低温条件下BAF+SPD组合工艺对滇池入湖河水的脱氮效果

为缓解湖泊富营养化问题，需进一步降低入湖河流氮的含量。针对滇池流域新运粮河的低C/N水质特征，研究了冬季低温条件下的微曝气生物滤池（BAF）及固相反硝化（SPD）组合异位脱氮工艺。结果表明，BAF+SPD组合工艺启动挂膜阶段，约3周后，NH₄⁺-N的去除率达80%以上，而反硝化细菌增殖相对缓慢，约5周后，NO₃^--N的去除率达80%以上；稳定运行的低温阶段，除降雨时间外，NH₄⁺-N平均去除率达80%，出水NH₄⁺-N浓度<1 mg/L；NO₃^--N平均去除率达到85%以上，出水NO₃^--N浓度<1 mg/L；TN平均去除率达80%以上，出水TN浓度<2 mg/L，主要水质指标达到国家地表水Ⅴ类标准。     

复合沸石滤床修复北方景观水体的实验研究

以天然矿物质沸石、细砂及煤渣取代传统滤料构建复合基质生态床，表面种植景观植物，采用下向流-上向流运行方式修复北方景观水体。分别进行静态实验及不同循环速率下的动态实验，考察对水体污染物去除过程。结果表明，2种运行方式下对水体NH⁺₄-N去除率都在85%以上，其中以1 h为循环周期的运行方式去除率达97%，较静态提高12.8%；TN去除率最高为84%；TP去除不稳定，过程缓慢。煤渣层对NH⁺₄-N的去除效果差，硝化作用不彻底与反硝化作用的加强使下层出水NH⁺₄-N 、NO^-₂-N及NO^-₃-N浓度均高于上层。提高循环速率有利于对氮的去除。     

人工湿地基质对 NH+4-N 吸附性能简

为研究建筑废物红砖和工业废物煤渣用作人工湿地脱氮基质的可行性，分别通过静态吸附实验和动态NH₄⁺-N去除效果实验进行考察。结果表明，红砖和煤渣对NH₄⁺-N最大静态吸附量分别为0.2533 mg/g和0.0533 mg/g，其吸附等温曲线均符合Freundlich型吸附方程，吸附常数分别为0.0419和0.0091；红砖煤渣组合对污水中NH₄⁺-N平均动态脱除率达到41.18%，高于红砖的37.63%和煤渣的30.92%。     

利用13X沸石分子筛净化含NH+4-N废水的实验研究

研究了13X沸石分子筛在静态和动态条件下对中低浓度含NH⁺₄-N废水的吸附性能，包括影响吸附的主要因素、沸石对NH⁺₄-N的吸附效果和沸石的再生等。静态实验结果表明，pH值为6.5～7.5，吸附时间35 min，吸附温度20～30℃的条件下，沸石对50 mL NH⁺₄-N初始浓度（C0）为80 mg/L的废水吸附效果最佳，吸附过程符合Langmuir型吸附等温式，饱和吸附量为8.61 mg/g。动态条件下，随水力停留时间增加，沸石对NH⁺₄-N的吸附量上升，最大饱和吸附量可达24.20 mg/g，吸附过程符合Thomas吸附模型。直接焙烧法对吸附后的沸石进行再生活化处理效果良好。实验证明，利用13X沸石净化中低浓度含NH⁺₄-N废水具有良好的工业化应用前景。     

UASB反应器厌氧氨氧化菌的脱氮特性研究

研究UASB厌氧氨氧化（ANAMMOX）反应器运行情况，采用普通城市污水厂活性污泥接种，人工合成废水，pH值在7.4～7.8之间，温度控制在(32±1)℃。在反应器稳定运行270～450 d之间的180 d中，对NH⁺₄-N和NO^-₂-N去除率均达到99.9％以上，总氮去除率保持在90％以上，NO^-₃-N产生量在20～30 mg/L之间波动。研究表明,UASB厌氧氨氧化反应器处理废水效果明显，对NH⁺₄-N、NO^-₂-N和TN去除率高，NO^-₂-N和NH⁺₄-N比值可以指示厌氧氨氧化反应器性能的演变。UASB反应器稳定运行阶段容积负荷的影响较小，ANAMMOX菌对合成废水适应性强，反应器抗冲击能力较强，受冲击后恢复迅速。出水pH值稳定在8.5附近，pH值变化情况可作为反应器运行状况的指示。关键词硝化厌氧氨氧化上流式厌氧污泥床生物脱氮     

