Biodegradability of organic substances by ATP test

The aerobic biodegradability of organic substances in water is characterized by determination of energy change ‐ ATP content in microbial cells during biodegradation. A satisfactory result is obtained under the following conditions: the initial concentration of tested substance is 100mg/l (as DOC), the amount of the inoculum in the biological medium is 500mg/l (as MLSS), and the duration of test time is 14 days. The evaluating system (peak time, peak height and IA index) is proposed to assess the biodegradability of 46 organic compounds and 7 wastewaters.     

基于控制单元的水环境容量分配研究

以常州武南河控制单元的COD容量分配为例,构建“污染源类型-污染源细类-排污单位”3层分配结构,逐层逐类选取多水平指标体系,以各指标初始权重和量化值乘积耦合的方法计算各分配对象的综合权重,并以此为依据进行水环境容量的逐层分配.首层分配结果:生活污染和养殖业承担污染削减的主要任务,COD削减率分别为41.6％和35.5％;次层分配结果:分散养殖削减比例(43.2％)高于集中养殖(31.5％),农村生活污染削减比例(47.3％)高于城镇生活污染(28.5％),各镇(区)种植业污染无需削减,工业污染则主要由纺织染整企业等进行重点削减;末层分配结果:各镇(区)分散养殖、集中养殖、农村生活污染、城镇生活污染的削减比例与次层保持一致,印染企业削减比例高于纺织企业.逐层分配中各分配对象的COD削减比例均低于50％,说明分配结果具有可行性.     

Gridded usage inventories of chlordane in China

Chlordane (1,2,4,5,6,7,8,8-octachloro-3a,4,7, 7a-tetra-hydro-4,7-methanoindane) is one of organochlorine pesticides (OCPs) which has been listed as one of the persistent organic pollutants (POPs) to be reduced and finally eliminated in the Stockholm Convention on Persistent Organic Pollutants, because of its great persistence, toxicity, bio-accumulation and long-range transport potential. It is critical to create a national chlordane usage inventories for China to compile chlordane emission inventories, which is helpful for carrying out risk assessments and other researches related to chlordane in China. The annual data of chlordane usage was calculated and modified in accordance with the reported annual production of chlordane which was caculated on the basis of the termite distribution, the data of chlordane usage rate and the annual new construction area (NCA).With the help of Geographic Information System, the usage data of this NCA were allocated to a grid system then, with a 1/4° longitude by 1/6° latitude resolution and a size for each grid cell of approximately 25 km by 25 km. Between 1988 and 2008, the total usage of chlordane in China was 2745 t, accounting for approximately 80% of the production in the same period. Zhejiang Province was the largest consumer of chlordane in China, whose usage adds up to 980 t, greatly exceeding other provinces/regions, followed by Jiangsu Province (534 t) and Sichuan Province (428 t). The region with the least usage of chlordane was Beijing. Provinces of Guizhou, Henan and Hebei did not use any chlordane, even though termites had occurred in these provinces. Gridded usage inventories showed that the intensive use of chlordane was concentrated in the southeast part of China, Yangtze River Delta and Pearl River Delta in particular. The satisfaction of the inventories was supported by the consistence between the estimated data of annual usage and the reported annual production of chlordane, and by the consistence between distribution pattern of chlordane’s usage and ambient air concentration.     

Substance flow analysis for an urban drainage system of a representative hypothetical city in China

This paper discusses the use of substance flow analysis (SFA) as a tool to support quantified research on urban drainage systems. Based on the principle of mass balance, a static substance flow model is established to describe and examine the routes and intensities of water, chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) for a representative hypothetical city (RH city) in China, which is a devised and scaled city using statistical characteristics of urban circumstances at the national level. It is estimated that the annual flux of water, COD, TN and TP through the urban drainage system in 2010 was 55.1 million m³, 16037.3 t, 1649.5 t and 209.7 t, respectively. The effluent of wastewater treatment plant (WWTP) was identified as the most important pathway for pollutant emissions, which contributed approximately 60% of COD, 65% of TN and 50% of TP to receiving water. During the wastewater treatment process, 1.0 million m3, 7042.5 t, 584.2 t and 161.4 t of the four studied substances had been transmitted into sludge, meanwhile 3813.0 t of COD and 394.0 t of TN were converted and emitted to the atmosphere. Compared with the representative hypothetical city of 2000, urban population and the area of urban built districts had expanded by approximately 90% and 80% respectively during the decade, resulting in a more than threefold increase in the input of substances into the urban drainage system. Thanks to the development of urban drainage systems, the total loads of the city were maintained at a similar level.     

