偶氮染料脱色菌Lysinibacillus sp. FS1的脱色性能

从佛山某工业园印染废水处理厂曝气池中,经梯度驯化筛选出一株对多种染料具有较强脱色能力的菌株FS1,通过16S rDNA基因序列分析初步鉴定为Lysinibacillus sp.,研究了该菌株在不同营养条件(氮源、碳源、碳源浓度),不同培养条件(pH、温度、供氧条件),不同染料(甲基橙、亚甲基蓝、中性红、酸性红B)和染料浓度下的脱色性能。结果表明,该菌株的最佳脱色条件:温度30~40℃,pH 7~9,氯化铵1 g/L, 葡萄糖2 g/L的厌氧条件下培养脱色效果最好,10 h时对酸性红B脱色率可达98.73%左右,且脱色过程符合一级反应动力学方程:-ln(At/A0)=0.0588t-0.0448。该菌株可降解多种染料,脱色率均随污染强度的升高先增大后减小,对高浓度染料和混合染料也表现出很好的脱色效果,是一株高效广谱的染料降解菌,具有处理印染废水的开发应用价值。     

Temporal trends of hydrocarbons in sediment cores from the Pearl River Estuary and the northern South China Sea

Concentrations and fluxes of unresolved complex mixture of hydrocarbons (UCM) and polycyclic aromatic hydrocarbons (PAHs) were analyzed for two ²¹⁰Pb dated sediment cores from the Pearl River Estuary (PRE) and the adjacent northern South China Sea (NSCS). Compound-specific stable carbon isotopic compositions of individual n-alkanes were also measured for identification of the hydrocarbon sources. The historical records of PAHs in the NSCS reflected the economic development in the Pearl River Delta during the 20th century. PAHs in the NSCS predominantly derive from combustion of coal and biomass, whereas PAHs in the PRE are a mixture of petrogenic and pyrogenic in origins. The isotopic profiles reveal that the petrogenic hydrocarbons in the PRE originate predominantly from local spillage/leakage of lube oil and crude oils. The accumulation rates of pyrogenic PAHs have significantly increased, whereas UCM accumulation has slightly declined in the NSCS in the recent three decades.     

Titanium dioxide mediated photocatalytic degradation of 17beta-estradiol in aqueous solution

Photocatalytic degradation of 17beta-estradiol (E2) in aqueous medium mediated with titanium dioxide (TiO(2)) was studied. Moreover, effect of TiO(2) dosage on the degradation efficiency was investigated. Particular attention was paid to the identification of intermediates and analysis of photocatalytic degradation mechanism of E2 under neutral and alkaline conditions. The degradation efficiency of E2 increased with increasing concentration of TiO(2) but decreased due to light scattering as TiO(2) concentration was greater than 0.5mgml(-1). Several intermediates were formed during photocatalytic degradation of E2. However, only a few of the compounds could be identified and confirmed by LC-MS and LC-MS/MS. Six intermediates were observed by photocatalytic oxidation under alkaline conditions, namely 2-hydroxyestradiol, 10epsilon-17beta-dihydroxy-1,4-estradien-3-one (DEO), 10epsilon-hydroperoxide-17beta-hydroxy-1,4-estradien-3-one and three kinds of dicarboxylic acids formed by the opening of aromatic ring. In addition to the six intermediates mentioned above, 17beta-hydroxy-1,4-estradien-3-one (EO) was observed under neutral conditions and in the presence of methanol. Based on these intermediates, which were hardly degraded even after E2 was fully degraded, the mechanism of E2 degradation by TiO(2) photocatalysis was elucidated.     

Helping small businesses implement toxics use reduction techniques: dry cleaners, auto shops, and floor finishers assisted in creating safer and healthier work places

The Toxics Use Reduction Institute (TURI), Boston Public Health Commission (BPHC), and Vietnamese American Initiative for Development (Viet-AID) have worked with small business sectors to reduce their use of toxic chemicals. Three cases, described here, in dry cleaning, auto shops and floor finishing share common approaches for creating successful models of effective dissemination of toxics use reduction in small businesses. These include direct business support, peer-to-peer training and promotion of alternatives, and collaborations with stakeholders to achieve greener businesses. These results were achieved despite predictable barriers of lack of resources, suspicion of safer alternatives, and language and cultural barriers.     

