Instability caused by high strength of cheese whey in a UASB reactor

Abstract

The anaerobic digestion of cheese whey was studied in a UASB reactor. The profiles of the reactor, i.e., the distributions of the substrate concentration and pH under different operating conditions were developed. From the concentrations of substrates measured at various levels above the bottom of the reactor, two reaction stages, namely acidogenesis and methanogenesis, were distinguished. The instability caused by high influent concentration was interpreted as the accumulation of VFAs in the acidogenic stage beyond the assimilative capacity of the methanogenic stage. A range of stable operating conditions was predicted from the results of the profile measurements. The optimal influent concentration was found to be between 25 and 30 g COD/L at an HRT of 5 days for system stability. Other options fro stability control were discussed.

Dispersed plug flow model for upflow anaerobic sludge bed reactors with focus on granular sludge dynamics

“…Results from an experimental study by Yan et al [37,38] on the treatment of high strength cheese whey in a UASB reactor were used to validate the integrated structured model developed above. Salient features of the experimental protocol used are given in Table 1.…”

“…The remaining parameters in Table 4 were tuned to fit the data of Yan et al . [37,38] using literature analogies (where possible) as first approximations. The rational behind these choices is described briefly below.…”

“…Since the seed sludge characteristics were not given in Yan et al [37,38], the initial quantity of the various bacterial groups involved, as well as inactive VSS, in the seed sludge (total quantity of VSS inoculated to the reactor was 86.54 g) was arbitrarily fixed in the model as follows (g VSS per reactor):…”

Production d'acides gras par biodégradation anaérobie du perméat de lactosérum dans un bioréacteur en continu /

“…D'après plusieurs auteurs, le système UASB demeure un des meilleurs traitements anaérobies du perméat Schroder et De Haast, 1989;Yan et al, 1989Yan et al, , 1990Yan et al, , 1993Gutierrez et al, 1991;Ozturk et al, 1993;Hwang et Hansen, 1992;Cohen et al, 1994;Strydom et al, 1995 (Samson etal., 1990).…”

The treatment of cheese whey wastewater by sequential anaerobic and aerobic steps in a single digester at pilot scale

“…In effect, since whey is rich in lactose, it tends to acidify rapidly resulting in a pH drop (pH 4). At that pH the concentration of the non-dissociated VFAs in the bulk liquid is too high inhibiting the methanogens and destabilizing the digester (Yan et al, 1993). Acidification of the whey wastewater also leads to the use of buffering in the digester.…”