Scenario-based assessment and multi-objective optimization of urban development plan with carrying capacity of water system

• Impact of urban development on water system is assessed with carrying capacity. • Impacts on both water resource quantity and environmental quality are involved. • Multi-objective optimization revealing system trade-off facilitate the regulation. • Efficiency, scale and structure of urban development are regulated in two stages. • A roadmap approaching more sustainable development is provided for the case city. Environmental impact assessments and subsequent regulation measures of urban development plans are critical to human progress toward sustainability, since these plans set the scale and structure targets of future socioeconomic development. A three-step methodology for assessing and optimizing an urban development plan focusing on its impacts on the water system was developed. The methodology first predicted the pressure on the water system caused by implementation of the plan under distinct scenarios, then compared the pressure with the carrying capacity threshold to verify the system status; finally, a multi-objective optimization method was used to propose regulation solutions. The methodology enabled evaluation of the water system carrying state, taking socioeconomic development uncertainties into account, and multiple sets of improvement measures under different decisionmaker preferences were generated. The methodology was applied in the case of Zhoushan city in South-east China. The assessment results showed that overloading problems occurred in 11 out of the 13 zones in Zhoushan, with the potential pressure varying from 1.1 to 18.3 times the carrying capacity. As a basic regulation measure, an environmental efficiency upgrade could relieve the overloading in 4 zones and reduce 9%‒63% of the pressure. The optimization of industrial development showed that the pressure could be controlled under the carrying capacity threshold if the planned scale was reduced by 24% and the industrial structure was transformed. Various regulation schemes including a more suitable scale and structure with necessary efficiency standards are provided for decisionmakers that can help the case city approach a more sustainable development pattern.     

两阶段曝气生物滤池的硝化性能

曝气生物滤池(BAF)是近年来受到广泛关注的一种新型污水处理技术,具有占地面积少、投资费用低、处理效率高、出水水质好等优点。现已被应用于许多污水处理厂的二级处理、深度处理以及污水的回用。实验以陶粒为填料,自行设计了升流式两阶段BAFs(UBAFs)处理模拟生活污水,考察了反应器运行条件对COD与氨氮去除影响,并探讨了UBAFs反应器内氮流失及同步硝化反硝化情况。结果表明,UBAFs对生活污水处理具有良好的净化效果。在进水COD和氨氮浓度分别为200~363 mg/L和16.8~31.3 mg/L条件下,UBAFs处理出水水质均达到《城市污水再生利用城市杂用水水质》(GB/T 18920-2002)标准,能够满足回用要求。通过采用氮平衡分析方法和借助电子扫描电镜技术,初步认为UBAFs反应器脱氮方式是由于在UBAFs第一阶段局部厌氧环境中以传统方式进行硝化反硝化脱氮,第二阶段是在好氧条件下,异养好氧硝化菌的同步硝化反硝化脱氮。     

PEM式臭氧消毒在地上游泳池水处理中的应用

采用臭氧法水处理系统对地上游泳池的循环水进行灭菌消毒,研究了臭氧用量、循环水流量和运行时间等因素对臭氧法灭菌效果的影响。结果表明,3组PEM臭氧发生器应用于21.2 m3的地上游泳池,在4 m3/h的循环水流量下运行12 h后,水中的细菌总数与大肠杆菌群数达到国家标准,去除率均在99%以上。与盐电解法水处理系统相比较,臭氧法水处理系统的优势在于:杀菌快速高效、出水水质的理化指标较好和运行费用低廉。     

Changes in Soil Particulate Organic Matter, Microbial Biomass, and Activity Following Afforestation of Marginal Agricultural Lands in a Semi-Arid Area of Northeast China

