Changes in Microfauna at the Time of Occurrence and Disappearance of Filamentous Bulking

1991 ◽  
Vol 23 (4-6) ◽  
pp. 907-916 ◽  
Author(s):  
M. Terashi ◽  
S. Hamada
Keyword(s):  
Hydrogen Sulfide ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Filamentous Bacteria ◽  
Filamentous Bulking ◽  
Final Effluent ◽  
Low Do

In the activated sludge process, the cause of filamentous bulking is often the filamentous bacteria Type 021N. At the Kitaminato sewage treatment plant, it was found that when the DO in the aeration tank decreased, filamentous bulking occurred. If the low DO condition is allowed to continue, anaerobic degraded organic matter is produced which creates a favorable condition for the multiplication of Type 021N. Entosiphon sp. is reported to show resistance to low DO; however, sometimes before filamentous bulking occurs, Entosiphon sp. itself multiples. Also if Entosiphon sp. increases and Cinetochilummargaritaceum, of the Ciliophora, multiples, then bulking by Type 021N has been seen not to occur. Cinetochilummargaritaceum has low resistance to hydrogen sulfide; therefore, hydrogen sulfide must not be present in the aeration tank and this means that bulking by Type 021N can not become serious. However, if filamentous bulking becomes serious, only increasing the DO level in the aeration tank will not cause the disappearance of the filamentous bulking. At this stage, if we allow 30% of the final effluent to flow back into the grit chamber, then Type 021N decreases. This is because Trithigmostomacucullulus, of the Ciliophora, increases to 3,000 number/ml, and it ingests Type 021N.

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.

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.

Lysis of filamentous bacteria by surfactants

1996 ◽  
Vol 34 (5-6) ◽  
pp. 145-153 ◽  
Author(s):  
Katsura Kitatsuji ◽  
Hiroshi Miyata ◽  
Tetsuro Fukase
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
High Rate ◽  
Synthetic Surfactant ◽  
Aeration Tank ◽  
Filamentous Bacteria ◽  
Toc Removal ◽  
Synthetic Surfactants

A microbial substance that lyses filamentous bacteria was obtained. The substance also exhibited some properties of a bio-surfactant. Lysing of filamentous bacteria with synthetic surfactants was also examined. Several synthetic surfactants were found to be capable of lysing filamentous bacteria. Nonionic synthetic surfactants with an HLB of 11-15 were found to lyse type 1701 and type 021N in an activated sludge sampled from a sewage treatment plant. Use of the synthetic surfactant to lyse filamentous bacteria was also demonstrated in a continuous-feed aeration tank, and settleability of sludge was improved. The surfactants did not adversely effect floc-forming microorganisms as evidenced by the high rate of TOC removal. The results indicate that synthetic surfactants can be used to prevent filamentous bulking in the activated sludge process.

scholarly journals Modelling of hydrogen sulfide fate and emissions in extended aeration sewage treatment plant using TOXCHEM simulations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Haider M. Zwain ◽  
Basim K. Nile ◽  
Ahmed M. Faris ◽  
Mohammadtaghi Vakili ◽  
Irvan Dahlan
Keyword(s):  
Hydrogen Sulfide ◽  
Wind Speed ◽  
Statistical Evaluation ◽  
Loading Rate ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Mean Square ◽  
Sewage Treatment Plants ◽  
The Ideal

AbstractOdors due to the emission of hydrogen sulfide (H2S) have been a concern in the sewage treatment plants over the last decades. H2S fate and emissions from extended aeration activated sludge (EAAS) system in Muharram Aisha-sewage treatment plant (MA-STP) were studied using TOXCHEM model. Sensitivity analysis at different aeration flowrate, H2S loading rate, wastewater pH, wastewater temperature and wind speed were studied. The predicted data were validated against actual results, where all the data were validated within the limits, and the statistical evaluation of normalized mean square error (NMSE), geometric variance (VG), and correlation coefficient (R) were close to the ideal fit. The results showed that the major processes occurring in the system were degradation and emission. During summer (27 °C) and winter (12 °C), about 25 and 23%, 1 and 2%, 2 and 2%, and 72 and 73% were fated as emitted to air, discharged with effluent, sorbed to sludge, and biodegraded, respectively. At summer and winter, the total emitted concentrations of H2S were 6.403 and 5.614 ppm, respectively. The sensitivity results indicated that aeration flowrate, H2S loading rate and wastewater pH highly influenced the emission and degradation of H2S processes compared to wastewater temperature and wind speed. To conclude, TOXCHEM model successfully predicted the H2S fate and emissions in EAAS system.

