填料传质性能对污水生物反应处理工艺的影响研究

通过水力自旋填料与常规生物填料的对比试验,研究了传质性能对污水生物反应处理工艺的影响.结果表明:生物反应器内物系间的传质条件对氧传递效率有较大影响;SCMT型自旋传质填料良好的传质性能,能够创造理想的传质条件,使生物反应器内DO基本保持一致;使用SCMT型自旋传质填料生物反应器处理城市污水,可以在较短的停留时间(1.00 h)或较小的气水比(体积比,4∶1)的情况下,出水水质达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)二级标准.     

生物悬浮填料对微孔曝气氧传质影响的中试研究

生物填料在污水处理中常用来增加生物量以提高污水的净化效率,同时生物填料的加入会影响曝气氧转移效率.考察了典型的SPR-1生物悬浮填料在清水中对微孔曝气氧传质过程的影响.结果表明,在水深为6.00 m时,SPR-1生物悬浮填料有助于促进微孔曝气的氧传质,当填料填充率为40％,单位体积通气量为0.755 m3/h时,氧总转移系数(KL a20)和标准氧转移效率(SOTE)提高程度最大,分别为19.32％和5.78％;当水深为2.33 m时,SPR-1生物悬浮填料对微孔曝气氧传质有阻碍作用.在实际污水处理过程中,可以根据水深,调节填料填充率来使填料最大限度地促进氧传质.     

生物填料塔处理餐厅污水传质反应研究

从传质和生化反应基本过程出发,经合理简化,将复杂的生物填料塔中三相传质生化反应过程综合为一个有效生化反应过程并得到其数学模型。模型中综合参数——总传质有效因数η可通过容易测定的本征反应和实际反应速率来确定;实验研究了不同入塔污水CODCr和入塔水量对η的影响。结果表明：入塔污水CODCr较高时,有较大的孕;当入塔水量增大,传质效果增加η增大。     

有机复合填料生物滤床对甲苯气体的净化

利用一种新型有机复合填料作为生物滤床中微生物的附着载体,接种经过驯化筛选的专性甲苯降解菌,填装于生物过滤塔中净化低浓度甲苯气体。研究了新型有机复合填料在长期运行时的情况,考察了进气流量、入口浓度、床层温度和填料湿度对生物滤床的影响,最终经过优化得出,此种填料的生物滤床能够为微生物提供良好的附着生长环境,并能保持滤床的高效稳定运行,当进气流量为0.4 m3/h,入口浓度为400 mg/m3,床层温度为30℃,填料湿度为50%时,生化去除量达到30.6 g/(m3.h),并且在此条件下滤床具有良好的耐冲击性能。     

矿物棉填料孔隙率对生物滴滤池水处理效果的影响

针对生物滴滤池因接触时间短而导致出水不达标的问题,采用3种容重(80、100、120 kg· m-3)的矿物棉作为滤池填料,考察了填料孔隙率对保水性的影响,分析了不同容重填料的生物滴滤池去除污染物的效能,探究了填料孔隙率对微生物群落特征的影响.结果 表明,矿物棉载体的吸水、保水性能随其孔隙率增加呈现先增加后减小的趋势;...     

厌氧/特异性移动床生物膜反应器处理低碳氮比工业废水脱氮效果优化分析

采用SDC-03型填料作为生物载体,对厌氧/特异性移动床生物膜反应器(A/SMBBR)工艺处理低碳氮比工业废水的挂膜启动及稳定运行过程进行优化分析。通过单因素试验和基于Box-Behnken设计的响应曲面法考察了碳源投加量(以乙醇为碳源)、水力停留时间(HRT)及填料填充率对系统TN去除率的影响及其交互作用。结果表明:(1)3个参数对TN去除率影响顺序为填料填充率碳源投加量HRT,其中填料填充率和HRT之间的交互作用最显著。(2)模型预测的最佳条件为碳源投加量90mg/L、HRT=3.0d、填料填充率55%,TN去除率预测值为90.78%。在该条件下TN去除率实际值达91.02%,与模型预测值基本一致,表明响应曲面模型与实际情况拟合良好。     

