Effects of inorganic nutrients on the regrowth of heterotrophic bacteria in drinking water distribution systems

Three laboratory-scale water pipe systems were set up to study the effects of adding three inorganic nutrients (ammonium, nitrate or phosphate) on biofilm formation in water pipes. The results showed that the effects of adding ammonium or nitrate on the biofilm formation were insignificant when levels below 0.1 mg N/l were added. Analogous results were observed when phosphate was added at levels below 0.005 mgP/l. However, as the addition of ammonium increased to 0.5 mgN/l, significant effects on biofilm formation were observed. Similar results were obtained phosphate was added at levels above 0.01 mgP/l. Batch tests were also conducted using water samples collected from a Taiwanese drinking water distribution system. The results indicated that the addition of ammonium, nitrate or phosphate to treatment plant effluent stimulates bacterial growth. In the distributed water of an urban area, the addition of nitrate or phosphate stimulated bacterial growth. The bacterial growth in the distributed water of a suburban area was not stimulated by adding any of these three inorganic nutrients.     

垃圾渗滤液电化学催化氧化法深度处理研究

研究利用电化学催化氧化法深度处理经生物处理后的垃圾渗滤液时，电压、氧化时间、氯离子浓度及温度对有机物降解的影响。试验结果表明：在电压3．5V，电流密度为7．0mA／cm^2．氧化时间2．5h．氯离子的浓度2000mg／L的条件下，垃圾渗滤液的CODCr由464．0mg／L降低到200．0mg／L，NH3^-N的去除率大于95％。     

鱼组织中多环芳烃的测定

研究了鱼体中２－５环多环芳烃的分析方法，方法包括皂化，萃取，氧化铝柱色谱分组、ＳｅｐｈａｄｅｘＬＨ－２０凝胶色谱净化，以及气相色谱和高效液相色谱方法分离测定，其方法对多环芳烃的添加回收率在６０％之间，检测限为０．１ｐｐｂ。应用本方法测定了北京地区两个鱼样体内多环芳烃的含量。     

粉煤灰利用的最佳方式——粉煤灰半钢性路面应用研究

通过对粉煤灰半钢性路面结构研究和技术性能分析,可以证明修路是利用粉煤灰的最佳方式之一,粉煤灰半钢性路面有资源充足、结构合理、技术先进、经济等特点,既节省了投资、延长了道路使用寿命又保护了环境.     

Carbamazepine degradation by heterogeneous activation of peroxymonosulfate with lanthanum cobaltite perovskite: Performance, mechanism and toxicity

The widely used carbamazepine(CBZ) is one of the most persistent pharmaceuticals and suffers insufficient removal efficiency by conventional wastewater treatment.A synthesized Co-based perovskite(LaCoO_3) was used to activate peroxymonosulfate(PMS) in order to degrade CBZ.Results showed that LaCoO_3 exhibited an excellent performance in PMS activation and CBZ degradation at neutral pH,with low cobalt leaching.The results of FT-IR and XPS verified the high structurally and chemically stability of LaCoO_3 in PMS activation.Electron spin resonance(ESR) analysis suggested the generation of radical species,such as sulfate radicals(SO_4·~-) and hydroxyl radicals(·OH).Radical quenching experiments further revealed the responsibility of SO_4·~-as the dominant oxidant for CBZ oxidation.Ten products were detected via the oxidation of CBZ,with the olefinic double bond attacked by SO_4·~-as the initial step.Hydroxylation,hydrolysis,cyclization and dehydration were involved along the transformation of CBZ.The toxicity of CBZ solution was significantly reduced after treating by PMS/LaCoO_3.     

Separating method and dynamic processes of Nano-Al13

In order to investigate the characteristics of pure Nano-Al₁₃, Nano-Al₁₃ was separated and purified from a series of poly-aluminum chloride (PAC) solutions which had the same Al₁₃ percentage but different total Al concentrations, by using column chromatography, ethanol-acetone resolving and SO²⁻ ₄/Ba²⁺ displacement. The Al₁₃ species yield was characterized by Al-ferron timed complexation spectrophotometry and ²⁷Al-NMR (nuclear magnetic resonance). The coagulation efficiency of Nano-Al₁₃, PAC and AlCl₃ in synthetic water was also investigated by Jar tests. The dynamic process and aggregation state of kaolin suspensions coagulating with Nano-Al₁₃, PAC and AlCl₃ were similarly investigated using a photometric dispersion analyzer 2000 (PDA2000). The experimental results indicated that the ethanol-acetone resolving method was simple and could separate the PAC solution at different concentrations, while column chromatography could separate PAC solutions at low concentrations. The SO₄ ²⁻/Ba²⁺ displacement method could separate PAC solutions at high concentrations. However, extra inorganic cation and anion could be added in the solution during separation. The coagulation efficiency and dynamic experimental results showed that Nano-Al₁₃ with high positive-charged species was effective in removing turbidity and color. The dynamic process results showed that Nano-Al₁₃ also had the best recovery capability after shearing compared with PAC and AlCl₃ because the Nano-Al₁₃ conformation is more effective in charge neutralization. Translated from Acta Scientiae Circumstantiae, 2005, 25(6): 767–772 [译自: 环境科学学报]     

漓江风景区环境现状及变化趋势研究

本文根据漓江风景区的水环境、声环境、生态系统和大气环境的现状 ,提出当前存在的主要问题和今后的变化趋势。     

某造纸企业扩建项目环境影响评价工作中清洁生产方案的制定

某造纸企业现有1#～4#生产线在原料储存、工艺技术、设备维护及管理等方面存在较多问题,现拟扩建5#生产线,针对现有工程存在的具体问题及扩建工程原料采用进口木浆的特点,环评制定了1#～4#线集中制浆技改、4#线除渣、1#、4#线节电改造、污水处理站节电改造、可控硅改变频、5#线白水回用等一系列清洁生产方案,并进行可行性分析,给出清洁生产方案实施前后的环境效益对比分析.