RPB-O3/H2O2法处理硝基苯模拟废水

在超重力场中,研究了硝基苯模拟废水的臭氧/双氧水(O3/H2O2)法处理效果,考察了超重力因子β、H2O2浓度、初始p H、液体流量及处理时间等因素对硝基苯去除率的影响。结果表明,硝基苯去除率随超重力因子β和处理时间的增加而增大,而随H2O2浓度、初始p H和液体流量的增加呈先增大后降低的趋势。当硝基苯初始浓度300 mg/L,工艺条件β=80、p H=10.0、臭氧质量浓度约为40 mg/L、H2O2浓度为4.9 mmol/L、液体流量为120 L/h时,循环处理35 min硝基苯去除率可达96.7%。处理时间60 min后,废水中硝基苯含量1.4 mg/L,COD为39 mg/L,达国家一级排放标准(GB 8978-1996)。在此条件下,硝基苯的降解过程符合准一级反应动力学。     

电网发展、清洁电源接入与地区能源效率

鉴于我国已经建成全球规模最大的超高压和特高压电网,彻底弥补了电力跨区配置的电网基础设施短板,并且为清洁电源并入电网和跨区消纳提供了完善的基础设施,不仅克服我国电力负荷中心和能源基地的区域布局不协调,而且有益于缓解日益严峻的能源利用率低下和环境污染问题。本文利用1991—2012年全国29个省市面板数据实证研究了清洁电源并网对地区全要素能源效率的影响。为保证实证结果稳健性分别在线性和非线性实证框架下采用系统广义矩估计(SYS-GMM)和面板平滑转换模型(PSTR)两种方法估计了清洁电源接入高压、超高压和特高压电网的地区全要素能源效率异质性效应。实证结果显示:(1)我国电网基础设施对地区全要素能源效率具有明显的增进效应,特别是超高压电网在促进全要素能源效率提升上表现的最为突出,在特高压骨干网架尚未形成的情况下起到了支柱性作用。(2)高压、超高压、特高压与清洁电源交互项的估计系数始终位于负数区间,反映清洁电源并网的能源效率绩效并不明显,受限于并网规模和机制缺陷,还没有发挥出全要素能源效率提升作用。(3)随着人均GDP的不断提高,各等级电网对地区能源效率的益处越来越明显,并且存在着门槛效应。(4)特高压电网对地区能源效率的积极作用主要表现在东部沿海高收入省份,这些省份作为电力消费负荷中心,大规模接入清洁电源对能源效率改善裨益明显。接下来,需要根据地区的能源禀赋结构选择清洁电源的并网模式,完善的电网基础设施、合理的电源结构还需要配置以高效的清洁电源并网机制才能不断增进地区全要素能源效率。     

Role of illumination intensity in microcystin development using Microcystis aeruginosa as the model algae

Environmental Science and Pollution Research - Microcystis aeruginosa (M. aeruginosa) is one of the most common genera of cyanobacteria in algal blooms. In the present work, the impact of the...     

The influence of Chinese population policy change on resources and the environment

Universal two-child policy has been implemented since the end of 2015 in China. This policy is anticipated to bring a significant increase in the total population, with profound influences on the resources and environment in the future. This paper analyzes the changing dynamics of urban and rural population, and forecasts urban and rural population from 2016 to 2030 at national and provincial scale using a double log linear regression model. Drawing upon the results of these two predictions, the impact of the population policy change on Chinese resources consumption and environmental pollution are predicted quantitatively. Given the future total population maintains current levels on resources consumption and environmental emission, the additional demand of resources and environment demand for the new population is forecasted and compared against the capacity on supply side. The findings are as follows: after implementing the universal two-child policy, China’s grain, energy consumption, domestic water demand, and pollutant emissions are projected to increase at different rates across provinces. To meet the needs arising from future population growth, food and energy self-sufficiency rate will be significantly reduced in the future, while relying more on imports. Stability of the water supply needs to be improved, especially in Beijing, Henan, Jiangsu, Qinghai, and Sichuan where the gap in future domestic water demand is comparatively larger. Environmental protection and associated governing capability are in urgent need of upgrade not least due to the increasing pressure of pollution.     

