石油污染生物修复研究进展

石油污染多见于油田附近的土壤污染和海上油轮泄漏造成的海域污染,自1970s便出现了利用微生物降解石油污染物的生物修复研究,总结了1970s至今的相关文献发现石油污染生物修复技术受到越来越多的关注,其目前的主要研究方向包括:添加辅助营养物质或辅助乳化剂、石油污染降解过程的生物标记研究、菌株具体降解途径、工程示范研究.而由于石油污染成分复杂,不同微生物可利用的石油底物不同,降解途径也不同,因此传统的石油污染生物修复研究存在效率不高、难以维持等问题,而随着1990s以来分子生物学技术的迅速发展,其在石油污染生物修复中得到越来越多的应用,并有效地提高了修复效率.其应用主要包括以下两方面:(1)在掌握已有石油污染物生物降解途径和降解基因的基础上,研究针对石油污染不同底物的高效降解菌株,构建高效基因工程菌或功能互补的混合菌剂.譬如石油污染物的生物降解过程中,一系列的加氧酶/羟化酶起着最重要的作用,其中包括了单加氧酶和双加氧酶等.它们一般作用于降解的加羟基或后续的开环过程.而不同的脱氢酶、脱羧基酶、辅酶A连接酶等,则对底物加氧后的降解起着重要作用.因此本文重点分析整理了一系列典型石油污染物降解途径中的加氧酶及其参考菌株.(2)由于下游多态性分析方法的进步,越来越多的研究利用PCR对修复过程中群落的重要降解基因进行扩增,譬如对芳烃开环有重要作用的儿茶酚1,2-双加氧酶(C120)、儿茶酚2,3-双加氧酶(C23O)以及对长链烷烃降解起作用的alkB,alkM等基因,并进而应用rDNA扩增及限制性位点分析、梯度凝胶电泳、末端限制性片段长度多态性分析等方法监测研究石油污染的生物降解过程.本文总结了近年来石油污染修复中应用上述方法的研究,为今后的石油污染生物修复工作提供参考.     

稻草及稻草循环利用后的废弃物还田效益研究

本文针对中南丘陵水稻产区农田稻草经过稻草直接还田(鲜稻草)、稻草过腹还田(新鲜牛粪)、稻草栽培食用菌后还田(新鲜菌渣)、稻草产沼气后还田(新鲜沼渣)等几种主要的循环利用方式后的废弃物还田,结合化肥配施对水稻产量及土壤基本理化性状影响的研究,以期寻找一种既能达到有机废弃物的循环再利用,改善生态环境,又能够改良土壤理化性状并达到水稻丰产的目的.试验结果显示:相对于常规的化肥施用,几种有机废弃物还田加化肥配施均有利于土壤有机质(1.71%～6.98%),碱解氮(4.30%～15.05%),有效磷(11.22%～21.43%)等养分的提高;增加了土壤团聚体R0.25(干筛6.60%～8.74%,湿筛2.64%～45.06%)、平均质量直径(干筛26.91%～52.69%,湿筛4.55%～32.73%)及几何平均直径(干筛17.88%～35.56%,湿筛3.08%～6.15%);在产量方面,虽较常规施肥有所下降,但经济效益却是增加的,较常规施肥增收75.6元·hm2到1 057.0元·hm2,其中沼渣还田的增益率最高达8.59%.     

Feasibility of weeds-based compost-cultivated Agaricus bisporus北大核心CSCD

Making full use of local weed resources to produce Agaricus bisporus is of great importance in reducing production costs and protecting the environment. In this paper, three trial experiments were conducted on the basis of weed diversity investigation around the Miyun Reservoir and the adjustment of formulation and technology in the industrial production of A. bisporus. Compost samples from different phases of the composting process and at various cultivation stages were collected for the determination of their physical-chemical properties, lignocellulose content, lignocellulolytic enzyme activities, and bacterial communities enrichment by 16S rRNA gene sequencing. The yield of mushrooms in each different trial was also calculated. The results showed several types of reservoir weeds with high, thick and hard stems. The saturated moisture of weeds was 76.78% after baling. The water content, carbon content, and C/N ratio of the samples decreased gradually during composting, but had little change during cultivation. The nitrogen content decreased at the end of phase I and increased at the end of phase II. During composting, the loss rates of hemicellulose and cellulose were both between 40% and 60%, and the loss rate of lignin was between 20% and 30%. During cultivation, instead, the loss rate of lignin was between 16% and 21%. The changes in the content of cellulose and hemicellulose of compost were consistent with that of the activity of the related degradation enzymes. A total of 432 595 valid sequences were obtained by Illumina sequencing for the samples derived from the three composting trials, and the average length of the sequences was 441 bp. Taxonomic analysis showed that the dominant bacteria were Prevotella (phylum Bacteroidetes), Bacillus (phylum Firmicutes), Thermus, Truepera, and Caldicoprobacter (phylum Deinococcus-Thermus), Thermopolyspora (phylum Actinobacteria), and Pseudoxanthomonas (phylum Proteobacteria). The yield of the three trials was in the range of 17.1-19.7 kg/m2. It is thus feasible to use reservoir weeds compost instead of wheat straw compost for the cultivation of A. bisporus. © 2018 Science Press. All rights reserved.     

