Abstract. Urban wastewater treatment plants (WWTPs) as an important engineering facility for urban water pollution prevention and control, the appropriate location selection for the WWTPs is the most important stage in the process of wastewater treatment. Improper site selection can lead to degradation of the water environment. Phnom Penh is located in the delta between the Mekong River and Tonle Sap River, with dense population, and most residents are religious. There are no sufficient and proper WWTPs available in many areas resulting in the environmental degradation and human health issues, so it is used as the study area. In the article, we proposed a new indicator system to select the location for WWTPs. The indicator system is established from RS/GIS data, which integrates social-cultural and multiple others factors, and more comprehensively analyzes the spatial distribution of suitable and demand areas for WWTPs. Finally, the minimize facilities and maximize coverage model are further used for spatial location selection of WWTPs, which can supply scientific plan and technological support for location selection of the WWTPs.

Aeromonas veronii infection of fish has become a significant problem in aquaculture. In this study, pure bacterial cultures were isolated from diseased ornamental fish suffering high mortality rate in China. These fish included zebrafish (Danio rerio), goldfish (Carassius auratus), oscar (Astronotus ocellatus), parrotfish (Amphilophus spp.) and crucian carp (Cyprinus carpio koi). Using morphologic, physiological, and biochemical characteristics and 16S rRNA sequences analysis, nine isolates, namely strains ZG-1, ZG-2, DW-1, DW-2, KL-1, DT-116, LS-912, SJ-1 and SJ-2 were identified as A. veronii. A phylogenetic tree constructed on the basis of 16S rRNA sequences strongly indicated that the isolates were most closely related to the species A. veronii (98.43-100% similarities). The pathogenicity of the isolate was confirmed in zebrafish with median lethal dose (LD50) ranging between 1.15×10 6 CFU/mL and 3.94×10 8 CFU/mL. Antibiotic susceptibility tests showed that the isolated strains were all susceptible to cephalosporins and chloramphenicol. Furthermore, histopathology of zebrafish showed leukocyte infiltration of gill filaments, necrosis of the hepatic cell and glomerulus hemorrhage. These results will provide a scientific reference for the prevention, control, and understanding of the pathogenic mechanism of A. veronii infection in fish. The IJA appears exclusively as a peer-reviewed on-line open-access journal at http://www.siamb.org.il/. To read papers free of charge, please register online at registration form. Sale of IJA papers is strictly forbidden.