Design procedure for carbon removal in contact stabilization activated sludge process

2004 ◽  
Vol 48 (11-12) ◽  
pp. 285-292 ◽  
Author(s):  
M. Sarioğlu ◽  
D. Orhon ◽  
E. Görgün ◽  
N. Artan
Keyword(s):  
Activated Sludge ◽  
Design Procedure ◽  
Domestic Wastewater ◽  
Activated Sludge Process ◽  
Distribution Factor ◽  
Treatment Efficiency ◽  
Conventional Activated Sludge ◽  
High Fraction ◽  
Reducing Costs ◽  
Factor Α

The contact stabilization activated sludge process (CSASP) has been adopted and applied in full scale plants treating domestic sewage. Acquiring smaller volume thereby reducing costs and achieving the same treatment efficiency as the conventional activated sludge plants are the main advantages of the CSASP. This activated sludge modification is especially ideal for small to mid-scale plants where influent wastewater contains a high fraction of particulate COD. The simulation results reveal that the same amount of mass sludge can be retained in the system with almost 30% volume reduction compared to conventional activated sludge plants. It is also found that the CSASP treatment efficiency increases when the particulate COD fraction of an influent domestic wastewater increases. The most important process component in the design of CSASP is the sludge distribution factor (α) which directly affects the effluent characterization Having most of the biomass in the stabilization reactor (meaning low α values) decreases the nominal hydraulic retention time (θHN) of the system. However the sludge distribution factor must be high enough to ensure an acceptable effluent quality.

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.

High rate and compact single sludge pre-denitrification process for retrofit

1994 ◽  
Vol 30 (6) ◽  
pp. 31-40 ◽  
Author(s):  
Hiroyshi Emori ◽  
Hiroki Nakamura ◽  
Tatsuo Sumino ◽  
Tadashi Takeshima ◽  
Katsuzo Motegi ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
High Rate ◽  
Activated Sludge Process ◽  
Nitrogen And Phosphorus ◽  
Conventional Activated Sludge ◽  
Treatment Techniques ◽  
Conventional Activated Sludge Process ◽  
Denitrification Process

For the sewage treatment plants near rivers and closed water bodies in urbanized areas in Japan and European countries, there is a growing demand for introduction of advanced treatment processes for nitrogen and phosphorus from the viewpoints of water quality conservation and environmental protection. In order to remove nitrogen by the conventional biological treatment techniques, it is necessary to make a substantial expansion of the facility as compared with the conventional activated sludge process. In such urbanized districts, it is difficult to secure a site and much capital is required to expand the existing treatment plant. To solve these problems, a compact single sludge pre-denitrification process using immobilized nitrifiers was developed. Dosing the pellets, which are suitable for nitrifiers growth and physically durable, into the nitrification tank of single sludge pre-denitrification process made it possible to perform simultaneous removal of BOD and nitrogen in a retention time equal to that in the conventional activated sludge process even at the low water temperature of about 10 °C. The 3,000 m3/d full-scale conventional activated sludge plant was retrofitted and has been successfully operated.

Advanced Treatment of Domestic Wastewater Using Sequencing Batch Reactor Activated Sludge Process

1993 ◽  
Vol 28 (10) ◽  
pp. 267-274 ◽  
Author(s):  
M. Imura ◽  
E. Suzuki ◽  
T. Kitao ◽  
S. Iwai
Keyword(s):  
Activated Sludge ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Domestic Wastewater ◽  
Experimental Period ◽  
Small Scale ◽  
Experimental Plant ◽  
Activated Sludge Process ◽  
Nitrogen And Phosphorus ◽  
Experimental Apparatus

In order to apply a sequencing batch reactor activated sludge process to small scale treatment facilities, various experiments were conducted by manufacturing an experimental apparatus made of a factory-produced FRP cylinder transverse tank (Ø 2,500mm). Results of the verification test conducted for one year by leading the wastewater discharged from apartment houses into the experimental apparatus were as follows. Excellent performance was achieved without any addition of carbon source, irrespective of the organic compound concentration and the temperature of raw wastewater. Organic substances, nitrogen and phosphorus were removed simultaneously. Due to the automated operation format, stable performance was obtained with only periodic maintenance. Though water depth of the experimental plant was shallow, effective sedimentation of activated sludge was continued during the experimental period. Regarding the aerobic and anaerobic process, nitrification and denitrification occurred smoothly.

