基于生态位测度的关键种企业作用前提研究

关键种企业是企业群落内开展废料、副产品交换等工业共生活动所不可或缺的重要动力,本文借助"生物生态位"理论对典型企业群落的企业生态位进行了测度,并据此对群落内的关键种企业进行了识别.另外,采用"物种生态关联度"计算方法对典型企业群落的生态、产业关联度进行了测算.在获得上述两个指标数据的基础上,结合典型企业群落中产业类型数量、产业链数量、工业食物链数量等统计数据,分别对生态关联度--企业生态位、产业关联度--生态关联度、企业类数--生态关联度等两两因素闻的作用关系进行了相关性研究.研究发现:企业群落的生态关联度决定了工业共生体的规模及稳定性,而在历史与现实的各类诱因下,生态关联效应的形成却表现出较强的偶然性.本研究结论对于认识生态工业发展的本质面貌、制定合理的生态产业政策具有重要的启示作用.     

农村环境问题及其对策

通过对农村环境问题的阐述并对这些问题产生的原因进行分析,提出农村环境问题的解决方法及对策建议。     

我国纺织噪声暴露现状及听力损失情况预测

通过对国内纺织业从业人员数量、工龄的统计和企业实地噪声情况的调查,借鉴ISO1999—1975（E）和其它相关方法预测我国纺织行业噪声暴露情况和从业人员的听力损失情况。经过预测,结果显示纺织从业人员暴露于85dB以下噪声的约有289．3万人,85～95dB约有381．2万人,高于95dB约有329．5万人;对于听力损失的预测,采用悲观和乐观法分别进行预测,结果表明约有100．57万人和21．61万人患有听力损失;结合实际调研情况对预测数据进行修正,结果表明目前我国纺织行业约有70．96万人患有听力损失。     

护听器选择方法研究

简要介绍了护听器选择原则和一般要求,比较了评价护听器声衰减性能和选择护听器的常用方法,结合我国国情,给出了选择护听器的建议。     

改进型曝气生物滤池对生活污水氮去除的影响

采用下向流中部曝气的运行方式,对生活污水进行了处理,考察了气水比、有机负荷对生物滤池的去除效果及其沿程生化特性。结果表明:水力停留时间为8 h,气水比为10∶1条件下可获得最佳的处理效果,COD、TN和NH4+-N的平均去除率分别为92.5%、48.6%和69.4%。进水有机负荷增加,COD和NH4+-N的去除率下降,TN的去除率可达60.5%。结合理论分析,对脱氮性能进行了探讨。     

Occurrence, compositional patterns, and possible sources of polybrominated diphenyl ethers in agricultural soil of Shanghai, China

The present study analyzed surface soil collected from agricultural region of Shanghai to determine the occurrence, compositional patterns and possible sources of polybrominated diphenyl ethers (PBDEs). The results showed that 32 PBDEs were detected among 44 target PBDEs. Total PBDE concentrations ranged from 129 to 1245 ng kg⁻¹ with a mean of 429 ng kg⁻¹. BDE209 was the predominant congener in a range of 33.2-796 ng kg⁻¹ with a mean of 254 ng kg⁻¹. Meanwhile, BDE47, BDE49, BDE153, BDE190, and BDE99 have the most abundant with high concentrations and detectable frequencies. PBDE congeners and homologues analysis and principal component analysis (PCA) also revealed that the major source of PBDE in the soil samples was associated with the prevalent use of technical decabromodiphenyl ether (Deca-BDE) and pentabromodiphenyl ether (Penta-BDE). The correlation analysis proved that there was a significant correlation between total organic carbon (TOC) and lower brominated PBDEs, indicating the significant diffuse nature of the sources of these congeners.     

Arsenic desorption from ferric and manganese binary oxide by competitive anions: significance of pH

Ferric and manganese binary oxide (FMBO) has been used to remediate an arsenic (As)-polluted river in China, but insufficient data was available to (1) evaluate its effects on the environment and (2) propose a feasible strategy of addressing the arsenic-bearing FMBO. The desorption behavior of arsenic in the presence of four competitive anions (i.e., phosphate, silicate, sulfate, and bicarbonate) at different concentrations was investigated with pH ranging from 3 to 11. The presence of these anions promoted the desorption of arsenic from arsenic-bearing FMBO and followed the sequence of phosphate > silicate > sulfate approximately equal to bicarbonate across a wide pH range. Desorption of arsenate (As[V]) was more significant than that of arsenite (As[III]). Sequence dissolution of arsenic-bearing FMBO particles by NH4-oxalate/oxalic acid and hydrochloric acid were performed. The laboratory results indicated that As(III) was primarily occluded in the crystalline parts of the FMBO. The desorption behavior of arsenic could be described by kinetic models using the Elovich and power function equations under different pH conditions and was related to the adsorption of phosphate and silicate. pH played an important role in the desorption of arsenic, because of its effects on the species distribution of anions, surface charge of the arsenic-bearing FMBO, and subsequent electrostatic forces between anions and FMBO.     

