初始温度对人粪便好氧堆肥过程的影响

温度是好氧堆肥过程中需要控制的一个重要因素。不同的初始温度直接影响了堆肥过程中微生物活性及有机物的降解。为了研究初始温度对粪便好氧堆肥过程的影响,采用序批式好氧堆肥反应器,以新鲜锯末为载体,控制含水率在55%~60%的范围左右并强制通风的好氧条件下,进行了初始温度分别为25、35、45和55℃,20 d为一个周期好氧堆肥实验,研究了不同初始温度条件下堆肥过程有机物降解、氮的迁移转化及种子发芽指数的变化。结果表明,初始的高温度会抑制堆肥反应的进行,但初始温度越高,水解效果越显著;初始的高温有利于COD的去除,最终COD的去除率分别为88.2%、89.3%、92.0%和89.9%。初始高温对种子发芽率有抑制作用,同时延迟了堆肥的腐熟期。     

卧式螺旋污泥好氧动态堆肥技术的研究

利用卧式螺旋式污泥好氧堆肥装置进行间歇式动态堆肥,对污水厂厌氧消化污泥进行了中温堆肥试验研究.通过控制各组堆肥的含水率、物料配比和通气量,重点探讨各种条件下堆体温度与有机物降解的关系.试验结果表明,厌氧消化污泥以木屑为调理剂在装置中可以实现好氧堆肥处理,其适宜的物料控制参数为:污泥:木屑=10:1～1.5(湿重比),堆肥含水率50%～60%;过程控制参数为:通风量为6.7～8.3 m3/h·t,发酵周期为8 d,温度45℃.     

好氧堆肥反应器对人粪便堆肥中温降解的中试研究

控制温度为（35±2）℃，以新鲜锯末为空白载体，在控制含水率为55%~60%和强制通风的好氧条件下，进行为期15 d的实验，进行了人粪便好氧堆肥的中试研究，重点分析了在堆肥过程中有机物的降解、氮素的迁移转化规律及生物量的变化。结果表明，粪便中有机物含量在前2天稍微上升，然后迅速下降，最终去除率为71.82%；随着NH₃-N释放量的增加，堆料中N_tot含量从第4天开始减少，最终损失 22.61%，其中N_org损失占74.35%，NH₃-N占23.52%；所损失的氮素有91.66%以氨氮的形式释放。粪便中的有机物和氮的含量能在8~10 d后达到稳定，且堆体无臭味；粪便中溶解性有机物为微生物的生长提供营养物质，因此生物量变化的过程与有机物降解的有着紧密的联系；病原菌在堆肥过程中得到有效去除，表明该反应器堆肥的无害化。     

新型堆肥生物反应器人粪便堆肥功效的评价

利用以锯末为载体的Bio-Lux S15型生态卫生设备，对人粪便进行了连续性堆肥实验，考察了BOD₅、粪大肠菌和蛔虫卵的灭活以及最终产品N、P和K等肥料成分的含量。实验结果表明，最初30 d，BOD₅的累积去除率由27％快速增加到50％，之后的30 d维持在50％左右，随后下降至40％左右。生态卫生设备中维持50～60℃的温度是杀灭粪便病原微生物的适宜条件，可保证粪便投入后在24 h内，粪大肠菌的灭活率达到99.99％，蛔虫卵的灭活率在2 h内达100%。对反应周期内载体的N、P和K等肥料成分的分析结果表明，反应过程中3种肥分都持续积累，在反应末期，按TN、P₂O₅和K₂O计算的3种肥分最终分别达到25.1、123.4和2.0 g/kg，基本上达到了农用肥料的国家标准，表明以锯末为载体的反应器具有良好的堆肥效果。     

垃圾堆肥工艺过程动态模拟及优化研究

选取通气量、含水率、温度、底物浓度等作为堆肥控制因子,在堆肥生物反应动力学的基础上,根据堆肥反应过程的物料平衡和能量平衡,以及微生物比生长速度与含水率、堆肥温度的依存关系,结合翻转式堆肥反应装置操作运行条件,对厨房垃圾好氧堆肥过程中堆温、含水率、有机物、微生物量及氧气消耗量等变化进行计算机模拟计算,并将模拟结果与堆肥实验结果进行对比。结果证明,除了由于反应装置保温不理想引起堆温和含水率二者有偏差外,总体模拟计算结果与实际堆肥结果基本吻合。另外还开展了利用所开发的模型进行堆肥通气优化的应用研究。模型计算结果表明当出口氧气控制在10%～18%时,采用间歇供氧,不仅能提高堆肥效率,而且可以使供氧时间减少40%以上。经过堆肥实验验证模拟结果是正确的。由此可见,利用模型模拟堆肥过程,快速优化堆肥方案是可行与有效的。     

