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 Reliability of removal of selected pollutants in different technological solutions of household wastewater treatment plants

2017 ◽  
Vol 35 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Michał Marzec
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Total Suspended Solids ◽  
Hybrid Reactor ◽  
Limit Values

AbstractThe reliability of removal of selected contaminants in three technological solutions of the household sewage treatment plants was analysed in this paper. The reliability of the sewage treatment plant with activated sludge, sprinkled biological deposit and hybrid reactor (activated sludge and immersed trickling filter) was analyzed. The analysis was performed using the Weibull method for basic indicators of impurities, BOD5, COD and total suspended solids. The technological reliability of the active sludge treatment plant was 70% for BOD5, 87% for COD and 66% for total suspended solids. In the sewage treatment plant with a biological deposit, the reliability values determined were: 30% (BOD5), 60% (COD) and 67% (total suspended solids). In a treatment plant with a hybrid reactor, 30% of the BOD5and COD limit values were exceeded, while 30% of the total suspended solids were exceeded. The reliability levels are significantly lower than the acceptable levels proposed in the literature, which means that the wastewater discharged from the analysed wastewater treatment plants often exceeds the limit values of indicators specified in currently valid in Poland Regulation of the Minister of Environment for object to 2000 population equivalent.

scholarly journals Tolerable Risk for Hydrogen Sulfide in Sewage Treatment Plant- STP

2022 ◽  
Vol 16 (4) ◽  
pp. 74
Author(s):  
Mohieldeen M. A. Ahmed ◽  
Mohammed H. M. Gaily ◽  
Khalid M.O. Ortashi ◽  
Omer M.A. Al Ghabshawi ◽  
Nagwa F. Bashir ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Radiation Hazard ◽  
Activated Sludge Process ◽  
Outlet Channel ◽  
Toxic Gas ◽  
Inlet Chamber

Hydrogen sulphide is a toxic gas, it can cause a range of physiological responses from simple annoyance to permanent injury and death. There are a number of approaches to deal with the impacts of toxic gases. This study focused on minimizing the hazard exposure for hydrogen sulfide in the different operational zones for activated sludge process in sewage waterplant. Research tools/ approaches conducted were interviews, toxic gas testers, analysis report interpretation &amp; quantitative risk assessment method. The study was conducted on Arabian Peninsula during the period (September 2019- September 2021). The (13) operational locations tested for toxic gas concentrations were inlet chamber, outlet channel, coarse /fine screens, primary sedimentation tank, activated sludge tanks, secondary sedimentation tanks, gas desulfurization unit, disc filters, chlorine dosing unit, sludge dewatering, sludge silos and digester tanks. The study found that the highest concentration for H<sub>2</sub>S in the inlet chamber/ outlet channel. The severity hazards in the sewage treatment plant using activated sludge process are the asphyxiation by H<sub>2</sub>S was extremely high can cause harm to public health, followed by the radiation hazard followed by electrical hazard, then (working at height, mechanical, traffic, health, chemical, physical, ergonomic, environmental, microbial and natural). The frequency of hazards occurrence is asphyxiation by H<sub>2</sub>S was extremely high followed by the radiation hazard and health hazard including the infection with Covid 19 virus followed by mechanical hazard then (electrical, traffic, ergonomic, natural, chemical, physical and natural). Control measures were recommended to minimize the risk of asphyxiation by H<sub>2</sub>S in the working environment at the STP.

Numerical simulation of a secondary clarifier in a sewage treatment plant using modified Bingham model

2011 ◽  
Vol 38 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Mohammad Reza Saffarian ◽  
Mohammad Hossein Hamedi ◽  
Mehrzad Shams
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Computational Domain ◽  
Bingham Model ◽  
Consolidation Process ◽  
Solids Concentration ◽  
Secondary Clarifier ◽  
Sediment Flow