New approaches to minimize excess sludge in activated sludge systems

2001 ◽  
Vol 44 (10) ◽  
pp. 203-208 ◽  
Author(s):  
G.-H. Chen ◽  
S. Saby ◽  
M. Djafer ◽  
H.-K. Mo
Keyword(s):  
Activated Sludge ◽  
Activated Sludge Process ◽  
Conventional System ◽  
Excess Sludge ◽  
Active Sludge ◽  
New Approaches ◽  
Conventional Activated Sludge ◽  
Sludge Settleability ◽  
Activated Sludge Systems ◽  
Sludge Production

This paper presents three new approaches to reduce excess sludge production in activated sludge systems: 1) modification of conventional activated sludge process with insertion of a sludge holding tank in the sludge return line; 2) chlorination of excess sludge so as to minimize excess sludge production; and 3) utilization of a metabolic uncoupler, 3, 3′, 4′, 5-Tetrachlorosalicylanilide (TCS) to maximize futile activity of sludge microorganisms thereby leading to a reduction of sludge growth. Pilot study was carried out to evaluate this modified activated sludge process (OSA). It has been confirmed that the OSA process is effective in reducing excess sludge; particularly when the ORP level in the sludge holding tank was kept at -250 mV, more than 50% of the excess sludge was reduced. This process can maintain the effluent quality and even perform with a better sludge settleability than a conventional system. Experimental work on the second approach showed that chlorination treatment of excess sludge at a chlorine dose of 0.066 g Cl2/g MLSS reduced the excess sludge by 60%, while concentration of THMS was found below 200 ppb in the treated sludge. However, such sludge chlorination treatment sacrificed sludge settleability. Thus, it is not feasible to introduce the chlorination step to a conventional system. The third approach confirmed that addition of TCS could reduce sludge growth effectively if the TCS concentration is greater than 0.4 ppm. A 0.8-ppm concentration of TCS actually reduced excess sludge by 45%. It was also experimentally demonstrated that presence of TCS increases the portion of active sludge microorganisms over the entire microbial population.

Removal Efficiency of Environmental Endocrine Disrupting Chemicals Pollutants-Phthalate Esters in Northern WWTP

2013 ◽  
Vol 807-809 ◽  
pp. 694-698
Author(s):  
Rong Xin Huang ◽  
Zhen Xing Wang ◽  
Gang Liu ◽  
Qi Jin Luo
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Phthalate Esters ◽  
Endocrine Disrupting Chemicals ◽  
Treatment Plant ◽  
Activated Sludge Process ◽  
Wastewater Reclamation ◽  
Conventional Activated Sludge

In order to guarantee the reliability and security of reclaiming water, research on the removal efficiency of the environmental endocrine chemicals (EDCs) --the Phthalate Esters (PAEs) in conventional secondary activated sludge and wastewater reclamation and reuse process was undergoing at Harbin wastewater treatment plant (WWTP). The wastewater samples were colleted from every unit effluent of WWTP. The results showed that contamination of EDCs were presented in municipal wastewater at Harbin and the concentrations of the four PAEs were 21.01μg/L for Di-n-butyl Phthalate (DBP); 9.63μg/L for Di-n-octyl Phthalate (DnOP); 4.56μg/L for Diethyl Phthalate (DEP); 1.96μg/L for Dimethyl Phthalate (DMP) respectively in the influent. The conventional activated sludge has good removal efficiencies performance on DMP, DEP and DBP. With the increasing of molecular weight and branch chains of PAEs contaminations, the removal rate of the four PAEs in the conventional activated sludge process decreased from 99.82%(DMP)，90.60%(DEP)，90.10%(DBP) to the only 45.13% removal rate for DnOP, which was mostly removed from primary treatment but no from secondary activated sludge process; Coagulation-air flotation plus filtration process was not a feasible way to remove PAEs from reclaiming treatment units.

Feasibility of the membrane bioreactor process for water reclamation

2001 ◽  
Vol 43 (10) ◽  
pp. 203-209 ◽  
Author(s):  
S. Adham ◽  
P. Gagliardo ◽  
L. Boulos ◽  
J. Oppenheimer ◽  
R. Trussell
Keyword(s):  
Literature Review ◽  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Cost Evaluation ◽  
Water Reclamation ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
In Series ◽  
Volumetric Loading ◽  
Conventional Activated Sludge Process

The feasibility of the membrane bioreactor (MBR) process for water reclamation was studied. Process evaluation was based on the following: literature review of MBRs, worldwide survey of MBRs, and preliminary costs estimates. The literature review and the survey have shown that the MBR process offers several benefits over the conventional activated sludge process, including: smaller space and reactor requirements, better effluent water quality, disinfection, increased volumetric loading, and less sludge production. The MBR process can exist in two different configurations, one with the low-pressure membrane modules replacing the clarifier downstream the bioreactor (in series), and the second with the membranes submerged within the bioreactor. Four major companies are currently marketing MBRs while many other companies are also in the process of developing new MBRs. The MBR process operates in a considerably different range of parameters than the conventional activated sludge process. The preliminary cost evaluation has shown that the MBR process is cost competitive with other conventional wastewater treatment processes.

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