Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

This article present an analysis of the effects that can be generated in a culture medium of algae chlorophytes if concentrations of phosphate, nitrite, nitrate and ammonium wastewater where they are generated, present variations. This study was developed with residual water from the outlet of trickling filter of treatment plant of the Universidad de San Carlos de Guatemala, located in zone 12 of Guatemala City. This plant was selected because it has typical wastewater of domestic origin characteristics, and previous studies was found to be viable crop development chlorophytes algae in water from its trickling filters. For the development of the study was necessary to change the original nutrient concentrations as follows: a) phosphate from 204.00 to 19.00 mg / l; b) ammonium 17.50-1.00 mg / l; c) Nitrate 114.00-76.00 mg / l; and d) nitrite 1.55-0.10 mg / l. These maximum and minimum values a factorial experimental design with the aim of determining the effect of variations in the initial concentration of nutrients relative to the final concentration thereof was applied. The results showed that in the middle of chlorophyte algae no effective absorption of phosphates, nitrates, ammonium and nitrites when ammonium is present in high concentration, the phosphate in low concentration, the nitrate maximum concentration and nitrite maximum concentration, giving values 19.00 phosphate to 7.08 mg / l, 17.50 to 8.94 ammonium mg / l, nitrates 116.00 to 60.16 mg / l, nitrite 0.10 to 1.55 mg/l. An important aspect observed during the research was that in combinations where the ammonia is in a low concentration and phosphate in concentration no absorption ammonium by the means of chlorophyte algae as a negative effect was obtained having an increased maximum ammonium 1.00 to 2.33 mg / l. Finally it was determined that the effect of the maximum and minimum concentrations of nitrite have no impact in terms of the absorption of nutrients in the medium of algae chlorophytes.

This article presents the evaluation of the turbidity and water color removal efficiency by using a natural coagulant based seed tamarind (Tamarindus indica), so that can be replaced the aluminum sulfate on coagulation-flocculation processes and thereby to have an efficient, economical alternative and that did not affect to the environment. This research was developed at the Laboratory Unified of Chemical and Microbiology Sanitary “Dr. Alba Tabarini Molina” of the University of San Carlos Of Guatemala; assays to samples were performed on a laboratory scale, with tap water, which were modified with kaolin to obtain the required turbidity and color values, in order to have similar characteristics to water prior to be treated in a treatment plant. Results showed the efficiency of the coagulant in obtaining turbidity removal percentages after coagulation- flocculation up to 94.3% (7.9 NTU); and up to 99.9% (0.4 NTU) after filtration. The color was placed after the coagulation-flocculation processes between 18.2 and 207.2 CU and after filtering 0.2 to 14.5 CU. Reaching average values of turbidity of 1.68 NTU and 4.4 UC at the end of the filtering process, which fulfills the standards of water quality for both Honduras and Guatemala of turbidity an color; so the use of seeds of tamarind as natural coagulant is an efficient alternative, which does not affect the environment and can be used in the water purification replacing chemicals such as aluminum sulfate.

When comparing the use of methods: alternating blocks and historical hyetograph, for the selectionl of design storms and flows in the basin of the Chiquito River, the difference between them is significant in the distribution and amount of precipitation. But there are some historical hyetographs, whose distribution and peak flows are similar to the distribution method of alternate blocks. The hyetographs presenting this similarity are the storms: August 8, 2001, October 23, 2006, May 24, 2011. The year 2011 is the most similar storm in all aspects with the generated by alternating blocks, precipitation generated by both methods is 103.1 mm and 123.7 mm, and peak flow at about 500 and 540 m3/s, respectively, for a return period 100 years. Method of alternating blocks is applicable within the Chiquito River basin for design storms, because, some storms have been found with similar distribution, such as 2001, 2006 and 2011, presented in this article. In the comparison of 7 scenarios of distribution, the historical hyetograph generated less precipitation than the method of alternating blocks with percentages in the range of 41 to 83%. However, in 2 stages of distribution, the method of historical hyetograph presented a higher rainfall that generated by the method of alternating blocks with percentages about 135 to 145%, respectively.

