厌氧膜生物反应器出水生物脱氮技术研究

为解决AnMBR（厌氧膜生物反应器）出水NH₄+脱除的问题,提出利用AnMBR出水中残余COD_Cr、溶解性CH₄以及低价态硫元素,通过构建缺氧滤池和好氧滤池进行生物异养和硫自养脱氮的方法,进一步削减AnMBR出水COD_Cr、去除溶解性CH₄、同时同步生物脱氮.结果表明:①缺氧滤池与好氧滤池经过120 d单独驯化与33 d串联驯化后,在HRT（hydraulic retention time,水力停留时间）为6 h、进水为实际AnMBR出水的工况条件下,出水ρ（TN）为17.93 mg/L,去除率为52.7%;出水ρ（NH₄+-N）为2.78 mg/L,去除率为92.3%,达到GB 18918-2002《城镇污水处理厂污染物排放标准》一级B标准.在HRT为8 h工况条件下,出水ρ（TN）为14.60 mg/L,去除率为59.0%;出水ρ（NH₄+-N）为2.22 mg/L,去除率为93.7%,达到GB 18918-2002一级A标准.②脱氮滤池中氮脱除路径主要包括残余COD_Cr异养反硝化、溶解性CH₄异养反硝化和硫自养反硝化,并通过物料衡算评价了三者对于氮脱除的贡献,在HRT为6 h的工况条件下,脱氮滤池脱氮过程中残余COD_Cr异养反硝化、溶解性CH₄异养反硝化和硫自养反硝化三者占比分别为54.1%、24.3%和21.5%;在HRT为8 h的工况条件下,脱氮滤池脱氮过程中3种途径占比分别为70.4%、13.8%和15.8%.研究显示,脱氮滤池可以实现对AnMBR出水的低耗生物脱氮以及整体水质的达标排放.      

Profiles of and variations in aluminum species in PAC-MC used for the removal of blooming microalgae

Polyaluminum chloride modified clay (PAC-MC) is a safe and efficient red tide control agent that has been studied and applied worldwide. Although it is well known that the distribution of hydrolytic aluminum species in PAC affects its flocculation, little is known about the influence of particulars aluminum species on the microalgae removal efficiency of PAC-MC; this lack of knowledge creates a bottleneck in the development of more efficient MCs based on aluminum salts. The ferron method was used in this study to quantitatively analyze the distributions of and variations in different hydrolytic aluminum species during the process of microalgae removal by PAC-MC. The results showed that Al_a, which made up 5%–20% of the total aluminum, and Al_p, which made up 15%–55% of the total aluminum, significantly affected microalgae removal, with Pearson's correlation coefficients of 0.83 and 0.89, respectively. Most of the aluminum in the PAC-MC sank rapidly into the sediments, but the rate and velocity of settlement were affected by the dose of modified clay. The optimal dose of PAC-MC for precipitating microalgae was determined based on its aluminum profile. These results provide guidance for the precise application of PAC-MC in the control of harmful algal blooms.     

Source emissions and climate change impacts on the multimedia transport and fate of persistent organic pollutants, Chaohu watershed, eastern China

Emission intensity and climate change control the transport flux and fate of persistent organic pollutants (POPs) in multiple environmental compartments. This study applied a multimedia model (BETR model) to explore alternations in the spatio-temporal trends of concentrations and transport flux of benzopyrene (BaP), phenanthrene (Phe), perfluorooctane sulfonates (PFOS) and polychlorinated biphenyls (PCBs) in the Chaohu watershed, located in the lower reaches of the Yangtze River, China in response to changes in source emissions and climate. The potential historic and future risks of these pollutants also were assessed. The results suggest that current trends in concentrations and transport were similar to that of their emissions between 2005 and 2018. During the next 100 years, temporal trends and spatial patterns were not predicted to change significantly, which is consistent with climate change. Based on sensitivity and correlation analyses, climate change had significant effects on multi-media concentrations and transport fluxes of BaP, Phe, PFOS and PCBs, and rainfall intensity was the predominant controlling factor. Risk quotients (RQs) of BaP and Phe-in soil increased from 0.42 to 0.95 and 0.06 to 0.35, respectively, from 2005 to 2090, indicating potential risks. The RQs of the other examined contaminants exhibited little potential risk in soil, water, or sediment. Based on spatial patterns, it was inferred that the ecosystem around Lake Chaohu is the most at risk. The study provides insights needed for local pollution control of POPs in the Chaohu watershed. In addition, the developed approach can be applied to other watersheds world-wide.     

