Control of activated sludge filamentous bulking

A Single Model for Mass Transfer and Growth for Biodegradation Rates in Activated Sludge

“…Although data are scattered, it is evident that the measured K 1 values are proportional to these maximal respiration rates. Chudoba et al (1985) also concluded that so-called bulking sludge, with a high volume per mass, had a lower K 1 . They postulated this as an intrinsic speci"c property of "lamentous species, but if K 1 is caused by mass transfer limitation, the same mass transfer over a larger surface area would give a smaller gradient between mixed liquor and biomass and this will give a lower value of K 1 .…”

“…values against maximal sludge activity (expressed as respiration rate) of the corresponding sludge sample. Based on data of Chudoba et al (1985).…”

“…(8) an apparent K 1 will exist that is strongly in#uenced by the mass transfer between mixed liquor and suspended solids. K 1 values measured by Chudoba et al (1985) are in the range 100}3200 g/L. These measurements are based on respirometry with sludges from a culture with a relatively high arti"cial speci"c load (each substance 20% of 1 g COD/g SS/day).…”

“…3 all data for K 1 of Chudoba et al (1985) for the 11 di!erent substances are plotted against the maximal speci"c respiration rates (R ) of the corresponding sludge samples. Although data are scattered, it is evident that the measured K 1 values are proportional to these maximal respiration rates.…”

“…Assuming that these systems will operate at 1/10 of the maximum growth rates, this would mean that K 1 values are between 10 and 3000 g/L. Several authors mention that the K 1 values are in#uenced by the process conditions (Grady et al, 1996;Ellis et al, 1994;Chudoba et al, 1985;Blok, 1976).…”