Evaluation of efficiency of aircraft liquid waste treatment and identification of daily inspection indices: a case study in Changchun, China

Evaluation of the efficiency of aircraft liquid waste treatment has previously been conducted to prevent pollution of the environment. The current study aimed to provide a set of practical methods for efficient airport sanitary supervision. Aircraft liquid waste was collected at Longjia International Airport, Changchun from multiple flights. The efficiency of liquid waste treatment as well as the water quality of the wastewater processed via a second-stage wastewater facility were examined by measuring a number of physical, chemical, and biological indices. Our results indicated that treatment solely via resolvable sanitizing liquid was not sufficient. Although the contents of first-class pollutants all met the requirements of the standard criteria, the contents of a number of second-class pollutants did not satisfy these criteria. However, after further treatment via a second-stage wastewater facility installed at the airport, all indices reached second-grade requirements of the discharge standard. We suggest that daily inspection and quarantine indices at airports should include the suspension content, biological oxygen demands after 5 days, chemical oxygen demand total organic carbon content, amino nitrogen content, total phosphorous content, and the level of fecal coliforms.     

Application of an enzyme-linked immunosorbent assay for the detection of clenbuterol residues in swine urine and feeds

The present study outlines applications of an enzyme-linked immunosorbent assay (ELISA) for the analysis of clenbuterol residues. Antisera were raised from rabbits immunized with diazotized clenbuterol-bovine serum albumin (BSA) conjugate. The assay was specific to clenbuterol with a half-maximum inhibition concentration (IC₅₀) of 1.8 ng/mL and 2.5 ng/mL in blank swine urine and phosphate buffer solution, respectively. The assay had high cross-reactivity (86%) with mabuterol, but low with other adrenergic agonists and antagonists. The average recovery of clenbuterol, as measured with the ELISA, ranged from 90% to 112% in swine urine samples and from 86% to 95% in feeds, respectively. This new assay was compared with commercial ELISA test kits. An excellent correlation (r ² = 0.98) between the two methods and satisfactory recoveries suggest that the new assay can be suitable for the determination of clenbuterol residues in real samples. The assay was used to analyze clenbuterol residues in 103 swine urine samples and 68 feed samples collected from northern China. Approximately 50% of the urine samples and 25% of the feed samples analyzed were found positive (concentration of clenbuterol ≥ 1 ppb). The results indicate that clenbuterol was misused in some of the areas surveyed.     

汶川地震灾区受灾群众重建意愿实证研究

选择何种重建方式(原址重建或异地搬迁等)是灾后重建的首要问题.所谓重建意愿即在原居住地受到地震等自然灾害破坏时,受灾居民对不同重建方式(原址重建还是异地搬迁或者两者之间的状态)的选择倾向.了解灾区群众的重建意愿及其因素影响是受灾县(市)制订灾后重建规划、并推动实施的重要前提.通过对五大极重灾区1243户城乡受灾居民家庭问卷调查、深度访谈.结果表明:受灾居民所在县(市)、目前安置地、户口类型、受教育程度、适应新环境能力及未来经济预期等因素对其重建意愿有显著影响.研究认为:选择重建方式应在尊重群众意愿的前提下,结合实际充分论证;在此基础上,应结合目前的临时安置地对城乡布局合理规划;应将灾后重建和城乡统筹及生态扶贫相结合来考虑,着力提高受灾居民的就业技能和受教育程度,从而提高适应新环境生产生活的能力;加大在灾区的产业恢复重建力度,特别尽快恢复关系民生的产业以及就业容量大的产业.     

