三峡水库消落区土壤、植物汞释放及其在斑马鱼体的富集特征

利用室内模拟试验,探讨了三峡水库消落区淹没后土壤、植物汞释放特征及其在斑马鱼体的富集水平.结果表明,随淹水时间的延长,淹没土壤中总汞(THg)含量下降;水体THg浓度总体明显升高.淹没土壤及水体中甲基汞(MMHg)含量总体明显上升,其中稗草+土壤处理水体中增加尤为明显,淹水21 d后,其浓度是土壤处理的2.52倍.表明消落区土壤、植物是水库水体汞的一个重要来源.供试稗草淹水分解造成水体pH及溶解氧(DO)含量下降、溶解性有机碳(DOC)含量上升,对土壤MMHg含量无明显影响,对水体MMHg影响较大.供试斑马鱼头部、内脏及肌肉中THg含量总体明显上升,与水体中THg浓度具有显著相关性(P<0.01).鱼体头部、内脏及肌肉中均出现不同程度的MMHg富集现象,以头部与肌肉最为明显.淹水21 d后,添加土壤处理的鱼体头部、内脏及肌肉MMHg增加的含量分别是对照的1.75~6.25、3.53~8.38、2.22~3.36倍;稗草+土壤处理的分别是土壤处理的3.57、2.37、1.52倍.可见,淹没土壤是鱼体MMHg增加的重要来源,淹没植物改变原水环境条件影响其向水体释汞过程能提高鱼体中MMHg含量.     

SBR-BAF组合工艺在肉鸡屠宰废水处理工程中的应用研究

屠宰废水有机污染物浓度较高,且含有脂肪、蛋白质等大分子有机物和毛发等杂物。采用前处理、SBR-BAF组合处理工艺在铁岭市某肉鸡屠宰企业废水处理工程的实际应用,取得了较为显著的效果。出水水质满足《辽宁省废水综合排放标准》(DB 21/1627-2008)直排标准和《肉类加工工业水污染物排放标准》(GB13457-92)[1]动植物油一级标准要求。组合处理工艺、设备运行安全可靠,可在同类肉鸡屠宰废水处理工程中推广应用。     

Implications of urine-to-feces ratio in the thermophilic anaerobic digestion of swine waste.

Thermophilic anaerobic digestion of swine manure represents a potential waste treatment technology to address environmental concerns, such as odor emissions and removal of pathogenic microorganisms. However, there are concerns relative to the stability of this process when swine manure is the sole substrate. In this study, the potential of biogas production from swine manure as the sole substrate under thermophilic (50 degrees C) conditions was investigated in the laboratory, to determine whether separation of urine and feces as part of the waste collection process would benefit anaerobic digestion. Effluent from a continuously stirred tank reactor was used as the inoculum for batch tests, in which the substrate contained three different concentrations of urine (urine-free, as-excreted urine-to-feces ratio and double the as-excreted urine-to-feces ratio). Inocula were acclimated to these same urine-to-feces ratios to determine methane production. Results show that both urine-free and as-excreted substrates were not inhibitory to anaerobic inocula. Anaerobic microorganisms can be readily acclimated to substrate with double the as-excreted urine concentration, which contained nitrogen concentrations up to 7.20 g/L. Cumulative methane production reached similar levels in the batch tests, regardless of the substrate urine concentration.     

沼泽红假单胞菌W12对活性黑5的厌氧脱色和降解作用

从处理印染废水的厌氧移动床生物膜反应器（moving bed biofilm reactor, MBBR）中分离到一株具有高效脱色活性的沼泽红假单胞菌W12。经实验确定W12对活性黑5（reactive black 5,RB5）脱色的适宜条件为：pH＜10;有光照;谷氨酸盐或乳酸盐作为碳源,当乳酸钠为碳源时浓度应＞500 mg/L;盐度不超过5％;RB5浓度不大于700 mg/L。紫外可见光谱扫描结果表明,RB5的脱色和降解过程生成芳香胺类化合物,这些中间产物可进一步降解。此外发现,RB5诱导生成的胞外代谢物能提高W12的脱色活性。     

Ambient air monitoring of PCDD/Fs and co-PCBs in Gyeonggi-do, Korea

We started the monitoring for PCDD/Fs in ambient air and soil in August 2001, and co-PCBs in January 2002. Decreasing of PCDD/Fs and co-PCBs levels in ambient air were observed. The higher PCDD/Fs levels were found in winter and lower in autumn. We found that the industrial incinerators influenced the PCDD/Fs levels in ambient air. In the 2,3,7,8-substituted PCDD/Fs concentration profiles, the three major congeners occupied 67% of the total mass. In case of co-PCBs, PCB#118, #105 and #77 were observed as the main congeners. Five cluster groups discriminated by ratio of four components, O(8)CDD, 1,2,3,4,6,7,8-H(7)CDD, 1,2,3,4,6,7,8-H(7)CDF and O(8)CDF, were obtained from HCA (hierarchical cluster analysis).     

