油管加热炉燃烧及排放特性的研究

随着油田的开发,采油管柱不断地加深,管壁结垢、结蜡和稠油堆积等难清洗的旧油管也在增多。此类油管因得不到清洗修复或修复质量不高而造成浪费和出现质量问题,大大地增加了开发成本。基于此,提出了加热炉燃烧加热清洗的方法来处理其表面的附着物。利用傅立叶红外分析仪(FTIR)和烟气分析仪KM9106等仪器对油管加热炉燃烧及排放特性...     

污泥好氧颗粒化过程中微生物群落结构的演变与分析

为了揭示颗粒污泥形成过程中微生物群落结构多样性的演变过程,以人工配水为进水,在SBR中采用厌氧/好氧循环的手段成功培育出具有聚磷特性的颗粒污泥,利用基于16S rDNA的PCR-DGGE技术获得了微生物群落的DNA特征指纹图谱,对条带进行了统计分析和切胶测序,并建立了系统发育树。结果表明,污泥沉降性能的改善要先于颗粒污...     

Particle-bound Dechlorane Plus and polybrominated diphenyl ethers in ambient air around Shanghai, China

In present study, atmospheric particles from Shanghai, the biggest city and the most important industrial base in China, were analyzed for polybrominated diphenyl ethers (PBDEs) and Dechlorane Plus (DP). Concentrations of ∑(20)PBDEs and DP both exhibited the changing trend of industrial area > urban areas. Jiading District had the highest levels of particulate PBDEs and DP with values of 744 ± 152 pg/m(3) and 5.48 ± 1.28 pg/m(3), respectively. Compared with similar data in other areas of the world, PBDEs in Shanghai were at medium pollution level, while DP was at lower level, which reflected their different production and use in Shanghai. The results from multiple linear regression analysis suggested that deca-BDE mixture was the most important contributor of particulate PBDEs in Shanghai. The fractions of anti-DP showed no significant differences to those of the technical mixtures (p > 0.05), which suggested that no obviously stereoselective process occurred in ambient air around Shanghai.     

Biosynthesis of polyhydroxyalkanoate by Gamma proteobacterium WD-3 from volatile fatty acids

The production of copolymers of poly-β-hydroxyalkanoates (PHA) is generally a high cost process. To reduce the production costs, inexpensive carbon sources such as volatile fatty acids (VFAs) from acidified wastewater can be used. Therefore, isolation of bacterial strains that can produce PHA copolymers using VFAs as a sole carbon source would be a beneficial alternative. In this study, a strain of PHA accumulating bacterium was isolated from the wastewater treatment plant of a soybean processing facility in Harbin. The strain was identified as γ-proteobacterium according to its 16S rDNA information and was originally named as strain WD-3. The strain accumulated a mass of PHA up to 45% of its dry cell weight when it was cultured under the optimum fermentation condition in this study when butyrate was used as the carbon source. In addition, WD-3 could synthesize PHA copolymers of poly-hydroxybutyrate and poly-hydroxyvalerate (PHV) either from C-even substrates or from C-odd substrates, and one-third of the copolymer was PHV. Results from this study demonstrated that small molecule organic acids can be used by the strain of WD-3 as the carbon source for growth and PHA production. The maximum PHA yield in the study was 0.45 g g⁻¹ dry cell.     

T-RFLP detection of nitrifying bacteria in a fluidized bed reactor of achieving simultaneous nitrification-denitrification

Steady simultaneous nitrification-denitrification (SND) was achieved in a fluidized bed reactor (FBR) by the control of DO concentration without physical separation of the aerobic and anoxic zones. The performance and composition of nitrifying bacteria were examined in this study. The ammonium removal efficiency was higher than 80% and the DO concentration (1-5 mg l(-1)) had little influence on it. More than 50% total nitrogen (TN) removal efficiency was achieved when DO was less than 3 mg l(-1) and in many cases the removal efficiency varied between 60-70%. The volumetric loading of TN varied between 0.12 and 0.20 kg Nm(-3)d(-1). 16S rRNA-based terminal restriction fragment length polymorphism analysis was used to characterize the diversity and distribution of the ammonia oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the FBR. The results indicated that, the composition and number of both AOB and NOB changed with position in the reactor and operating time. Nitrosomonas sp. was found to be dominant species of the AOB community, and Nitrobacter sp. also existed in the system. The SND mechanism in the FBR was proved to be the vertical stratification of active populations; however, the presence of microenvironments within the biofilm cannot be ruled out.