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 Determination of Kinetic Constants for Treating Tannery Wastewater Using Activated Sludge Process (ASP)

2021 ◽  
pp. 115-122
Author(s):  
Baviya. K. R ◽  
Sathyamoorthy. G. L
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Second Order ◽  
Process Efficiency ◽  
Tannery Wastewater ◽  
Scale Model ◽  
Aeration Tank ◽  
Order Kinetic ◽  
Activated Sludge Process ◽  
Local Conditions

A study was conducted to evaluate the feasibility of Activated Sludge Process (ASP) for the treatment of tannery wastewater and to develop a simple design criterion under local conditions. A bench scale model comprising of an aeration tank and final clarifier was used for this purpose. The Lab scale reactor was operated continuously and settled tannery wastewater was used as influent to the aeration tank. Five days Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) of the influent and effluent were measured to find process efficiency at various mixed liquor volatile suspended solids (MLVSS) and Hydraulic Detention Time (θ).The results of the study demonstrated that an efficiency of above 90% and 80% for BOD5 and COD, respectively could be obtained if the ASP is operated at an MLVSS concentration of 3500 mg/L keeping an aeration time of 12 hours.ASP is a feasible treatment technology for tannery wastewater treatment, by conducting experiments at the HRTs of 12,10,8,6 and 2 h, it was found that the maximum COD removal efficiency of 84.20% was recorded at 12 h HRT. In this study, the Mathematical Models such as Monod, Grau Second Order, Modified Stover-Kicannon and First Order Kinetic Models were applied for the performance evaluation of the Reactor at any given time and found that the data were in good agreement with the observed ones in the models, such as, Grau second order and Monod. Further, the correlation coefficient value (R2) obtained for the experimental and predicted effluent COD concentration using the above mentioned (Grau second order and Monod) models also confirmed the suitability applying the models to predict the performance of the reactor under lab scale-controlled environmental conditions.

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 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.

scholarly journals Modèle de référence pour évaluer différentes stratégies de contrôle dans des usines de traitement des eaux usées

2005 ◽  
Vol 15 (2) ◽  
pp. 543-556 ◽  
Author(s):  
O. A.Z. Sotomayor ◽  
S. W. Park ◽  
C. Garcia
Keyword(s):  
Activated Sludge ◽  
Task Group ◽  
Activated Sludge Process ◽  
Matlab Simulink ◽  
Qualité De L’Eau ◽  
On Line ◽  
Do Concentration ◽  
Donnent Lieu ◽  
Temps Reel ◽  
Facteurs Économiques

Dans la majorité des pays, il existe des lois strictes pour réglementer la qualité de l'eau provenant des systèmes de traitement d'eaux usées. Ces spécifications légales sont essentiellement influencées par des questions telles que la santé publique, l'environnement et les facteurs économiques. Les objectifs fondamentaux des procédés de traitement des eaux usées sont d'atteindre, avec l'utilisation d'énergie et à des coûts opérationnels minimaux, une concentration de matière biodégradable et de nutriments suffisamment basse dans les effluents et une production minimale de boues. Les systèmes de traitement des eaux usées sont de grandes dimensions et complexes. Ils sont aussi sujets à des variations importantes dans le flux d'entrée et dans la composition de l'eau à l'entrée, qui ne sont pas bien connues. Le procédé est multivariable, avec beaucoup de couplages croisés et nonlinéarités importantes. La dynamique dépend de la variabilité des flux d'entrée et de la complexité des phénomènes physico-chimiques et biochimiques. Le comportement dynamique démontre une énorme variation de temps de réponse (de quelques minutes jusqu'à plusieurs jours). Ces problèmes, combinés aux objectifs les plus importants du traitement des eaux usées, donnent lieu à une demande de techniques de commande avancées, qui peuvent conduire à une réduction du volume à traiter, une diminution importante dans l'utilisation des produits chimiques, et une possibilité d'économie d'énergie et une diminution des coûts d'opération. Dans ce travail, un " benchmark " (modèle de référence) d'un système complet de traitement des eaux usées a été développé, pour évaluer, à partir de simulations, la performance des différentes stratégies de commande proposées, y compris les techniques de respirométrie ("respirometry"). Ce travail s'aparente au Programme Européen d'Action COST (COST 624), et au projet "Respirometry in Control of the Activated Sludge Process (IWA Respirometry Task Group"). Le "Benchmark" représente un procédé de prédénitrification de la boue activée pour éliminer la matière organique et l'azote des effluents domestiques. Le simulateur est basé sur des modèles largement acceptés par la communauté internationale et il a été implanté dans un environnement Matlab/Simulink. La topologie du système et le développement complet du simulateur sont présentés dans ce travail. L'effet des conditions initiales et des caractéristiques du flux d'entrée (valeurs moyennes) sont analysés, aussi bien qu'un test en boucle ouverte. Les stratégies suivantes ont été sélectionnées en guise d'illustration de l'application de la commande automatique dans le "benchmark" (seulement avec commande proportionnel-intégral monovariable): commande basée sur la concentration d'oxygène dissous ("DO concentration-based control"), commande par respirométrie (commande par biomasse active et commande par taux de respiration bactérienne), et commande par concentration de nitrate (commande par dosage externe de carbone et recyclage du flux interne). Le "benchmark" est continuellement mis a jour et sa prochaine version va incorporer des fonctions d'optimisation en temps réel (on line) pour le procédé.