Afforestation of agricultural lands has been one of the major land use changes in China in recent decades. To better understand the effect of such land use change on soil quality, we investigated selected soil physical, chemical and microbial properties (0–15 cm depth) in marginal agricultural land and a chronosequence of poplar (Populus euramericana cv. ‘N3016’) plantations (5-, 10-, 15- and 20-years old) in a semi-arid area of Northeast China. Soil bulk density significantly declined after conversion of agricultural lands to poplar plantations. Soil total organic carbon (TOC) and nitrogen (TN) concentrations, microbial biomass C (MBC) and potential N mineralization rate (PNM) decreased initially following afforestation of agricultural lands, and then increased with stand development. However, soil metabolic quotient (qCO₂) exhibited a reverse trend. In addition, soil particulate organic matter C (POM-C) and N (POM-N) concentrations showed no significant changes in the first 10 years following afforestation, and then increased with stand age. These findings demonstrated that soil quality declined initially following afforestation of agricultural lands in semi-arid regions, and then recovered with stand development. Following 15 years of afforestation, many soil quality parameters recovered to the values found in agricultural land. We propose that change in soil quality with stand age should be considered in determining optimum rotation length of plantations and best management practices for afforestation programs.     

CCS scenarios optimization by spatial multi-criteria analysis: Application to multiple source sink matching in Hebei province

A method, based on spatial analysis of the different criteria to be taken into consideration for building scenarios of CO₂ capture and storage (CCS), has been developed and applied to real case studies in the Hebei province. Totally 88 point sources (42 from power sector, 9 from iron and steel, 18 from cement, 16 from ammonia, and 3 from oil refinery) are estimated and their total emission amounts to 231.7 MtCO₂/year with power, iron and steel, cement, ammonia and oil refinery sharing 59.13%, 25.03%, 11.44%, 3.5%, and 0.91%, respectively. Storage opportunities can be found in Hebei province, characterised by a strong tectonic subsidence during the Tertiary, with several kilometres of accumulated clastic sediments. Carbon storage potential for 25 hydrocarbon fields selected from the Huabei complex is estimated as 215 MtCO₂ with optimistic assumption that all recovered hydrocarbon could be replaced by an equivalent volume of CO₂ at reservoir conditions. Storage potential for aquifers in the Miocene Guantao formation is estimated as 747 MtCO₂ if closed aquifer assumed or 371 MtCO₂ if open aquifer and single highly permeable horizon assumed. Due to poor knowledge on deep hydrogeology and to pressure increase in aquifer, injecting very high rates requested by the major CO₂ sources (>10 MtCO₂/year) is the main challenge, therefore piezometry and discharge must be carefully controlled. A source sink matching model using ArcGIS software is designed to find the least-cost pathway and to estimate transport route and cost accounting for the additional costs of pipeline construction due to landform and land use. Source sink matching results show that only 15–25% of the emissions estimated for the 88 sources can be sequestrated into the hydrocarbon fields and the aquifers if assuming sinks should be able to accommodate at least 15 years of the emissions of a given source.     

高膜通量厌氧微网生物反应器处理生活污水的研究

将动态膜技术与厌氧膜生物反应器相结合,形成一体式厌氧微网生物反应器(AnFBR),用于城市生活污水的处理,研究了在高膜通量条件下,AnFBR的运行情况和对生活污水的处理效果。结果表明,AnFBR在膜通量为72 L/(m2.h)条件下可连续稳定运行40 d;系统对COD平均去除率为58.4%,对TN和NH3-N有一定的去除效果;出水SS最高为15.0 mg/L,出水中污染物粒径在10μm以下;微网动态膜对小分子物质的截留量不高,但对分子量大于1 000 kU的物质有明显的截留效果,进水中的大部分大分子物质被转化为小分子物质;AnFBR在保留了泥水分离特点的情况下还具有结构简单、膜通量高、微网过滤周期长等优点。     