SMW围护结构的深基坑隆起变形有限元分析

影响基坑基底隆起的因素存在极大的模糊性和随机性,基底隆起变形量的计算是一个复杂的非线性过程,而采用有限元法对基坑基底隆起变形量进行分析是个有效的途径。本文以上海某深基坑为例,基于ABAQU S软件对该基坑基底隆起变形量进行有限元分析。研究表明,基底隆起最大变形量发生在离基坑侧壁约以SMW围护桩入土深度为半径的圆内侧。本文将为基坑隆起问题的定量研究提供有价值的参考。     

Sewage sludge disintegration by high-pressure homogenization: A sludge disintegration model

High-pressure homogenization (HPH) technology was applied as a pretreatment to disintegrate sewage sludge. The effects of homogenization pressure, homogenization cycle number, and total solid content on sludge disintegration were investigated. The sludge disintegration degree (DDCOD), protein concentration, and polysaccharide concentration increased with the increase of homogenization pressure and homogenization cycle number, and decreased with the increase of sludge total solid (TS) content. The maximum DDCOD of 43.94% was achieved at 80 MPa with four homogenization cycles for a 9.58 g/L TS sludge sample. A HPH sludge disintegration model of DD_COD= kN^aP^b was established by multivariable linear regression to quantify the effects of homogenization parameters. The homogenization cycle exponent a and homogenization pressure exponent b were 0.4763 and 0.7324 respectively, showing that the effect of homogenization pressure (P) was more significant than that of homogenization cycle number (N). The value of the rate constant k decreased with the increase of sludge total solid content. The specific energy consumption increased with the increment of sludge disintegration efficiency. Lower specific energy consumption was required for higher total solid content sludge.     

山东临沂市集体林权改革环境影响调查研究—以小山口村、魏城村和南垛庄铺为例

本文选取小山口村、魏城村和南垛庄铺三个林权改革试点村作为调查对象,通过描述统计、交叉列联表分析和Ridit分析,就林权改革的方式、林改对经济和环境产生的影响及林权流转三个方面的问题对山东临沂市的集体林权制度改革现状展开调查研究。分析发现,在历经3年的林改中,临沂市始终坚持尊重实际、区别对待,灵活选择林权改革的方式,使当地的林权制度改革受到村民的欢迎。此外,林权改革后,当地的经济收入和生态环境及对林业的投入均有不同程度的提高和改善,村民的营林、护林积极性也大大增加。但是在涉及到林权流转方面的问题时,大部分的村民不能清楚认识到林权的价值,从而使落实处置权的目标短期内难以实现。     

大气细颗粒物(PM_(2.5))在环境科学中的研究简述

细颗粒物作为一种重要的大气污染物,其形态与组成非常复杂,本身所具有的毒性和对环境的有害性已日益受到重视。文章对细颗粒物PM2.5在环境科学中的研究进行了概括,提出了自己的一些见解。     

国外城市建设中的若干减灾对策

本文介绍了国外部分城市在防灾、抗灾、减灾方面的一些有益的经验和作法,这对于我国城市今后的规划和建设将起到一定的积极作用。     

城乡交通一体化驱动下江苏农村医疗卫生服务可达性

农村医疗卫生服务均等化是国家乡村振兴规划的主要目标。在城乡交通一体化驱动下，机动化出行已然成为广大农户交通出行的优先偏好，在此背景下，农村医疗卫生服务均等化研究具有时代紧迫性和必要性。以江苏为例，基于GIS网络分析方法分别测度步行、电动车和汽车出行方式下农村医疗卫生服务可达性水平，力图揭示城乡交通一体化驱动下农村医疗卫生服务可达性与供需匹配特征。研究表明：步行方式下农村医疗卫生可达性水平低，而电动车能保证大部分农村享受较高水平卫生站可达性，汽车则使大多数农户享受高水平的医院可达性，城乡交通一体化是促进农村医疗卫生服务均等化发展的关键因素，它能够有效地破解农村医疗服务均等化过程中农村医疗卫生服务供给不足、供需不符和利用率低下问题，为农户共享高质量医疗卫生服务创造必要条件。有鉴于此，为了实现城乡医疗卫生服务均等化目标，应继续加快城乡交通一体化步伐，探讨构建城乡交通一体化框架下医疗卫生服务体系规划方案，优化城乡医疗卫生服务设施布局。