Can floor-area-ratio incentive promote low impact development in a highly urbanized area?—A case study in Changzhou City,China

As an environmental friendly measure for surface runoff reduction, low impact development (LID) has been applied successfully in urban areas. However, due to high price of land and additional expense for LID construction in highly urbanized areas, the developers of real estate would not like to proceed LID exploitation. Floor area ratio (FAR) refers to “the ratio of a building’s total floor area to the size of the piece of land upon which it is built.” Increasing FAR indicates that the developers can construct higher buildings and earn more money. By means of awarding FAR, the developers may be willing to practice LID construction. In this study, a new residential district is selected as a case study to analyze the tradeoff between the runoff reduction goal achieving by LID practices and the incentive of awarding FAR to promote LID construction. The System for Urban Stormwater Treatment and Analysis IntegratioN (SUSTAIN) model is applied to simulate the runoff reduction under various LID designs and then derive the Pareto-optimal solutions to achieve urban runoff reduction goals based on cost efficiency. The results indicates that the maximum surface runoff reduction is 20.5%. Under the extremity scenarios, the government has options to award FAR of 0.028, 0.038 and 0.047 and the net benefits developers gain are 0 CNY, one million CNYand two million CNY, respectively. The results provide a LID construction guideline related to awarding FAR, which supports incentive policy making for promoting LID practices in the highly urbanized areas.

Open image in new window

     

北京与成都大气污染特征及空气质量改善效果评估

近年来我国空气质量持续改善,大气颗粒物浓度明显降低.为探究气象条件和减排措施对细颗粒物（PM_2.5）浓度的相对贡献,选取两个典型代表城市——北京和成都,对比分析两城市所处的地理环境条件、污染排放以及气象扩散条件.结果表明,北京与成都2013~2018年重污染天数及污染过程显著减少,SO₂和PM_2.5浓度降幅明显,与2013年相比,两城市2018年SO₂浓度的降幅分别为77.8%和70.9%,PM_2.5浓度分别降低了42.7%和48.5%.冬季PM_2.5浓度下降速率最大,每年分别以13.5μg·m^-3和14.1μg·m^-3的速率降低.2013~2018年成都较北京风速偏小,温度偏高约3℃,静小风日数偏多,冬季静小风频率高,混合层高度、大气容量指数以及通风系数明显偏小,大气扩散条件较差.综合静稳天气指数（SWI）和环境气象指数（EMI）结果表明北京大气扩散条件优于成都,但近几年的变化程度有所不同.2014~2018年两城市的EMI呈减小趋势,2018年成都地区EMI降幅最显著,气象条件明显好转.与2014年相比,2018年北京与成都全年大气污染减排对PM_2.5浓度的贡献分别为33.5%和24.0%,气象条件的贡献分别为7.2%和11.1%;冬季减排贡献分别为31.7%和32.5%,气象条件的贡献比全年的大.     

污水厂污泥在亚/超临界丙酮中的液化行为

利用直接热化学液化技术,在1000mL的反应釜中,考察了液化温度、污泥/溶剂配比(R1)、催化剂以及溶剂填充率(R2)对污水厂污泥在亚/超临界丙酮中的液化行为的影响.结果表明,约300℃条件下,污泥液化较为彻底,过低或过高的温度液化效果反而较差.当温度超过340 ℃时,丙酮溶剂参与反应能力增强,促进油产率的增加,至380℃时油产率保持稳定.在其他液化条件相同的情况下,发现污泥在R1为10/200、R2为20%、添加5%剂量的NaOH作为催化剂,获得较好的液化效果.红外光谱(FTIR)和气相色谱/质谱分析(GC-MS)分析表明,生物油的主要成分是含氮杂环、羧酸、酯、酮等化合物,主要的官能团包括胺基、羟基、烷基和羰基等.     

青海省1998—2012年草地生态系统服务功能价值评估

由于人类活动对草地生态系统的干扰,草地退化加剧,科学评估草地生态系统服务功能的价值对于草地保护与管理决策具有重要意义。论文通过整合青海省多源、多尺度、多过程的生态环境数据,结合大规模的野外调查数据,构建各类专项和综合数据库,以千年生态评估生态系统服务分类系统和Costanza等的分类方法为基础,结合青海省生态系统特征及生态地位,选取了青海省生态系统服务指标评估体系。开发定量核算青海省生态系统服务功能及其价值的数据-模型融合平台,对青海省1998—2012年的草地生态系统固碳释氧、水文调节、土壤保持、生物多样性等16种生态系统服务功能价值进行了全面的评估,成功实现了草地生态系统服务价值评估的动态化、精细化和智能化。结果表明：1998—2012年草地生态系统服务功能总价值在2 349.97~3 374.49亿元之间,均值为2 935.63亿元,是青海省2012年全省GDP的1.55倍,平均每公顷达92.87万元。最后,以此为基础,提出青海省草地生态系统适应性管理策略,为青海省生态立省战略提供决策支持和依据。     

载铁活性炭对水中草甘膦吸附性能研究

通过浸渍-焙烧法制备载铁活性炭,并用SEM电镜分析了载铁活性炭表面形态,研究了载铁活性炭(Fe-AC)对草甘膦溶液的吸附等温线和吸附动力学,并分析了各种影响因素对载铁活性炭吸附性能的影响.实验表明,Freundlich方程可以对Fe-AC草甘膦吸附等温线进行很好拟合,最大吸附量约为5.8mmol/g;其吸附动力学过程用Lagergren方程拟合,吸附速率常数在0.088min-1左右,且随着温度的升高逐渐减小.根据Kannan & Sundaram颗粒内扩散模型拟合,颗粒内扩散速率常数kp大于10mg·min-1/2/g,并随着起始温度的升高而减小.由于草甘膦的存在形态和Fe-AC材料表面性质的变化,AC-Fe对草甘膦的吸附能力随水溶液的pH升高而降低.NaCl的存在产生拮抗效应使得Fe-AC对草甘膦的吸附容量大大下降,随着NaCl浓度增加至4g/L后,盐析效应开始占主导地位,使得Fe-AC的吸附容量略有增加;由于草甘膦分子的空间位阻效应和亚磷酸根与载铁活性炭表面形成较强的络合物,使得随亚磷酸根浓度的升高Fe-AC对草甘膦的吸附量持续下降.     

