水生生物对碳基纳米材料的物种敏感性分布研究

碳基纳米材料(CNMs)是科学研究中最热门的材料之一,然而CNMs对生态物种具有潜在的毒害作用.为了评估CNMs对生态物种的生态风险,通过广泛查阅,整理与分析了5种CNMs对22种单一水生物种的急性毒性数据,基于均值效应浓度值(EC₅₀)构建物种敏感性分布(SSD)模型,并计算得到5%危害浓度(Hazardous Concentration for 5%of species,HC₅)和潜在影响比例(Potential Affected Fractions,PAF).研究结果发现：富勒烯(C₆₀)、石墨烯纳米片(GN)、氧化石墨烯(GO)、单壁碳纳米管(SWCNTs)、多壁碳纳米管(MWCNTs)的HC₅值分别为1.88、0.37、0.13、1.31、0.74 mg·L^-1,表明二维石墨烯家族材料比零维C₆₀和一维碳纳米管对水生生物表现出更高的生态风险.与5种金属基纳米颗粒物(MNPs)相比,CNMs对水生生物的生态风险低于MNPs.通过对不同暴露浓度下CN...     

A~3/O-MBR工艺反硝化除磷性能研究

为探究自行设计的A~3/O-MBR工艺脱氮除磷性能,以模拟生活污水为处理对象,重点研究了在内循环回流比(γ)为100%,硝化液回流比(α)分别为100%、200%、300%条件下系统反硝化除磷特性。结果表明:缺氧II区是工艺反硝化除磷的关键,系统具有优良的同步脱氮除磷效果,ρ(COD)出水均低于50 mg/L。当回流比为200%时,系统对TN、TP去除效果最好,平均去除率分别为75.46%和88.94%,出水平均ρ(TN)、ρ(TP)分别为14.97 mg/L和0.48 mg/L。通过静态释/吸磷试验测定不同硝化液回流比条件下反硝化聚磷菌占总聚磷菌的比例及污泥含磷量,当回流比为200%时,反硝化聚磷菌所占比例最高达95.47%,该回流比条件下缺氧II区污泥含磷量最高为23.07 mg/L,最大吸磷量为0.2136 g/d。     

聚磷菌与聚糖菌竞争影响因素的研究进展

根据国内外文献的有关报道,综述了在强化生物除磷系统中聚糖菌与聚磷菌相互竞争的有关影响因素,并指出了今后的研究方向。     

Enhanced biological phosphorus removal using thermal alkaline hydrolyzed municipal wastewater biosolids

This study reports the feasibility of using municipal wastewater biosolids as an alternative carbon source for biological phosphorus removal. The biosolids were treated by a lowtemperature, thermal alkaline hydrolysis process patented by Lystek International Inc.(Cambridge, ON, Canada) to produce short-chain volatile fatty acids and other readily biodegradable organics. Two sequencing batch reactors(SBRs) were operated with synthetic volatile fatty acids(Syn VFA) and readily biodegradable organics produced from the alkaline hydrolysis of municipal wastewater biosolids(Lystek) as the carbon source, respectively.Municipal wastewaters with different strengths and COD:N:P ratios were tested in the study. The reactors' performances were compared with respect to nitrogen and phosphorus removal. It was observed that phosphorus removal efficiencies were between 98%–99% and 90%–97% and nitrogen removal efficiencies were 78%–81%, and 67% for the Syn VFA and Lystek, respectively. However, the kinetics for phosphorus release and uptake during the anaerobic and aerobic stages with Lystek were observed to be significantly lower than Syn VFA due to the presence of higher order VFAs(C4 and above) and other fermentable organics in the Lystek.     

