This communication reports the isolation, purification and characterization of key enzymes involved in dissimilatory sulfate reduction of a sulfate reducing bacterium classified as Desulfovibrio desulfuricans subspecies desulfuricans New Jersey (NCIMB 8313) (Ddd NJ). The chosen strain, originally recovered from a corroding cast iron heat exchanger, was grown in large scale batch cultures. Physico-chemical and spectroscopic studies of the purified enzymes were carried out. These analyses revealed a high degree of similarity between proteins isolated from the DddNJ strain and the homologous proteins obtained from Desulfomicrobium baculatus Norway 4. In view of the results obtained, taxonomic reclassification of Desulfovibrio desulfuricans subspecies desulfuricans New Jersey (NCIMB 8313) into Desulfomicrobium baculatus (New Jersey) is proposed. (C) 1996 Academic Press, Inc.

Owing to the existing or predictable water deficiencies in the South of Portugal, it is necessary to carry out the appropriate management of water resources, by reducing and/or minimizing the negative impacts of untreated/treated domestic effluents in the aquatic environment. As Portugal has a great diversity of ecoclimatic areas, five different stabilization pond systems were chosen to carry out a control study during one year (from March 1991 to March 1992). According to Pina Manique & Albuquerque the ecological classification of these stations is different, varying from Ibero-mediterranean (continental) up to mediterranean (maritime). The physical and chemical parameters studied were: temperature, pH, dissolved oxygen, conductivity, BOD, COD, nitrates, nitrites, ammonia and total nitrogen, total suspended and volatile solids, total phosphorus and orthophosphates. The microbiological parameters studied were: total and faecal coliforms, faecal Streptococci, Clostridium perfringens and Pseudomonas aeruginosa. The correlations between climatic parameters and the efficiency of the removal of organic matter were analysed.

The analytical values obtained from five WSP systems located in different ecoclimatic zones in the centre and South of Portugal, were subjected to a statistical analysis of K and K20 values (as used in the van Hoff-Arrhenius equation) utilizing an analysis of variance and a vectorial analysis of principal components. Significant differences between K and K20 values in facultative, maturation ponds and in the whole system were verified. The projection of the first principal components of eigenvectors made possible the classification of the stations, showing the existence of similarities and discrepancies in their removal BOD kinetics behaviour. The K20 value must be estimated and taken into account for the design of waste stabilization ponds.

Portugal has a great diversity of ecoclimatic areas and Sesimbra was chosen to carry out a study on WSP efficiencies over five years (1989 to 1993). According to Pina Manique & Albuquerque (1954), the climate is classified as Atlantic Mediterranean (AM). Some environmental and climatic parameters have been studied in order to define the area. The treatment system at Sesimbra has three ponds: anaerobic, facultative and maturation. The physical and chemical parameters studied in the WSP system were: Temperature, pH, Dissolved Oxygen, Conductivity, BOD5, COD, nitrates, nitrites, ammonia and total nitrogen, total and volatile suspended solids, total phosphorus and orthophosphates. Algal populations and the following microbiological parameters were studied: total and fecal coliforms, fecal Streptococci, Clostridium perfringens, Pseudomonas aeruginosa and some Enterobacteriaceae. The K and K20 kinetic parameters were studied and derived for the three ponds utilizing the seasonal regional characteristics from the surrounding area. These values were then correlated with temperature and the subsequent removal efficiencies for each pond deduced. The data obtained indicate a necessity to determine the seasonal fluctuations of the K and K20 kinetic parameters for the WSP systems.

Electrical dark conductivity (σd) and surface composition of undoped and doped a-Si:H thin films have been investigated, using coplanar I−V as a function of temperature and Auger electron spectroscopy (AES). The films were prepared by rf glow discharge deposition on standard soda-lime glass and on alkali-free glass substrates. Comparing these two sets of substrates for undoped films, we find that σd of the films deposited on soda-lime glass substrates at room temperature is higher by more than two orders of magnitude, their activation energy is lower by about a factor of 3, and their photosensitivity (σph/σd) is lower by two orders of magnitude than that of the films deposited on alkali-free glass substrates. We suggest that Na ions, leached from the glass into the a-Si:H overlayer play a significant role in determining the film conductivity by creating electrically active donorlike states. This conclusion is supported by similar measurements on p- and n-type a-Si:H films on the same substrates and by AES results. Films of a-Si:H, grown on thin a-Si:C:H interlayers on soda-lime glass, showed very low Na concentrations and low dark conductivities as found by AES and electrical measurements, respectively. The role of the a-Si:C:H interlayers as diffusion barriers is discussed. © 1989, American Vacuum Society. All rights reserved.