A numerical scheme for simulation of activated sludge sediment flow in a circular secondary clarifier is developed. The flow and settling processes are simulated, using the k–ε turbulence model on a two-dimensional axisymmetric and orthogonal grid. To incorporate the sedimentation of the activated sludge in the field of gravity, a convection–dispersion equation governing the mass transfer in the clarifier is extended. The computational domain includes the sludge blanket where the viscosity is affected by the rheological behavior of the sludge. The double-exponential equation is used to describe the dependence of the settling velocity on the solids concentration. The compression and consolidation process of the activated sludge is simulated by this equation. The experimental data provided by Weiss et al. show that the rheograms follow the Bingham law at low-shear rates. The modified Bingham model was introduced to overcome the blanket height overestimation problem with the results showing that the local sludge distribution in the clarifier has an excellent agreement with the concentration profile measurements by Weiss et al. (2007) and the sludge viscosity dominates the flow and sedimentation of activated sludge within the sludge blanket.

A Study on Application of the Technology for Activated Sludge Reducing

2017 ◽  
Vol 1 ◽  
pp. 1
Author(s):  
Zhan Yang
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Activated Sludge Process ◽  
Sludge Treatment ◽  
Microbial Decomposition ◽  
Physical Chemical

Activated sludge process is the most widely used technology in sewage bioremediation up to now. However, there is also a serious problem with this technology, that is, a great amount of sludge will be left over. In view of this situation, a study has been carried out through the domestic activated technology for sludge treatment and also research on the effective sludge treatment. They made use of the microbial decomposition to decompose the oxide by using the means of physical, chemical, biological, etc. to minimize the effluent from the sewage treatment plant and thus, reduced the amount of sludge produced.

Potential Utilization of OECD 302 B Test in Biodegradability Assessment of Metalworking Fluids

2013 ◽  
Vol 726-731 ◽  
pp. 2256-2259
Author(s):  
Kristina Gerulova ◽  
Jozef Fiala ◽  
Zuzana Szabova ◽  
Eva Buranská ◽  
Petra Paulocikova ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Adsorption Rate ◽  
Metalworking Fluids ◽  
Lag Phase ◽  
Biological Degradation ◽  
B Test

The main aim of this study was to evaluate the ability of the activated sludge from sewage treatment plant to degrade a part of the 12 randomly selected metalworking fluids (MWFs) according to OECD 302B (with different addition of activated sludge AS 0.25 g/l, 0.50 g/l and 1.00 g/l of suspended solids - SS). The degradability test showed that, after the first 3 hours of cultivating, adsorption grew with the increasing amount of inoculums. In the case of AS addition 1.00 g/l of SS were the adsorption rate lower than 20 % in four samples, in the case of AS addition 0.50 g/l of SS in 9 samples and in the case of AS addition 0.25 g/l of SS in all 12 tested samples. In four samples were also observed the lag phase (adaptation of the bacterias to the presented carbon source). If occur adsorption rate more than 20% it is probably impossible to distinguish biological degradation of organic matter from abiotic elimination from the suspension.

A study on filamentous bacteria in activated sludge process of sewage treatment plant in Dubai, United Arab Emirates

2009 ◽  
Vol 4 (2) ◽  
Author(s):  
S. M. Faheem ◽  
M. A. Khan
Keyword(s):  
Activated Sludge ◽  
United Arab Emirates ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Differential Staining ◽  
Type I ◽  
Activated Sludge Process ◽  
Filamentous Bacteria ◽  
Mixed Liquor

A study was conducted on filamentous bacteria implicated in bulking and foaming problems in activated sludge process of sewage treatment plant in Dubai, United Arab Emirates over a period of six months. To determine morphological characteristics of diverse filaments, foam and mixed liquor samples were collected and studied using various simple and differential staining techniques. Fluorescent in situ hybridization analysis was carried out in mixed liquor samples with nocardioform group specific probes using VIT kit (Vermicon Identification Technology, Vermicon, Munich). The dominant filamentous bacteria identified from mixed liquor and foam samples included: A long branched form of Gram varibale nocardioform actinomycetes species, Thiothrix, Eikelboom Type 021N, Sphaerotilus natans, Beggiatoa and Nostocoida limicola type I. Occasionally attached growth forms of Eikelboom type 0041/0675 like filaments were observed in mixed liquor and foam samples especially during warm weather. All filamentous bacteria identified were found in both the samples throughout the study period. FISH analysis successfully identified filamentous and non-filamentous morphotypes of nocardioform group members. It is concluded that specific filamentous bacterial population in mixed liquor and foaming activated sludge was constant and not dependent on variable wastewater characteristics.