Atmospheric deposition of phthalate esters in a subtropical city

In Chinese cities, air pollution has become a serious and aggravating environmental problem undermining the sustainability of urban ecosystems and the quality of urban life. Bulk atmospheric deposition samples were collected two-weekly, from February 2007 to January 2008, at three representative areas, one suburban and two urbanized, in the subtropical city, Guangzhou, China, to assess the deposition fluxes and seasonal variations of phthalate esters (PAEs). Sixteen PAE congeners in bulk deposition samples were measured and the depositional fluxes of ∑₁₆PAEs ranged from 3.41 to 190 μg m^?2 day^?1, and were highly affected by local anthropogenic activities. The significant relationship between PAEs and particulate depositional fluxes (correlation coefficient R² = 0.72, P < 0.001) showed PAEs are associated primarily with particles. Temporal flux variations of PAEs were influenced by seasonal changes in meteorological parameters, and the deposition fluxes of PAEs were obviously higher in wet season than in dry season. Diisobutyl phthalate (DiBP), Di-n-butyl phthalate (DnBP), and Di(2-ethylhexyl) phthalate (DEHP) dominated the PAE pattern in bulk depositions, which is consistent with a high consumption of the plasticizer market in China. PAE profiles in bulk deposition showed similarities exhibited in both time and space, and a weak increase of high molecular weight PAE (HMW PAE) contribution in the wet season compared to those in the dry season. Average atmospheric deposition fluxes of PAEs in the present study were significantly higher than those from other studies, reflecting strong anthropogenic inputs as a consequence of rapid industrial and urban development in the region.     

事故状态下污染物排放对水环境影响的预测研究

对辽河油田欢喜岭采油厂在事故状态下污染物排放对大凌河水域环境的影响进行预测研究。计算了洪水淹没、油罐冒顶泄漏、油井井喷泄漏、联合站泄漏、管道泄漏、暴雨径流带走落地油等16种情景下对该河流水质的影响情况,并建立数学模型,进行情景模拟。研究结果表明,事故状态下对大凌河水质影响的次序由大到小依次为:洪水淹没、油罐冒顶泄漏、油井井喷泄漏、联合站泄漏、管道泄漏、暴雨径流。     

Iron improving bio-char derived from microalgae on removal of tetracycline from aqueous system

Novel magnetic carbonaceous bio-char was hydrothermal prepared from microalgae under different loadings of iron and its structures and surface chemistry were characterized with Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and nitrogen adsorption-desorption isotherm (BET). The morphology of bio-char changed from sheet to particle as iron loading increased and its surface area also increased. When 3.0 g of dried microalgae and 6.0 mmol iron salt ((NH₄)₂SO₄·FeSO₄·6H₂O) were mixed and treated, the obtained bio-char possessing the highest amount of oxygen-containing functional groups resulted in the best adsorption performance on tetracycline (TC). This adsorption process was fitted to Langmuir adsorption isotherm and the maximum adsorption capacity was 95.86 mg/g, which is higher than other bio-char reported. The iron loading contributed to the higher adsorption capacity of bio-char, which may be due to three factors, the high surface area, more hydrogen bonding, and bridging effects of the structural Fe for TC. Our data suggest that bio-char may have more important role in stabilization of pollutants in the environment.     

燃煤烟气低温SCR脱硝中试研究

低温选择性催化还原(SCR)脱硝是国内外脱硝技术研发的热点,但目前主要集中在实验室小试范围,无法完全反映催化剂在实际烟气中的运行状况。在30 t/h循环流化床燃煤锅炉脱硫除尘装置后建设了2 000~5 000 m3/h的SCR脱硝中试装置,经系统研究发现,中试使用的蜂窝式催化剂对SO2和NO具有很强的吸附能力,且反应温度、喷氨速率和气体空速均会影响催化脱硝效率。为期5 d的连续运行实验结果表明,催化剂的脱硝效率一直稳定在30%~50%,并未发现明显的失活,这证明设计除雾除尘器、较大的混合器、混合器与反应器间较长的管路均有利于缓解催化剂因SO2、H2O和飞灰中的碱性金属导致的失活。