The role of Mn oxide doping in phosphate removal by Al-based bimetal oxides: adsorption behaviors and mechanisms

This study investigated the behaviors and mechanisms of phosphate adsorbed onto manganese (Mn) oxide-doped aluminum (Al) oxide (MODAO). The isotherm results demonstrated that the maximum amount of phosphorus (P) adsorbed onto MODAO was 59.8 mg/g at T?=?298 K (pH 6.0). This value was nearly twice the amount of singular AlOOH and could increase with rising temperatures. The kinetic results illustrated that most of the P was adsorbed onto MODAO within 5 h, which was shorter than the equilibrium time of phosphate adsorption onto AlOOH. The Elovich model effectively described the adsorption kinetic data of MODAO because of its heterogeneous surface. The optimal solution pH for phosphate removal was approximately 5.0 because of electrostatic interaction effects. Meanwhile, the decrease in P uptake with increasing ion strength suggested that phosphate adsorption occurred through an outer-sphere complex. Phosphates would compete for adsorption sites on the surface of MODAO in the presence of fluoride ion or sulfate. In addition, the spectroscopic analysis results of Fourier transform infrared spectroscopy and X-ray photoemission spectroscopy indicated that removal mechanisms of phosphate primarily include adhesion to surface hydroxyl groups and ligand exchange.     

Temperature influence on biological phosphorus removal induced by aerobic/extended-idle regime

Previous researches have demonstrated that biological phosphorus removal (BPR) from wastewater could be driven by the aerobic/extended-idle (A/EI) regime. This study further investigated temperature effects on phosphorus removal performance in six A/EI sequencing batch reactors (SBRs) operated at temperatures ranging from 5 to 30 °C. The results showed that phosphorus removal efficiency increased with temperature increasing from 5 to 20 °C but slightly decreased when temperature continually increased to 30 °C. The highest phosphorus removal rate of 97.1 % was obtained at 20 °C. The biomass cultured at 20 °C contained more polyphosphate accumulating organisms (PAO) and less glycogen accumulating organisms (GAO) than that cultured at any other temperatures investigated. The mechanism studies revealed that temperature affected the transformations of glycogen and polyhydroxyalkanoates, and the activities of exopolyphosphatase and polyphosphate kinase activities. In addition, phosphorus removal performances of the A/EI and traditional anaerobic/oxic (A/O) SBRs were compared at 5 and 20 °C, respectively. The results showed the A/EI regime drove better phosphorus removal than the A/O regime at both 5 and 20 °C, and more PAO and less GAO abundances in the biomass might be the principal reason for the higher BPR in the A/EI SBRs as compared with the A/O SBRs.     

Enhancement of nitric oxide decomposition efficiency achieved with lanthanum-based perovskite-type catalyst

Direct decompositions of nitric oxide (NO) by La_0.7Ce_0.3SrNiO₄, La_0.4Ba_0.4Ce_0.2SrNiO₄, and Pr_0.4Ba_0.4Ce_0.2SrNiO₄ are experimentally investigated, and the catalysts are tested with different operating parameters to evaluate their activities. Experimental results indicate that the physical and chemical properties of La_0.7Ce_0.3SrNiO₄ are significantly improved by doping with Ba and partial substitution with Pr. NO decomposition efficiencies achieved with La_0.4Ba_0.4Ce_0.2SrNiO₄ and Pr_0.4Ba_0.4Ce_0.2SrNiO₄ are 32% and 68%, respectively, at 400 °C with He as carrier gas. As the temperature is increased to 600 °C, NO decomposition efficiencies achieved with La_0.4Ba_0.4Ce_0.2SrNiO₄ and Pr_0.4Ba_0.4Ce_0.2SrNiO₄, respectively, reach 100% with the inlet NO concentration of 1000 ppm while the space velocity is fixed at 8000 hr^?1. Effects of O₂, H₂O_(g), and CO₂ contents and space velocity on NO decomposition are also explored. The results indicate that NO decomposition efficiencies achieved with La_0.4Ba_0.4Ce_0.2SrNiO₄ and Pr_0.4Ba_0.4Ce_0.2SrNiO₄, respectively, are slightly reduced as space velocity is increased from 8000 to 20,000 hr^?1 at 500 °C. In addition, the activities of both catalysts (La_0.4Ba_0.4Ce_0.2SrNiO₄ and Pr_0.4Ba_0.4Ce_0.2SrNiO₄) for NO decomposition are slightly reduced in the presence of 5% O₂, 5% CO₂, or 5% H₂O_(g). For durability test, with the space velocity of 8000 hr^?1 and operating temperature of 600 °C, high N₂ yield is maintained throughout the durability test of 60 hr, revealing the long-term stability of Pr_0.4Ba_0.4Ce_0.2SrNiO₄ for NO decomposition. Overall, Pr_0.4Ba_0.4Ce_0.2SrNiO₄ shows good catalytic activity for NO decomposition.

Implications: Nitrous oxide (NO) not only causes adverse environmental effects such as acid rain, photochemical smog, and deterioration of visibility and water quality, but also harms human lungs and respiratory system. Pervoskite-type catalysts, including La_0.7Ce_0.3SrNiO₄, La_0.4Ba_0.4Ce_0.2SrNiO₄, and Pr_0.4Ba_0.4Ce_0.2SrNiO₄, are applied for direct NO decomposition. The results show that NO decomposition can be enhanced as La_0.7Ce_0.3SrNiO₄ is substituted with Ba and/or Pr. At 600 °C, NO decomposition efficiencies achieved with La_0.4Ba_0.4Ce_0.2SrNiO₄ and Pr_0.4Ba_0.4Ce_0.2SrNiO₄ reach 100%, demonstrating high activity and good potential for direct NO decomposition. Effects of O₂, H₂O_(g), and CO₂ contents on catalytic activities are also evaluated and discussed.