Indigenous Coliphages and RNA-F-Specific Coliphages Associated with Suspended Solids in the Activated Sludge Process

1989 ◽  
Vol 21 (3) ◽  
pp. 73-78 ◽  
Author(s):  
Awrapin Ketratanakul ◽  
Shinichiro Ohgaki
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Host Strain ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
E Coli ◽  
K 12

The occurrence of indigenous coliphages and RNA-F-specific coliphages associated with suspended solids in the activated sludge process was investigated using E. coli K-12,F+(A/λ) as the host strain. Indigenous coliphages and RNA-F-specific coliphages adsorbed to suspended solids were detected in significant numbers in raw sewage. The adsorbed phages ranged from 12% to 30% of the total Indigenous coliphages in the raw sewage. Of these adsorbed phages, 6% to 20% were RNA-F-specific coliphages. Over 97% of the coliphages in the aeration tank were associated with suspended solids and most of these were RNA-F-specific coliphages,

Stabilization of Activated Sludge Processes During Wet Weather Flow through Microscreening

1994 ◽  
Vol 29 (1-2) ◽  
pp. 393-399
Author(s):  
K.-D. Kummer ◽  
W. F. Geiger
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Treatment Facility ◽  
Process Modification ◽  
Flow Through ◽  
Wet Weather ◽  
Wet Weather Flow ◽  
Activated Sludge Processes

In the activated sludge process, between the aeration tank and the final clarifier, offline microscreening is introduced to separate activated sludge and purified water. The intention is to reduce the drifting of activated sludge from the aeration tank into the final clarifier. Sludge drifting usually occurs during wet weather flow loading of the treatment facility and can cause higher concentrations of ammonia and suspended solids in the effluent. Laboratory and half-technical scale experiments demonstrate that microscreening is suitable for this application. It is expected that the operational stability of activated sludge processes could be improved significantly by this process modification.

Effect of important operational parameters on performance of coarse pore filtration activated sludge process

2002 ◽  
Vol 46 (9) ◽  
pp. 229-236 ◽  
Author(s):  
M.R. Alavi Moghaddam ◽  
H. Satoh ◽  
T. Mino
Keyword(s):  
Activated Sludge ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Operational Parameters ◽  
Solid Retention Time ◽  
Effluent Quality ◽  
Membrane Pores ◽  
Filtration Membrane ◽  
Operation Pressure ◽  
Filter Clogging

A coarse pore filter can be applied inside the aeration tank instead of sedimentation tank for liquid separation from the sludge. It has pores, which are irregular in shape, and much bigger than micro-filtration membrane pores in size. The objective of the study was to investigate the effect of important operational parameters such as flux, aeration intensity, and solid retention time (SRT) on the performance of the coarse pore filtration activated sludge process. The effect of these parameters was studied in laboratory scale experiments. It was found that the flux had a significant role in the effluent quality of this system. The effluent SS and turbidity were not changed significantly at different aeration intensities. Three SRTs, 10, 30 and longer days (without excess sludge) were used for three reactors to check the effect of this parameter on the system performance. The results of the reactors with SRTs about 10 and 30 days have shown very good effluent quality without any filter clogging for more than 4 months operation. For the reactor with long SRT, the filter clogging was observed after about 80 days of operation, which caused the increase of the operation pressure and deterioration in the effluent quality for a few days.

scholarly journals Application of synthetic and grafted polymeric flocculants in agricultural wastewater treatment

2021 ◽  
Vol 8 (3) ◽  
pp. 2829-2836
Author(s):  
Mohamed N Ali ◽  
Mohammed S Fahmy ◽  
Rehab M Elhefny
Keyword(s):  
Activated Sludge ◽  
Agricultural Sector ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Sedimentation Stability ◽  
Agricultural Wastewater ◽  
High Concentrations ◽  
Filtration Stage ◽  
Organic Particles ◽  
Low Dosage

