Monitoring aerobic sludge digestion by online scanning fluorometry

Application of flat-sheet membrane to thickening and digestion of waste activated sludge (WAS)

“…In this study, about 80% destruction efficiency of MLSS and 73% destruction efficiency of MLVSS were achieved at the end of the operation (15 d) and DO concentration 0.5-1.5 mg/L in the MSTD process, which are higher than those reported by other researchers using conventional aerobic digestion process for WAS treatment. Bernard and Gray [26] found that a reduction of 42-53% MLSS and 53-64% MLVSS was achieved under SRT 35 d at ambient temperature (about 20 • C) when they used aerobic digestion process to treat three domestic sludges with feeding MLVSS 3-5 g/L; about 50% MLVSS destruction rate was also reported by Novak et al [27] under SRT 50 d, initial total solids (TS) 10-13 g/L and digestion temperature 20 • C. Arunachalam et al [28] further studied the effect of DO concentration on sludge digestion efficiency and observed that about 62% MLVSS destruction efficiency was reached by employing aerobic digestion process under DO 0.2-1 mg/L, initial TS 28 g/L and SRT 19 d at room temperature about 20 • C and about 62.5% MLVSS destruction under DO 3-4 mg/L, initial TS 16 g/L and SRT 15 d. The higher digestion efficiency achieved in the MSTD process could be attributed to the fact that in this process the influent undigested sludge with low concentration was continuously fed into the reactor and the influent undigested sludge would be blended with the previously digested sludge existing in the reactor to continue the digestion process. In fact, it has been proven that the destruction efficiency of MLSS and MLVSS in aerobic digestion can be enhanced by addition of digested sludge into the digester filled with undigested WAS and the digested sludge could serve as the source of viable cell mass needed for degradation of organic solids [29].…”

A comparison of analytical techniques for evaluating food waste degradation by anaerobic digestion

“…In addition, sample M2 had a fluorescence peak at an excitation of 300 nm. In general, peaks at lower excitation/emission wavelengths can be attributed to protein fluorescence [42]. It can be hypothesized that M2 digestion was incomplete when compared with results from M1 reactor.…”

Addition of an aerated iron‐rich waste‐activated sludge to control the soluble sulphide concentration in sewage

“…sulphide or hydrogen gas) is provided (Benz et al 1998; Kelly & Derek 2000; Heitmann & Blodau 2006). Moreover, if the WAS has been aerated, the NO 3 − ‐N concentration exceeds 10 mg/L due to nitrification (Arunachalam et al 2005). The WAS can thus also provide electron acceptors such as nitrate and humic substances, which can favour the biological oxidation of sulphide by SOB (McInerney et al 1996; Garcia De Lomas et al 2005; De Gusseme et al 2009).…”