Kinetic Model of Sequencing Batch Activated Sludge Process for Municipal Wastewater Treatment

1991 ◽  
Vol 23 (4-6) ◽  
pp. 1097-1106 ◽  
Author(s):  
H. Nakazawa ◽  
K. Tanaka
Keyword(s):  
Wastewater Treatment ◽  
Kinetic Model ◽  
Activated Sludge ◽  
Mathematical Models ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Activated Sludge Process ◽  
Municipal Wastewater Treatment ◽  
Operational Conditions ◽  
Aeration Time

Mathematical models based on the kinetic aspect of the sequencing batch activated sludge process were developed to explain the characteristics of the process treating municipal wastewater. These models are a steady-state model dealing with the overall relationship between biomass concentrations in a reactor and operational conditions of the process, and a kinetic model dealing with the behaviors of biomass and substrate in a reactor within one cycle time of the process. Applying these mathematical models for the results of pilot-scale experiments for municipal wastewater treatment, reasonable parameters' values were obtained and the effects of operating strategies including the aeration time ratio and the solids retention time became clear for the process performance.

scholarly journals Molecular analyses of pure cultures of filamentous bacteria isolated from activated sludge

2005 ◽  
Author(s):  
◽  
Dashika Naidoo
Keyword(s):  
Activated Sludge ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Control Strategies ◽  
In Situ Hybridisation ◽  
Process Efficiency ◽  
Nucleotide Sequencing ◽  
Activated Sludge Process ◽  
Filamentous Bacteria ◽  
Morphological Variations ◽  
Pure Cultures

The activated sludge process is the mostl used biological treatment process. Engineers and microbiologists are constantly seeking ways to improve process efficiency, which can be attributed to the increasing demand for fresh water supplies and proper environmental management. Since the inception of the activated sludge process, bulking and foaming have been major problems affecting its efficiency. Filamentous bacteria have been identified as the primary cause of bulking and foaming. Numerous attempts have been made to resolve this problem. Some of these attempts were effective as interim measures but failed as long term control strategies. The identification of filamentous bacteria and the study of their physiology have been hampered by the unreliability of conventional microbiological techniques. This is largely due to their morphological variations and inconsistent characteristics within different environments. To fully understand their role in promoting bulking and foaming, filamentous bacteria need to be characterized on a molecular level. The aim of this study was, therefore, to identify filamentous bacteria in pure culture with the purpose of validating these findings to the physiological traits of the pure cultures when they were isolated. Fourteen different filamentous cultures were used for this study. The cultures were identified using specific oligonucleotide probes via fluorescent in situ hybridisation and nucleotide sequencing. Prior to sequencing, an agarose gel and a denaturing gradient gel Electrophoresis profile were determined for each isolate. The various techniques were optimised specifically for the filamentous isolates. The isolates were identified as Gordonia amarae, Haliscomenobacter hydrossis, Acinetobacter sp./Type 1863, Type 021N, Thiothrix nivea, Sphaerotilus natans and Nocardioform organisms.

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