Use of additive and pretreatment to control odors in municipal kitchen waste during aerobic composting

The effects of adding a bulking agent and chemically pretreating municipal kitchen waste before aerobic composting were studied using a laboratory-scale system. The system used 20-L reactors and each test lasted 28 days. The objective was to decrease NH₃ and H₂S emissions during composting. The bulking agent, dry cornstalks, was mixed with the kitchen waste to give a mixture containing 15% (wet weight) bulking agent. A combined treatment was also conducted, in which kitchen waste mixed with the bulking agent was pretreated with ferric chloride (FeCl₃). Less leachate was produced by the composted kitchen waste mixed with bulking agent than by the kitchen waste alone, when the materials had reached the required maturity. The presence of cornstalks also caused less H₂S to be emitted, but had little impact on the amount of NH₃ emitted. The FeCl₃ was found to act as an effective chemical flocculant, and its presence significantly decreased the amounts of NH₃ and H₂S emitted. Kitchen waste mixed with cornstalks and treated with FeCl₃ emitted 42% less NH₃ and 76% less H₂S during composting than did pure kitchen waste.     

A study of farmers' flood perceptions based on the entropy method: an application from Jianghan Plain,China

Using survey data from 280 farmers in Jianghan Plain, China, this paper establishes an evaluation index system for three dimensions of farmers' flood perceptions and then uses the entropy method to estimate their overall flood perception. Farmers' flood perceptions exhibit the following characteristics: (i) their flood‐occurrence, flood‐prevention, and overall flood perceptions gradually increase with age, whereas their flood‐effects perception gradually decreases; (ii) their flood‐occurrence and flood‐effects perceptions gradually increase with a higher level of education, whereas their flood‐prevention perception gradually decreases and their overall flood perception shows nonlinear change; (iii) flood‐occurrence, flood‐effects, and overall flood perceptions are higher among farmers who serve in public offices than among those who do not do so; (iv) the flood‐occurrence, flood‐effects, and overall flood perceptions of farmers who work off‐farm are higher than those of farmers who work solely on‐farm, contrary to the flood‐prevention perception; and (v) the flood‐effects and flood‐prevention perceptions of male farmers are lower than those of female farmers, but the flood‐occurrence and overall flood perceptions of male farmers are higher than those of female farmers.     

Decomposition dynamic of higher plant pigments by HPLC analysis

IntroductionHigh performanceliquidchromatographic (HPLC )systemsweredevelopedforhigherplantpigmentsinthelate1970’sandearly 1980’s .Subsequently ,morecomplexHPLCsystemsweredevelopedforchlorophyllsandcarotenoidsfrommicroalgaeandnaturalphytoplanktonpopulations(Gieskes,1991;Hodgson ,1997;Bris,1998) .Bothreversedphaseandnormalphasesystemswereused .TheHPLCtechniquewasusedmorerecentlyforplantpigmentanalysis,andithasledtoasignificantincreaseinseparationandinthenumberofpigmentsthatcanbeidentifi…     

Diversity surveys of soil bacterial community by cultivation--based methods and molecular fingerprinting techniques

By combining the cultivation methods with molecular fingerprinting techniques, the diversity surveys of soil bacterial community in 13 areas of China were carded out. The cultivable heterotrophic diversity was investigated by colony morphology on solid LB medium. Genetic diversity was measured as bands on denaturing gradient gel electrophoresis(DGGE) by the extraction and purification of the total soil DNA, and amplification of bacterial 16S rDNA fragments by polymerase chain reaction(PCR). The Shannon-Wiener indices of diversity(H), richness(S) and evenness(EH) were employed to estimate the diversity of soil bacterial community. The results showed that there was an obvious diversification existed in soil from the different areas. However, the genetic diverslty estimated by PCR-DGGE can provide more comprehensive information on bacterial community than the cultivation-based methods. Therefore, it is suggested to combine the traditional methods with genetic fingerprinting techniques to survey and estimate soil bacterial diversity.     

