The impact of floc size on respiration inhibition by soluble toxicants—a comparative investigation

Autotrophic denitrification and inhibitory effect caused by the injection of spent sulfidic caustic in a modified Ludzack-Ettinger process

“…SOUR inhi-bition was calculated via the following equation [24]. (2) where SOUR toxin is the SOUR of the mixed liquor in the presence of a given toxin concentration and SOUR control is the SOUR without any SSC injection.…”

“…The large number of toxic compounds in wastewater has necessitated the use of short-term biological screening tests designed for a rapid estimation of the acute toxicity of a test substance on microorganisms. Among them, the inhibition of specific oxygen uptake rate (SOUR) [24][25][26][27] is used to evaluate the toxic effects of substance on heterotrophs of activated sludge. The respiration of activated sludge may prove useful for this purpose, as the concentration of dissolved oxygen (DO) can be readily determined, and can be employed in calculations of the oxygen uptake rate (OUR).…”

Influence of solid retention time on sludge characteristics and effluent quality in immersed membrane bioreactor

“…In the experiment, average size of sludge particles bigger than 30 μm and the membrane filtration resistance is relatively stable when SRT is 5, 10 or 20 days. These particles which are of identical magnitude level with the membrane pore are particularly easy to jam the membrane pore [37][38][39][40] . When SRT is 30 days, average size of sludge particles is 14 µm and the number of particles smaller than 1µm accounts for 23% of the total particles (as seen in Figure 7), that is to say, there are a number of tiny particles in the mixed liquor.…”

Effects of carbamazepine in peak injection on fouling propensity of activated sludge from a MBR treating municipal wastewater

“…In the literature, a few studies have been carried out to investigate the effects of peak chemical stress, including pharmaceutical micropollutants, on the microbial activity of MBR sludges. Henriques et al [33] observed that a cadmium shock load (20 mg L À 1 ) caused about 50% inhibition of heterotrophic respiration (through measurement of specific oxygen uptake rates) on MBR sludge. Lesage et al [34] found that a peak concentration (130 mg L À 1 ) of a toxic compound, 2,4 dimethylphenol (DMP), could cause 50% inhibition of respiration on MBR sludge.…”