Screening of trace metal supplementation for black water anaerobic digestion

37 Páginas; 3 Figuras; 7 TablasCommunity on-site separation of wastewater is a treatment approach that leads to more efficient processes. Black water has high organic matter content and can be a suitable feedstock for anaerobic treatment systems. Biological methane production (BMP) tests were conducted using Plackett-Burman design to screen the effects of adding Fe, Ni, Cu, Co, Mn, Ba and Se, with simulated black water (SBW) as the substrate. In the inoculum, most metals were found mainly in the organic matter/sulfide and residual fractions except for Mn, which was present at 12.3% in the bioavailable fractions (exchangeable and carbonates), and Ba, which was evenly distributed among all the fractions. Ba had a significant negative effect on methane production and Mn addition enhanced the toxic effect. A specific methanogenic activity (SMA) between 18% and 27% lower than the control, was predicted at a total Ba concentration of approximately 1000-1200 mg L-1. Similar SMA was predicted at Ba concentration between 400 and 600 mg L-1 when 0.55 mg L-1 of Mn is added. Se and Cu additions demonstrate the potential to improve the methane production from SBW. The SMA was predicted to reach 12 mLCH4 gCOD-1 d-1 when Cu and Se are supplied at total concentrations of 3.0 mg L-1 and 0.98 mg L-1, respectively.This research was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico under the grants 406751/2013-7, 150521/2014-6, 150641/2015-0 and 150475/2016-0; the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Fundação de Amparo à Pesquisa do Estado de São Paulo under the Grant FAPESP – Process 2013/50351-4.Peer reviewe