Long-term exposure to air pollution and cerebrovascular disease: findings from Beijing Health Management Cohort study

● This study explored the long-term association by double robust additive models. ● Individual exposure concentrations were assessed by integrating GAM, LUR and BPNN. ● PM_2.5, SO₂ and NO₂ are positively associated with cerebrovascular disease. ● CO could reduce the risk of cerebrovascular disease with the highest robustness. ● The elderly, women and people with normal BMI are at higher risk for air pollution. The relationship between air pollution and cerebrovascular disease has become a popular topic, yet research findings are highly heterogeneous. This study aims to investigate this association based on detailed individual health data and a precise evaluation of their exposure levels. The integrated models of generalized additive model, land use regression model and back propagation neural network were used to evaluate the exposure concentrations. And doubly robust additive model was conducted to explore the association between cerebrovascular disease and air pollution after adjusted for demographic characteristics, physical examination, disease information, geographic and socioeconomic status. A total of 25097 subjects were included in the Beijing Health Management Cohort from 2013 to 2018. With a 1 μg/m³ increase in the concentrations of PM_2.5, SO₂ and NO₂, the incidence risk of cerebrovascular disease increased by 1.02 (95% CI: 1.008–1.034), 1.06 (95% CI: 1.034–1.095) and 1.02 (95% CI: 1.010–1.029) respectively. Whereas CO exposure could decrease the risk, with an odds ratio of 0.38 (95% CI: 0.212–0.626). In the subgroup analysis, individuals under the age of 50 with normal BMI were at higher risk caused by PM_2.5, and SO₂ was considered more hazardous to women. Meanwhile, the protective effect of CO on women and those with normal BMI was stronger. Successful reduction of long-term exposure to PM_2.5, SO₂ and NO₂ would lead to substantial benefits for decrease the risk of cerebrovascular disease especially for the health of the susceptible individuals.     

高炉煤气泄露危害后果定量评价

2008年12月24日9时许,唐山遵化市港陆钢铁有限公司2号高炉重力除尘器顶部泄爆板爆裂造成煤气泄漏,事故发生时当班工人共44人,共造成44人中毒,其中17人死亡,27人受伤的重大安全事故。因此高炉煤气泄漏造成中毒、爆炸等事故是高炉炼铁系统存在的主要危险有害因素之一。     

基于灰局势决策的安全投资状况评价

对企业现有安全投资状况进行评价是合理进行安全投资的前提和基础。为此,将灰局势决策方法应用于安全投资状况评价问题上,通过一系列灰处理过程,得到一个可以评价各参评年份安全投资状况的综合效果测度值,以此为标准对安全投资状况进行综合评价。通过实例评价及分析,清晰展现了企业以往安全投资状况,为今后科学合理地制定安全投资策略指明了方向。     

深核集团安全生产管理实践

深核集团是一家投资管理型公司,下属多家子公司,行业跨度较大;各企业内部管理较多依靠社会聘用人员,产线员工均以外来劳务工为主,人员流动性大;设备自动化程度不高,部分设施陈旧,以上种种因素都加大了安全生产管理的难度。     

金属氧化物催化剂上吡啶催化燃烧

为了研究催化燃烧法净化挥发性有污染物的可能性,考察了金属氧化物催化剂上吡啶的氧化活性及氧化过程ＮＯｘ控制能力,吡啶氧化产物ＮＯｘ随反应温度升高呈现极大值。催化剂的氧化活性ＮＯｘ控制能力呈正比关系。     

生物水解（酸化）法处理高浓度洁霉素废水的降解机理研究

在应用生物水解（酸化）法处理高浓度洁霉素生产废水中试试验中,着重研究水解（酸化）反应中起主要作用的微生物菌群及其降解效率。同时采用GPC（凝胶渗透色谱）、GC/MS（色谱一质谱）等分析手段对水解（酸化）反应过程中有机物形态变化进行研究。结果表明,在水解（酸化）反应中起主要作用的有埃希氏菌属、发酵单胞菌属、气单胞菌属、变形杆菌属、柠檬酸杆菌属等。同时,水解（酸化）反应具有将洁霉素废水中的大分子有机物降解为小分子有机物的作用,可提高废水的可生化性。