Selected organochlorine pesticide and polychlorinated biphenyl residues in house dust in Singapore

Although the use of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) has been prohibited in Singapore since 1980, OCPs and PCBs still can be detected in the environment and represent a potential threat to public health. In this study, OCPs and PCBs were measured in house dust samples collected from 31 homes across the island-state of Singapore. Organochlorine pesticides, such as hexachlorocyclohexanes (HCHs), chlordanes and dichlorodiphenyltrichloroethanes (DDTs) were tested, with a range of 相似文献   

Optimizing mixture properties of biodiesel production using genetic algorithm-based evolutionary support vector machine

Nowadays, biodiesel is used as one of the alternative renewable energy due to the increasing energy demand. However, optimum production of biodiesel still requires a huge number of expensive and time-consuming laboratory tests. To address the problem, this research develops a novel Genetic Algorithm-based Evolutionary Support Vector Machine (GA-ESIM). The GA-ESIM is an Artificial Intelligence (AI)-based tool that combines K-means Chaotic Genetic Algorithm (KCGA) and Evolutionary Support Vector Machine Inference Model (ESIM). The ESIM is utilized as a supervised learning technique to establish a highly accurate prediction model between the input--output of biodiesel mixture properties; and the KCGA is used to perform the simulation to obtain the optimum mixture properties based on the prediction model. A real biodiesel experimental data is provided to validate the GA-ESIM performance. Our simulation results demonstrate that the GA-ESIM establishes a prediction model with better accuracy than other AI-based tool and thus obtains the mixture properties with the biodiesel yield of 99.9%, higher than the best experimental data record, 97.4%.     

不同培养条件下锰过氧化物酶(MnP)的合成及其对甲基橙的降解

高效、大规模、低成本合成木质素降解酶是直接采用其降解难降解有机污染物所必须解决的问题.对锰过氧化物酶(MnP)降解甲基橙和在非灭菌的反应器中连续合成MnP的可行性进行考察.结果表明,在采用2 mmol H2O2和1.5 mmol MnSO4的降解体系中,获最大脱色效果,且100、200和300 U/L的MnP可在8h内将甲基橙分别脱色18％、23％和35％;在非灭菌的反应器水平上实现了固定化培养的P.chrysosporium连续23 d合成MnP,但MnP酶活仅为2～ 23 U/L,难以酶解甲基橙;然而,在摇瓶培养条件下固定化的P.chrysosporium合成的MnP却能达1 152 U/L.因此,直接采用MnP对污染物进行降解以及在非灭菌的反应器中持续合成MnP是可行的,但就在非灭菌条件下如何提高MnP的合成量还有待开展深入的研究.     

以膨润土为辅助添加剂固化/稳定化污泥的试验研究

针对传统以水泥固化污泥,带来的水泥用量大与固化体的浸出液pH过高等问题,提出了以膨润土为添加剂辅助水泥固化/稳定化污泥的思路.通过开展无侧限抗压强度试验、毒性浸出试验,测量掺入膨润土后污泥固化体的强度、重金属浸出率、浸出液COD及pH值,研究该固化/稳定化方法的效果.结果表明,膨润土的掺入极大地提高了固化体的抗压强度,将掺入量为0.4(相对污泥的质量比)的水泥一半用膨润土替代时,固化体的强度提高了6左右.体积安定性也能够满足要求.随膨润土掺入量增加,固化体中锌、铅的浸出率与浸出液的pH值呈现不断减小的趋势,锌与铅的浸出率分别由6.9%下降至0.25%,9.6%下降至5%,pH值由12.3下降至12.1.在强碱条件下及烘干或风干条件下,铜会随着有机物的分解而析出,从而增加铜的浸出率,而膨润土的加入能弥补水泥造成的强碱环境及风干或烘干过程对固化污泥中铜的稳定产生的不利影响.     

Ensuring the continued success of a mulch biowall at a trichloroethylene-contaminated superfund site: Lessons learned

Trichloroethylene (TCE) is a toxic organic compound, which can adversely affect human health. The chemical is one of the most frequently found contaminants in groundwater in the United States and around the world. A landfill in Maryland contaminated with high levels of TCE decades ago was added to the U.S. Environmental Protection Agency's National Priority List (NPL) in 1994. A biowall was installed on the site in 2013 to promote the bioremediation of TCE and subsequently of its degradation products. Six-year monitoring data indicated a steady removal of >99% groundwater TCE at the wall since installation. However, a concurrent buildup of intermediate byproducts was observed downgradient of the wall. An examination of the entire system was necessary to find the reason behind the inefficiency of the biowall. In this study, the background of the site, remediation plan, and installation were assessed. Monitoring data, including the concentration of TCE and its degradation byproducts, and geochemical and physical characteristics were evaluated to understand the conditions and challenges facing decision-makers of this project and possible options to improve biowall efficacy.