Anaerobic Storage of Activated Sludge: Effects on Conditioning and Dewatering Performance

1993 ◽  
Vol 28 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Jacob H. Bruus ◽  
Jimmy R. Christensen ◽  
Hanne Rasmussen
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Working Hours ◽  
Bulk Water ◽  
Optimal Dosage ◽  
Nitrogen And Phosphorus ◽  
Waste Products ◽  
Anaerobic Storage

Since dewatering equipment is commonly operated only during normal working hours, activated sludge must often be stored in an anaerobic condition prior to conditioning. It is the objective of this study to investigate the influence of anaerobic storage on conditioning requirements and dewatering performance on a laboratory scale. Sludges were collected at two large treatment plants (removal of organic matter, nitrogen and phosphorus) and one small treatment plant (removal of organic matter). Thickened activated sludges from the three wastewater treatment plants were stored anaerobically in the laboratory and analyzed frequently during fourteen days of storage. Both organic and inorganic conditioning was used. Turbidity and Dissolved Organic Carbon (DOC) in the sludge bulk water increased as a result of the anaerobic storage. These parameters indicated a release of colloids, dissolved exopolymers and fermentation waste products such as fatty acids to the bulk water. These constituents consumed additional cationic polyelectrolyte. Filterability at the optimal dosage of polyelectrolyte was not affected by anaerobic storage. Therefore, polyelectrolyte requirements are governed by the bulk water constituents, whereas filterability of the sludge is determined by the degree of sludge floc conditioning. Iron requirements seemed unaffected by anaerobic storage, but lime requirements to obtain good filterability increased with anaerobic storage time.

scholarly journals Activated Sludge Microbial Community and Treatment Performance of Wastewater Treatment Plants in Industrial and Municipal Zones

2020 ◽  
Vol 17 (2) ◽  
pp. 436 ◽  
Author(s):  
Yongkui Yang ◽  
Longfei Wang ◽  
Feng Xiang ◽  
Lin Zhao ◽  
Zhi Qiao
Keyword(s):  
Wastewater Treatment ◽  
Microbial Community ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Wastewater Sludge ◽  
Community Diversity ◽  
Nitrogen And Phosphorus ◽  
Metabolic Functions

Controlling wastewater pollution from centralized industrial zones is important for reducing overall water pollution. Microbial community structure and diversity can adversely affect wastewater treatment plant (WWTP) performance and stability. Therefore, we studied microbial structure, diversity, and metabolic functions in WWTPs that treat industrial or municipal wastewater. Sludge microbial community diversity and richness were the lowest for the industrial WWTPs, indicating that industrial influents inhibited bacterial growth. The sludge of industrial WWTP had low Nitrospira populations, indicating that influent composition affected nitrification and denitrification. The sludge of industrial WWTPs had high metabolic functions associated with xenobiotic and amino acid metabolism. Furthermore, bacterial richness was positively correlated with conventional pollutants (e.g., carbon, nitrogen, and phosphorus), but negatively correlated with total dissolved solids. This study was expected to provide a more comprehensive understanding of activated sludge microbial communities in full-scale industrial and municipal WWTPs.

Experiences with a large-size WWTP based on activated sludge-biofiltration processes: 25 months of operation

2004 ◽  
Vol 50 (6) ◽  
pp. 285-293 ◽  
Author(s):  
I. Licskó ◽  
G. Csanád Szabó ◽  
Z. Melicz
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Chemical Precipitation ◽  
High Load ◽  
Plant Performance ◽  
Nitrogen And Phosphorus ◽  
Special Configuration ◽  
Flow Recirculation ◽  
Test Operation

The South-Budapest Wastewater Treatment Plant (SBWWTP) had been operated as a high-load activated sludge (AS) plant since the middle of the 60s. According to the requirements proposed by the water authorities the treatment process had to be upgraded into nutrient (phosphorus and nitrogen) removal. The upgrade of the plant comprised implementation of BIOFOR type nitrifying (NP) and post-denitrifying (DN) biofilters downstream of the AS stage. Phosphorus removal was obtained by chemical precipitation that can be done at five different points for feeding ferric-sulfate (Fe2(SO4)3). Partial flow recirculation was administered from the nitrifying BIOFOR unit ahead of the AS basin for pre-denitrification utilizing raw wastewater as carbon source. The plant performance was monitored since the test operation period for 25 months. Experience revealed that significant nitrification occurs in the high-load activated sludge basin originally designed for carbon removal. During the summer period (characterized by temperature of 20-25°C) about 37-42% ammonium conversion rate was observed in the reactor. The decreasing temperature in the wintertime resulted in lower nitrification rates, of about 6-10%. The combined activated sludge-biofiltration process proved its viability in the removal of organic matter, nitrogen and phosphorus. In this special configuration the AS system plays a key role in the nitrogen and organic matter removal.