温度对复合厌氧折流板膜生物反应器处理生活污水效能的影响简

将新型CAMBR反应器（厌氧折流板反应器（ABR）与膜生物反应器（MBR）优化组合）用于处理生活污水，研究温度对该反应器处理效能的影响。实验水力停留时间7.5 h，混合液回流比设置为200%，pH值为6.5~8.5，溶解氧3 mg/L左右。控制3个温度梯度：高温（32~37℃），中温（20~25℃），低温（5~10℃），每个温度运行35 d。结果表明，在高温条件下，系统出水COD、NH₄⁺-N、TN和TP平均浓度分别为25、0.5、12.5和0.7 mg/L。在中温条件下，系统出水COD、NH₄⁺-N、TN和TP浓度分别30、1.2、12.5和0.4 mg/L。在低温条件下，COD和TP分别经过15 d和20 d调整适应，出水可恢复至35 mg/L和1 mg/L。由于低温（10℃以下）对硝化细菌产生强烈抑制，出水NH₄⁺-N去除率最终稳定在35%，TN去除率为40%。低温条件下，该反应器应用于污水处理中需注意适当保温，以保证出水水质。     

C/N比和曝气量影响MBR同步硝化反硝化的研究

通过连续运行MBR研究了C/N比和曝气量对同步硝化反硝化的影响，结果表明，在环境温度13～23℃，MLSS为6.0～6.8 g/L，进水NH⁺₄-N浓度50 mg/L，曝气量0.5 m³/h，HRT为6 h实验条件下，总氮去除率随着进水C/N比的增加而增加，在C/N比为6∶1～8∶1时，TN去除率达到79%～89%，低的C/N比抑制反硝化，过高的C/N比增加了碳源补加的成本。改变反应曝气量，当C/N比为6∶1，曝气量为0.4 m³/h时，TN的去除率达到了最大值85%。曝气量过高或过低，TN去除率均下降。并对在不同曝气量下MBR 内的DO 值分布进行了初步研究。     

pH值控制MAP法脱氮进程的可行性研究

MAP沉淀法处理高NH₃-N废水，操作简便，处理效果好。本试验以NH₃-N浓度为1 000 mg/L的模拟废水为研究对象，研究结果表明，在Mg²⁺∶PO^3-₄∶NH⁺₄=1.2∶1.2∶1（摩尔比）、NaOH投加量为675 g/L的条件下NH₃-N去除率高达98%以上。试验选择出水pH作为控制反应进程的参数，并建立了出水pH与NH₃-N去除率之间的关系。通过调整NaOH投加量控制出水pH在7.5～8之间时，NH₃-N去除率最高，可达98%以上。X-衍射图谱及定量分析表明，沉淀物中MAP的纯度较高，具有一定的回收价值。     

污水生物生态处理工艺中的脱氮机理研究

通过水解池-美人蕉湿地、水解/接触氧化池-菖蒲湿地现场实验装置考察了生物-生态工艺深度净化分散生活污水的效果。结果表明,水解池-美人蕉湿地尽管湿地停留时间达到7 d，出水NH⁺₄-N仍难以达到一级A（GB18918-2002）标准；而增加接触氧化池后，湿地停留时间仅2 d，组合工艺出水水质远优于一级A出水要求。美人蕉湿地脱氮的主要途径是湿地微生物的硝化/反硝化，植物吸收约占28%。对经接触氧化处理，NH⁺₄-N、NO^-₃-N浓度均较高的进水，菖蒲湿地可在C/N小于2时高效脱氮。菖蒲湿地对TN的去除占组合工艺TN去除量的79%，其中植物吸收仅占湿地除氮总量的8%。湿地介质的厌氧氨氧化活性试验表明，菖蒲湿地介质表面的微生物在无有机碳源存在的条件下，可使培养液中的NH⁺₄-N与NO^-₃-N、NO^-₂-N短期内发生同步脱氮，厌氧氨氧化可能是菖蒲湿地在进水低碳源条件下脱氮的主要原因。     

附加回流的生物接触氧化工艺净化滇池大清河水质的示范工程研究

针对滇池流域污染最为严重的大清河，采用附加回流生物接触氧化工艺（IBCOP）开展河道水体的旁路处理示范工程研究。IBCOP示范工程的设计规模为1 000 m³/d，HRT为4.75 h，在2007年11月至2008年4月冬旱季期间，根据气候和进水水质条件调节回流比，示范工程运行了3种工况。研究结果表明：示范工程对COD和NH⁺₄-N具有较高的去除效果，平均去除率为46.8%和48.8%，高回流比有利于去除NH⁺₄-N；受到低温、低碳源、高进水DO和生物膜生长不佳等因素影响，示范工程对TN去除效果较低，平均去除率为10.2%，调节回流比不能显著改善碳源不足的情况；水绵的吸收和底泥的沉积是示范工程除磷的主要机理，TP平均去除率为17.9%，低TP浓度进水、生物膜的脱落以及高回流比不利于除磷。     

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle.     