Due to the large amounts of freshwater consumed in Egypt by the agricultural sector that is more than 85% of Egypt share of freshwater in addition to the high concentrations of salts, chemicals and nutrients produced from fertilizers. Reduction of these pollutants concentrations to an acceptable level and breaking the sedimentation stability of colloidal substances and organic particles for reuse for irrigation purposes was associated with the application of biological treatment with coagulants addition. The flocculation process was performed by using polydiallyldimethylammonium chloride (polyDADMAC) and polyacrylamide grafted oatmeal (OAT-g-PAM). The scale-pilot consists of an aeration tank equipped with an air blower, sedimentation tank followed by a filtration stage through 20 cm of pottery scrubs media. To study the performance of synthetic and grafted polymeric flocculants, 3 trials were performed. Activated sludge process without adding any polymeric flocculants was the control trial. In the second trial, polyDADMAC was added with a dose of 5 mg/l. Finally, OAT-g-PAM with a dose of 1.25 mg/l was used in the third trial. The physicochemical properties of agricultural wastewater were measured at the national research center in Cairo. It was found that OAT-g-PAM incorporated with activated sludge process was the most effective in treating agricultural wastewater as it achieved COD, BOD,TKN, TP, and TSS removal efficiency up to 92.29%, 93.13%, 90.64%, 90.46%, and 92.5%, respectively which made it suitable to reuse for agricultural purposes, in addition to its ability to biodegrade, environmentally friendly, and low dosage required compared to polyDADMAC.

The Infuence of the Depth of the Secondary Sedimentation Tanks on the Sedimentation Efficiency at Bromma Sewage Treatment Plant

1988 ◽  
Vol 20 (4-5) ◽  
pp. 143-152 ◽  
Author(s):  
M. Tendaj-Xavier ◽  
J. Hultgren
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Ferrous Sulphate ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Design Flow ◽  
Activated Sludge Process ◽  
Solids Concentration ◽  
Rapid Flow

Bromma sewage treatment plant is the second largest plant in Stockholm with a design flow of 160,000 m3/d. The wastewater is treated mechanically, chemically by pre-precipitation with ferrous sulphate, and biologically by the activated sludge process. The requirements for the plant are 8 mg BOD7/l, 0.4 mg P/l and 2 mg NH4+-N/l. The requirement for ammonia refers to the period July-October. In order to meet those rather stringent requirements, the biological step was expanded 3 years ago with 6 new sedimentation tanks. The 6 new tanks have the same area as the 6 old ones but they have only a depth of 3.7 m compared with the depth of the old tanks, 5.7 m. Experience from the first years of operation of the new tanks is that these tanks are more sensitive and less efficient than the older ones. It seems that the effluent suspended solids concentration from the old tanks is less influenced by rapid flow variations than the concentration in the effluent from the new secondary sedimentation tanks. During the nitrification period denitrification takes place to some degree in the secondary sedimentation tanks. This may cause loss of solids and it has been observed that the deeper old tanks usually produce an effluent of better quality and seem to be less influenced by denitrification than the new ones.

scholarly journals Activated Sludge Process and its Suitability for Treatment of Tannery Waste Water

2016 ◽  
Vol 59 (1) ◽  
pp. 60-62
Author(s):  
Niaz Ahmed Memon ◽  
Nisar Ahmed ◽  
Nusrat Jalbani ◽  
Tahira Ayaz ◽  
Razia Bagum ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Process Efficiency ◽  
Activated Sludge Process ◽  
Simple Design ◽  
Local Conditions ◽  
Detention Time ◽  
Aeration Time ◽  
Do Concentration ◽  
Tannery Waste Water

This study was conducted for the treatment of tannery wastewater and to develop simple design criteria under local conditions. BOD5, COD, total Cr, SO4 2-, S2-, SS, TDS and TS of the influent and effluent were measured to find process efficiency at various mixed liquor volatile suspended solids (MLVSS), dissolved oxygen (DO) and hydraulic detention time. Results of the study demonstrated that an efficiency of above parameters 93.0%, 92.5%, 94.9%, 62.6%, 98.2%, 87.9%, 82.1% and 82.4%, respectively, could be obtained if the activated sludge process (ASP) is operated at the MLVSS concentration of 3500-4500 mg/L, (DO) concentration of 4.1-5.5 mg/L keeping an aeration time of 12 h. 

