Tannery Effluent: A Challange Met by Anaerobic Fixed Film Treatment,

Studies have shown that pretreated tannery beam-house waste waters can be treated with an anaerobic process to routinely remove more than 60 percent of the applied TCOD with hydraulic detention times less than one day and loadings on the order of 2.25 Kg TCODcu m 3 -day. The lack of noticeable production of volatile fatty acids and pH depression accross the columns for these loading conditions suggests that the rate limiting step for this anaerobic process is the degradation of proteins into peptides and amino acids. The anaerobic system proved to be remarkably insensitive to variations in feed type, loading conditions, shut down periods and the introduction of air into the system. The massive accumulation of solids within the reactors suggests the employment of larger support media than that used in this study and that a down flow mode of operation be used for systems where reaction conditions may result in precipitate formation in order to minimize the potential for plugging and solids accumulation. Gas collection systems for methane recovery will have to include provision for sulfide scrubbing.