Avaliação de nitrogênio e fósforo dos efluentes tratados dos abatedouros na cidade de Pelotas/RS

The flesh agroindustrial sector is of great economic importance in Rio Grande do Sul, however this activity is also recognized by the high pollution potential. Considering the difficulties to fulfill the stringent nitrogen and phosphorus emission standards, this study aimed to assess the treated effluents of four slaughterhouses of the region of Pelotas/RS, relating them to the emission standards established by CONSEMA Resolution number 128/2006, after four years of the end of the period prescribed by law. All assessed companies fulfill the established discharge standard for phosphorus, but in relation to the KTN parameter, only 50% of the assessed companies fulfilled what is recommended by law, by concentration or by minimum removal efficiency. The results also indicated that two slaughterhouses must continue investing in the effluents treatment system to fulfill the applicable environmental law.

Spectral examination of a multiple-flame photometric detector for use in chromatography

An examination of the emission spectra produced in a novel multiple-flame photometric detector (mFPD) was performed and directly compared to spectra obtained from a conventional single-flame FPD mode. Through monitoring a broad spectral range from 250 to 850 nm, it was found that the mFPD produces sulfur emission predominantly as S2*, but HSO* can also be isolated in the red spectral region. Further, phosphorus emission in the mFPD was found to stem from HPO*, while carbon emission was attributed to CH* and C2*. Finally, background emission in the mFPD was determined to be from OH*. Qualitatively, these finding agree very well with the species found in a conventional single-flame FPD. However, quantitatively, the mFPD spectra consistently produced analyte emission bands that were relatively more intense, by as much as a factor of 3. In contrast with this, hydrocarbon spectra in the mFPD yielded significantly reduced relative intensities, owing to decreased C2* emission. As well, aromatic and aliphatic hydrocarbons produced much more similar distributions of CH* and C2* emission in the mFPD than in the conventional single-flame FPD mode. The results indicate that a relative reduction of C2 radical and an increase of oxidized carbon in the analytical flame of the mFPD could play a central role in the observed quenching-resistant behavior of this detector.

Comparative study of two watershed scale models to calculate diffuse phosphorus pollution

The aim of this study was to compare and assess models having different principles to calculate diffuse phosphorus emissions on a selected watershed. The empirical MONERIS model and the physically based SWAT model were evaluated for comparative purposes. The approaches were applied for a sub-basin of the Hungarian Zala River watershed for five years. The calculated river loads were checked by the measured values at the catchment outlet. Due to the dissimilar results of water balance and erosion calculations, a highly different phosphorus emission was computed. It was also concluded that in the case of transport-limited watersheds, the SWAT model calculates phosphorus river loads slightly inaccurately, since it does not include the description of fate of inorganic phosphorus interacting with sediment during the channel transport. When these processes are taken into account, modeling results fit better the measured loads. The MONERIS model calculates acceptable river load by assuming very intensive in-stream retention. Additionally, the empirical method can be useful for long-term investigations as a decisions support tool for preliminary design. However, for detailed emission assessment and scenario development the physically based approach seems to be more appropriate.