Comparison of Yields and Decay Rates for a Biological Nutrient Removal Process and a Conventional Activated Sludge Process

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2195-2198 ◽  
Author(s):  
S. A. McClintock ◽  
V. M. Pattarkine ◽  
C. W. Randall
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Pilot Scale ◽  
Decay Rates ◽  
Growth Yields ◽  
Biological Nutrient Removal ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Aerobic Process ◽  
Solids Retention

Two pilot-scale activated sludge reactors, one VIP (named after Virginia Initiative Plant) biological nutrient removal (BNR) process and one conventional, fully aerobic process, were operated over a range of solids retention times (SRT's) and under the same conditions so that growth yields and specific decay rates could be evaluated and compared. True growth yields (Y's) for the BNR and the conventional processes were equal and were 0.41 gVSS/gCOD. The specific decay rate, b, for the BNR process, 0.063 d, was lower than in the fully aerobic process, 0.110 d-1, indicating that decay occurs at a much lower rate in the anoxic and anaerobic zones of the BNR process.

PACTTM process for treatment of kraft mill effluent

1997 ◽  
Vol 35 (2-3) ◽  
pp. 283-290 ◽  
Author(s):  
R. M. Narbaitz ◽  
R. L. Droste ◽  
L. Fernandes ◽  
K. J. Kennedy ◽  
D. Ball
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Pulp Mill ◽  
Operating Conditions ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Adsorbable Organic Halides ◽  
Organic Halides ◽  
Solids Retention ◽  
Year 2000

The PACTTM process (powdered activated carbon addition to the activated sludge process) was evaluated for the treatment of Kraft pulp mill wastewater in a series of bench scale experiments. Possibly due to the relatively low strength wastewater, the PACTTM process with carbon doses between 0.5 and 1.0 g/L of influent only performed marginally better than the conventional activated sludge process. Chemical oxygen demand and toxicity, evaluated with the Microtox® assay, were among the parameters monitored. For the operating conditions tested the solids retention time had no impact on performance. The main improvement was increased in adsorbable organic halides (AOX) removal, the magnitude of the improvement was dependent on the wastewater batch and the carbon dose. However conventional activated sludge treatment will meet Ontario's year 2000 AOX regulations. An empirical model from the literature described the data fairly well.

Filter clogging in coarse pore filtration activated sludge process under high MLSS concentration

2006 ◽  
Vol 54 (10) ◽  
pp. 55-66 ◽  
Author(s):  
M.R. Alavi Moghaddam ◽  
Y. Guan ◽  
H. Satoh ◽  
T. Mino
Keyword(s):  
Activated Sludge ◽  
Settling Tank ◽  
Activated Sludge Process ◽  
Filamentous Bacteria ◽  
Membrane Pores ◽  
Conventional Activated Sludge ◽  
Filtration Membrane ◽  
Aerobic Process ◽  
Filter Clogging ◽  
Secondary Settling

Coarse pore filtration activated sludge process is a type of hybrid process in which the secondary settling tank of the conventional activated sludge process is replaced by non- woven and coarse pore filter modules. The filter has pores, which are irregular in shape, and much bigger than micro-filtration membrane pores in size. The objective of the study is to find out the effect of the microbial community structure on filter clogging in the coarse pore filtration activated sludge process under high MLSS concentration in aerobic and anoxic/aerobic (A/A) conditions. Filter clogging started from day 65 and 70 in the A/A and aerobic process, respectively, but it was more severe in the A/A process compared to that in the aerobic process. EPS contents of sludge did not change significantly during the operation in both processes, and did not have a crucial effect on the observed filter clogging. There was no strong evidence for direct effect of the type and number of metazoa on filter clogging. The main difference between aerobic sludge and A/A sludge during the filter clogging period was the relative abundance of filamentous bacteria. According to the obtained results, it can be concluded that a higher presence of filamentous bacteria could reduce the severity of filter clogging in a coarse pore filtration activated sludge process.

Effectiveness of the membrane bioreactor in the biodegradation of high molecular-weight compounds

1996 ◽  
Vol 34 (9) ◽  
pp. 197-203 ◽  
Author(s):  
H. Winnen ◽  
M. T. Suidan ◽  
P. V. Scarpino ◽  
B. Wrenn ◽  
N. Cicek ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Extended Period ◽  
Membrane System ◽  
Pilot Scale ◽  
Synthetic Wastewater ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Heterotrophic Microorganisms

The activated sludge process has been used extensively to treat municipal wastewater. The membrane bioreactor (MBR) process is a modification of the conventional activated sludge process where the clarifier is replaced with a membrane system for separation between the mixed liquor and the effluent. This paper presents the biological and physical performance data of a pilot-scale membrane bioreactor system, fed with a synthetic wastewater. At steady state, particularly high effluent quality was obtained and maintained for an extended period of time. Heterotrophic plate counting showed that the membrane retains heterotrophic microorganisms. Bacteriophage MS-2 was used to determine the retention of viruses. The membrane proved to retain the MS-2 virus.