竹制填料生物接触氧化工艺处理污染河水简

针对受污染的湖溪河水质特征,以传统弹性塑料填料做对比,研究以竹球和竹丝为填料的生物接触氧化工艺,考察填料的挂膜时间、生物量和污水处理效果;确定连续曝气和间歇曝气时反应器的最优运行工况：连续曝气时为HRT=7.5 h,DO=3 mg/L;间歇曝气时为厌氧1.2 h、好氧6.3 h交替运行。实验结果表明,与弹性塑料填料相比,竹制填料挂膜速度快,竹球填料的水处理效果最好;连续曝气最优工况下竹球填料反应器中COD、TN、NH₃-N和TP的平均去除率分别为66.7%、47.9%、57.1%和30.6%;间歇曝气最优工况下竹球填料反应器中COD、TN、NH₃-N和TP的平均去除率分别64.08%、39.95%、60.7%和54.68%;竹制填料可替代传统的塑料填料作为生物接触氧化工艺的载体填料。     

竹制填料生物接触氧化工艺处理污染河水

针对受污染的湖溪河水质特征,以传统弹性塑料填料做对比,研究以竹球和竹丝为填料的生物接触氧化工艺,考察填料的挂膜时间、生物量和污水处理效果;确定连续曝气和间歇曝气时反应器的最优运行工况：连续曝气时为HRT：7．5h,DO=3mg／L;间歇曝气时为厌氧1．2h、好氧6．3h交替运行。实验结果表明,与弹性塑料填料相比,竹制填料挂膜速度快,竹球填料的水处理效果最好;连续曝气最优工况下竹球填料反应器中COD、TN、NH3-N和TP的平均去除率分别为66．7％、47．9％、57．1％和30．6％;间歇曝气最优工况下竹球填料反应器中COD、TN、NH3-N和TP的平均去除率分别64．08％、39．95％、60．7％和54．68％;竹制填料可替代传统的塑料填料作为生物接触氧化工艺的载体填料。     

芦苇生物炭复合载体固定化微生物去除水中氨氮

为了去除水体中的氮素并实现水生植物的有效利用,以芦苇生物炭为无机载体,结合海藻酸钠(SA)、聚乙烯醇(PVA)作为复合载体,固定驯化后的硝化污泥制成固定化颗粒,去除水中氨氮。通过考察固定化颗粒机械强度、酸碱稳定性及传质性能,探究了生物炭添加量及生物炭粒径对固定化颗粒降解氨氮性能的影响。结果表明,芦苇生物炭有丰富的孔结构,表面含有较多的含氧官能团和胺基、磺酸基、羧基和酰胺基等基团,从而具有良好的吸附性能以及较强的酸碱缓冲能力,有利于微生物的黏附和增殖。以添加芦苇生物炭作为复合载体,固定化颗粒的破损率降低了2.4%,酸碱稳定性和传质性分别提升12.5%和55.8%;在72 h内,可以使氨氮降解率达到96.3%。此外,不同粒径生物炭的固定化颗粒对氨氮的吸附量有显著影响,随着生物炭粒径从0.60 mm减小至0.15 mm,氨氮的最大吸附量可以从0.30 mg·g~(-1)增加到0.46 mg·g~(-1)。因此,在固定化微生物的载体中添加生物炭,可以提升固定化颗粒性能,打通微孔孔道从而有利于基质的运输和扩散;同时减小生物炭粒径,为微生物提供更多的吸附位点,从而显著提高固定化微生物对氨氮的降解能力。     

