可持续发展的排水系统设计

摘要：城市排水系统是保护公共生产、生活安全以及防护洪水的首要部分。世界众多国家利用多年时间出台了相关立法并提高了城市排水系统的设计标准。排水系统设计依靠成熟的软件工具已经进化成一个非常规范化的产业。这篇文章着眼于新的工业推动力,独特的可持续发展力,综述在设计时结合可持续排水系统的方式,讨论在未来设计过程改进的方式。     

黑臭河道中聚乙烯醇/海藻酸钠固定微米沸石粉去除氨氮

采用聚乙烯醇和海藻酸钠对微米沸石粉进行固定,通过批次吸附实验探究水凝珠去除氨氮的效果及其机制.结果表明:PAZ-20的投加量超过10 g·L-1时,氨氮去除率达到了 80％之上.pH为3～8时,pH增加对PAZ吸附氨氮影响不大,当pH从9增至11时,氨氮去除率随pH的增大而显著减小,PAZ吸附氨氮的最佳pH为7.水温为5～25℃时,氨氮去除率随温度升高而逐渐上升,25～35℃内略有上升,水温升至401,氨氮去除率有所下降.准二级动力学方程和Langmuir吸附等温线模型能够更好地拟合PAZ吸附氨氮.PAZ-20对于水中阳离子的吸附能力为:K+＞Mg2+＞Na+＞Ca2+.共存阳离子对PAZ吸附氨氮的影响程度为:K+＞Na+＞Ca2+＞Mg2+.扫描电镜和傅里叶红外光谱分析显示微米沸石粉被良好地固定在聚乙烯醇/海藻酸钠中.PAZ可用于黑臭河道的治理,且受共存阳离子的干扰较小.     

HLB-MR反应器直接处理城市污水及回收有机物

采用中空纤维超滤膜组件构建了高负荷生物絮凝-膜反应器（HLB-MR）,对其直接处理城市污水及回收有机物进行了研究.结果表明：当水力停留时间（HRT）为1.0h,固体停留时间（SRT）为0.2d时,该工艺可回收进水总COD的60.8%,据估算约有39%的进水总COD可通过中温厌氧消化转化为甲烷能源回收,有机物的甲烷转化率为活性污泥法剩余污泥的2倍以上,能实现污水中有机物的高效回收和利用;经过有机物回收后膜出水的COD能稳定保持在30mg/L左右,且出水中氮、磷营养物保有值均较高又不含固体杂质和病原体,可将其用作灌溉用水,实现水资源回用;SRT分别为0.2,0.6,1.0d时,反应器对胶体COD絮凝效率分别为81.9%、95.1%、96.8%,絮凝效率越高,膜污染越轻,良好的生物絮凝效果可有效减轻膜污染,保证工艺的稳定运行.     

Low-carbon transition of iron and steel industry in China: Carbon intensity,economic growth and policy intervention

As the biggest iron and steel producer in the world and one of the highest CO₂ emission sectors, China's iron and steel industry is undergoing a low-carbon transition accompanied by remarkable technological progress and investment adjustment, in response to the macroeconomic climate and policy intervention. Many drivers of the CO₂ emissions of the iron and steel industry have been explored, but the relationships between CO₂ abatement, investment and technological expenditure, and their connections with the economic growth and governmental policies in China, have not been conjointly and empirically examined. We proposed a concise conceptual model and an econometric model to investigate this crucial question. The results of regression, Granger causality test and impulse response analysis indicated that technological expenditure can significantly reduce CO₂ emissions, and that investment expansion showed a negative impact on CO₂ emission reduction. It was also argued with empirical evidence that a good economic situation favored CO₂ abatement in China's iron and steel industry, while achieving CO₂ emission reduction in this industrial sector did not necessarily threaten economic growth. This shed light on the dispute over balancing emission cutting and economic growth. Regarding the policy aspects, the year 2000 was found to be an important turning point for policy evolution and the development of the iron and steel industry in China. The subsequent command and control policies had a significant, positive effect on CO₂ abatement.     

新疆焉耆盆地平原区地下水质量评价与污染成因探讨

地下水作为一种洁净而又丰富的淡水资源,已经成为新疆工农业生产及生活的主要水源,起着至关重要的作用。本文依据2014年42组地下水样品,采用溶解性总固体(TDS)、总硬度(TH)、Cl~-、SO_4~(2-)、NO_3~-、F~-、铁(Fe)、锰(Mn)为评价项目,利用单项指标评价法进行地下水质量评价,统计了新疆焉耆盆地平原区各评价指标在不同水质级别所占的比例;采用8组2011年和2014年同一监测井的化学组分浓度对比法进行地下水污染评价,对地下水水质变化趋势进行分析;分析了地下水的污染原因。地下水质量评价结果表明2014年潜水、浅层承压水和深层承压水Ⅳ-Ⅴ类水质所占比例之和分别25.0%、45.5%和29.7%,部分地区地下水受地表水补给导致铁含量超标;地下水污染评价结果表明2011~2014年地下水劣变程度为"潜水深层承压水浅层承压水"。影响焉耆盆地平原区地下水水质的主要因素是人类活动,尤其是城镇化的快速发展以及农业生产。     