垃圾堆肥工艺过程动态模拟及优化研究

选取通气量、含水率、温度、底物浓度等作为堆肥控制因子，在堆肥生物反应动力学的基础上，根据堆肥反应过程的物料平衡和能量平衡，以及微生物比生长速度与含水率、堆肥温度的依存关系，结合翻转式堆肥反应装置操作运行条件，对厨房垃圾好氧堆肥过程中堆温、含水率、有机物、微生物量及氧气消耗量等变化进行计算机模拟计算，并将模拟结果与堆肥实验结果进行对比。结果证明，除了由于反应装置保温不理想引起堆温和含水率二者有偏差外，总体模拟计算结果与实际堆肥结果基本吻合。另外还开展了利用所开发的模型进行堆肥通气优化的应用研究。模型计算结果表明：当出口氧气控制在10％-18％时，采用间歇供氧，不仅能提高堆肥效率，而且可以使供氧时间减少40％以上。经过堆肥实验验证模拟结果是正确的。由此可见，利用模型模拟堆肥过程，快速优化堆肥方案是可行与有效的。     

温度对生活垃圾堆肥效率的影响

温度是堆料中微生物生命活动的重要标志,它直接影响堆肥反应速率,是堆肥能否顺利进行的主要因素。本试验利用可自动加热堆肥反应器,在一定条件下研究不同温度对生活垃圾堆肥效率的影响。通过监测出口气体中O2和CO2气体的浓度,计算堆料中有机物降解速率。试验表明,当反应条件为生活垃圾∶成熟堆肥=80∶20,有机物约为60%,初始含水率为55%,初始C/N比为25,堆肥温度控制在55℃左右时,能加速高温菌繁殖,从而加快垃圾分解速度,大大缩短堆肥腐熟时间。     

山羊粪污颗粒静态好氧堆肥过程的生物强化

对山羊粪便颗粒进行了理化表征,发现其外表致密内芯多孔的结构特点,且其总体C/N比为25.69~27.88,适合直接堆肥,提出采用生物接种破坏表层,强化堆肥进程的思路。研究结果表明,生物接种可以大大强化堆肥过程中的生化反应进程,缩短堆肥发酵周期。产物中N、P含量随着生物接种量的增加而增大。当以VT-1000菌剂按10 mL/kg干物质接种时,堆体温度在2 d内就达到50℃,在高温期50~60℃维持7 d以上,其堆肥腐熟后物料TN、TP分别增加0.70%和1.59%,其C/N<15,更趋于稳定化,且最终产物中粪大肠菌群数<3个/g,未检验出蛔虫卵,实现了无害化处理。     

粪便中温好氧堆肥过程有机物的降解研究

为了生态厕所的推广使用、便于操作和节约能耗,多采用无加热的设施,即在自然条件下(对于小型生态厕所,接近中温条件)的好氧堆肥处理.了解中温好氧堆肥过程有机物的降解特性,对于生态厕所的推广使用和简化设计、操作等具有重要意义.采用密闭式好氧堆肥反应器,模拟中温(35℃)的堆肥温度,以新鲜锯末为空白载体,在含水率为60％以及连...     

温度对生活垃圾堆肥效率的影响

温度是堆料中微生物生命活动的重要标志，它直接影响堆肥反应速率，是堆肥能否顺利进行的主要因素。本试验利用可自动加热堆肥反应器，在一定条件下研究不同温度对生活垃圾堆肥效率的影响。通过监测出口气体中O2和CO2气体的浓度，计算堆料中有机物降解速率。试验表明，当反应条件为生活垃圾：成熟堆肥=80：20，有机物约为60％，初始含水率为55％，初始C／N比为25，堆肥温度控制在55℃左右时，能加速高温菌繁殖，从而加快垃圾分解速度，大大缩短堆肥腐熟时间。     

Evaluation of trichloroethene recovery processes in heterogeneous aquifer cells flushed with biodegradable surfactants

The ability of two biodegradable surfactants, polyoxyethylene (20) sorbitan monooleate (Tween 80) and sodium dihexyl sulfosuccinate (Aerosol MA), to recover a representative dense non-aqueous-phase liquid (DNAPL), trichloroethene (TCE), from heterogeneous porous media was evaluated through a combination of batch and aquifer cell experiments. An aqueous solution containing 3.3% Aerosol MA, 8% 2-propanol and 6 g/l CaCl(2) yielded a weight solubilization ratio (WSR) of 1.21 g TCE/g surfactant, with a corresponding liquid-liquid interfacial tension (IFT) of 0.19 dyn/cm. Flushing of aquifer cells containing a TCE-DNAPL source zone with approximately two pore volumes of the AMA formulation resulted in substantial (>30%) mobilization of TCE-DNAPL. However, a TCE mass recovery of 81% was achieved when the aqueous-phase flow rate was sufficient to displace the mobile TCE-DNAPL toward the effluent well. Aqueous solutions of Tween 80 exhibited a greater capacity to solubilize TCE (WSR=1.74 g TCE/g surfactant) and exerted markedly less reduction in IFT (10.4 dyn/cm). These data contradict an accepted empirical correlation used to estimate IFT values from solubilization capacity, and indicate a unique capacity of T80 to form concentrated TCE emulsions. Flushing of aquifer cells with less than 2.5 pore volumes of a 4% T80 solution achieved TCE mass recoveries ranging from 66 to 85%, with only slight TCE-DNAPL mobilization (<5%) occurring when the total trapping number exceeded 2 x 10(-5). These findings demonstrate the ability of Tween 80 and Aerosol MA solutions to efficiently recover TCE from a heterogeneous DNAPL source zone, and the utility of the total trapping number as a design parameter for a priori prediction of DNAPL mobilization and bank angle formation when flushing with low-IFT solutions. Given their potential to stimulate microbial reductive dechlorination at low concentrations, these surfactants are well-suited for remedial action plans that couple aggressive mass removal followed by enhanced bioremediation to treat chlorinated solvent source zones.     

