Microbial community composition of biofilm developed on zeolite fixed bed anaerobic bioreactor to treat nickel polluted wastewater

The electroplating industry is one of the most important heavy metal sources which discharges and contaminates environmental systems as aquatic and terrestrial since it is using high volumes of water during the process. The high concentrations of nickel in water may cause several damages to animals and humans as gastrointestinal distress, nausea, pulmonary fibrosis and skin dermatitis. Anaerobic wastewater treatment offers an excellent option to remove heavy metals as nickel at the same time that offers the recovery energy advantage of methane production. The aim of this work was to analyze the microbial community composition of a developed biofilm associated to zeolite used as fixed bed the performance efficiency of a lab-scale anaerobic bioreactor zeolite packed for nickel removal treatment from real industrial wastewater. For this propose, a 2L up flow zeolite packed anaerobic bioreactor was constructed and fed with heterotrophic microorganisms as bio-adsorbents, coming from an anaerobic industrial sludge bed. Real industrial wastewater was collected from an electroplate factory located in Hermosillo Sonora Mexico and treated. Nickel removal was performed from 250 ppm to 500 ppm of metal in Ni2+ form, and methane production was also assessed. Physic-chemical analyses as COD, pH (Standard Methods, 1995) methane production and Nickel concentration by atomic absorption analyses (AA) were done as well, scanning electron microscopy (SEM) of microbial biofilm that was colonized the zeolite were performed.?