Approach of technical decision-making by element flow analysis and Monte-Carlo simulation of municipal solid waste stream

This paper deals with the procedure and methodology which can be used to select the optimal treatment and disposal technology of municipal solid waste （MSW）, and to provide practical and effective technical support to policy-making, on the basis of study on solid waste management status and development trend in China and abroad. Focusing on various treatment and disposal technologies and processes of MSW, this study established a Monte-Carlo mathematical model of cost minimization for MSW handling subjected to environmental constraints. A new method of element stream （such as C, H, O, N, S） analysis in combination with economic stream analysis of MSW was developed. By following the streams of different treatment processes consisting of various techniques from generation, separation, transfer, transport, treatment, recycling and disposal of the wastes, the element constitution as well as its economic distribution in terms of possibility functions was identified. Every technique step was evaluated economically. The Mont-Carlo method was then conducted for model calibration. Sensitivity analysis was also carried out to identify the most sensitive factors. Model calibration indicated that landfill with power generation of landfill gas was economically the optimal technology at the present stage under the condition of more than 58% of C, H, O, N, S going to landfill. Whether or not to generate electricity was the most sensitive factor. If landfilling cost increases, MSW separation treatment was recommended by screening first followed with incinerating partially and composting partially with residue landfilling. The possibility of incineration model selection as the optimal technology was affected by the city scale. For big cities and metropolitans with large MSW generation, possibility for constructing large-scale incineration facilities increases, whereas, for middle and small cities, the effectiveness of incinerating waste decreases.     

Development of a cloud condensation nuclei (CCN) counter using a laser and charge-coupled device (CCD) camera

A continuous flow streamwise thermal gradient cloud condensation nuclei (CCN) counter with an aerosol focusing and a laser-charge-coupled device (CCD) camera detector system was developed here. The counting performance of the laser-CCD camera detector system was evaluated by comparing its measured number concentrations with those measured with a condensation particle counter (CPC) using polystyrene latex (PSL) and NaCl particles of varying sizes. The CCD camera parameters (e.g. brightness, gain, gamma, and exposure time) were optimized to detect moving particles in the sensing volume and to provide the best image to count them. The CCN counter worked well in the particle number concentration range of 0.6–8000 #·cm⁻³ and the minimum detectable size was found to be 0.5 μm. The supersaturation in the CCN counter with varying temperature difference was determined by using size-selected sodium chloride particles based on K?hler equation. The developed CCN counter was applied to investigate CCN activity of atmospheric ultrafine particles at 0.5% supersaturation. Data showed that CCN activity increased with increasing particle size and that the higher CCN activation for ultrafine particles occurred in the afternoon, suggesting the significant existence of hygroscopic or soluble species in photochemically-produced ultrafine particles.     

资源型地区自然资源对经济增长影响的实证分析——基于2000-2016年中国重点煤炭城市样本

大多数资源型地区在自然资源开采过程中经济增长长期呈现缓慢现象。如何利用资源优势、摆脱资源瓶颈、实现经济可持续发展是资源型地区面临的关键问题。以2000-2016年我国重点煤炭城市面板数据为样本,探讨资源型地区自然资源影响经济增长的不同途径。结果显示：资源型地区短期受益于“资源红利”,但长期由于容易出现资源产业依赖行为而对其他经济活动和资源依赖产业产生“挤出效应”,影响长期经济增长速度;同时,资源型地区容易表现出依靠物质资本投资实现经济增长的“粗放型增长”特征。本文研究结论丰富了自然资源对经济增长影响机制的探索,对资源型地区如何实现可持续发展也具有一定的实践启示。     

毛乌素沙漠东南缘DGS1层段CaCO_3记录的全新世气候变化

毛乌素沙漠东南缘萨拉乌苏河流域滴哨沟湾剖面DGS1层段主要由沙丘砂、湖沼相和次生黄土组成。根据测年结果,该层段为全新世风沙沉积序列。通过对该层段CaCO_3的分析,发现CaCO_3含量在沙丘砂、湖沼相和次生黄土依次变化于0,35%~2.74%(平均值1.03%)、0.13%~60.31%(平均值22.16%)和8.64%~12.83%(平均值9.21%),并与DGS1层段粒度Mz(平均粒径)呈显著相关(相关系数0.68)。研究表明,毛乌素沙漠冬季风盛行时期沙丘砂堆积,CaCO_3发生迁移;夏季风盛行时期湖沼相发育,CaCO_3相对聚集。据此,我们认为CaCO_3含量变化揭示了毛乌素沙漠在全新世以来经历了多次冬夏季风交互演替的气候变化过程,全新世气候波动主要可分为4个阶段:全新世早期回暖期、全新世鼎盛期、暖冷过渡期和冷干气候不稳定期。     

Innovative method of culturing bdelloid rotifers for the application of wastewater biological treatment

