Six upflow anaerobic sludge blanket (UASB) reactors were concurrently operated for 146 d to examine the effects of calcium on the sludge granulation process during start-up. Introduction of Ca at concentrations from 150 to 300mg/l enhanced the biomass accumulation and granulation process. The calcium concentration in the granules was nearly proportional to the calcium concentration in the feed,...

In recent years, lots of the extracellular polymeric substances (EPS) related researches have focused on its role in the granulation and structural stability of aerobic sludge. Three-dimensional fluorescence spectrum (3D-EEM) and fourier transform infrared spectroscopy (FTIR) technologies were used to analyse the main components of sludge EPS during aerobic sludge granulation in this study. Res...

Micropowder (20-250 µm) made from ground dry waste sludge from a municipal sewage treatment plant was added in a sequencing batch reactor (R2), which was fed by synthetic wastewater with acetate as carbon source. Compared with the traditional SBR (R1), aerobic sludge granulation time was shortened 15 days in R2. Furthermore, filamentous bacteria in bulking sludge were controlled to accelerate a...

Biogranulation has been studied widely and successfully industrialized for the last two decades. Biogranulation technology for wastewater treatment includes anaerobic and aerobic granulation processes. Even though anaerobic granulation has been relatively well studied and known, studies on aerobic granulation have begun recently. The aerobic granular sludge is known to have denser and stronger ...

Quorum sensing is a concentration-sensing mechanism that plays a vital role in sludge granulation. In this study, the regularities of distribution of different signal molecules, including intra- and interspecific signal molecules (diffusible signal factor, DSF), interspecific signal molecules (autoinducter-2, AI-2) and intraspecific signal molecules (acyl-homoserine lactones, AHLs), from three ...

Experiments were performed in parallel using six identical UASB (upflow anaerobic sludge blanket) reactors to examine the effects of iron (Fe2+) on sludge granulation during start-up. Introduction of Fe2+ at concentrations of 300 and 450 mg/L enhanced the granulation process in UASB reactors, while dosage of Fe2+ (150 mg/L) had little effect on the sludge granulation. The Fe2+concentration in g...

This study cultivated denitrifying granular sludge in three UASB reactors by the semi-starvation fluctuation C/N ratio strategy (reactor 1 (R1): constant C/N ratio; R2: regular fluctuation C/N ratio; and R3: semi-starvation fluctuation C/N ratio (SSF)). Microbial aggregates appeared in R1, R2 and R3 on days 28, 14 and 6, respectively. Compared with the results in R1 and R2, the guanosine tetrap...

Aerobic granulation of activated sludge was successfully achieved in a full-scale sequencing batch reactor (SBR) with 50,000 m(3) d(-1) for treating a town's wastewater. After operation for 337 days, in this full-scale SBR, aerobic granules with an average SVI30 of 47.1 mL g(-1), diameter of 0.5 mm, and settling velocity of 42 m h(-1) were obtained. Compared to an anaerobic/oxic plug flow (A/O)...

One of the main challenging issues for aerobic nitrifying granules in treating high strength ammonia wastewater is the long granulation time required for activated sludge to transform into aerobic granules. The present study provides a novel strategy for enhancing aerobic nitrifying granulation by applying an intensity of 48.0mT static magnetic field. The element analysis showed that the applie...

n this paper, a mathematical model has been derived to predict the granulation time of anaerobic sludge in UASB reactors. In the proposed model, some physical, chemical and biological parameters affecting the granulation phenomena have been considered. To validate the model, 12 pilot-scale experiments in 4 UASB reactors are carried out and the results are discussed here. The reactors are starte...