Book review

The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

Observations on the influence of water and soil pH on the persistence of insecticides

Abstract

The pH‐disappearance rate profiles were determined at ca. 25°C for 24 insecticides at 4 or 5 pH values over the range 4.5 to 8.0 in sterile phosphate buffers prepared in water‐ethanol (99: 1 v/v). Half‐lives measured at pH 8 were generally smaller than at lower pH values. Changes in half lives between pH 8.0 and 4.5 were largest (>1000x) for the aryl carbamates, carbofuran and carbaryl, the oxime carbamate, oxamyl, and the organophosphorus insecticide, trichlorfon. In contrast, half lives of phorate, terbufos, heptachlor, fensulfothion and aldicarb were affected only slightly by pH changes. Under the experimental conditions described half lives at pH8 varied from 1–2 days for trichlorfon and oxamyl to >1 year for fensulfothion and cyper‐methrin. Insecticide persistence on alumina (acid, neutral and basic), mineral soils amended with aluminum sulfate or calcium hydroxide to different pH values and four natural soils of different pH was examined. No correlation was observed between the measured pH of these solids and the rate of disappearance of selected insecticides applied to them. These observations demonstrate the difficulty of extrapolating the pH dependent disappearance behaviour observed in homogeneous solution to partially solid heterogeneous systems such as soil.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

Radionuclides in pinon pine (Pinus edulis) nuts from los alamos national laboratory lands and the dose from consumption

Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of ³H, ¹³⁷Cs, ⁹⁰Sr, ^totU, ²³⁸Pu, ^{239, 240}Pu, and²⁴¹ Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of ³H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.     

Degradation and sorption of imidacloprid in dissimilar surface and subsurface soils

Degradation and sorption/desorption are important processes affecting the leaching of pesticides through soil. This research characterized the degradation and sorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) in Drummer (silty clay loam) and Exeter (sandy loam) surface soils and their corresponding subsurface soils using sequential extraction methods over 400 days. By the end of the incubation, approximately 55% of imidacloprid applied at a rate of 1.0 mg kg^?1 degraded in the Exeter sandy loam surface and subsurface soils, compared to 40% of applied imidacloprid within 300 days in Drummer surface and subsurface soils. At the 0.1 mg kg^?1 application rate, dissipation was slower for all four soils. Water-extractable imidacloprid in Exeter surface soil decreased from 98% of applied at day 1 to > 70% of the imidacloprid remaining after 400 d, as compared to 55% in the Drummer surface soil at day 1 and 12% at day 400. These data suggest that imidacloprid was bioavailable to degrading soil microorganisms and sorption/desorption was not the limiting factor for biodegradation. In subsurface soils > 40% of ¹⁴C-benzoic acid was mineralized over 21 days, demonstrating an active microbial community. In contrast, cumulative ¹⁴CO₂ was less than 1.5% of applied ¹⁴C-imidacloprid in all soils over 400 d. Qualitative differences in the microbial communities appear to limit the degradation of imidacloprid in the subsurface soils.     

Biochemical interaction of six op delayed neurotoxicants with several neurotargets

Abstract

Five organophosphorous insecticides: Leptophos, EPN, Cyano‐fenphos, trichloronate and salithion proved to cause irreversible ataxia not only to chicken but also to mice and sheep. TOCP was included as a reference. Cyanofenphos blocked the catecholamine B‐receptor binding activity with ³H‐norepinephrine at a level similar to that of the specific inhibitor propranolol in the mouse heart preparation. In the lamb heart preparation, the B‐receptor was more sensitive to Leptophos, salithion and TOCP than to propranolol. The six compounds and their oxons were screened for their in‐vitro inhibition to monamine oxidase (MAO), acetyl cholinesterase (AChE) and neurotoxic esterase (NTE) in the brain of either mouse, lamb or chicken. It is believed that their AChE inhibition stands for their acute toxicity, while NTE inhibition is responsible for their paralytic ataxia.