• An innovative method of culturing bdelloid rotifer fed on flour was proposed. • Rotifer fed on flour grew faster than that fed on bacteria or Chlorella vulgaris. • The optimum mass culture conditions for rotifer fed on flour were investigated. • The cultured rotifer could improve sludge settleability in the SBR. This study aims to establish a simple and efficient method for the mass culture of bdelloid rotifers, which is the basis for the application of bdelloid rotifers as biological manipulators to improve wastewater biological treatment performance. A common bdelloid rotifer, Habrotrocha sp., in a wastewater biological treatment system was selected as the culture target. Rotifers fed on flour could reproduce faster than those fed traditional food such as Chlorella vulgaris or mixed bacteria. As a rotifer food, flour has the advantages of simple preparation, effortless preservation, and low cost compared to live Chlorella vulgaris or mixed bacteria, so it is more suitable for the mass culture of rotifers. The optimal rotifer culture conditions using flour as food were also studied. According to the experimental results, the recommended rotifer culture conditions are a flour particle size of 1 μm, a flour concentration of 6 × 10⁶ cell/mL, a temperature of 28℃, a pH level of 6.5 and salinity of 100–500 mg/L. In addition, the sludge volume index in the sequencing batch reactor (SBR) with the addition of cultured rotifers was 59.9 mL/g at the end of operation and decreased by 18.2% compared to SBR without rotifer, which indicates that the cultured rotifers still retained the function of helping to improve sludge settling. This function may be related to the rotifer’s role in inhibiting bacteria from producing loosely bound extracellular polymeric substances in the SBR.     

海岛地区地质灾害易发性评价模型构建研究 ——以岱山县衢山镇为例

以岱山县衢山镇为研究区,以斜坡单元为评价单元,在重点分析地质环境条件与地质灾害相关性的基础上,筛选影响地质灾害易发性的主要参评因子,构建评价模型,并完成指标因子的分析与量化,并借助层次分析法和综合危险指数法确定易发性的综合评分,进而划定易发程度等级和修编易发程度分区.评价模型的构建过程可为海岛地区地质灾害易发性评价提供...     

环境监测能力建设项目管理思路与实现

近年来,环境监测能力建设项目资金投入不断加大,项目规模增长迅速,实施任务日益繁重,项目绩效考核要求越来越高,但项目管理还处于比较粗放的状态。在分析环境监测能力建设项目管理现状和需求的基础上,提出通过转变项目管理模式、强化信息支撑手段、完善制度建设、培养管理人才等多种手段,提高项目管理的科学性和时效性,实现重点项目管理的精细化、科学化和规范化。     

江苏省机动车和非道路移动机械排气污染防治立法探索和思考

随着燃煤、工业、扬尘等大气污染源的治理力度不断加强，机动车和非道路移动机械等移动源的排放贡献率逐步增加，已成为城市最主要的大气污染源之一。《江苏省机动车和非道路移动机械排气污染防治条例》已于2022年11月25日通过江苏省第十三届人民代表大会常务会员会第三十三次会议审议， 自2023年5月1日起施行。该条例的施行将为协同开展机动车和非道路移动机械排气监管，深入打好污染防治攻坚战提供有力的法规支撑。介绍了这部法规的背景、立法修订的必要性、制度设计的主要内容及创新亮点，分析了存在的不足并提出建议，为未来移动源立法工作提供地方经验和参考。     

江苏省“两个率先”地表水环境质量指标考核的几点思考

回顾了江苏省"两个率先"中有关地表水环境质量考核指标近年来的考核情况,指出了存在考核断面综合代表性不足、多种考核结果不统一、考核指标设置不合理、质量控制措施不健全和信息公开不全面等问题。提出了"十三五"考核实施建议,应理顺考核体制机制,统一考核点位和办法,加强考核信息公开,引导公众有序参与和有力监督环境质量考核工作,促进水环境质量改善。     

Accelerated sunlight photocatalysis through improved electron mobility between g-C3N4 and BiPO4 nanomaterial

Herein, we report a detailed study on creating heterojunction between graphitic carbon nitride (g-C₃N₄) and bismuth phosphate (BiPO₄), enhancing the unpaired free electron mobility. This leads to an accelerated photocatalysis of 2,4-dichlorophenols (2,4-DCPs) under sunlight irradiation. The heterojunction formation was efficaciously conducted via a modest thermal deposition technique. The function of g-C₃N₄ plays a significant role in generating free electrons under sunlight irradiation. Together, the generated electrons at the g-C₃N₄ conduction band (CB) are transferred and trapped by the BiPO₄ to form active superoxide anion radicals (?O₂^?). These active radicals will be accountable for the photodegradation of 2,4-DCPs. The synthesized composite characteristics were methodically examined through several chemical and physical studies. Due to the inimitable features of both g-C₃N₄ and BiPO₄, its heterojunction formation, 2.5wt% BiPO₄/g-C₃N₄ achieved complete 2,4-DCP removal (100%) in 90 min under sunlight irradiation. This is due to the presence of g-C₃N₄ that enhanced electron mobility through the formation of heterojunctions that lengthens the electron-hole pairs’ lifetime and maximizes the entire solar spectrum absorption to generate active electrons at the g-C₃N₄ conduction band. Thus, this formation significantly draws the attention for future environmental remediation, especially in enhancing the entire solar spectrum’s harvesting.

Graphical abstract