A Study on Application of the Technology for Activated Sludge Reducing

2017 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Zhan Yang
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Activated Sludge Process ◽  
Sludge Treatment ◽  
Microbial Decomposition ◽  
Physical Chemical

Activated sludge process is the most widely used technology in sewage bioremediation up to now. However, there is also a serious problem with this technology, that is, a great amount of sludge will be left over. In view of this situation, a study has been carried out through the domestic activated technology for sludge treatment and also research on the effective sludge treatment. They made use of the microbial decomposition to decompose the oxide by using the means of physical, chemical, biological, etc. to minimize the effluent from the sewage treatment plant and thus, reduced the amount of sludge produced.

Diagnosis Expert System for the Activated Sludge Process Using Biota Observed by Microscopic Examination

1993 ◽  
Vol 28 (11-12) ◽  
pp. 231-237
Author(s):  
M. Ichikawa ◽  
K. Simizu ◽  
K. Iwahori
Keyword(s):  
Expert System ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Activated Sludge Process ◽  
Bench Scale ◽  
Data Measurement ◽  
Measurement Results ◽  
Scale Experiment

A diagnosis expert system for the activated sludge process was developed in conformity to our experience and reported studies. Using the biota observed by microscopic and data measurement easily obtained, i.e. pH or DO etc., the process treatability or the activated sludge condition was diagnosed and evaluated by this system. In this paper, the effectiveness of the diagnosis expert system was investigated using the microscopic and measurement results from both the actual sewage treatment plant and the bench-scale experiment. As a result, the low loading and the progress of nitrification were presumed in the case of the actual plant and the variations of treatment condition depending on DO set values were evaluated satisfactorily in the case of the bench-scale experiment. Therefore, it was shown that this system was applicable to the diagnosis of the activated sludge process.

Steps in Planning the Expansion of the Large Sewage Treatment Plant at Buchenhofen, Operated by the Wupper Watershed Management Association

1990 ◽  
Vol 22 (7-8) ◽  
pp. 123-129 ◽  
Author(s):  
Jörg Londong ◽  
Stefan Zander
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Surface Water Quality ◽  
Class Ii ◽  
Activated Sludge Process ◽  
Quality Class

Sewage from 700,000 PE, roughly half of which is discharged by industry, is treated at the Buchenhofen plant operated by the WWMA, using a conventional, activated-sludge process without specific nutrient elimination. A draft management plan has been prepared for the receiving stream of the treatment plant, the Lower Wupper. The chief forms of use for the waters are fixed in binding agreements. The use entailing the strictest limiting values is recreational fishing, which demands surface water quality class II. Very substantial demands, which must be regarded as at least equivalent to state-of-the-art technology, are imposed on the Buchenhofen facility. The Institut für Siedlungswasserbau, Wassergütewirtschaft und Abfalltechnik at the University of Stuttgart was commissioned to formulate realistic purification objectives for the treatment plant and to prepare expansion concepts. At Buchenhofen, the single-stage activated sludge process with nitrification and preliminary de-nitrification has proved to be the most effective method for eliminating nitrogen while simultaneous precipitation followed by flocculation-filtration is the best process for eliminating phosphorus. For purely scientific reasons, however, the extreme demands in terms of ammonium and nitrite rule out expansion of a treatment plant of this size. The proposed designs therefore require validation through commercial-scale testing. Only after a 6- to 12-month test series has been evaluated will a draft design be prepared for approval, ultimately enabling the plant to be expanded and to fulfil the management planning objective of achieving surface water quality class II in the Wupper.

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