scholarly journals Systematic Modeling of Municipal Wastewater Activated Sludge Process and Treatment Plant Capacity Analysis Using GPS-X

2020 ◽  
Vol 12 (19) ◽  
pp. 8182
Author(s):  
Nuhu Dalhat Mu’azu ◽  
Omar Alagha ◽  
Ismail Anil
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Systematic Approach ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Plant Performance ◽  
Capacity Analysis ◽  
Activated Sludge Process ◽  
Effluent Quality

Mathematical modeling has become an indispensable tool for sustainable wastewater management, especially for the simulation of complex biochemical processes involved in the activated sludge process (ASP), which requires a substantial amount of data related to wastewater and sludge characteristics as well as process kinetics and stoichiometry. In this study, a systematic approach for calibration of the activated sludge model one (ASM1) model for a real municipal wastewater ASP was undertaken in GPS-X. The developed model was successfully validated while meeting the assumption of the model’s constant stoichiometry and kinetic coefficients for any plant influent compositions. The influences of vital ASP parameters on the treatment plant performance and capacity analysis for meeting local discharge limits were also investigated. Lower influent chemical oxygen demand in mgO2/L (COD) could inhibit effective nitrification and denitrification, while beyond 250 mgO2/L, there is a tendency for effluent quality to breach the regulatory limit. The plant performance can be satisfactory for handling even higher influent volumes up to 60,000 m3/d and organic loading when Total Suspended Solids/Volatile Suspended Solids (VSS/TSS) and particulate COD (XCOD)/VSS are maintained above 0.7 and 1, respectively. The wasted activated sludge (WAS) has more impact on the effluent quality compared to recycle activated sludge (RAS) with significant performance improvement when the WAS was increased from 3000 to 9000 m3/d. Hydraulic retention time (HRT) > 6 h and solids retention time (SRT) < 7 days resulted in better plant performance with the SRT having greater impact compared with HRT. The plant performance could be sustained for a quite appreciable range of COD/5-day Biochemical Oxygen Demand (BOD5 in mgO2/L) ratio, Mixed Liquor Suspended Solid (MLSS) of up to 6000 mg/L, and when BOD5/total nitrogen (TN) and COD/TN are comparatively at higher values. This work demonstrated a systematic approach for estimation of the wastewater treatment plant (WWTP) ASP parameters and the high modeling capabilities of ASM1 in GPS-X when respirometry tests data are lacking.

Fuzzy Control of a Dynamic Activated Sludge Process for the Forecast and Control of Effluent Suspended Solid Concentration

1993 ◽  
Vol 28 (11-12) ◽  
pp. 355-367 ◽  
Author(s):  
Y. P. Tsai ◽  
C. F. Ouyang ◽  
M. Y. Wu ◽  
W. L. Chiang
Keyword(s):  
Fuzzy Control ◽  
Activated Sludge ◽  
Flow Rate ◽  
Suspended Solid ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Solid Concentration ◽  
Suspended Solid Concentration ◽  
And Control ◽  
Influent Flow

The effluent total BOD (or COD) concentration of the activated sludge process (A.S.P.) usually increases with suspended solid concentration. How to reduce effluent S.S. concentration, therefore, is the key issue of treatment efficiency for A.S.P. The varied return sludge and influent flow rate are two major operational factors of those affecting effluent S.S. concentration. However, the wastewater flow rate and substrate concentration in municipal wastewater treatment plant, due to the differences of city scale and life style, are significantly time-varied every day. Based on the above, the purpose of this study is to control in timely fashion return sludge flow rate with the variation of influent flow rate to minimize effluent S.S. concentration and meanwhile decrease the effluent total BOD (or COD) concentration. The fuzzy control theory is utilized in this study to forecast and control effluent S.S. concentration and further predict the MLSS concentration in aeration tank. It reveals that the inferred control strategies not only enable one to decrease effluent S.S.

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