序言

正享誉海内外的著名鱼类学家和淡水生态学家、我国淡水生态学奠基人和鱼类实验生物学主要开创者、中国科学院水生生物研究所研究员(原所长和名誉所长)、中国科学院院士刘建康先生于2017年秋天离开了我们。为深切缅怀刘建康先生对我国鱼类学和淡水生态学的卓越贡献,同时呼吁加强水生生物多样性与流域生态系统的保护,我们应《生态毒理学报》编辑委员会的邀请一起策划组织了主题为"水生生物完整     

Investigation of the effects of humic acid and H<Subscript>2</Subscript>O<Subscript>2</Subscript> on the photocatalytic degradation of atrazine assisted by microwave

A solution of atrazine in a TiO₂ suspension, an endocrine disruptor in natural water, was tentatively treated by microwave-assisted photocatalytic technique. The effects of mannitol, oxygen, humic acid, and hydrogen dioxide on the photodegradation rate were explored. The results could be deduced as follows: the photocatalytic degradation of atrazine fits the pseudo-first-order kinetic well with k = 0.0328 s^?1, and ·OH was identified as the dominant reactant. Photodegradation of atrazine was hindered in the presence of humic acid, and the retardation effect increased as the concentration of humic acid increased. H₂O₂ displayed a significant negative influence on atrazine photocatalysis efficiency. Based on intermediates identified with gas chromatography-mass spectrometry (GC-MS) and Liquid chromatography-mass spectrometry (LC-MS/MS) techniques, the main degradation routes of atrazine are proposed.     

Abatement of sulfide generation in sewage by glutaraldehyde supplementation and the impact on the activated sludge accordingly

Hydrogen sulfide emission in sewer systems is associated with toxicity, corrosion, odour nuisance and high costs treatment. In this study, a novel method to inhibit sulfide generation from sewage by means of glutaraldehyde supplementation has been suggested and evaluated under anaerobic conditions. Different concentrations of glutaraldehyde at 10, 15, 20, 30 and 40 mg·L^-1 have been investigated. Besides, the possible impacts of glutaraldehyde supplementation on an activated sludge system and an appraisal of the economic aspects are presented as well. As observed from the experimental results, a dosage of 20 mg·L^-1 glutaraldehyde resulted in a significant decrease of the sulfide production by 70%–80% in the simulated sewage. Moreover, the impacts of additional glutaraldehyde at 20 mg·L^-1 on activated sludge, in terms of chemical oxygen demand removal and oxygen uptake rates, were negligible. From an economical point of view, the cost of the commercial glutaraldehyde products required in the operation, which was calculated on the basis of activated sulfide removal avoidance, was around €3.7–4.6 S·kg^-1. Therefore it is suggested that glutaraldehyde supplementation is a feasible technique to abate the sulfide problems in sewer systems. Yet further research is required to elucidate the optimum “booster” dosage and the dosing frequency in situ accordingly.     

用苎麻生物脱胶废水生产热带假丝酵母单细胞蛋白

采用热带假丝酵母处理苎麻生物脱胶废水。将COD为23 060 mg/L的苎麻生物脱胶废水稀释1倍后进行发酵处理,COD去除率最高,为60.85%。发酵条件的正交实验结果表明:在发酵温度为35℃、初始发酵pH为7.0、接种量为10%、发酵时间为48 h的条件下,苎麻生物脱胶废水COD去除率最高;发酵温度为30℃、初始发酵pH为7.0、接种量为10%、发酵时间为48 h的条件下,单细胞蛋白生成量最高。发酵时间为48 h时,灭菌的发酵培养基的COD去除率为75.75%,单细胞蛋白生成量为5.375 g/L;未灭菌的发酵培养基的COD去除率为72.25%,单细胞蛋白生成量为2.875 g/L。     

硫酸盐对医药化工废水厌氧系统运行稳定性的影响

以获得硫酸盐还原能力的厌氧装置为研究对象,研究进水中不同硫酸盐浓度对厌氧反应器的运行效果的影响。试验结果表明:硫酸盐添加量为300 mg/L时,厌氧反应器出水COD浓度最低,COD去除率为76.1%,同时厌氧反应器出水中VFA的浓度最低;在硫酸盐添加量为400 mg/L时,此条件下获得产甲烷量最高,达240~260 mL/g;出水硫化氢浓度则随着硫酸盐添加量的增加而增加。在500 m3的UASB反应器内进行连续厌氧处理试验,结果表明添加硫酸盐后厌氧反应器的运行情况稳定。     

同时产甲烷化反硝化系统中丙酸转化能力的研究

厌氧丙酸积累造成的酸败问题一直是制约厌氧反应器稳定运行的重要因素之一。通过建立同时产甲烷反硝化功能的厌氧反应系统,来研究该系统对丙酸转化的能力。试验结果表明:在同时产甲烷化反硝化功能的厌氧反应器中加入10 mmol/L丙酸,该系统能够继续保持稳定运行,COD去除率可达95.5%左右,丙酸去除率达96%以上;而加入丙酸的对照组中,出水COD去除率下降到10%以下,对于丙酸几乎没有任何降解。同时,在实际的UASB厌氧"酸败"反应器中,以ρ(COD)/ρ(NO3-N)=12.5∶1投加硝酸盐能较快降低水中VFA的浓度,使反应器得到快速恢复。     

次氯酸钙法处理发泡剂生产废水

采用废漂白液(次氯酸钙)处理发泡剂偶氮二甲酰胺生产废水。废水pH为8～9时,加入质量分数3％～5％的漂白液和1‰PAM絮凝剂,反应2h,沉淀澄清。实验室试验中COD去除率为88％,工业处理试验中COD平均由626mg／L降为105mg／L,去除率为83．2％。该法工艺简单,以废治废,费用低,处理效果好。