Anaerobic digestion in mesophilic and room temperature conditions: Digestion performance and soil-borne pathogen survival

Tomato plant waste(TPW) was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS(total solid) concentrations of 2%, 4% and 6% respectively, at mesophilic(37 ± 1°C) and room(20–25°C) temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416 L/kg VS(volatile solids). The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR(polymerase chain reaction) were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA(volatile fatty acid) concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety.     

Temporal and spatial changes of microbial community in an industrial effluent receiving area in Hangzhou Bay

Anthropogenic activities usually contaminate water environments, and have led to the eutrophication of many estuaries and shifts in microbial communities. In this study, the temporal and spatial changes of the microbial community in an industrial effluent receiving area in Hangzhou Bay were investigated by 454 pyrosequencing. The bacterial community showed higher richness and biodiversity than the archaeal community in all sediments. Proteobacteria dominated in the bacterial communities of all the samples; Marine_Group_Ⅰ and Methanomicrobia were the two dominant archaeal classes in the effluent receiving area. PCoA and AMOVA revealed strong seasonal but minor spatial changes in both bacterial and archaeal communities in the sediments. The seasonal changes of the bacterial community were less significant than those of the archaeal community, which mainly consisted of fluctuations in abundance of a large proportion of longstanding species rather than the appearance and disappearance of major archaeal species. Temperature was found to positively correlate with the dominant bacteria, Betaproteobacteria, and negatively correlate with the dominant archaea,Marine_Group_Ⅰ; and might be the primary driving force for the seasonal variation of the microbial community.     

Are there higher pedestrian fatalities in larger cities?: A scaling analysis of 115 to 161 largest cities in the United States

Objective: In 2012, 4,743 pedestrians were killed in the United States, representing 14% of total traffic fatalities. The number of pedestrians injured was higher at 76,000. Therefore, 36 out of 52 of the largest cities in the United States have adopted a citywide target of reducing pedestrian fatalities. The number of cities adopting the reduction goal during 2011 and 2012 increased rapidly with 8 more cities. We examined the scaling relationship of pedestrian fatality counts as a function of the population size of 115 to 161 large U.S. cities during the period of 1994 to 2011. We also examined the scaling relationship of nonpedestrian and total traffic fatality counts as a function of the population size.

Methods: For the data source of fatality measures we used Traffic Safety Facts Fatality Analysis Reporting System/General Estimates System annual reports published each year from 1994 to 2011 by the NHTSA. Using the data source we conducted both annual cross-sectional and panel data bivariate and multivariate regression models. In the construction of the estimated functional relationship between traffic fatality measures and various factors, we used the simple power function for urban scaling used by Bettencourt et al. (2007 Bettencourt LMA, Lobo J, Helbing D, Kühnert C, West GB. Growth, innovation, scaling and the pace of life in cities. Proc Natl Acad Sci USA. 2007;104:7301–7306.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar], 2010 Bettencourt LMA, Lobo J, Strumsky D, West GB. Urban scaling and its deviations: revealing the structure of wealth, innovation and crime across cities. PLoS ONE. 2010;5:e13541.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and the refined STIRPAT (stochastic impacts by regression on population, affluence, and technology) model used in Dietz and Rosa (1994 Dietz T, Rosa EA. Rethinking the environmental impacts of population, affluence and technology. Human Ecology Review. 1994;1:277–300. [Google Scholar], 1997 Dietz T, Rosa EA. Effects of population and affluence on CO₂ emissions. Proc Natl Acad Sci USA. 1997;94:175–179.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and York et al. (2003 York R, Rosa EA, Dietz T. STIRPAT, IPAT and IMPACT: analytic tools for unpacking the driving forces of environmental impacts. Ecol Econ. 2003;46:351–365.[Crossref], [Web of Science ®] , [Google Scholar]).

Results: We found that the scaling relationship display diseconomies of scale or sublinear for pedestrian fatalities. However, the relationship displays a superlinear relationship in case of nonpedestrian fatalities. The scaling relationship for total traffic fatality counts display a nearly linear pattern. When the relationship was examined by the 4 subgroups of cities with different population sizes, the most pronounced sublinear scaling relationships for all 3 types of fatality counts was discovered for the subgroup of megacities with a population of more than 1 million.

Conclusions: The scaling patterns of traffic fatalities of subgroups of cities depend on population sizes of the cities in subgroups. In particular, 9 megacities with populations of more than 1 million are significantly different from the remaining cities and should be viewed as a totally separate group. Thus, analysis of the patterns of traffic fatalities needs to be conducted within the group of megacities separately from the other cities with smaller population sizes for devising prevention policies to reduce traffic fatalities in both megacities and smaller cities.     

