Effects of tetrahydrofuran on dissolved oxygen,pH, culturable aerobic microbes and enzyme activity in wastewater

Tetrahydrofuran (THF) is easy to volatilize and hard to biodegrade. Little is known about the influence and fate of tetrahydrofuran in the environment. The effects of THF were examined on dissolved oxygen, pH, culturable aerobic microbes (bacteria, actinomycetes, and fungi) and four selected enzymes (protease, phosphatase, amylase, and lipase) in wastewater. The wastewater containing some activated sludge was taken from the aeration basin in Sibao sewage plant in Hangzhou, China. THF at lower concentrations of enhanced aerobic respiration and higher concentrations decreased utilization of oxygen in wastewater. The short-term influence of THF on pH was not obvious, but the long-term effect was apparent. Inhibition of THF on culturable aerobic microbes rose with increasing THF concentrations but decreased with prolongation of incubation time. No effect of THF on the activity of protease, phosphatase, amylase, and lipase was found. Data indicate that lower concentrations of THF exert no marked influence on wastewater in an urban sewage plant.     

吹扫捕集/气相色谱/质谱法测定水体中54种常见挥发性有机物的研究

运用吹扫捕集/气相色谱/质谱(P＆T/GC/MS)法对水体中54种常见的挥发性有机物(VOCs)进行了测定.结果表明,VOCs的色谱分离情况较好,平均加标回收率为88.5%～117.0%,相对标准偏差为0.71%～8.50%,准确度和精密度均符合有关分析测试的要求;方法检出限为0.10～0.61μg/L,远低于<地表水环境质量标准>(GB 3838-2002)、<生活饮用水卫生标准>(GB3838-2002)及国外相关标准的限值;54种VOCs的线性范围不同,低沸点的VOCs线性范围较宽,高沸点的VOCs的线性范围较窄,因此在分析VOCs样品配制标准工作曲线时,应注意不同沸点VOCs的线性范围.     

强化活性炭处理工艺去除焦化厂生化出水中的氰化物

以某焦化厂生化出水为研究对象,考寨了金属负载活性炭(简称负载炭)和Fenton氧化预处理等强化活性炭工艺对总氰化物(TCN)的去除效果.在TCN批式实验中,对负载炭的金属离子种类和固定方式进行了考察,同时研究了接触时间、DO对游离氰(KCN配水)、络合氰(K3Fe(CN)6配水)及焦化厂生化出水中TCN的去除效果.结果表明,负载金属离子可以有效提高活性炭对TCN的去除量,KI固定后的载铜活性炭对TCN的去除更有效.吸附作用在活性炭去除TCN过程中起着主要作用,同时TCN在活性炭表面也发生缓慢的催化氧化反应.在穿透实验中,采用了小型炭柱穿透和微型快速穿透实验方法,得到的TCN穿透曲线基本相同.含不同比例原煤炭和负载炭的小型炭柱处理经Fenton氧化预处理的焦化厂生化出水时,在18 d的启动阶段后形成生物活性炭柱,其出水能长期达到<城镇污水处理厂污染物排放标准>(GB 18918-2002)规定的要求.载铜话性炭可以提高活性炭工艺对TCN的去除能力,确保处理全程(57 d)出水的TCN达标.     

Cell absorption induced desorption of hydrophobic organic contaminants from digested soil residue

Oral ingestion of contaminated soil is an important pathway of human exposure to hydrophobic organic contaminants (HOCs), particularly for children in developing countries. The mobilization potential of various contaminants from ingested soil is often characterized using an in vitro gastrointestinal model, based on the quantities of contaminants remaining in digestive fluid after digestion and separation. Recently, it was experimentally demonstrated that a large fraction of mobilized contaminants sorbed on the digested residue could be released if the dissolved fraction was removed by intestinal absorption. This hypothesis was further tested in this study. Soil spiked with dichlorodiphenyltrichloroethane and its metabolites (DDXs) and polycyclic aromatic hydrocarbons (PAHs) was digested using an in vitro gastrointestinal model. A human colon carcinoma cell line (Caco-2) was cultured in digestive fluid with or without soil residue (pre-equilibrated with the soil) for 2 h. A large proportion of the contaminants (37-68%) was sorbed on the digested residue. Without this residue, 66 ± 13% of DDXs and 73 ± 14% of PAHs dissolved in the fluid, as means and standard deviations, were absorbed by the cell monolayer after exposure. With both digestive fluid and residue, the sorbed fraction of PAHs and DDXs decreased by 38-92%, while the ratios of the cellular to the dissolved concentrations were 2.7-2.8 times higher than those without the residue. This supported the hypothesis that the cell absorption of dissolved HOCs induces desorption of the sorbed fraction from digestive residue, and the desorbed HOCs can be absorbed as well.     

