Utility of a source-related matrix in basin management studies: a practice on a sub-Basin in Turkey.

According to the water framework directive (WFD), the chemical status should be determined for each water body in a basin through monitoring and evaluation studies, and the gap between the status of water bodies and good water status should be revealed in river basin management plans. In this context, the methodology starting with the evaluation of the monitoring results of the priority substances (PSs) until the end of determining the measures to achieve good condition in surface waters was given in this study. The key aim was to provide a useful methodology defined as a matrix for determining the sources of pollutants that caused this gap. This matrix was applied to the most polluted sub-basin of Küçük Menderes Basin located on the western part of the Turkey. Monitoring studies were carried out in 21 water bodies for a 1-year period for 45 PSs and monitoring results were compared with environmental quality standards (EQS). It was determined that 13 of 45 PSs in 15 water bodies exceeded the EQS. The common PSs in the basin were lead, nickel, fluoranthene, benzo(a)pyrene, C10-13 chloroalkanes, and 4-nonylphenols and average rates of exceeding the EQS were 58.3%, 36.4%, 91.5%, 99.9%, 74.8%, and 49.4%, respectively. The detailed emission inventory of each water body in the basin has been made. Potential sources of PSs were searched via the matrix formed and a total number of 420 basic and supplementary measures were proposed to improve the water quality of the sub-basin.

Comparative analysis of nitrifying bacteria in full-scale oxidation ditch and aerated nitrification biofilter by using fluorescent in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE).

In this study, nitrification performances and composition of nitrifying populations in a full-scale oxidation ditch and a high-rate submerged media nitrification biofilter were comparatively analyzed. In addition to different reactor configurations, effects of differing operational conditions on the nitrification efficiency and bacterial diversity were also explored and evaluated thoroughly. In microbial analysis of sludge samples fluorescent in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE) techniques were used complementary to each other. The extended aeration oxidation ditch subjected to the study is operated as a nitrogen and phosphorus removal system consisting of anaerobic, anoxic, and aerobic zones. The high-rate submerged media aerated filter is operated as nitrification step following the conventional activated sludge unit and the nitrified wastewater is discharged to the sea without complete nitrogen removal. In situ hybridization results have indicated that Nitrosomonas-like ammonia oxidizing and Nitrospira-related nitrite oxidizing bacteria were intensively present in vigorous flocs in nitrification biofilter while carbonaceous bacteria belong to beta subclass of Proteobacteria were considerably dominant in oxidation ditch. Low quantities of nitrifiers in oxidation ditch were also confirmed by the dissimilarity in intensive bands between two systems obtained with DGGE analysis.