太湖表层沉积物重金属的分布、来源与生态风险评价

对2010年太湖表层沉积物样品进行pH、温度、氧化还原电位、含水率、孔隙度、粒径、总磷和烧失量这8种理化指标和Cu、Zn、Ni、Cr、Pb、Ba、Mn、Co和V这9种重金属含量测定分析.结果表明,太湖表层沉积物重金属含量大小为：Mn>Ba>Zn>Cr>V>Ni>Pb>Cu>Co,且各重金属含量均超过背景值,这9种重金属与太湖流域地质作用紧密相连,同时也受到了不同程度人类活动的影响.通过聚类分析和重金属空间分布分析可知,北太湖段和南太湖段重金属含量均从湖岸向湖心有所减少,西太湖段重金属含量从湖岸向湖心有所增高,湖心区重金属含量分布相对均匀.通过相关性分析可知,不同重金属在不同程度上具有正相关性,反映其具有同一污染来源.通过PCA和PMF分析可知,太湖重金属来源多样,交通和工业复合源是最主要的来源,成岩作用是第二主要来源,农业是第三主要来源.此外,收集分析了2000~2020年太湖表层沉积物重金属的污染情况,通过重金属地累积指数和潜在生态风险指数可知,Cu、Zn、Ni、Cr和Pb的污染程度和潜在生态风险均呈下降趋势.这为太湖今后的重金属污染控制提供了有力的理论支撑.     

Degradation of tris(1-chloro-2-propanyl) phosphate by the synergistic effect of persulfate and zero-valent iron during a mechanochemical process

This study revealed a dual pathway for the degradation of tris(1-chloro-2-propanyl) phosphate (TCPP) by zero-valent iron (ZVI) and persulfate as co-milling agents in a mechanochemical (MC) process. Persulfate was activated with ZVI to degrade TCPP in a planetary ball mill. After milling for 2 h, 96.5% of the TCPP was degraded with the release of 63.16, 50.39, and 42.01% of the Cl^?, SO₄^2?, and PO₄^3?, respectively. In the first degradation pathway, persulfate was activated with ZVI to produce hydroxyl (·OH) radicals, and ZVI is oxidized to Fe(II) and Fe(III). A substitution reaction occurred as a result of the attack of ·OH on the P–O–C bonds, leading to the successive breakage of the three P–O–C bonds in TCPP to produce PO₄^3?. In the second pathway, a C–Cl bond in part of the TCPP molecule was oxidized by SO₄·^? to carbonyl and carboxyl groups. The P–O–C bonds continued to react with ·OH to produce PO₄^3?. Finally, the intermediate organochloride products were further reductively dechlorinated by ZVI. However, the synergistic effect of the oxidation (·OH and SO₄·^?) and the reduction reaction (ZVI) did not completely degrade TCPP to CO₂, resulting in a low mineralization rate (35.87%). Moreover, the intermediate products still showed the toxicities in LD₅₀ and developmental toxicant. In addition, the method was applied for the degradation of TCPP in soil, and high degradations (>?83.83%) were achieved in different types of soils.

     

Pilot-scale anaerobic co-digestion of municipal biomass waste and waste activated sludge in China: Effect of organic loading rate

The effects of organic loading rate on the performance and stability of anaerobic co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) were investigated on a pilot-scale reactor. The results showed that stable operation was achieved with organic loading rates (OLR) of 1.2–8.0 kg volatile solid (VS) (m³ d)^?1, with VS reduction rates of 61.7–69.9%, and volumetric biogas production of 0.89–5.28 m³ (m³ d)^?1. A maximum methane production rate of 2.94 m³ (m³ d)^?1 was achieved at OLR of 8.0 kg VS (m³ d)^?1 and hydraulic retention time of 15 days. With increasing OLRs, the anaerobic reactor showed a decrease in VS removal rate, average pH value and methane concentration, and a increase of volatile fatty acid concentration. By monitoring the biogas production rate (BPR), the anaerobic digestion system has a higher acidification risk under an OLR of 8.0 kg VS (m³ d)^?1. This result remarks the possibility of relating bioreactor performance with BPR in order to better understand and monitor anaerobic digestion process.     

含油污泥的水热法减量处理

采用水热技术处理含油污泥,考察了反应温度和反应时间对水热处理后含油污泥性质的影响,分析了含油污泥的减量化效果。实验结果表明：对含水率为70.6%（w）、含油率为32.0%（w）的含油污泥进行水热处理时,与反应时间相比,反应温度对含油污泥的脱水性能影响更大,是影响含油污泥热水解反应的重要因素;含油污泥经水热处理后,脱水性能得到改善,在所有实验条件下减量化率均高于78.8%,其中,在反应温度190 ℃、反应时间30 min的条件下,减量化率达到88.2%。     

青岛近海秋季生物气溶胶分布特征

生物气溶胶是大气气溶胶的重要组成部分,对生物气溶胶的分布特征进行分析对于了解其对人体健康和大气环境的影响具有重要作用.于2007年9-10月运用安德森6级生物粒子采样器在青岛近海连续采集生物气溶胶样品,探讨陆源和海源细菌及真菌的浓度和粒径分布特征.结果表明,青岛近海生物气溶胶中陆源细菌浓度高于海源细菌,而陆源真菌浓度低于海源真菌,海源菌总数高于陆源菌;陆源和海源细菌及真菌浓度分布表现为上午﹥下午﹥中午.9-10月陆源和海源细菌主要分布在大于2.1 (m的粒子中,占总数的80.0%以上,呈偏态分布;9月陆源和海源真菌主要分布在2.1~7.0 (m的粒子中,10月陆源和海源真菌主要分布在1.1~4.7 (m的粒子中,呈对数正态分布.总体而言,青岛近海生物气溶胶受到陆地与海洋的双重影响,海洋影响更为显著.