The effect of cattle slurry electroflotation products as fertilizers on gaseous emissions and grassland yield

The climatic conditions of the Basque Country (northern Spain) provide the favorable conditions for the growth of grasslands and the development of livestock enterprises. The intensification of the farms is leading to serious environmental risks due to the great generation of manures and slurries and their subsequent inefficient management. Their application involves N losses that can be pollutant. The environmental company ADE BIOTEC S.L. is developing the process called "electroflotation" with the aim of reducing the volume of slurries from intensive livestock farms. The process consists basically of an electrolysis of the slurry catalyzed by iron which leads to the flocculation of the solid particles, giving as a final result a solid and a liquid fraction. The objective of this work was to assess the usefulness of these two fractions as fertilizers. With this aim, the environmental risk of their application was determined regarding gaseous emissions to the atmosphere (i.e., of NO, NH(3), N(2)O, and CO(2)) and their fertilizer capacity was investigated by determining their effects on grassland yield and N uptake in comparison to the untreated slurry. The untreated slurry and the solid and the liquid fractions were all applied at a rate of 70 kg NH(4)(+)-N ha(-1). The application of the products of electroflotation did not affect N(2)O and CO(2) losses, being of the same magnitude as those caused by the application of the original slurry. However, after their application, a reduction in NH(3) volatilization losses was induced in the short term and a reduction in NO losses was caused in the long term. The solid and liquid fractions both increased biomass yield with respect to the untreated slurry. The solid fraction even induced a higher N uptake than the liquid fraction and the untreated slurry.     

低温作业对人体的危害及防寒工作服的性能评价

防寒工作服是冬季保护石油行业室外作业人员的重要措施。文章阐述了低温环境对石油行业室外作业人员身体健康的影响,列举了防寒工作服生产和检测的重要性能参数和测定方法,概括了国内外对于防寒工作服生产和检测的相关标准,展望了防寒工作服研发应用空间和发展方向,对防寒工作服的研究和配备有一定的参考价值。     

Sewage pollution effects on mesozooplankton structure in a shallow temperate estuary

The effects of a sewage effluent with no treatment on the mesozooplankton structure and the environmental quality were evaluated in the Bahía Blanca Estuary, during June to November 1995. The highest values of particulate organic matter, nutrients and specially phosphate, were observed in the effluent discharge zone. In addition, taxa richness, mesozooplankton abundance and Shannon diversity values were lower in the sewage discharge area compared with the less polluted area. Eurytemora americana and Acartia tonsa as well as larvae of Balanus glandula, Neohelice granulata and Spionidae were found in the discharge area with lower densities. These results highlight the importance of sewage effluent effects on mesozooplankton community providing background data to use in other monitoring programmes.     

On-line batch production of ferrate with an chemical method and its potential application for greywater recycling with Al(III) salt

Ferrate(VI) salt is an oxidant and coagulant for water and wastewater treatment. It is considered as a possible alternative method in greywater treatment. However, challenges have existed in putting ferrate(VI) technology into full-scale practice in water and wastewater treatment due to the instability of ferrate solution and high production cost of solid ferrate products. This study demonstrated a new approach of greywater treatment with on-line batch production of Fe(VI) to which Fe(III) salt was oxidized at a weak acidity solution. A series of experiments were conducted to investigate the effect of Fe(VI) on light greywater (total organic carbon (TOC) = 19.5 mg/L) and dark greywater (TOC = 55 mg/L) treatment under different conditions with varying pH and Fe(VI) doses. In addition, the combination use of Fe(VI) and Al(III) salts was proved to be more efficient than using the Fe(VI) salts alone at greywater recycling. The optimum dosage of Fe(VI)/Al(III) salts was 25/25 mg/L for light greywater, 90/60 mg/L for dark greywater, respectively. The TOC values of both light greywater and dark greywater were reduced to less than 3 mg/L with the dosages. The cost for treating greywater was 0.06–0.2 $/ton at ferrate(VI) dosage of 25–90 mg/L and 0.008–0.024 $/ton at AlCl₃ dosage of 25–60 mg/L. The full operating cost needs further assessment before the Fe(VI)/Al(III) technology could be implemented in greywater treatment.     

Distribution patterns of nitroaromatic compounds in the water, suspended particle and sediment of the river in a long-term industrial zone (China)

Nitroaromatic compounds are known to be hazardous to ecological and human health. To assess the status of nitroaromatic compounds contamination in the main rivers in the important industrial bases of the northeastern China, we collected water, suspended particulate matter (SPM) and sediment samples from 28 sites in the Daliao River watershed and analysed them for eight nitroaromatic compounds by gas chromatography. The total concentrations of eight nitrobenzenes in the water column including aqueous and SPM phases ranged from 740 to 15,828 ng L^???1, with a mean concentration of 3,460 ng L^???1. The total concentrations of eight nitrobenzenes in the sediment were 7.47 to 8,185.76 ng g^???1, with a mean concentration of 921.98 ng g^???1, and several times higher than those found from the Yellow River in China. 4-Nitrotoluene was the predominant contaminant in the water and sediment of the three rivers of the Daliao River watershed. 2,6-Dichloro-4-nitroaniline was generally dominant in the SPM. The levels of nitroaromatic compounds were different among different sites in the Daliao River watershed, mainly caused by the distribution of pollution sources. No obvious correlation was found between the total concentrations of eight nitrobenzenes concentrations and TOC or the slit-clay content of the sediments.     

