复合工艺在城市污水处理厂改造中的应用

水污染控制的主要任务是有机物的降解和氮磷的去除。我国现有污水处理厂大多采用传统活性污泥法 ,对于氮、磷的去除往往不能达到新实施的《城镇污水处理厂污染物排放标准 (GB18918- 2 0 0 2 )》的要求。而生物膜、活性污泥复合工艺为我国城市污水处理厂的扩建和改造提供了一条经济、高效的途径。     

The application of a mulch biofilm barrier for surfactant enhanced polycyclic aromatic hydrocarbon bioremediation

Lab scale mulch biofilm barriers were constructed and tested to evaluate their performance for preventing the migration of aqueous and surfactant solubilized PAHs. The spatial distribution of viable PAH degrader populations and resultant biofilm formation were also monitored to evaluate the performance of the biobarrier and the prolonged surfactant effect on the PAH degrading microorganism consortia in the biobarrier. Sorption and biodegradation of PAHs resulted in stable operation of the system for dissolved phenanthrene and pyrene during 150 days of experimentation. The nonionic surfactant could increase the solubility of phenanthrene and pyrene significantly. However, the biobarrier itself couldn't totally prevent the migration of micellar solubilized phenanthrene and pyrene. The presence of surfactant and the resultant highly increased phenanthrene or pyrene concentration didn't appear to cause toxic effects on the attached biofilm in the biobarrier. However, the presence of surfactant did change the structural composition of the biofilm.     

Effects of low concentrations of the phenylurea herbicide diuron on biofilm algae and bacteria

A system of recirculating channels was used in this study to examine the long-term effects (29 d) of environmentally realistic concentrations of the herbicide diuron (from 0.07 to 7 μg L⁻¹) on biofilm communities. The autotrophic activity of biofilms was affected by this herbicide, as reflected by a marked decrease in the photosynthetic efficiency. Diuron exposure also increased chlorophyll-a content and reduced the biovolume of diatom taxa at low concentrations. The effects on bacteria were also remarkable. Bacterial abundance was reduced after a week of exposure to the herbicide at a range of concentrations. Effects were on the number of live bacteria and on the increase in the leucine-aminopeptidase activity. It is suggested that inputs of herbicides to the river ecosystem at low concentrations may cause a chain of effects in the biofilm, which include inhibitory effects on algae but also indirect effects on the relationships between biofilm components.     

Degradation of MTBE and TBA by a new isolate from MTBE-contaminated soil

Methyl ten-butyl ether （MTBE）, a gasoline additive, possesses serious problems to the environmental health. In the present study, a bacterial culture named A-3 which could effectively degrade MTBE was isolated from the MTBE contaminated soil. The isolate was identified as Chryseobacterium sp., a new species capable of degrading MTBE. In order to enhance its degradation ability, selected environment factors were investigated. The results showed that the optimal temperature was in the range of 25-30℃, the pH was 7.0, the inoculum size was 2 × 10^8 CFU/ml and the optimal concentration of MTBE was from 50 to 100 mg/L. The maximum MTBE utilization rate （Vmax） was 102 nmol MTBE/（mg cell protein.h）. Furthermore, it was found that the isolate could also degrade tert-butyl alcohol （TBA）. The degradation rates of TBA were much faster than those of MTBE. The additional TBA would lead to the decrease of the initial MTBE degradation rate and the inhibitory effect of TBA increased with the increase of TBA concentration. Similar protein profiles at least seven peptides were demonstrated after SDS-PAGE analysis of crude extracts obtained from the cells growing in MTBE and TBA culture.     

生物填料在重污染河道治理中的应用研究

将生物填料应用于城市重污染河道治理,研究了随时间的推移,填料垂直方向上生物膜的膜量、膜组成、膜活性变化规律以及生物填料对水质的改善效果.试验结果表明,该生物填料生物膜活性以比基质耗氧速率表示为0.153～0.174 mg/(g·h) .在挂膜进行到第40天、悬挂密度为24根/m2 时,对水质改善达到最佳效果,对TN、TP、COD、Chla、浊度的去除率分别为53%、35%、50%、5%、44%.     

