Effect of ammonium, sulfides, tannins, and tannery wastewater on the methanogenic activity of anaerobic sludge from a UASB reactor

ROSARIO DEL CARMEN FARFÁN; WALTER ALFREDO TEJERINA; VIVIANA ISABEL LIBERAL; CARLOS MARIO CUEVAS; LUCAS SEGHEZZO

Isla de Pascua, Chile

Simposio; IX Taller y Simposio Latinoamericano de Digestión Anaerobia; 2008

International Water Association (IWA)

Tannery wastewater might have a hugely negative environmental impact when discharged in water bodies without adequate treatment. Aerobic systems have been used so far to treat tannery wastewater but high investment and operation costs are important obstacles for the widespread use of these methods in developing countries. Development and dissemination of efficient and cheap anaerobic wastewater treatment methods could have a positive effect on the sustainability of the entire water and wastewater management system in the region. Toxicity to anaerobic bacteria of some compounds used in the tanning process may hinder the use of anaerobic technologies to treat tannery wastewater. This work shows results of anaerobic toxicity assays (ATA) in which high concentrations of ammonium, sulfides, and tannins negatively affected the MA of fresh and old anaerobic sludge from a UASB (Upflow Anaerobic Sludge Blanket) reactor. MA was also inhibited by raw tannery wastewater. In long-term tests with and without addition of sodium acetate as cosubstrate, around 40% of the wastewater COD was removed. Lag phases up to 2 months were observed in some ATA but the sludge recovered its MA even for high concentrations of toxics or wastewater. Results from this study suggest that UASB technology seems promising for the pre-treatment of tannery wastewater.