The effect of physicochemical, phytoplankton and seasonal factors on faecal indicator bacteria in northern brackish water

The relationships existing between the numbers of coliforms, faecal coliforms, faecal streptococci, C. perfringens, certain physicochemical parameters, phytoplankton, and seasonal factors in an eutrophic northern brackish water were investigated during a period of 1 year. Seasonal fluctuation of the faecal indicator bacteria was noted. A highly significant correlation was found between the non spore-forming faecal indicator bacteria examined. Of the physicochemical parameters examined the pH-value and temperature were found to have the most effect on the number of faecal indicator bacteria but nutrients, especially total nitrogen and nitrate nitrogen were also significant. The lack of correlation between C. perfringens and the other indicator bacteria was found to be related, in part, to the variation in pH. Thus C. perfringens can be considered as a useful indicator in ecosystems having stress factors. The results in this study show that many stress factors affect the number of faecal indicator bacteria. Therefore it is necessary to estimate the quality of water using a combination of several parameters.     

Electrostatic precipitator collection efficiency and trace element emissions from co-combustion of biomass and recovered fuel in fluidized-bed combustion

Particle and trace element emissions from energy production have continuously been subject to tightening regulations. At the same time, not enough is known on the effect of different combustion processes and different fuels and fuel mixtures on the particle characteristics and particle removal device operation. In this investigation, electrostatic precipitator fractional collection efficiency and trace metal emissions were determined experimentally at a 66 MW biomass-fueled bubbling fluidized-bed combustion plant. The measurements were carried out at the inlet and outlet of the two-field electrostatic precipitator (ESP) at the flue gas temperature of 130-150 degrees C. Two fuel mixtures were investigated: biomass fuel containing 70% wood residue and 30% peat and biomass with recovered fuel containing 70% wood residue, 18% peat, and 12% recovered fuel. The particle mass concentration at the ESP inlet was 510-1400 mg/Nm3. Particle emission at the ESP outlet was 2.3-6.4 mg/Nm3. Total ESP collection efficiency was 99.2-99.8%. Collection efficiency had a minimum in particle size range of 0.1-2 microm. In this size range, collection efficiency was 96-97%. The emission of the trace metals As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, Tl, and V was well below the regulation values set by EU directive for waste incineration and co-incineration.     

源自欧洲边缘地区或芬兰背景的建筑

芬兰建筑在国际上获得声誉,主要是因为芬兰建筑师阿尔瓦·阿尔托的成就。阿尔托的重要意义和他对现代主义建筑令人惊叹的影响力都已得到广泛认同。终其职业生涯,阿尔托都活跃在国际建筑舞台上,在德国、意大利和美国等地都能找到他的作品。然而,