The effect of chemical bulking control on biological nutrient removal in a full scale activated sludge plant

1996 ◽  
Vol 34 (3-4) ◽  
pp. 275-282 ◽  
Author(s):  
G. B. Saayman ◽  
C. F. Schutte ◽  
J. van Leeuwen
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Pilot Scale ◽  
Full Scale ◽  
City Council ◽  
Phosphate Removal ◽  
Biological Nutrient Removal ◽  
Removal Processes ◽  
The City

The use of chemicals for sludge bulking control has a direct effect on the biological nutrient removal processes in activated sludge systems designed for this purpose. Chlorine has been used on full scale but information on the use of ozone and hydrogen peroxide is limited to pilot scale tests. The objective of this study was to investigate the effects of chlorine, ozone and hydrogen peroxide on nutrient removal processes when used on a continuous basis for bulking control in a full scale biological nutrient removal activated sludge plant. The full scale studies were conducted over a period of 39 months at the Daspoort sewage works of the City Council of Pretoria. The results indicate that at low dosages the oxidants have limited effects on the nutrient removal processes but at higher levels chlorine had a detrimental effect resulting in the phosphate limit of 1 mg P.1−1 being exceeded. It is concluded that chlorine is the most effective of the three oxidants for bulking control, but that it should be used with caution in order not to upset the biological phosphate removal processes. Ozone at low levels had a small but consistent positive effect on bulking control as well as on nutrient removal. The effects of hydrogen peroxide were very small except at high dosages.

Long-term performance of side-stream deammonification in a continuous flow granular-activated sludge process for nitrogen removal from high ammonium wastewater

2015 ◽  
Vol 71 (8) ◽  
pp. 1241-1248 ◽  
Author(s):  
Babak Rezania ◽  
Donald S. Mavinic ◽  
Harlan G. Kelly
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Biomass Concentration ◽  
Granular Sludge ◽  
Operating Conditions ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Wide Range ◽  
Nitrite Oxidizing Bacteria ◽  
Solids Retention

An innovative granular sludge deammonification system was incorporated into a conventional-activated sludge process. The process incorporated an internal baffle in the bioreactor for continuous separation of granular biomass from flocculent biomass, which allowed for controlling the solids retention time of flocculent sludge. The process was evaluated for ammonium removal from municipal digested sludge dewatering centrate under various operating conditions lasting over 450 days. The process successfully removed, on average, 90% of the ammonium from centrate at various ammonium loading reaching 1.4 kg/m3d at 20 hours hydraulic retention time. Controlling the retention time of the flocculent biomass and maintaining low nitrite concentration were both found to be effective for nitrite oxidizing bacteria management, resulting in a low nitrate concentration (below 50 mg/L) over a wide range of flocculent biomass concentration in the bioreactor.

A co-beneficial system using aquatic plants: bioethanol production from free-floating aquatic plants used for water purification

2013 ◽  
Vol 67 (11) ◽  
pp. 2637-2644 ◽  
Author(s):  
S. Soda ◽  
D. Mishima ◽  
D. Inoue ◽  
M. Ike
Keyword(s):  
Activated Sludge ◽  
Aquatic Plants ◽  
Nutrient Removal ◽  
Plant Biomass ◽  
High Growth ◽  
Domestic Wastewater ◽  
Coli Strain ◽  
Activated Sludge Process ◽  
Bioethanol Production ◽  
Conventional Activated Sludge

A co-beneficial system using constructed wetlands (CWs) planted with aquatic plants is proposed for bioethanol production and nutrient removal from wastewater. The potential for bioethanol production from aquatic plant biomass was experimentally evaluated. Water hyacinth and water lettuce were selected because of their high growth rates and easy harvestability attributable to their free-floating vegetation form. The alkaline/oxidative pretreatment was selected for improving enzymatic hydrolysis of the aquatic plants. Ethanol was produced with yields of 0.14–0.17 g-ethanol/g-biomass in a simultaneous saccharification and fermentation mode using a recombinant Escherichia coli strain or a typical yeast strain Saccharomyces cerevisiae. Subsequently, the combined benefits of the CWs planted with the aquatic plants for bioethanol production and nutrient removal were theoretically estimated. For treating domestic wastewater at 1,100 m3/d, it was inferred that the anoxic–oxic activated sludge process consumes energy at 3,200 MJ/d, whereas the conventional activated sludge process followed by the CW consumes only 1,800 MJ/d with ethanol production at 115 MJ/d.

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