Nutrient removal in the wastewater, has been of interest due to the effects caused when it is present in high concentrations, so this article focuses on assessing nutrient removal. It analyzed the parameters of nitrate (NO3-N), ammonia nitrogen (NH3-N) and phosphate (PO43-) of wastewater, from efluent of the trickling filter module of the plant wastewater treatment University of San Carlos, these parameters were evaluated on the day of the sampling and the day increased presence of algae naturally generated. The research was conducted with 10 samples that allow a confidence level of 95% in the results, maximum growth of algae was identified, This result as a parameter of measuri the true color, during 14 days of observation, it was determined that the seventh day, from sampling, the highest value of true color units (UD) is presented increase of 5 UD to 40 UD. The average value of ammoniacal nitrogen (NH3-N) decreases from 1.15 mg /l to 0.42 mg/l equivalent to a reduction of 63.3%, nitrate (NO3-N) of 344.3 mg/l to 415.8 mg/l equivalent to a 20.8% increase and phosphate (PO43-) of 18.27 mg/l to 13.72 mg/l equivalent to a reduction of 24.9%. With the objective to determine what happens to the nitrogen cycle, nitrite (NO2--N) is evaluated, resulting in an increase of 5.9 times the initial average value of 0.2 mg/l to 1.4 mg/l, confirming that the removal process is performed nitrogen cycle.

Nutrient removal in wastewater has become in recent years a topic of wide discussion in the scientific community, due to the impacts posed to water resources in contact with high levels of nutrients. A lot of water resources are exposed to accelerated eutrophication processes, one of the main causes for it are the discharges of wastewater. This situation has prompted several researchers to develop technologies for nutrient removal, one of these is the use of chlorophyte algae. Several studies, have had favorable results in the laboratory by inoculating different species of chlorophyte algae, therefore it is important to establish whether is possible or not that residual water from trickling filters can promptly develop chlorophyte algae naturally (without inoculation) and determine the biomass that can be generated in this type of application. The study achieved favorable results in identifying chlorophytes algae developed naturally (in natural conditions of lighting and temperature), obtaining an average production of chlorophytes algae ranging between 481 and 13,718 cells per milliliter. During the study, it was possible to identify two species of algae Scenedesmus sp., and Chlorella sp., which in studies conducted by (Mahapatra, Chanakya, & Ramahandra, 2013) , have reached acceptable efficiencies in nutrient removal. This study opens the possibility to develop appropriate technologies for Central American countries, for using biological process with chlorophytes algae in wastewater for nutrient removal in a third degree stage.

The percentages of removal between a prototype of gravel and soil and other with a pet and soil are analyzed, where it is shown that the difference does not exceed 5%, so that replacing the gravel material by pet may become an option for the Treatment of domestic wastewater without affecting the performance that allows the reduction of contaminants. The system consists of a primary treatment and 2 prototypes as secondary treatment, at a depth of 1.5 meters the removal efficiency was 95% in the parameters of: total suspended solids, color, biochemical oxygen demand to five days and Chemical Oxygen demand. The reduction of these pollutants reached a concentration lower than that established in Acuerdo Gubernativo 236-2006 "Reglamento de las descargas y reuso de aguas residuales y de la disposición de lodos". However, parameters such as nitrogen, total phosphorus and fecal coliforms reduced in 4 logarithmic cycles do not exceed 85% of removal in both prototypes, and therefore do not comply with the mentioned Guatemalan legislation.

Review of Pablo Sutherland.

Tem-se por objetivo neste texto apresentar uma possibilidade de leitura da obra Contos de enganar a morte (2003), de Ricardo Azevedo, na qual se considera o papel do leitor e da linguagem híbrida, resultante da junção de dois discursos: o literário e o da tradição popular. Para a consecução do objetivo, pretende-se apresentar uma reflexão fundamentada pela estética da recepção acerca do que propicia o prazer na leitura e quais elementos determinam o papel do leitor implícito. Constrói-se, neste texto, a hipótese de que a estratégia do escritor em resgatar a cultura, pela apresentação de contos breves e cômicos, retirados do imaginário popular, tanto permite ao seu leitor contato com um texto atraente e lúdico, quanto lhe faculta a ampliação de conhecimentos e de conceitos prévios, por meio do emprego da memória. Norteia a análise dessa obra,a concepção de que a leitura literária pode atuar como fator de valoração da identidade do jovem leitor, pois por meio dela, ele é capaz de elevar sua autoestima, pois se reconhece como herdeiro de um patrimônio cultural, além de servir como instrumento de reflexão acerca de questões que inquietam e amedrontam a criança, como a morte. Justamente, por isso, o texto literário atua como instrumento de emancipação pessoal e de formação do leitor.

Neste traballo realizaremos un achegamento crítico no que pretendemos cuestionar a realidade literaria que se lle presenta ao alumnado sobre o tema, así como a visión parcial do corpus ao que se dá acollida nos manuais de distintas editoriais empregadas no sistema educativo galego.