新型填料曝气生物滤池处理抗生素类废水

针对抗生素类制药工业废水难处理的特点,将某高效复合微生物菌群负载在以中孔和大孔为主的污泥炭颗粒的表面和孔隙内部,制备得到生物改性污泥炭。采用装填生物改性污泥炭的新型填料曝气生物滤池及向下流、中下部曝气的运行方式对以抗生素类制药废水为主的混合工业废水絮凝沉淀池出水中的主要污染物进行深度处理。结果表明,污泥炭载体在水中发挥2种作用,即吸附功能和载体功能,污泥炭表面及内部孔隙结构非常发达,为不同种类和功能的高效微生物菌群的构建和负载提供了良好的载体;采用粒径为8~10 mm的生物改性污泥炭、HRT 100 min及气水比3∶1,进水COD浓度96~123 mg/L、NH3-N浓度8.8~17.4 mg/L、TP浓度0.390~0.623 mg/L、pH 6~9,新型填料曝气生物滤池对混合工业废水中的COD、NH3-N和TP的平均去除率分别为47.2%、49.2%和35.6%,相比污水厂常规陶料填料生物滤池分别提高了27.9、21.6和12.8个百分点,该工艺处理效果稳定,运营管理简单,为极难生物降解的抗生素类废水为主的混合工业废水的深度处理提供了新思路。     

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.     

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.     

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.     

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.     

土壤中砷的化学平衡

本文比较详细地综述了砷的化学特性,环境背景值及来源和循环,土壤中砷的三大化学平衡即沉淀溶解平衡,氧化还原平衡,吸附解吸平衡,以及微生物对砷的转化。     

Elemental uptake by edible herbs and lettuce (Latuca sativa)

The total concentration of toxic elements (aluminum, cadmium, chromium and lead) and selected macro and micro elements (iron, manganese, copper and zinc) are reported in six leafy edible vegetation species, namely lettuce, spinach, cabbage, chards and green and red types of Amaranth herbs. Although spinach and chards had greater than 125 mv of iron, both the amaranthus herbs recorded > than 320 μ g g^{? 1} dry weight. In both the spinach and chard species, the Mn and Zn levels were appreciable recording > 225 μ g g^{? 1} and 150 μ g g^{? 1} dry weight, respectively. Aluminum concentrations were (in μ g g^{? 1} dry weight) lettuce (10), cabbage (11), spinach (167), chards (65), amaranthus green (293) and amaranthus red (233). All the micro and macro elements and the toxic elements (Ni, Cr, Cd and Pb) elements analyzed, were below the recommended maximum permitted levels (RMI) in vegetables. Further the elemental uptake and distribution of the nine elements, at three growth stages of the lettuce plant grown on soil bed under controlled conditions are detailed. In the soil, except for iron (16%), greater than 33% of the other cations were in exchangeable form. Generally in the lettuce plant, roots retained much of the iron (> 224 μ g g^{? 1}) and aluminum (> 360 μ g g^{? 1}), while leaves had less than 200 μ g g^{? 1} of iron and 165 μ g g^{? 1} of Al. Although the concentrations of elements marginally decreased with growth, the lettuce leaves had significant amounts of Mn (30 μ g g^{? 1}), Zn (50 μ g g^{? 1}) and Cu (3.6 μ g g^{? 1}). Some presence of lead in leaves (2.0 μ g g^{? 1}) was noticed, but all the toxic and other elements analyzed were well below the RMI values for the vegetables.     

The dissipation of nonlyphenol in stream and pond water under simulated field conditions

Abstract

The dissipation of 1.0 ppm nonylphenol in stream and pond water, incubated in flasks at 16°C under simulated field conditions up to 44 days indicated that the half‐life was 2.5 days if the flasks were open, and 16 days if they were closed. A transformed product was detected in the closed flasks.

Translocation of nonylphenol in water occurred when treated water samples were incubated in the presence of sediment. After 10 days, nonylphenol was detected only in the sediment, but not in water (detection limit = 10 ppb). About 80% of the nonylphenol was degraded in 71 days, but no degradation occurred if the water and the sediment were autoclaved prior to incubation.