Measuring biomass specific ammonium, nitrite and phosphate uptake rates in aerobic granular sludge

Aerobic granular sludge (AGS) technology offers the possibility to remove organic carbon, nitrogen and phosphorus in a single reactor system. The granular structure is stratified in such a way that both aerobic and anaerobic/anoxic layers are present. Since most of the biological processes in AGS systems occur simultaneously, the measurement and estimation of the capacity of specific conversions is complicated compared to suspended biomass. The determination of the activities of different functional groups in aerobic granular sludge allows for identification of the potential metabolic capacity of the sludge and aids to analyze bioreactor performance. It allows for comparison of different sludges and enables improved understanding of the interaction and competition between different metabolic groups of microorganisms. The most appropriate experimental conditions and methods to determine specific ammonium, nitrite and phosphate uptake rates under normal operation of AGS reactors were evaluated and described in this study. Extra biomass characterization experiments determining the maximum uptake rate of these compounds on optimized conditions were performed as well to see how much spare capacity was available. The methodologies proposed may serve as an experimental frame of reference for investigating the metabolic capacities of microbial functional groups in biofilm processes.     

强化生物除磷系统微生物群落结构对水温变化响应的试验研究

在富集聚磷菌(PAOs)且具有较高磷去除率的强化生物除磷(EBPR)系统中,通过对系统水温的控制,研究了EBPR系统微生物群落结构对温度升高和恢复的响应.结果表明,运行温度上升后,EBPR系统除磷效率急速下降.处理水温为25℃和30℃的系统恢复至20℃运行后能够恢复至原始的良好除磷状态,而处理水温为35℃的系统崩溃(磷...     

Effect of nitrification inhibitor DMPP on nitrogen leaching, nitrifying organisms, and enzyme activities in a rice-oilseed rape cropping system

DMPP （3,4-dimethylpyrazole phosphate） has been used to reduce nitrogen （N） loss from leaching or denitrification and to improve N supply in agricultural land. However, its impact on soil nitrifying organisms and enzyme activities involved in N cycling is largely unknown. Therefore, an on-farm experiment, for two years, has been conducted, to elucidate the effects of DMPP on mineral N （NH4^＋- N and NO3^--N） leaching, nitrifying organisms, and denitrifying enzymes in a rice-oilseed rape cropping system. Three treatments including urea alone （UA）, urea ＋ 1% DMPP （DP）, and no fertilizer （CK）, have been carded out. The results showed that DP enhanced the mean NH4^＋-N concentrations by 19.1%-24.3%, but reduced the mean NO3^--N concentrations by 44.9%-56.6% in the leachate, under a two-year rice-rape rotation, compared to the UA treatment. The population of ammonia oxidizing bacteria, the activity of nitrate reductase, and nitrite reductase in the DP treatment decreased about 24.5%-30.9%, 14.9%-43.5%, and 14.7%-31.6%, respectively, as compared to the UA treatment. However, nitrite oxidizing bacteria and hydroxylamine reductase remained almost unaffected by DMPP. It is proposed that DMPP has the potential to either reduce NO3^--N leaching by inhibiting ammonia oxidization or N losses from denitrification, which is in favor of the N conversations in the rice-oilseed rape cropping system.     

细菌粘膜对船体表面污损生物附着的影响

细菌粘膜是一个复杂而又可以控制的生态系，它对海中设施有影响，也和大型污损生物的附着有关。本文研究了防污漆表面细菌粘膜的组成，并利用筛选得到的菌株制成人工细菌粘膜验证其对污损生物的附着影响作用，实验结果得到具有抑制作用和促进作用的菌体。     

Removal of nitrogen and phosphorus in a combined A2/O-BAF system with a short aerobic SRT

A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter （A^2/O-BAF） combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobic sludge retention time （SRT） for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A^2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitdfying phosphate-accumulating organisms （DPAOs）. The ratio of DPAOs to phosphorus accumulating organisms （PAOs） could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A^2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A^2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A^2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent return rates should be controlled with 1--4 mg/L nitrate nitrogen in the anoxic zone effluent of A^2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.     

污水处理过程中聚糖菌的富集培养

研究了通过磷限制条件来达到聚糖菌的选择与富集,同时在驯化过程中还观察到,在第一阶段培养过程中,对除磷效果乙酸比丙酸更加有效。