) to final effluent (4 μg l⁻¹), and total OP0-5EO concentration decreased by 94% from 3.1 to 0.2 μg l⁻¹. In contrast, the carboxylated derivatives were formed during the process with NP0-1EC concentrations increasing from 1.4 to 24 μg l⁻¹. Short-chain APEOs were present in higher proportions in particulate matter, presumably due to greater affinity for solids compared to the long-chain homologues. NP (0.49 μg l⁻¹) and NP0-1EC (4.8 μg l⁻¹) were the only APEO-related compounds detected in a surface water sample from a WWTP-impacted estuary; implying that 90% of the mass was in the form of carboxylated derivatives. Sediment analysis showed nonylphenol to be the single most abundant compound in sediments from the Baltimore Harbor area, where differences in homologue distribution suggested the presence of treated effluent in some of the sites and non-treated sources in the rest.     

Prenatal and postnatal exposure to diazinon and its effect on spermatogram and pituitary gonadal hormones in male offspring of rats at puberty and adulthood

The objective of this research is to study the possible reproductive adverse effects of diazinon on rat offspring exposed in utero and during lactation. Twenty-four Sprague–Dawley female rats (10–12 week old) were randomly assigned to four groups, each consisting of six rats. Group 1 served as the control and these rats were given normal saline orally. Rats in groups 2, 3, and 4 were administered diazinon, dissolved in saline at 10, 15, 30 mg/ kg^?1 body weight, per oral, once daily, during mating, pregnancy and lactation. The male offsprings were examined at puberty and adulthood for body weight, testis weight, epididymis weight, sperm count, motility and morphology, pituitary-gonadal hormone levels. At 30 mg kg^?1 dose, the male offsprings showed a decrease in testicular weight, sperm count, motility, with an increase in abnormal sperm percentage and a decline in pituitary-gonadal hormones, at puberty. Upon attaining adulthood, there was a decrease in testicular weight, sperm count and motility with an increase in abnormal sperm percentage and a decrease in pituitary hormone level. There was evidence of some adverse reproductive effects on the male offspring at the 15 mg/ kg^?1 dose. Most of the adverse effects were irreversible and were evident at both puberty and adulthood in the offsprings, although a few parameters reverted to the normal growth pattern. Diazinon is a reproductive toxicant for male offsprings if exposed during prenatal and postnatal phases.     

Influence of aeration rate and reactor shape on the composting of poultry manure and sawdust

To achieve successful composting, all the biological, chemical, and physical characteristics need to be considered. The investigation of our study was based on various physicochemical properties, i.e., temperature, ammonia concentration, carbon dioxide concentration, pH, electrical conductivity (EC), carbon/nitrogen (C/N) ratio, organic matter (OM) content, moisture content, bacterial population, and seed germination index (GI), during the composting of poultry manure and sawdust for different aeration rates and reactor shapes. Three cylindrical-shaped and three rectangular-shaped pilot-scale 60-L composting reactors were used in this study, with aeration rates of 0.3 (low), 0.6 (medium), and 0.9 (high) L min^?1 kg^?1 DM (dry matter). All parameters were monitored over 21 days of composting. Results showed that the low aeration rate (0.3 L min^?1 kg^?1 DM) corresponded to a higher and longer thermophilic phase than did the high aeration rate (0.9 L min^?1 kg^?1 DM). Ammonia and carbon dioxide volatilization were directly related to the temperature profile of the substrate, with significant differences between the low and high aeration rates during weeks 2 and 3 of composting but no significant difference observed during week 1. At the end of our study, the final values of pH, EC, moisture content, C/N ratio, and organic matter in all compost reactors were lower than those at the start. The growth rates of mesophilic and thermophilic bacteria were directly correlated with mesophilic and thermophilic conditions of the compost. The final GI of the cylindrical reactor with an airflow rate of 0.3 L min^?1 kg^?1 DM was 82.3%, whereas the GIs of the other compost reactors were below 80%. In this study, compost of a cylindrical reactor with a low aeration rate (0.3 L min^?1 kg^?1 DM) was more stable and mature than the other reactors.

Implications: The poultry industry is growing in South Korea, but there are problems associated with the management of poultry manure, and composting is one solution that could be valuable for crops and forage if managed properly. For high-quality composting, the aeration rate in different reactor shapes must be considered. The objective of this study was to investigate various physicochemical properties with different aeration rates and rector shapes. Results showed that aeration rate of 0.3 L min^?1 kg^?1 DM in a cylindrical reactor provides better condition for maturation of compost.