Volatile fatty acids production from fish wastewater

Abstract

In this work, two experiments were carried out to investigate the production of volatile fatty acids (VFAs) through the anaerobic degradation of a wastewater collected from a fish processing industry. The first experiment was carried out in batches, at different initial pH values (5, 6, 7, 8 and 9). Acetate and propionate were the main products obtained at the end of the experiment. The highest production of VFAs (5276 mg COD/L) was obtained at pH 8. The second experiment was performed in an anaerobic continuous reactor at pH 5.5. Several conditions were tested to improve the VFAs production such as different HRT (18 h, 12 h and 8 h), different feed´s dilution (50 x, 25 x, 10 x, 2 x and 1 x) and different feed´s salinity (2.8 g/L and 20 g/L of salt). The increase of feed´s salinity appear to be the best strategy, since the concentration of VFAs increased (457 mg COD/L with 2,8 mg/L of salt to 788 mg COD/L with 20 mg/L of salt) and the percentage of CH4 in the reactor decreased.

El objetivo del trabajo fue la obtención de ácidos grasos volátiles (AGVs) a través de la degradación anaeróbica incompleta de un efluente procedente de una industria de procesamiento de pescado. Para ello se realizaron dos experimentos: El primero se llevó a cabo en un reactor anaerobio continuo. Durante el experimento se fueron variando distintos parámetros de operación: tiempo hidráulico de retención (TRH), dilución de la alimentación y salinidad de la misma, para encontrar las mejores condiciones para la producción de AGVs. El segundo experimento se llevó a cabo en ensayos por lotes a diferentes valores de pH: 5, 6, 7, 8 y 9. De esta forma se estudio cómo afectaban los distintos pHs a la producción de AGVs.