东北地区玉米低温冷害综合指标研究

在以往对低温冷害指标研究的基础上，将低温冷害成分不同的发育阶段进行分析，结合发育期日数和初霜日研究等，讨论分析了东北地区玉米的低温冷害问题，提出一个玉米低温冷害综合指标。该指标生物学和农学意义明确，计算较为方便，便于在预报上的应用。     

外循环三相流化床污水处理特性的研究

采用三相外循环生物流化床处理生活污水。该设备包含好氧区和缺氧区,可获得足够的停留时间造成缺氧条件,能保证有效去除NH3—N。实验在室温下进行,进水条件pH为7～8,CODCr为286-656mg／L,NH3-N为10～51mg／L。结果显示,控制水力停留时间在3h为宜,最佳通气量为0．09m^3／h,此时CODc和NH3-N的去除率分别达91％和96．6％,有较好的处理效果。同时实验确定了最佳膜厚为145μm。     

Monitoring biofouling based on aerobic respiration in reverse osmosis system

A monitoring method of biofouling in reverse osmosis (RO) system was proposed based on the fluorescent signal of resorufin, which is reduced by nicotinamide adenine dinucleotide released from viable cells during aerobic respiration. The fluorescent signal of resorufin reduced by planktonic cells and microorganisms of biofilm showed linearity, indicating its feasibility to monitor biofouling in a RO system. For the application of the method to the lab-scale RO system, the injection concentration of resazurin and the injection flow rate were optimized. Biofilm on RO membranes continuously operated in a lab-scale RO system was estimated by resorufin fluorescence under optimized detection condition. As a result, resorufin fluorescence on RO membrane showed a significant increase in which the permeability of RO system decreased by 30.48%. Moreover, it represented the development of biofilm as much as conventional biofilm parameters such as adenosine triphosphate, extracellular polymeric substances, and biofilm thickness. The proposed method could be used as a sensitive and low-cost technology to monitor biofouling without autopsy of membranes.     

接触氧化池改造

对污水站处理的核心工艺接触氧化池存在的问题进行了分析,通过分析找出四个方面的问题,针对四个问题,通过小型试验,模拟工艺,分甲乙两组进行试验,时试验数据及现象进行比较分析,找到解决的办法,结合《生物接触氧化池设计规程》的相关要求,进而对接触氧化池从填料、排泥、曝气方式、出水方式四个方面进行了改造,改造后运行实践表明,生物膜上微生物种类繁多,代谢正常,池面曝气均匀,排水设施均匀出水,杜绝了污泥厌氧现象,处理效果良好．运行稳定。     

南方稻区季节性干旱农户适应行为及其影响因素实证分析

气候异常给我国粮食生产带来的影响成为当前社会各界关注的焦点。受全球气候变暖影响,大范围持续性干旱成为农业生产的最严重威胁,特别是近年来南方稻区季节性干旱问题日趋严重,已严重危害到我国经济社会的和谐健康发展。因此,如何适应季节性干旱已成为当前全社会普遍关注的话题,农户作为农业生产的微观决策主体,其适应季节性干旱行为选择如何,其影响因素有哪些?此问题的解决是实现科学减灾的前提和基础。因此,论文利用南方稻区江西省41个县755份农户调查样本数据,从理论与实证上分析了季节性干旱农户适应行为及其影响因素,统计结果表明：面对季节性干旱时,68.6%的农户会采取相应的适应行为,并且补种（苗）、改种其他作物、调整播种和收获日期是农户最优先考虑采用的适应措施,而资金和劳力是农户采取适应行为措施最主要的限制因素。利用Probit回归模型、Poisson回归模型和Tobit回归模型实证分析了季节性干旱农户适应行为措施选择、采用规模和采用强度的影响因素,计量结果表明：社区资本、干旱发生频率、防灾信息的可获性等因素对农户适应行为采用意愿、规模和强度有正向影响,而所在村距最近公路远近和所处的地形特征对农户适应行为采用意愿、规模和强度有负向影响。因此,需要进一步丰富社区资本、加强农户防灾信息可获性以及加强交通基础设施建设等方面以促进农户采纳适应措施的积极性。