Sludge minimization by disintegration at different wastewater treatment plants

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Luchien Luning ◽  
Paul Roeleveld ◽  
Victor W.M. Claessen
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
New Technologies ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Biological Degradation ◽  
Ongoing Research ◽  
Sludge Minimization

In recent years new technologies have been developed to improve the biological degradation of sewage sludge by anaerobic digestion. The paper describes the results of a demonstration of ultrasonic disintegration on the Dutch Wastewater Treatment Plant (WWTP) Land van Cuijk. The effect on the degradation of organic matter is presented, together with the effect on the dewatering characteristics. Recommendations are presented for establishing research conditions in which the effect of sludge disintegration can be determined in a more direct way that is less sensitive to changing conditions in the operation of the WWTP. These recommendations have been implemented in the ongoing research in the Netherlands supported by the National Institute for wastewater research (STOWA).

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.

Analysis and design of suitable model structures for activated sludge tanks with circulating flow

1999 ◽  
Vol 39 (4) ◽  
pp. 55-60 ◽  
Author(s):  
J. Alex ◽  
R. Tschepetzki ◽  
U. Jumar ◽  
F. Obenaus ◽  
K.-H. Rosenwinkel
Keyword(s):  
Activated Sludge ◽  
Large Scale ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
High Sensitivity ◽  
Suitable Model ◽  
Model Structure ◽  
Analysis And Design ◽  
Hydraulic Behaviour ◽  
Model Structures

Activated sludge models are widely used for planning and optimisation of wastewater treatment plants and on line applications are under development to support the operation of complex treatment plants. A proper model is crucial for all of these applications. The task of parameter calibration is focused in several papers and applications. An essential precondition for this task is an appropriately defined model structure, which is often given much less attention. Different model structures for a large scale treatment plant with circulation flow are discussed in this paper. A more systematic method to derive a suitable model structure is applied to this case. Results of a numerical hydraulic model are used for this purpose. The importance of these efforts are proven by a high sensitivity of the simulation results with respect to the selection of the model structure and the hydraulic conditions. Finally it is shown, that model calibration was possible only by adjusting to the hydraulic behaviour and without any changes of biological parameters.

scholarly journals Efficiency and Technological Reliability of Contaminant Removal in Household WWTPs with Activated Sludge

2021 ◽  
Vol 11 (4) ◽  
pp. 1889 ◽  
Author(s):  
Agnieszka Micek ◽  
Krzysztof Jóźwiakowski ◽  
Michał Marzec ◽  
Agnieszka Listosz ◽  
Tadeusz Grabowski
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Treated Wastewater ◽  
Contaminant Removal ◽  
Nitrogen And Phosphorus ◽  
Wastewater Samples ◽  
Polish Law

The results of research on the efficiency and technological reliability of domestic wastewater purification in two household wastewater treatment plants (WWTPs) with activated sludge are presented in this paper. The studied facilities were located in the territory of the Roztocze National Park (Poland). The mean wastewater flow rate in the WWTPs was 1.0 and 1.6 m3/day. In 2017–2019, 20 series of analyses were done, and 40 wastewater samples were taken. On the basis of the received results, the efficiency of basic pollutant removal was determined. The technological reliability of the tested facilities was specified using the Weibull method. The average removal efficiencies for the biochemical oxygen demand in 5 days (BOD5) and chemical oxygen demand (COD) were 66–83% and 62–65%, respectively. Much lower effects were obtained for total suspended solids (TSS) and amounted to 17–48%, while the efficiency of total phosphorus (TP) and total nitrogen (TN) removal did not exceed 34%. The analyzed systems were characterized by the reliability of TSS, BOD5, and COD removal at the level of 76–96%. However, the reliability of TN and TP elimination was less than 5%. Thus, in the case of biogenic compounds, the analyzed systems did not guarantee that the quality of treated wastewater would meet the requirements of the Polish law during any period of operation. This disqualifies the discussed technological solution in terms of its wide application in protected areas and near lakes, where the requirements for nitrogen and phosphorus removal are high.

Comparison of two treatments for the removal of selected organic micropollutants and bulk organic matter: conventional activated sludge followed by ultrafiltration versus membrane bioreactor

2011 ◽  
Vol 63 (4) ◽  
pp. 733-740 ◽  
Author(s):  
E. Sahar ◽  
M. Ernst ◽  
M. Godehardt ◽  
A. Hein ◽  
J. Herr ◽  
...  
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Macrolide Antibiotics ◽  
Organic Micropollutants ◽  
Removal Rates ◽  
Conventional Activated Sludge

