The Relationship Between Mixed-Liquor Particle Size and Solids Retention Time in the Activated Sludge Process

2011 ◽  
Vol 83 (12) ◽  
pp. 2178-2186 ◽  
Author(s):  
Licheng Chan ◽  
Shao-Yuan Leu ◽  
Diego Rosso ◽  
Michael K. Stenstrom
Keyword(s):  
Particle Size ◽  
Activated Sludge ◽  
Retention Time ◽  
Activated Sludge Process ◽  
Mixed Liquor ◽  
Solids Retention Time ◽  
Solids Retention ◽  
The Relationship

Operating Experiences at Low Solids Retention Time

1984 ◽  
Vol 16 (12) ◽  
pp. 661-672 ◽  
Author(s):  
T E Wilson ◽  
W A Ambrose ◽  
H O Buhr
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Suspended Solids ◽  
Volume Index ◽  
Sludge Volume Index ◽  
Effluent Quality ◽  
Mixed Liquor ◽  
Solids Retention Time ◽  
Solids Retention ◽  
Typically Achieving

Five full scale activated sludge plants have been operated at low solids retention time (SRT, monthly averages as low as 0.8 days) and mixed liquor suspended solids (MLSS, monthly averages as low as 500 mg/l) values for 2 to 3 years. Operating results for this period are compared to 3 to 3-1/2 years of operation at conventional, higher, SRT and MLSS values. The data show that the lower SRT operation provided better effluent quality, typically achieving less than 15 mg/l of BOD5 or suspended solids, while not significantly increasing either the total (dry) sludge production or the sludge volume index (SVI). These data indicate that plants can be built and operated using significantly smaller tankage than conventionally accepted.

Particle Size Distribution to the Final Effluent Quality - Based on Turbidity

2013 ◽  
Vol 838-841 ◽  
pp. 1651-1654
Author(s):  
Meng Meng Yin ◽  
He Li Wang ◽  
Chao Yang
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Activated Sludge ◽  
Size Distribution ◽  
Activated Sludge Process ◽  
Effluent Quality ◽  
Mixed Liquor ◽  
Relationship Of ◽  
The Relationship ◽  
Final Effluent

This paper studies the particle size distribution (PSD) and final effluent quality in the activated sludge process. The PSD of final effluent and mixed liquor were determined, and it was found that the settlement in the process can remove particles between 100μm and 200μm easily, while difficult to remove the particles between 13.5μm to 65μm, which was in the supracolloidal (1-100μm) range and could cause problem at higher flows. The final effluent quality was measured by turbidity. The relationship of PSD-10 with turbidity, was analysed and the formed links were paired. Therefore, the PSD can be linked with final effluent quality and can be expected to use as an index to evaluate the final effluent quality future.

Nitrogen removal in activated sludge systems including denitrification in secondary clarifiers

1994 ◽  
Vol 30 (6) ◽  
pp. 101-111 ◽  
Author(s):  
H. Siegrist ◽  
W. Gujer
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Retention Time ◽  
Secondary Clarifier ◽  
Solids Retention Time ◽  
Solids Retention ◽  
Activated Sludge Systems

Denitrification in the secondary clarifier can contribute substantially to the nitrogen removal of activated sludge systems. This is illustrated on two treatment plants with different secondary clarifier systems. A model to estimate denitrification capacity and to design activated sludge systems for nitrogen removal is developed and verified with data from two treatment plants. The model includes denitrification in the secondary clarifier, wastewater composition (soluble readily biodegradable COD, particulate degradable COD), oxygen input into the anoxic volume, temperature, and solids retention time (SRT). The influence of aerated grit chambers and primary sedimentation on denitrification is discussed.

scholarly journals The potential of ultrasonic membrane anaerobic systems in treating slaughterhouse wastewater

2015 ◽  
Vol 5 (3) ◽  
pp. 293-300 ◽  
Author(s):  
N. H. Abdurahman ◽  
Y. M. Rosli ◽  
N. H. Azhari ◽  
Hayder A. Bari
Keyword(s):  
Steady State ◽  
Removal Efficiency ◽  
Retention Time ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Yield Coefficient ◽  
Slaughterhouse Wastewater ◽  
Mixed Liquor ◽  
Solids Retention Time ◽  
Solids Retention

Direct discharge of slaughterhouse wastewater causes serious environmental pollution due to its high chemical oxygen demand (COD), total suspended solids (TSS) and biochemical oxygen demand. In this study, an ultrasonic-assisted membrane anaerobic system was used as a novel method for treating slaughterhouse wastewater. Six steady states were achieved, using concentrations of 7,800–13,620 mg/l for mixed liquor suspended solids and 5,359–11,424 mg/l for mixed liquor volatile suspended solids (MLVSS). Kinetic equations were used to describe the kinetics of treatment at organic loading rates of 3–11 kg COD/m3/d. The removal efficiency of COD was 94.8–96.5% with hydraulic retention times of 308.6–8.7 days. The growth yield coefficient was found to be 0.52 g VSS/g. COD was 0.21 d−1 and methane gas production rate was 0.24–0.56 l/g COD/d. Steady-state influent COD concentrations increased from 8,000 mg/l in the first steady state to 25,400 mg/l in the sixth steady state. The minimum solids retention time, θcmin obtained from the three kinetic models was 6–14.4 days. The k values were 0.35–0.519 g COD/g VSS.d and μmax values were between 0.26 and 0.379 d−1. The solids retention time decreased from 600 to 14.3 days. The complete treatment reduced the COD content and its removal efficiency reached 94.8%.

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