Nano-selenium controlled cadmium accumulation and improved photosynthesis in indica rice cultivated in lead and cadmium combined paddy soils

Selenium nanoparticles (Se NPs) are less toxic and more biocompatible than selenite or selenate. However, studies involving spraying with Se NPs for reducing accumulation of cadmium (Cd) and lead (Pb) in rice grains have been rarely reported as yet. Herein, indica rice seedlings cultivated in Cd+Pb-spiked paddy soils (denoted as positive control) were sprayed with Se NPs sols for four times from tillering to booting stage. Compared to positive control, 50–100 μmol/L Se NPs downregulated Cd transporters-related genes such as OsLCT1, OsHMA2 and OsCCX2 in leaves and OsLCT1, OsPCR1 and OsCCX2 genes in node I at filling stage. Meanwhile, Se-binding protein 1 was distinctly elevated, involving the repression of Cd and Pb transportation to rice grains. Se NPs also differentially improved RuBP carboxylase and chlorophylls especially some key genes and proteins involving photosynthetic system. Besides, 25–50 μmol/L Se NPs diminished reactive oxygen species overproduction from NADPH oxidases whereas boosted glutathione peroxidase, reducing protein carbonylation in rice seedlings. However, the antioxidant isozymes and oxidatively modified proteins were slightly rebounded at 100 μmol/L. Se contents were noticeably elevated and confirmed to exist as selenomethionine in the rice grains following all the treatments by Se NPs. Thus, the optimal dosage of Se NPs for foliar application is 50 μmol/L, which significantly decreased Cd accumulation, improved photosynthesis and Se enrichment whereas caused no distinct reduction of Pb in the grains. Thus, an appropriate dosage of Se NPs can be conducted to decrease Cd accumulation, improve photosynthesis, and organic Se contents in rice grains.     

中国国土空间规划法律体系：问题检视与框架重构

通过对现行空间规划法律规范的体系性检视,发现由于立法策略、部门立法以及规划立法依附性等原因,其存在顶层立法付之阙如、外部结构冗杂扁平、内部规范碎片冲突等问题。遵循领域法、发展法以及体系化逻辑,国土空间规划立法应以现实问题与治理现代化为导向,在突破部门法壁垒的同时注重法制发展的接续性,力求实现国土空间规划法律体系的形式协调与价值融贯。构建国土空间规划法律体系,对内应确立国土空间规划法的基本法地位并辅之以配套立法,对外应注重与国土空间开发保护法等相关立法、国土空间政策与技术标准的衔接,最终构架起一个主轴明确、层次严密、差序有别的圆锥状国土空间规划法律体系。     

Sulfur deposition simulations over China, Japan, and Korea: a model intercomparison study for abating sulfur emission

In response to increasing trends in sulfur deposition in Northeast Asia, three countries in the region (China, Japan, and Korea) agreed to devise abatement strategies. The concepts of critical loads and source?Creceptor (S?CR) relationships provide guidance for formulating such strategies. Based on the Long-range Transboundary Air Pollutants in Northeast Asia (LTP) project, this study analyzes sulfur deposition data in order to optimize acidic loads over the three countries. The three groups involved in this study carried out a full year (2002) of sulfur deposition modeling over the geographic region spanning the three countries, using three air quality models: MM5-CMAQ, MM5-RAQM, and RAMS-CADM, employed by Chinese, Japanese, and Korean modeling groups, respectively. Each model employed its own meteorological numerical model and model parameters. Only the emission rates for SO₂ and NO_x obtained from the LTP project were the common parameter used in the three models. Three models revealed some bias from dry to wet deposition, particularly the latter because of the bias in annual precipitation. This finding points to the need for further sensitivity tests of the wet removal rates in association with underlying cloud?Cprecipitation physics and parameterizations. Despite this bias, the annual total (dry plus wet) sulfur deposition predicted by the models were surprisingly very similar. The ensemble average annual total deposition was 7,203.6?±?370 kt S with a minimal mean fractional error (MFE) of 8.95?±?5.24?% and a pattern correlation (PC) of 0.89?C0.93 between the models. This exercise revealed that despite rather poor error scores in comparison with observations, these consistent total deposition values across the three models, based on LTP group's input data assumptions, suggest a plausible S?CR relationship that can be applied to the next task of designing cost-effective emission abatement strategies.     

Does functional specialization affect collaborative development? Evidence from four Chinese metropolitan areas

Environmental Science and Pollution Research - The layout of urban spatial functions may play an important role in sustainable regional development. Given the rapid development of urbanization in...     

A novel nano-sized Co3O4@C catalyst derived from Co-MOF template for efficient Hg0 removal at low temperatures with outstanding SO2 resistance

Environmental Science and Pollution Research - Co3O4 is a promising Hg0 removal catalyst for industrial application. Operating temperature and low sulfur resistance are two of the main problems...     

Effects of nanopesticide chlorfenapyr on mice

The effects of chlorfenapyr nano preparation on mice were examined. The animals were administered with different doses of 4.84, 9.68, or 19.36?mg?kg^?1 of chlorfenapyr common preparation or nano preparation intraperitoneally (IP). Micronucleus (MN) test and comet assay (CA) experiments revealed that at the same dose, similar DNA damage in the peripheral blood lymphocytes of the mouse and chromosome damage in bone marrow cells of the mouse occurred with chlorfenapyr nano preparation; however, the severity of these effects was less than that found in common preparation. It is noteworthy that there were no differences in apoptotic ratio and live cell percentage in the liver cells of the mouse between these two pesticide formulations using flow cytometry. Data indicate that chlorfenapyr nanoformulation is less toxic to mouse cells than the common formulation.