Impact of Sewage Effluent Discharges prediction using QUAL2Kw in a sensitive protected area – Portugal

The quality of water, under the influence of the wastewater treatment plant's discharges, makes the simulation of the water parameters a key issue, broadly when considering intermittent rivers. In the case of study, the Pracana reservoir works as an example of the characterization, monitoring, and control of the impact of several, wastewater treatment plant's discharges, directly contributing to water quality. Proença-a-Nova's wastewater treatment plant contributes directly to the Pracana reservoir (Central Portugal), which is a protected field. Twelve georeferenced water samples were gathered, between the sewage discharge and downstream to the Pracana reservoir, at almost equal distances. Sampling campaigns were taken during three different periods: rainy winter (January), intermediate conditions (March) and dry season (June). The following chemical parameters were analyzed: Biochemical Oxygen Demand (BOD5), Dissolved Oxygen (DO), Dry Residue, Ptotal, Ntotal, pH, Temperature, and Microbiological Parameters. DO, BOD5 and Microbiological Parameters served as indicators, for environmental pollution evaluation. A coupled hydrodynamic and water dispersion model, QUAL2kw, was used for water's quality simulation. The results lead to conclude that the water quality is acceptable for multiple purposes, except for human consumption, mainly due to moderate to high values of BOD5.Águas do Centro Enterprise and by the Institute of Earth Sciences (ICT), under contracts UID/GEO/04683/2013 with FCT (the Portuguese Science and Technology Foundation

Effects of wastewater treatment plant’s discharges on a freshwater ecosystem—a case study on the Ramalhoso River (Portugal)

Sewage discharges constitute severe stress in freshwater ecosystems. The Ramalhoso River belongs to the Tagus river watershed and was chosen for a pilot study on the impact of wastewaters discharges in a freshwater ecosystem and its ability for self-depuration. Twelve water samples were collected along the river and were georeferenced. The first point is located upstream of the first discharge point, the second one corresponding to the discharge flow, and all the other samples located downstream of secondary inflows at approximately equal distances. Three sampling campaigns were conducted during the rainy winter (January), the intermediate conditions (March), and the dry season (June). The following chemical parameters were analyzed: Biochemical Oxygen Demand (5), Dissolved Oxygen concentration (DO), Ptotal, Ntotal, pH, temperature, total suspended solids (TSS), microbiological parameters (MP), and flow determination. Dissolved oxygen (DO), biochemical oxygen demand, for 5 days (BOD5), and the total suspended solids were used as indicators of environmental pollution. A coupled hydrodynamic and water dispersion model simulated different pollution scenarios using the QUAL2kw software to construct a water quality model. The simulation results are consistent with field observations and demonstrate that the model has been correctly calibrated, allowing feasibility studies of different treatment schemes and the development of specific monitoring activities.Águas do Centro Enterprise and by the Institute of Earth Sciences (ICT), under contracts UID/GEO/04683/2013 with FCT (Portuguese Science and Technology Foundation

Axion-like particles as ultra high energy cosmic rays?

If Ultra High Energy Cosmic Rays (UHECRs) with E>4 10^{19} eV originate from BL Lacertae at cosmological distances as suggested by recent studies, the absence of the GZK cutoff can not be reconciled with Standard-Model particle properties. Axions would escape the GZK cutoff, but even the coherent conversion and back-conversion between photons and axions in large-scale magnetic fields is not enough to produce the required flux. However, one may construct models of other novel (pseudo)scalar neutral particles with properties that would allow for sufficient rates of particle production in the source and shower production in the atmosphere to explain the observations. As an explicit example for such particles we consider SUSY models with light sgoldstinos.Comment: 5 pages, 2 postscript figures, ref. adde

Clustering in Highest Energy Cosmic Rays: Physics or Statistics?

Directional clustering can be expected in cosmic ray observations due to purely statistical fluctuations for sources distributed randomly in the sky. We develop an analytic approach to estimate the probability of random cluster configurations, and use these results to study the strong potential of the HiRes, Auger, Telescope Array and EUSO/OWL/AirWatch facilities for deciding whether any observed clustering is most likely due to non-random sources.Comment: 19 pages, LaTeX, 3 figure