Metabolic uncoupler, 3,3′,4′,5-tetrachlorosalicylanilide addition for sludge reduction and fouling control in a gravity-driven membrane bioreactor

• Effects of metabolic uncoupler TCS on the performances of GDMBR were evaluated. • Sludge EPS reduced and transformed into dissolved SMP when TCS was added. • Appropriate TCS increased the permeability and reduced cake layer fouling. • High dosage aggravated fouling due to compact cake layer with low bio-activity. The gravity-driven membrane bioreactor (MBR)system is promising for decentralized sewage treatment because of its low energy consumption and maintenance requirements. However, the growing sludge not only increases membrane fouling, but also augments operational complexities (sludge discharge). We added the metabolic uncoupler 3,3′,4′,5-tetrachlorosalicylanilide (TCS) to the system to deal with the mentioned issues. Based on the results, TCS addition effectively decreased sludge ATP and sludge yield (reduced by 50%). Extracellular polymeric substances (EPS; proteins and polysaccharides) decreased with the addition of TCS and were transformed into dissolved soluble microbial products (SMPs) in the bulk solution, leading to the break of sludge flocs into small fragments. Permeability was increased by more than two times, reaching 60–70 L/m²/h bar when 10–30 mg/L TCS were added, because of the reduced suspended sludge and the formation of a thin cake layer with low EPS levels. Resistance analyses confirmed that appropriate dosages of TCS primarily decreased the cake layer and hydraulically reversible resistances. Permeability decreased at high dosage (50 mg/L) due to the release of excess sludge fragments and SMP into the supernatant, with a thin but more compact fouling layer with low bioactivity developing on the membrane surface, causing higher cake layer and pore blocking resistances. Our study provides a fundamental understanding of how a metabolic uncoupler affects the sludge and bio-fouling layers at different dosages, with practical relevance for in situ sludge reduction and membrane fouling alleviation in MBR systems.     

Evaluation of combined developmental neurological toxicity of di (n-butyl) phthalates and lead using immature mice

Environmental Science and Pollution Research - In this study, the immature mice were taken to assess the potential neurological toxicity of lead (Pb) and di (n-butyl) phthalates (DBP) combination...     

铁路职工健康维护工作初探

从健康意识逐渐提高、健康知识不断增加、健康生活方式逐步建立及健康状况有所改善等方面阐述铁路实施健康行动计划后取得的成效,分析健康维护中存在的主要问题,即专业人员不足、服务方式较单一及高血压控制率有待提高,进而提出加强专业队伍建设、引进研发新设备、强化铁路健康教育及深化“四高”联防联控等进一步开展健康维护工作的建议。     

絮团粘性分维数的概念及其分析模型

水处理中的絮团具有复杂的形态结构,分维数是描述这种结构的有力工具。通过分析固液体系的粘度与絮团分维数之间的关系,提出了絮团粘性分维数的新概念及粘性分维数测定的数学物理模型,并进行了实验验证。与常用的质量分维数、边界分维数、面积分维数、体积分维数、表面积分维数等相比,絮团的粘性分维数及其测定模型具有易于测量、可同时表征不同类型絮团、可定量分析絮凝产品组成等特点,从而为絮团形态结构的定性及定量研究开辟了新的途径。     

改性氧化铝微波诱导催化氧化处理高浓度苯酚废水的研究

采用微波诱导催化氧化技术，以改性氧化铝为催化剂，对高浓度模拟苯酚废水进行氧化处理。考察了微波功率、催化剂投加量、H202投加量、废水pH值和微波反应时间等因素对苯酚去除效果的影响。实验结果表明，处理30mL质量浓度为1 100mg/L的苯酚模拟废水，在微波功率500W，催化剂加入量1 g(液固比30∶1)，30％双氧水...     

Heavy metal contamination in a vulnerable mangrove swamp in South China

Concentrations of six heavy metals (Cu, Ni, Zn, Cd, Cr, and Pb) in sediments and fine roots, thick roots, branches, and leaves of six mangrove plant species collected from the Futian mangrove forest, South China were measured. The results show that both the sediments and plants in Futian mangrove ecosystem are moderately contaminated by heavy metals, with the main contaminants being Zn and Cu. All investigated metals showed very similar distribution patterns in the sediments, implying that they had the same anthropogenic source(s). High accumulations of the heavy metals were observed in the root tissues, especially the fine roots, and much lower concentrations in the other organs. This indicates that the roots strongly immobilize the heavy metals and (hence) that mangrove plants possess mechanisms that limit the upward transport of heavy metals and exclude them from sensitive tissues. The growth performance of propagules and 6-month-old seedlings of Bruguiera gymnorhiza in the presence of contaminating Cu and Cd was also examined. The results show that this plant is not sufficiently sensitive to heavy metals after its propagule stage for its regeneration and growth to be significantly affected by heavy metal contamination in the Futian mangrove ecosystem. However, older mangrove seedlings appeared to be more metal-tolerant than the younger seedlings due to their more efficient exclusion mechanism. Thus, the effects of metal contamination on young seedlings should be assessed when evaluating the risks posed by heavy metals in an ecosystem.