The variation of street air levels of PAH and other mutagenic PAC in relation to regulations of traffic emissions and the impact of atmospheric processes

The occurrence of particle associated PAH and other mutagenic PAC was determined in 1996 in the street air of Copenhagen. In addition, particle extracts were tested for mutagenicity. The measurements were compared with previous measurements in 1992/1993. The levels had decreased in this period. The decrease was caused by an implementation of light diesel fuels for buses and the exchange of older petrol-driven passenger cars with catalystequipped new ones. About 65% of the reduction was caused by the application of the light diesel fuels. Under special conditions, chemical processes in the atmosphere produced many more mutagens than the direct emissions. The concentrations of S-PAC and N-PAC were 10 times lower than those of PAH, while the levels of oxy-PAH were in the same order of magnitude as those of PAH. Benzanthrone, an oxy-PAH, is proposed to be formed in the atmosphere in addition to direct emissions. Benzo(a)pyrene, often applied as an air quality criteria indicator, was photochemically degraded in the atmosphere. A strong increase in the mutagenic activities was observed to coincide with a depletion of benzo(a)pyrene.     

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.     

Teratological effects of pesticides in vertebrates: a review

Abstract

In the last decades, the use and misuse of pesticides in the agriculture have increased, having a severe impact on ecosystems and their fauna. Although the various effects of pesticides on biodiversity have been already documented in several studies, to our knowledge no consistent overview of the impact of pesticides in vertebrates, both terrestrial and aquatic, is available. In this review, we try to present a concise compilation of the teratogenic effects of pesticides on the different classes of vertebrates – mammals, birds, reptiles, amphibians and fish.     

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.     

Knowledge transfer initiative between molecular biologists and environmental researchers and regulators

A Natural Environment Research Council (NERC) funded Knowledge Transfer (KT) workshop was held in the United Kingdom (UK) to identify the needs and opportunities in the application of molecular biology and ‘omics’ techniques to environmental monitoring and risk assessment. Attendees highlighted a lack of effective communication between end-users and researchers as well as difficulties with data interpretation as reasons behind the slow uptake of molecular biology and omics techniques. A number of promising areas in which new techniques could be implemented at a practical level in the very near future were identified, thereby raising the profile of these recent technologies and providing vital proof of concept work. Molecular taxonomy, bacterial source tracking and pre-screening of chemicals for potential toxicities were all viewed as areas in which omics and molecular techniques could have immediate value, with the aim of reducing cost, increasing efficiency and providing more comprehensive data of improved quality.     

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.     

Sorption and predicted mobility of herbicides in Baltic soils

This study was undertaken to determine sorption coefficients of eight herbicides (alachlor, amitrole, atrazine, simazine, dicamba, imazamox, imazethapyr, and pendimethalin) to seven agricultural soils from sites throughout Lithuania. The measured sorption coefficients were used to predict the susceptibility of these herbicides to leach to groundwater. Soil-water partitioning coefficients were measured in batch equilibrium studies using radiolabeled herbicides. In most soils, sorption followed the general trend pendimethalin > alachlor > atrazine～ amitrole～ simazine > imazethapyr > imazamox > dicamba, consistent with the trends in hydrophobicity (log K_ow) except in the case of amitrole. For several herbicides, sorption coefficients and calculated retardation factors were lowest (predicted to be most susceptible to leaching) in a soil of intermediate organic carbon content and sand content. Calculated herbicide retardation factors were high for soils with high organic carbon contents. Estimated leaching times under saturated conditions, assuming no herbicide degradation and no preferential water flow, were more strongly affected by soil textural effects on predicted water flow than by herbicide sorption effects. All herbicides were predicted to be slowest to leach in soils with high clay and low sand contents, and fastest to leach in soils with high sand content and low organic matter content. Herbicide management is important to the continued increase in agricultural production and profitability in the Baltic region, and these results will be useful in identifying critical areas requiring improved management practices to reduce water contamination by pesticides.