One-pot preparation of graphene oxide magnetic nanocomposites for the removal of tetrabromobisphenol A

A simple solvothermal method was used to prepare monodisperse magnetite (Fe₃O₄) nanoparticles attached onto graphene oxide (GO) sheets as adsorbents to remove tetrabromobisphenol A (TBBPA) from an aqueous solution. These Fe₃O₄/GO (MGO) nanocomposites were characterized by transmission electron microscopy. The adsorption capacity at different initial pH, contact duration, and temperature were evaluated. The kinetics of adsorption was found to fit the pseudo-second-order model perfectly. The adsorption isotherm well fitted the Langmuir model, and the theoretical maximum of adsorption capacity calculated by the Langmuir model was 27.26 mg?g^-1. The adsorption thermodynamics of TBBPA on the MGO nanocomposites was determined at 303 K, 313 K, and 323 K, respectively. The results indicated that the adsorption was spontaneous and endothermic. The MGO nanocomposites were conveniently separated from the media by an external magnetic field within several seconds, and then regenerated in 0.2 M NaOH solution. Thus, the MGO nanocomposites are a promising candidate for TBBPA removal from wastewater.     

Degradation of bisphenol A by microorganisms immobilized on polyvinyl alcohol microspheres

In this study, microorganisms （named B111） were immobilized on polyvinyl alcohol microspheres prepared by the inverse suspension crosslinked method. The biodegradation of bisphenol A （BPA） and 4-hydro- xybenzaldehyde, a degradation product of BPA, by free and immobilized B lll was investigated. The BPA degradation studies were carried out at initial BPA concentrations ranging from 25 to 150 mg·L^-1. The affinity constant Ks and maximum degradation rate Rmax were 98.3 mg·L^-1 and 19.7mg·mg^-1VSS·d^-1 for free B111, as well as 87.2mg·L^-1 and 21.1mg·mg^-1VSS·d^-1 for immobilized B 111, respectively. 16S rDNA gene sequence analyses confirmed that the dominant genera were Pseudomonas and Brevundimonas for BPA biodegradation in microorganisms B 111.     

Genotype variations in accumulation of cadmium and lead in celery (Apium graveolens L.) and screening for low Cd and Pb accumulative cultivars

To help reduce risks of heavy metal pollution, two pot experiments were conducted to investigate the variations, transfer potential, and stability of Cadmium (Cd) and Lead (Pb) accumulations in celery (Apium graveolens L.) and to screen for low Cd and Pb accumulative cultivars. The maximum differences in shoot Cd concentration were 4.7-fold under low-Cd exposure and 3.3-fold under high-Cd exposure. These genotype variations in Cd accumulation are sufficiently large to help reduce Cd contamination risk in soil by using the Low-Cd-Accumulative genotypes. Cd accumulation of the Low-Cd-Accumulative genotypes is significantly positive correlated with Pb accumulation. Evidence obtained proves that Cd and Pb accumulations in celery are stable and genotype-dependent at the cultivar level. The presence of high-Pb contamination in soil promoted Cd accumulation in shoots of celery. Celery is considered a species with high risks in Cd pollution and low risks in Pb pollution. Among the tested cultivars, cv. Shuanggangkangbing (SGKB) had the lowest shoot Cd and Pb accumulating abilities, and thus is the most important material for breeding of pollution-safe cultivars (PSCs) to minimize Cd and Pb accumulations in celery.     

潖江蓄滞洪区洪灾风险分析及避难转移安置研究

以潖江蓄滞洪区洪灾避难转移安置为研究对象,利用Mike21技术,建立潖江蓄滞洪区洪水演进数值模型,模拟北江遭遇300年一遇洪水时,在潖江口泄洪,潖江蓄滞洪区内洪水演进,分析潖江蓄滞洪区洪灾风险.通过实地调查,结合历史洪水情况,利用潖江蓄滞洪区DEM数据、Google地图及最快避难转移安置时间分析法,详细设计了潖江蓄滞洪区内各行政村落遭遇洪灾时避难转移与人员安置,为潖江蓄滞洪区启用预案科学编制及防洪减灾提供科学依据.     

巨灾定义与划分标准研究——基于近年来全球典型灾害案例的分析

近年来,全球受严重灾害影响的国家和地区频繁出现,导致大量人员伤亡和严重经济损失。巨灾作为区域经济社会可持续发展的主要障碍之一,各国政府以及科技、产业与社会各界人士予以高度重视。目前,国内外对巨灾的研究绝大多数集中于巨灾保险,虽有部分研究涉及到巨灾定义及划分标准,但因研究目的与学术背景不同,至今尚无相对公认的、统一的巨灾定义。对巨灾概念的由来和国内外目前的研究动态进行了较全面的综述,论述了突发性与渐发性巨灾的差异,结合近年来全球典型灾害案例,总结给出巨灾定义、划分指标与标准,并在此基础上对巨灾未来研究进行展望,提出了研究的关键问题并建议进行更深入的研究。旨在为完善区域灾害系统原理,进一步推动巨灾研究提供参考。