scholarly journals Fast formation of aerobic granules by combining strong hydraulic selection pressure with overstressed organic loading rate

2015 ◽  
Vol 80 ◽  
pp. 256-266 ◽  
Author(s):  
Yong-Qiang Liu ◽  
Joo-Hwa Tay
2003 ◽  
Vol 47 (11) ◽  
pp. 235-240 ◽  
Author(s):  
J.-H. Tay ◽  
S. Pan ◽  
S.T.L. Tay ◽  
V. Ivanov ◽  
Y. Liu

The effect of organic loading rate (OLR) on aerobic granulation was studied by adopting three column-shaped, sequential aerobic sludge blanket reactors (SASBR). The reactors had been fed with laboratory prepared, synthetic dextrose-nutrient broth substrate. Experimental results showed clearly that the formation, characteristics and stability of aerobic granules had a close relationship with the strength of OLR applied. Aerobic granules appeared firstly under the OLR of 4 kg COD×(m3·day)−1. The system stabilization was demonstrated by its little-changed amount and morphology of granules. The characteristics of the stabilized granules were: 5.4 mm in mean diameter, 1.29 in roundness, 118 mg O2·(mg VSS·hr)−1 in SPOUR. The respective biomass SVI was 50 mL·(g MLVSS)−1 and the averaged COD removal rate was 95%. Under the OLR of 8 kg COD·(m3·day)−1, granules appeared two days later than those for 4 kg COD·(m3·day)-1 and they always coexisted with flocs. The formed granule bed was not as compact as that under 4 kg COD·(m3·day)−1. There were no granules formed under the OLR of 1 kg COD·(m3·day)−1. Instead, flocs with rather loose structure dominated reactor mixed-liquor. The respective SVI's were 65 and 138 mL·(g MLVSS)−1 under OLR of 8 and 1 kg COD·(m3·day)−1. It was proposed that the growth and maintenance of aerobic granules follow the shear force balance theory. Under the OLR of 4 kg COD·(m3·day)−1, a balance was reached between the aeration shear force and organic loading rate. Under this favored condition aerobic granules formed quickly and, became stabilized with the experimental parameters remained unchanged.


1999 ◽  
Vol 40 (8) ◽  
pp. 229-236 ◽  
Author(s):  
F. Fdz-Polanco ◽  
M. D. Hidalgo ◽  
M. Fdz-Polanco ◽  
P. A. García Encina

In the last decade Polyethylene Terephthalate (PET) production is growing. The wastewater of the “Catalana de Polimers” factory in Barcelona (Spain) has two main streams of similar flow rate, esterification (COD=30,000 mg/l) and textile (COD=4000 mg/l). In order to assess the anaerobic treatment viability, discontinuous and continuous experiments were carried out. Discontinuous biodegradability tests indicated that anaerobic biodegradability was 90 and 75% for esterification and textile wastewater. The textile stream revealed some tendency to foam formation and inhibitory effects. Nutrients, micronutrients and alkali limitations and dosage were determined. A continuous lab-scale UASB reactor was able to treat a mixture of 50% (v) esterification/textile wastewater with stable behaviour at organic loading rate larger than 12 g COD/l.d (0.3 g COD/g VSS.d) with COD removal efficiency greater than 90%. The start-up period was very short and the recuperation after overloading accidents was quite fast, in spite of the wash-out of solids. From the laboratory information an industrial treatment plant was designed and built, during the start-up period COD removal efficiencies larger than 90% and organic loading rate of 0.6 kg COD/kg VSS.d (5 kg COD/m3.d) have been reached.


2000 ◽  
Vol 42 (12) ◽  
pp. 115-121 ◽  
Author(s):  
B. Wang ◽  
Y. Shen

A study on the performance of an Anaerobic Baffled Reactor(ABR) as a hydrolysis-acidogenesis unit in treating the mixed wastewater of landfill leachate and municipal sewage in different volumetric ratios was carried out. The results showed that ABR substantially improved the biological treatability of the mixed wastewater by increasing its BOD5/COD ratio to 0.4–0.6 from the initial values of 0.15–0.3. The formation of bar-shaped granular sludge of 0.5–5 mm both in diameter and length with an SVI of 7.5–14.2 ml/g was observed in all compartments of the ABR when the organic loading rate reached 4.71 kgCOD/m3 · d. The effects of the ratios of NH4+-N/COD and COD/TP in mixed wastewater on the operational performance were also studied, from which it was found that a reasonable NH4+-N/COD ratio should be lower than 0.02, and the phosphorus supplement was needed when the volumetric ratio was higher than 4:6 for stable operation of ABR.


2021 ◽  
Vol 123 ◽  
pp. 52-59
Author(s):  
L. Megido ◽  
L. Negral ◽  
Y. Fernández-Nava ◽  
B. Suárez-Peña ◽  
P. Ormaechea ◽  
...  

2015 ◽  
Vol 5 ◽  
pp. 46-54 ◽  
Author(s):  
Mélida del Pilar Anzola-Rojas ◽  
Samantha Gonçalves da Fonseca ◽  
Cynthia Canedo da Silva ◽  
Valeria Maia de Oliveira ◽  
Marcelo Zaiat

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