秦皇岛市泥石流发育特征及防治措施

近年来,随着社会经济的发展,人类工程活动频繁,泥石流地质灾害在我市每年新增灾害中占有相当大的比重,严重威胁着人民的生命财产安全。秦皇岛市泥石流主要发育在北部低山丘陵区,规模小,危害大。通过对泥石流发育特征的研究,阐明其形成条件与地形、地质环境、植被和降雨等因素的关系,并据此提出了群测群防,加强采矿活动正确管理、工程治理等防治措施。     

变频介质阻挡放电去除甲苯的实验研究

以甲苯为目标污染物,采用变频交流电源,利用介质阻挡放电(DBD)对其进行去除。实验过程中,场强、频率、气体流速和初始浓度是影响甲苯去除效果的4个主要因素。通过多因素正交实验,分析4个因素对去除效果影响的主次关系,获得了最优方案。进行单因素趋势实验,研究各因素单独对甲苯去除效果的影响趋势,得出各因素对甲苯降解效果影响的变化曲线,并对结果作出分析。实验结果表明,当场强为9.7 kV/cm,频率为400 Hz,气体流速为2.5 cm/s,初始浓度为700 mg/m3时,甲苯去除率可达80.9%。     

优化污水厂工艺参数强化处理阿特拉津的研究

研究了低浓度阿特拉津冲击对A/O工艺运行稳定性的影响,并探索了通过优化工艺参数强化处理低浓度阿特拉津的可行性。结果表明,和碳氧化活性相比,阿特拉津对活性污泥系统硝化活性的抑制作用更强,同时其代谢产生的氨氮又增加了系统负荷,最终导致氨氮去除率维持在较低水平上。采用调整A/O工艺参数的方式,可实现低浓度阿拉特津的强化处理,最优运行参数为硝化液回流比=200%,缺氧区/好氧区停留时间比=1∶3。在该运行工况下,目标污染物被高效去除,系统运行稳定。     

秦皇岛探测环境变化对气象要素的影响

为分析秦皇岛地面气象探测环境变化对气象要素的影响,采用距平百分率和线性倾向估计及趋势系数等方法,对秦皇岛气象站（54449）新、旧站址搬迁前后1989—1998、1999—2008年各10年,与没有迁站的昌黎站做同期资料比较,结果表明：秦皇岛探测环境变化对气象要素有显著影响：年平均气温、年极端气温较迁站前显著下降,相对湿度增大,日照时数明显减少,雾日增多。指出气象要素变化除具有随时间变化的共同差异外,主要受探测环境变化的影响。     

An observational study of the carrying capacity of suspended sediment during a storm event

We measured the in situ suspended sediment concentration (SSC) and hydrodynamics (waves, currents, and sea level) concurrently during a storm event using self-recording instruments at offshore of the Shandong Peninsula in the Yellow Sea. We analyzed the temporal variation in suspended sediment carrying capacity and its correlation with wave, current, and water-level conditions. There was about 40% increase in SSC during the storm event. A 3-4-h lag was observed between the peak of wave height and SSC. The SSC increased in a fluctuating pattern up to the peak then decreased rapidly. This process was positively correlated with wave height and duration. The maximum SSC was 524.3 mg/l, which is about 10 times of that under normal weather conditions. This peak was observed after of a series of 1.8 m waves. The increased suspended sediments were the fine particles resuspended by the storm waves from seabed near the observation spot and transported by northward ebb currents from Shidao Bay.     

Dietary exposure estimates of 16 polycyclic aromatic hydrocarbons (PAHs) in Xuanwei and Fuyuan, counties in a high lung cancer incidence area in China

Xuanwei and Fuyuan are located in the southwest of China and have the highest lung cancer incidence in China, possibly even highest in the world. Dietary samples were collected from these two counties and the contamination status of sixteen polycyclic aromatic hydrocarbons (PAHs) were determined. PAH components, food constituents, dietary exposure level, as well as spatial difference, were studied in the different groups. The percentage of dietary intake to total intake of PAHs was calculated and the relationship between the dietary intake of PAHs and the abnormal lung cancer incidence was primarily discussed. The results showed that rice and potatoes were the main foods of the local residents in Xuanwei and Fuyuan. The daily exposure doses of Bap (benzo[a]pyrene), total PAHs, and TEQs (toxic equivalents) based on Bap toxicity in two counties were estimated to be 458 ng d(-1), 14,532 ng d(-1), and 896 ng d(-1), respectively, which were much less than those in other cities reported previously. The lower ingestion amount of food with a relatively higher content of PAHs, such as meat and fish, could account for the lower exposure doses. PAHs with less than 4 rings occupied a high percentage of the total PAHs in food samples. The exposure doses varied significantly among different sites and even different families at the same site. Dietary exposure was not the main exposure route of PAHs at most sites. It appears that there was not a direct relationship between dietary exposure and the lung cancer incidence. However, high ratios of dietary intake to total PAHs intake (1.33%-70.61%) were found in several areas and rational diet suggestions should be given in these areas in the future.