Predicting organic contaminant concentrations in sediment porewater using solid-phase microextraction

Because of its cost and time saving features, solid-phase microextraction (SPME) is a leading candidate as a biomimic technique in assessing the bioavailable fraction of hydrophobic organic contaminants (HOCs) in sediment porewater. However, no predictive modeling framework in which to systematically address the effect of key parameters on SPME performance for this application exists. In this study, we derived two governing equations to predict (1) the minimum sediment volume (V(s)min) required to achieve non-depletive conditions, and (2) dissolved phase HOC porewater concentrations (C(pw)) as functions of HOC- and sediment specific characteristics in a conceptual three compartment system. The resulting model predicted that V(s)min was independent of HOC concentrations both in sediment and porewater, but did vary with hydrophobicity (characterized by logK(ow)), the fraction of sediment porewater (f(pw)), and the volume (V(f)) of the SPME sorbent phase. Moreover, the effects of these parameters were minimized (i.e., V(s)min reached plateaus) as logK(ow) approached 4-5. Model predictions of C(pw), a surrogate for SPME-based detection limits in porewater, decreased with increasing sediment volume (V(s)) at low V(s) values, but rapidly leveled off as V(s) increased. A third result suggested that the sediment HOC concentration required for SPME is completely independent of K(ow). These results suggest that relatively small sediment volumes participate in exchange equilibria among sediment, porewater and the SPME fiber, and that large sediment HOC reservoirs are not needed to improve the detection sensitivity of SPME-based porewater samplers. The ultimate utility of this modeling framework will be to assist future experimental designs and help predict in situ bioavailability of sediment-associated HOCs.     

Accumulation pattern of Dechlorane Plus and associated biological effects on rats after 90 d of exposure

Recent studies have indicated that Dechlorane Plus (DP) is widespread in the environments. However, different isomer-specific enrichment pattern of syn-DP and anti-DP was reported in biological samples from the field. In this study, Sprague–Dawley rats were consecutively exposed to commercial DP 25 by gavage for 90 d at different doses (0, 1, 10, and 100 mg kg^?1 d^?1) to investigate the accumulation pattern of syn-DP and anti-DP in liver, muscle, and serum of rats. The possible biological effects of DP on rats were also examined. Results showed that DP preferentially accumulated in the liver rather than in muscle at all exposure levels. No significant stereoselectivity of anti-DP or syn-DP in tissues was observed in the low DP exposure groups (0 and 1 mg kg^?1 d^?1) with f_anti values (defined as the concentration of the anti-DP divided by the sum of concentrations of anti- and syn-DP) ranging from 0.74 to 0.78. However, f_anti values reduced (f_anti ranged from 0.26 to 0.30) significantly in the high DP exposure groups (10 and 100 mg kg^?1 d^?1) and syn-DP was predominant in all tissues. Biochemical parameters in serum, the mRNA expression levels of certain enzymes and their activities in liver were detected. There was no observable-effect in histopathology and death during the experiment, although the mRNA expression levels of some genes in the low dosage group decreased significantly and enzyme activity of CYP 2B2 increased.     

啤酒废水处理技术的生产性应用

高浓度啤酒废水进行厌氧处理后 ,再与低浓度啤酒废水混合进行好氧处理 ,是一条经济合理的技术路线。采用以升流式厌氧污泥床 (UASB)和周期循环活性污泥系统 (CASS)为主的技术处理啤酒废水 ,工程应用表明该工艺技术具有先进实用的明显特征 ,能够有效的处理高浓度啤酒废水 ,处理水质稳定达到啤酒工业废水排放标准     

溶解氧对固定气体流量曝气系统亚硝化特性的影响

通过实时控制系统并结合其他工艺参数的调控,在SBR系统中实现了垃圾渗滤液短程硝化过程的快速启动,并在稳定期考察了固定气体流量曝气系统中溶解氧(DO)对短程硝化的影响。结果表明:在线监测p H的"氨谷"可判断氨氧化反应的终点;采用固定气体流量的曝气方式,使得单周期好氧段后期ρ(DO)高达7.95 mg/L,出水亚硝态氮积累率维持在98.3%左右,氨氮去除率高达96.5%;好氧段后期高溶解氧并没有导致硝化菌(NOB)的再次增长,短程硝化系统稳定。     

污水中易生物降解有机物的测定方法及研究进展

污水中的易生物降解有机物（SS）对生物脱氮除磷过程具有重要意义,也是活性污泥模型中的关键组分。介绍了污水中SS的测定方法,其中好氧呼吸计量法（包括连续OUR法和批式OUR法）和物料平衡法最为常用,而对比发现批式OUR法的测定结果最接近真实值。对文献数据统计表明,城市污水的SS浓度通常为20mg/L-40 mg/L,而工业废水中SS浓度受行业影响很大,SS/COD的波动范围为0.6%-44.0%。     

粉煤灰深度处理制药废水实验研究

Fenton是酸性条件下Fe2+催化H2O2生成强氧化性的.OH,但调节pH的过程中耗费大量的酸和碱,运行费用昂贵,故Photo-Fenton反应受到重视。维生素制药废水生化后含有大量难降解污染物,以低浓度、难生物降解的实际废水为对象进行深度处理实验,研究改性粉煤灰、H2O2及FeSO4.7H2O的投加量,反应时间等因素的影响和优化。