湿润剂表面张力对硫化矿尘吸湿效果的影响

采用毛细管反向渗透实验装置,以湿润剂表面张力为衡量指标,通过分析3种硫化矿尘在十二烷基苯磺酸钠（SDBS）、十二烷基磺酸钠(SDS)、十二烷基硫酸钠(K12)3种阴离子表面活性剂中的吸湿效果,比较得出3种表面活性剂湿润性能大小。利用ZISMA图得出表面活性剂在3种硫化矿表面铺展的临界表面张力值,并探究其值对湿润行为和湿润效果的影响。研究表明:3种阴离子活性剂的湿润性能SDBS＞SDS＞K12,湿润剂在3种硫化矿表面铺展的临界表面张力分别为27.3,26.6,26.0 mN/m,且吸湿增重和吸湿速度的峰值是受铺展润湿作用的影响。     

渤海中部油气开采区沉积物中石油烃环境质量

对渤海中部油气开采区表层和柱状沉积物中的石油烃含量进行了分析和环境质量评价,结果表明该区表层沉积物中石油烃的含量介于(10.15 ~ 151.72)10-6 之间,平均值为55.9910-6;研究区多数站位为中等污染,部分站位出现较高污染和重度污染,高值区分布在渤海湾沿岸、研究区东部和研究区中南部,表明石油烃污染受到沿岸人类排污和油气开采的显著影响.研究区沉积物中的石油烃在二十世纪三十年代之前处于低背景值阶段,之后受到人类活动的影响含量有所增加,其含量的变化与渤海石油开发勘探的历程基本相似.2011年6月发生的蓬莱19-3石油泄漏事件在附近的海底沉积物中有明显的显示,经过1 a后,石油泄漏事件的影响水平已显著降低.     

Occurance and control of manganese in a large scale water treatment plant

The continuous variations of dissolved oxygen (DO), manganese (Mn), pH, and their effect on manganese removal by different water treatment processes are investigated. The results show that the declined DO concentration and pH value in the bottom of reservoir results in the increasing release of Mn from sediment to source water. Manganese concentration increased from 0.1 to 0.4 mg·L^-1 under the condition that DO concentration decreased from 12.0 to 2.0 mg·L^-1 in raw water. The different water treatment processes exhibited different efficiency on manganese removal. The processes with recycling of the suspended sludge, low elevation velocity in settling tank and slow filter rate, will benefit the manganese removal. During a high release of manganese in raw water, traditional coagulation-sedimentation and filtration could not completely remove Mn, although granular activated carbon filtration (GAC) had been applied. At that case, preoxidation with chlorine or potassium permanganate (KMnO₄) was necessary to address the high manganese concentration.     

Practical evaluation for water utilities in China by using analytic hierarchy process

The risk of water utilities would include the water quality failure and the water quantity failure, from the source to the tap, including the catchment, treatment, distribution and the customer plumbing system. In this paper, we proposed a practical evaluation method based on the analytic hierarchy process (AHP). The hierarchical structure of the water utilities was established in terms of the fault event analysis from the past failure accidents. The severity of criteria was preset by the experts and the probability of criteria was determined by a modified CUWA-TSM sheet with the consideration of the actual situations of the supply system. The evaluation model was successfully performed by a case study. Although, the method in this paper may not be as good as the framework of WSPs, it has a great advantage compared to WSPs and TSM. The risk management can be applied through specific software packages with a user-friendly interface, which means it is easier to implement. In addition, it can point out the critical control points (CCPs) for the decision-makers. So we believe this method will improve and play a more and more active role in the development of the risk management in China water works.     

西藏日喀则机场周边风沙源空间分布及近34年的演变趋势

通过大量野外调查与遥感数据人机交互式目视解译方法,运用3S技术,解译了日喀则机场周边9县1975年、1990年、2000年和2008年4期遥感数据,分析了风沙化土地的空间分布,以及近34 a风沙化土地的演变趋势。结果表明:2008年日喀则机场周边共有风沙化土地50 053.31 hm²,其中,日喀则市、南木林县、白朗县和仁布县所占比例为51.41%。距离机场40 km内风沙化土地面积为21 338.54 hm²,占沙地总面积的42.63％,主要分布在仁布大桥以西、年楚河与雅鲁藏布江交汇处以东,高寒河谷两岸的南木林县和日喀则市江当乡境内的季节性边滩、江心洲和山坡上。1975-2008年间风沙化土地呈缓慢增长趋势,共增长了13.57%,年均增长率为175.94 hm²/a。以1990-1999年风沙化土地扩展最快, 2000-2008年增长最慢。气温升高、空气相对湿润程度下降是造成风沙化土地进一步扩展、蔓延的主要原因。