The potential of membrane bioreactor (MBR) systems to remove organic micropollutants was investigated at different scales, operational conditions, and locations. The effluent quality of the MBR system was compared with that of a plant combining conventional activated sludge (CAS) followed by ultrafiltration (UF). The MBR and CAS-UF systems were operated and tested in parallel. An MBR pilot plant in Israel was operated for over a year at a mixed liquor suspended solids (MLSS) range of 2.8–10.6 g/L. The MBR achieved removal rates comparable to those of a CAS-UF plant at the Tel-Aviv wastewater treatment plant (WWTP) for macrolide antibiotics such as roxythromycin, clarithromycin, and erythromycin and slightly higher removal rates than the CAS-UF for sulfonamides. A laboratory scale MBR unit in Berlin – at an MLSS of 6–9 g/L – showed better removal rates for macrolide antibiotics, trimethoprim, and 5-tolyltriazole compared to the CAS process of the Ruhleben sewage treatment plant (STP) in Berlin when both were fed with identical quality raw wastewater. The Berlin CAS exhibited significantly better benzotriazole removal and slightly better sulfamethoxazole and 4-tolyltriazole removal than its MBR counterpart. Pilot MBR tests (MLSS of 12 g/L) in Aachen, Germany, showed that operating flux significantly affected the resulting membrane fouling rate, but the removal rates of dissolved organic matter and of bisphenol A were not affected.

Interpretation of Experimental Data with Regard to the Activated Sludge Model No.1 and Calibration of the Model for Municipal Wastewater Treatment Plants

1992 ◽  
Vol 25 (6) ◽  
pp. 167-183 ◽  
Author(s):  
H. Siegrist ◽  
M. Tschui
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Municipal Wastewater Treatment ◽  
Activated Sludge Model

The wastewater of the municipal treatment plants Zürich-Werdhölzli (350000 population equivalents), Zürich-Glatt (110000), and Wattwil (20000) have been characterized with regard to the activated sludge model Nr.1 of the IAWPRC task group. Zürich-Glatt and Wattwil are partly nitrifying treatment plants and Zürich-Werdhölzli is fully nitrifying. The mixing characteristics of the aeration tanks at Werdhölzli and Glatt were determined with sodium bromide as a tracer. The experimental data were used to calibrate hydrolysis, heterotrophic growth and nitrification. Problems arising by calibrating hydrolysis of the paniculate material and by measuring oxygen consumption of heterotrophic and nitrifying microorganisms are discussed. For hydrolysis the experimental data indicate first-order kinetics. For nitrification a maximum growth rate of 0.40±0.07 d−1, corresponding to an observed growth rate of 0.26±0.04 d−1 was calculated at 10°C. The half velocity constant found for 12 and 20°C was 2 mg NH4-N/l. The calibrated model was verified with experimental dam of me Zürich-Werdhölzli treatment plant during ammonia shock load.

OPTIMIZING OPERATION OF WASTEWATER TREATMENT PLANTS BY OFFLINE AND ONLINE COMPUTER SIMULATION

1994 ◽  
Vol 30 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Ralf Otterpohl ◽  
Thomas Rolfs ◽  
Jörg Londong
Keyword(s):  
Computer Simulation ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Historical Analysis ◽  
Computer Work ◽  
Biological Phosphorus Removal ◽  
Wide Range

Computer simulation of activated sludge plant for nitrogen removal has become a reliable tool to predict the behaviour of the plant Models including biological phosphorus removal still require some practical experience but they should be available soon. This will offer an even wider range than today's work with nitrogen removal. One major benefit of computer simulation of wastewater treatment plants (WTP) is the optimization of operation. This can be done offline if hydrographs of a plant are collected and computer work is done with “historical” analysis. With online simulation the system is fed with hydrographs up to the actual time. Prognosis can be done from the moment of the computer work based on usual hydrographs. The work of the authors shows how accuratly a treatment plant can be described, when many parameters are measured and available as hydrographs. A very careful description of all details of the special plant is essential, requiring a flexible simulation tool. Based on the accurate simulation a wide range of operational decisions can be evaluated. It was possible to demonstrate that the overall efficiency in nitrogen removal and energy consumption of ml activated sludge plant can be improved.

Influence of Hydraulic Loading Rate on Horizontal Zeolite Wetland Effluent Quality

2012 ◽  
Vol 573-574 ◽  
pp. 659-662
Author(s):  
Hao Wang
Keyword(s):  
Wastewater Treatment ◽  
Loading Rate ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Secondary Effluent ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Hydraulic Loading Rate ◽  
Effluent Quality ◽  
Hydraulic Loading

In Tangshan area, the secondary effluent of wastewater treatment plants was used for this study. Horizontal zeolite wetland was carried out treating it. Hydraulic loading rate was the parameters for analyzing the nitrogen and phosphorus removal efficiency of pollutants from the secondary effluent of wastewater treatment plant. Zeolite constructed wetlands showed different behaviors for nitrogen and phosphorus removals.Under the optimum hydraulic loading rate, the primary pollutions were removed to a large extent.

Sign in / Sign up

Export Citation Format

Share Document