EPA PMF5．0在浦东新区降水源解析中的使用研究

使用EPA PMF5．0模型,以浦东新区降水源解析为例,按照使用前监测数据和不确定度数据收集、模型运行前数据判读、基本模型运行前最佳因子数确定以及模型旋转前后因子贡献比变化,对降水中多种阳离子和阴离子分别进行讨论,在离子贡献汇总中得到其主要贡献的阴阳离子。 EPA PMF5．0方法的使用,为大气降水在污染源治理和管理等领域提供了新的研究思路,同时也对基层监测站开展源解析具有参考作用。     

甲硫醇在苏玛罐及气袋中稳定性研究

以硅烷化苏玛罐和Tedlar气袋为保存容器,干燥空气为本底,利用低温冷阱浓缩-气相色谱/质谱联用法检测,研究甲硫醇气体样品在不同容器、温度和浓度等条件下的浓度变化趋势.结果表明,甲硫醇样品使用Tedlar气袋采样并在4℃环境下保存时具有相对较好的稳定性,对于浓度在约3 ppb至20 ppb的样品其保存有效期可达96 h;当有一定量的二甲二硫共存时,可延长甲硫醇的保存期限,以保证结果的有效性与准确性.     

镇江城市生物多样性现状研究

利用生态卫星遥感解析数据,评价得出镇江市生态环境质量指数维持在良好等级。对镇江市鸟类现状、森林生态系统植被现状、生物入侵情况进行了调查总结,分析了生物多样性变化的客观原因,并提出保护中存在的不足方面。     

Impact of urban water supply on energy use in China: a provincial and national comparison

To reduce greenhouse gas (GHG) emissions and help mitigate climate change, urban water systems need to be adapted so that electrical energy use is minimised. In this study, energy data from 2011 was used to quantify energy use in China’s urban water supply sector. The objective was to calculate the energy co-benefits of urban water conservation policies and compare energy use between China and other countries. The study investigated influencing factors with the aim of informing the development of energy efficient urban water infrastructure. The average energy use per cubic metre and per capita for urban water supply in China in 2011 was 0.29 kWh/m³ and 33.2 kWh/cap year, respectively. Total GHG emissions associated with energy use in the urban water supply sector were 7.63 MtCO₂e, or carbon dioxide equivalent. Calculations using these indicators showed significant energy savings could result from water conservation measures. A comparison between provinces of China showed a direct correlation between energy intensity of urban water supply and the population served per unit length of pipe. This may imply energy and emission intensity can be reduced if more densely populated areas are supplied by a corresponding pipe density, rather than by a low-density network operating at higher flow rates. This study also found that while the percentage of electrical energy used for urban water supply tended to increase with the percentage of population served, this increase was slower where water supply was more energy efficient and where a larger percentage of population was already supplied.     

挑檐抑制PMMA竖直火蔓延数值模拟研究

应用FDS数值模拟软件,建立PMMA竖直火蔓延模型,通过改变防火挑檐长度和宽度,设计一系列工况,对比分析挑檐长度、宽度以及宽长比对竖直火蔓延的影响。结果表明当挑檐长度为临界值时,随宽度的增加,挑檐上方壁面温度与热释放速率均逐渐降低;挑檐宽度为临界值时,随长度的增加,挑檐上方壁面温度与热释放速率逐渐降低;挑檐长度较长时,有效阻火的挑檐宽度随长度的增加而逐渐减小,最后固定不变,最终建立了防火挑檐的临界点与热释放速率的无量纲模型。     

Removal of nutrients and veterinary antibiotics from swine wastewater by a constructed macrophyte floating bed system

The potential of three varieties of Italian ryegrass (Lolium multiflorum Lam.), Dryan, Tachimasari and Waseyutaka, to improve the water quality of swine wastewater was evaluated using a constructed macrophyte floating bed system. With respect to reductions in levels of nutrients, chemical oxygen demand (COD), and sulfonamide antimicrobials (SAs, including sulfadiazine, sulfamethazine, and sulfamethoxazole), Dryan performed better than Tachimasari and Waseyutaka. For Dryan, total N was reduced by 84.0%, total P by 90.4%, COD by 83.4% and sulfonamide antimicrobials by 91.8–99.5%. Similar results were observed for Tachimasari and Waseyutaka. The results indicated that the treatment of swine wastewater using the constructed macrophyte floating bed system was effective in the removal of nutrients and veterinary antibiotics.     

Assessment of mutagenic potency of source water treated by ozone and adsorption processes

This research utilized the Ames test to determine the mutagenicity of water treated by advanced processes, including ozonation and granular activated carbon (GAC). Raw water samples for this research included those obtained from the Pan Hsin waterworks as well as samples containing humic acids. Treated samples were collected from the pilot‐scale advanced treatment plant. The Ames test was used to measure the mutagenicity of the water after each treatment process. For the Pan Hsin raw water samples treated with ozone or GAC, it was indicated that, regardless of whether samples were preozonated or not, they all showed a mutagenic potency less than 2 once the S9 enzyme was added. This level of mutagenicity is insignificant. The prepared humic acid samples, on the other hand, demonstrated a significant reduction in mutagenicity after the pre‐ozonation process, indicating that preozonation can lower the degree of mutagenicity. Furthermore, the mutagenicity of the prepared humic acid samples gradually decreased after the advanced treatment process. However, when chlorine was added later to these samples, the mutagenicity increased again. This research shows that the use of O3/GAC processes to treat water can successfully lower mutagenicity, indicating a great potential for applications in the treatment of drinking water.