Alkylphenol Polyethoxylate Metabolites in Canadian Sewage Treatment Plant Waste Streams

1998 ◽  
Vol 33 (2) ◽  
pp. 231-252 ◽  
Author(s):  
D.T. Bennie ◽  
C.A. Sullivan ◽  
H.-B. Lee ◽  
R.J. Maguire
Keyword(s):  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Dry Weight ◽  
Priority Substances ◽  
Waste Streams ◽  
Nonylphenol Ethoxylate ◽  
Almost All ◽  
Final Effluent

Abstract Nonylphenol polyethoxylates and their refractory metabolites, including nonylphenol, are on the second Priority Substances List (PSL2) to determine if they are "toxic" as defined under the Canadian Environmental Protection Act. This study addresses the need for data on their occurrence in raw sewage, final effluents and sludge in Canada. Samples of raw sewage, final effluent and sludge were collected from 16 wastewater treatment plants across Canada in 1995 and 1996. These samples were analyzed for 4-nonylphenol (4-NP), nonylphenol ethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO) and 4-4-tert-octylphenol (4-t-OP). Measurable quantities of these chemicals were found in almost all raw sewage and sludge samples. In the raw sewage, concentrations ranged from &lt;0.005 to 21 μg/L for 4-t-OP, from 0.69 to 155 μg/L for 4-NP, from 2.9 to 43 μg/L for NP1EO and from 0.26 to 24 μg/L for NP2EO. Sludge concentrations (based on dry weight) ranged from &lt;0.010 to 20 μg/g, from 8.4 to 850 μg/g, from 3.9 to 437 μg/g and from 1.5 to 297 μg/g for 4-t-OP, 4-NP, NP1EO and NP2EO, respectively. Of the final effluent samples, 60% contained detectable amounts of 4-t-OP and concentrations ranged from &lt;0.005 to 0.37 μg/L. Almost all of the final effluent samples had detectable levels of 4-NP, NP1EO and NP2EO. The 4-NP concentrations varied from &lt;0.020 to 13 μg/L, NP1EO was found in the range of 0.072 to 26 μg/L and NP2EO was found in the range of 0.099 to 21 μg/L.

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.

Evaluation of the Efficiency of a New Aeration System at Henriksdal Sewage Treatment Plant

1988 ◽  
Vol 20 (4-5) ◽  
pp. 85-92 ◽  
Author(s):  
L.-G. Reinius ◽  
J. Hultgren
Keyword(s):  
Air Flow ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Design Flow ◽  
The Other ◽  
Aeration Tank ◽  
Aeration System ◽  
Term Change ◽  
Fine Bubble

Henriksdal sewage treatment plant is the largest plant in Stockholm with a design flow of 370 000 m3/d. In one aeration tank of eleven a new fine-bubble aeration system has been in operation since August 1985. The tank is divided into 6 equal parts. The first part is an anoxic zone and the other five are aeration zones with tapered diffusers. Several instruments are installed in the block including separate air flow monitors in each of the five zones and D.O.-probes in the inlet and outlet of the zones. Equipment for flow measurement of settled sewage and return sludge is also installed. Every instrument is connected to a computer for data acquisition. To evaluate the efficiency of the aeration system the oxygenation transfer capacity has been calculated from the oxygen massbalance equation for each zone as a function of air flow. To solve this equation the respiration has to be known and this is done by a simple respirometer for samples of the MLSS in each zone. When the KLa-values are known as functions of the air flow the mass balance equation can be used to calculate the respiration rate in each zone. The computer has been logging data for 2 2 months, and it is possible to calculate the respiration rates in the different zones every hour during this period. It is very important to know the respiration along the tank and how it varies to get the optimal tapering of the diffusers when it is time to change the aeration system in the other 10 tanks. The calculations show a different pattern in the respiration over the year depending on the rate of nitrification. Another use of the calculation of the oxygenation transfer efficiency is to recognize if any long-term change occurs due to clogging of the diffusers.

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