某高含硫气田地面工程职业病危害防护设施效果评价

为了解高含硫气田地面工程职业病危害因素及防护设施的效果,文章采用职业卫生学调查、职业卫生检测和职业健康监护相结合的综合分析与评价方法,对某高含硫气田地面工程试运行期间的职业病危害防护设施效果进行评价。结果表明:项目运行过程中存在的主要职业病危害因素有硫化氢、一氧化碳、氮氧化物、二氧化硫、硫磺粉尘、噪声等12种,除锅炉、空气氮气站岗位噪声强度超过职业接触限值外,其余均符合国家职业卫生标准,职业健康检查无职业禁忌证及职业病,表明该项目的职业病危害防护设施设计合理,防护有效。     

Bio-syngas production with low concentrations of CO2 and CH4 from microwave-induced pyrolysis of wet and dried sewage sludge

This paper assesses the feasibility of producing syngas from sewage sludge via two pyrolysis processes: microwave-induced pyrolysis (MWP) and conventional pyrolysis (CP). The changes in the composition of the produced gas as a function of the pyrolysis treatment and the initial moisture content of the sludge were evaluated. It was found that MWP produced a gas with a higher concentration of syngas than CP, reaching values of up to 94vol%. Moreover, this gas showed a CO2 and CH4 concentration around 50% and 70%, respectively, lower than that obtained in the gas from CP. With respect to the effect of moisture on gas composition, this was more pronounced in CP than in MWP. Thus, the presence of moisture increases the concentration of H2 and CO2 and decreases that of CO, especially when CP was used. In order to elucidate the behaviour of CO2 during the pyrolysis, the CO2 gasification kinetics of the char obtained from the pyrolysis were investigated. It was established that in microwave heating the gasification reaction is much more favoured than in conventional heating. Therefore, the low concentration of CO2 and the high concentration of CO in the microwave pyrolysis gas could be due to the self-gasification of the residue by the CO2 produced during the devolatilization of the sewage sludge in the pyrolysis process.     

新型微波化学工艺处理电镀废水初探

简要介绍微波化学工艺的反应机理和技术特点,以现有理论为基础,借助工程实践初步探讨微波化学工艺对电镀废水的处理效果。通过广东省某电镀废水处理厂对微波化学工艺的实际应用表明,该技术工艺具有投资少、调试期短、运行费用低、处理效果显著等优点,具有较好的经济效益和环境效益。同时,又可以实现污水回用及废水资源化,符合国家环境保护政策,电镀废水经处理后,出水水质能够达到广东省DB44／26--2001《水污染物排放限值》一级标准。     

低磷胁迫对水稻地上部钙、镁吸收和积累的影响

采用瓮栽试验系统研究了低磷(P)胁迫条件下不同P效率水稻基因型在分蘖期、孕穗期和成熟期的钙(Ca)、镁(Mg)营养特性.结果表明,低P胁迫对不同基因型水稻Ca、Mg吸收的影响因生育期、基因型和部位不同而不同.分蘖期时,低P胁迫使水稻体内Ca含量增加,低P敏感基因型水稻地上部Mg含量增加,耐低P基因型则Mg含量降低.孕穗期时,低P胁迫使不同基因型水稻体内Ca、Mg含量下降.至成熟期,除99056外,其它基因型籽粒内Ca、Mg含量均降低;除99012外,其它基因型茎叶中Ca、Mg含量也降低.各个时期低P胁迫都降低了Ca、Mg在水稻地上部分的积累量,耐低P基因型只在孕穗期表现出相对的优势.低P胁迫同时降低了成熟期茎叶内Ca、Mg向籽粒的转移,但99056却例外.低P胁迫下,较之低P敏感基因型,耐低P基因型水稻对Ca、Mg的吸收和积累并没有表现出明显的优势.图4表7参26     

16种农药对东亚小花蝽的生态风险评估

东亚小花蝽是我国北方林木、果园和农田的优势天敌昆虫。为评估常用化学农药对东亚小花蝽的毒害作用,首次测定了16种田间常用化学农药对东亚小花蝽的24 h急性接触毒性,并进行了生态风险评估。结果表明所试除草剂、杀菌剂和杀虫剂中的吡蚜酮对东亚小花蝽较为安全,3倍田间最高推荐剂量下的校正死亡率低于33.33%。阿维菌素、甲氨基阿维菌素苯甲酸盐、吡虫啉和啶虫脒对东亚小花蝽的半数致死浓度LC0分别为36.567、15.798、4.992和4.487 mg a.i.·L~(-1)5,农田内风险可接受。噻虫嗪、联苯菊酯和呋虫胺对东亚小花蝽的LC_(50)分别为0. 002、0. 080和0. 968 mg a. i.·L~(-1),农田内危害商值分别为3 976.36、69.03和16.93,在农田内对东亚小花蝽造成的风险均不可接受。本研究的结果有助于合理施用化学农药以保护和利用东亚小花蝽。