ABSTRACT
RESUMEN El objetivo de esta investigación fue establecer el biofloc a tres relaciones carbono/ nitrógeno (C/N): 10/1, 15/1 y 20/1, determinando la secuencia de remoción de N, el perfil de sólidos y la caracterización del zooplancton, para tal fin se dispuso de tres tanques con volumen de 7000 L, incorporando oxígeno al agua a través de un aireador tipo soplador. Se utilizó como fuente de N balanceado, fuente de carbono melaza y bicarbonato de sodio como fuente alcalinizante. Al inicio se incrementó el nitrógeno amoniacal total NAT a 2 mg/L, la alcalinidad total (AT) a 120 mg/L y se adicionó como inóculo 10 litros/tanque de agua proveniente de un estanque de cultivo, al sexto y décimo días se adicionó balanceado incrementando teóricamente el NAT en 4 mg/L y a partir del día 12 en 1 mg/L. En las tres relaciones C/N se evidenciaron procesos de nitrificación durante la estabilización del biofloc, hasta llegar en el tiempo a concentraciones no letales de amonio y nitrito para peces, menores a 1 mg/L. En cuanto a los sólidos volátiles, se encontró una mayor concentración en la relación 20/1, lo cual puede atribuirse a la mayor adición de melaza, con la consecuente producción de SSV a partir de la dominancia de comunidades heterotróficas, en los tres macrocosmos se presentaron comunidades del zooplancton, no obstante, el T2 presentaron la mayor abundancia y riqueza de organismos. Las tres relaciones C/N en biofloc establecieron condiciones de calidad de agua y alimento vivo.
ABSTRACT The objective of this research was to establish the biofloc at three carbon/nitrogen (C/N) relationships: 10/1, 15/1 and 20/1, determining the N removal sequence, the solids profile and the characterization of the zooplankton, for this purpose three tanks with a volume of 7000 L were available, incorporating oxygen into the water through a blower-type aerator. It was used as a source of balanced N, a source of carbon molasses and sodium bicarbonate as an alkalizing source. At the beginning, the total ammoniacal nitrogen NAT was increased to 2 mg/L, the total alkalinity (AT) to 120 mg/L and 10 liters / tank of water from a culture pond was added as inoculum, on the sixth and tenth days it was he added balanced, theoretically increasing the NAT by 4 mg/L and from day 12 by 1 mg/L. In the three C / N relationships, nitrification processes were evidenced during the stabilization of the biofloc, until reaching non-lethal concentrations of ammonium and nitrite for fish, less than 1 mg/L in time. Regarding volatile solids, a higher concentration was found in the 20/1 ratio, which can be attributed to the greater addition of molasses, with the consequent production of SSV from the dominance of heterotrophic communities, in the three macrocosms there were Zooplankton communities, however, T2 presented the highest abundance and richness of organisms. The three C / N relationships in biofloc established conditions of water quality and live food.
ABSTRACT
In Argentina, legislation to control adverse impacts of effluent discharges and the quality of receiving waters is scant and relies mainly on the physicochemical characteristics of the effluents and receiving waters. Objectives of this study were to use standardized acute toxicity tests to assess treatment of petrochemical industry effluents and the toxicity of various treated industrial effluents in the Buenos Aires metropolitan area and their receiving waters. Tests for the first objective used Daphnia magna and Ceriodaphnia dubia; those for the second used D. magna, Spirillum volutans, and Scenedesmus spinosus. Chemical analyses demonstrated that the removal of aromatic hydrocarbon compounds (benzene, toluene, ethylbenzene, xylene, styrene, and naphthalene) from the petrochemical effluents ranged between 77 and 93%, but toxicity removal was significantly lower: untreated effluents were very toxic and treated effluents were very toxic to toxic [acute toxicity units (TUa) > 3]. Physicochemical parameters measured according to current Argentinian regulations indicated that industrial effluents (e.g., from textile and paper industries) were within established guidelines, but 25% of the samples were moderately to highly toxic (TUa > 1.33). However, for the receiving waters, toxicity tests were moderate to very toxic. The results show the need of including tests for toxicity of discharged effluents, and their effects on receiving waters of Argentina, especially for regulatory purposes.
Subject(s)
Environmental Monitoring/methods , Polycyclic Aromatic Hydrocarbons/toxicity , Waste Disposal, Fluid , Animals , Chlorophyta , Daphnia , Quality Control , Spirillum , Toxicity Tests , Water SupplyABSTRACT
Se presentan los primeros resultados de un proyecto de investigación iniciado en el Centro de Ingeniería Sanitaria conjuntamente con el Ente Regulador de Servicios Sanitarios, relacionado con la exigencia de ausencia de zoo y fitoplancton establecidas en las Normas de calidad de agua potable vigentes en la Pcia. de Santa Fe. Se realizaron ensayos de filtración en un filtro piloto, divididos en dos etapas, laboratorio y campo. Los objetivos fueron determinar la influencia de la velocidad de filtración en la remoción de organismos planctónicos y la evaluación del contaje de microorganismos como herramienta de control del proceso de filtración. No es conveniente utilizar velocidades de filtración mayores a 10 m/h. El trabajo tambien se encuentra en la revista ISA 38
