The use of an on-line respirometer for the screening of toxicity in the antwerp WWTP catchment area

1998 ◽  
Vol 37 (12) ◽  
pp. 213-218 ◽  
Author(s):  
D. Geenens ◽  
C. Thoeye
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Nitrification Inhibition ◽  
Environmental Legislation ◽  
Sewer System ◽  
Total Phosphorous ◽  
Wwtp Effluent ◽  
Pilot Work ◽  
On Line ◽  
Activated Sludge Processes

Following the new European and Flemish environmental legislation most of the existing Flemish wastewater treatment plants (WWTP) have to be adapted to achieve nutrient removal. The Antwerp WWTP Deurne-Schijnpoort (230,000 PE) is to be renovated to achieve a 10 mg/l total nitrogen and a 1 mg/l total phosphorous effluent consent. Six months of intensive pilot work at this plant has shown total nitrification inhibition of one- stage activated sludge processes. A mobile on-line respirometer was installed to monitor the activated sludge inhibition at the WWTP. Toxicity resulting in a substantial deterioration of the WWTP effluent was observed. Industrial discharges and main junctions in the sewer system were sampled for specific monitoring. An industrial source of inhibition could be pinpointed. Full-scale operating experiences with the respirometer during the measurements are reported.

Rapid quantification of polyhydroxyalkanoates (PHA) concentration in activated sludge with the fluorescent dye Nile blue A

2011 ◽  
Vol 64 (3) ◽  
pp. 747-753 ◽  
Author(s):  
M. Oshiki ◽  
H. Satoh ◽  
T. Mino
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Nile Blue ◽  
Maximum Level ◽  
Fluorescence Measurement ◽  
Batch Reactors ◽  
Floc Size ◽  
Nile Blue A ◽  
On Line ◽  
Rapid Quantification

The present study was conducted (1) to develop a rapid quantification method of polyhydroxyalkanoates (PHA) concentration in activated sludge by Nile blue A staining and fluorescence measurement and (2) to perform on-line monitoring of PHA concentrations in activated sludge. Activated sludge samples collected from laboratory scale sequencing batch reactors and full-scale wastewater treatment plants were stained with Nile blue A and their fluorescence intensities were determined. There was a high correlation (R2 > 0.97) between the fluorescence intensities of Nile blue A and PHA concentrations in activated sludge determined by gas chromatography. The Nile blue A staining and fluorescence measurement method allows us to determine PHA concentrations in activated sludge within only five minutes and up to 96 samples can be measured at once by using microplate reader. On-line monitoring of PHA concentrations in activated sludge was achieved by using a fluorometer equipped with a flow cell and the time point at which PHA concentration in activated sludge reached the maximum level could be identified. In addition, we examined the influence of pH, floc size and co-existing chemicals in activated sludge suspension on the fluorescence intensities of Nile blue A.

Modelling and simulation of the steady-state of secondary settlers in wastewater treatment plants

2001 ◽  
Vol 43 (7) ◽  
pp. 39-46 ◽  
Author(s):  
I. Queinnec ◽  
D. Dochain
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Steady State ◽  
Activated Sludge ◽  
Parameter Identification ◽  
Wastewater Treatment Plants ◽  
Operating Conditions ◽  
Sensitivity Studies ◽  
Activated Sludge Processes

This paper discusses the steady-state modelling of thickening in circular secondary settlers of activated sludge processes. The limitations of the solid flux theory basic models to represent steady-state operating conditions serve as a basis to introduce more sophisticated models derived from computational fluid dynamics. Parameter identification and sensitivity studies have been performed from lab-scale continuous experiments.

scholarly journals The microbiome and resistome of hospital sewage during passage through the community sewer system

2017 ◽  
Author(s):  
Elena Buelow ◽  
Jumamurat R. Bayjanov ◽  
Rob J.L. Willems ◽  
Marc J.M. Bonten ◽  
Heike Schmitt ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Point Sources ◽  
Resistant Bacteria ◽  
Sewer System ◽  
Sewerage System ◽  
Drug Resistant Bacteria ◽  
Wwtp Effluent ◽  
Antimicrobial Resistance Genes ◽  
Culture Independent ◽  
Hospital Sewage

AbstractEffluents from wastewater treatment plants (WWTPs) have been proposed to act as point sources of antibiotic-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) in the environment. Hospital sewage may contribute to the spread of ARB and ARGs as it contains the feces and urine of hospitalized patients, who are more frequently colonized with multi-drug resistant bacteria than the general population. However, whether hospital sewage noticeably contributes to the quantity and diversity of ARGs in the general sewerage system has not yet been determined.Here, we employed culture-independent techniques, namely 16S rRNA and nanolitre-scale quantitative PCRs, to describe the role of hospital effluent as a point source of ARGs in the sewer system, through comparing microbiota composition and levels of ARGs in hospital sewage with WWTP influent, WWTP effluent and the surface water in which the effluent is released.Compared to other sample sites, hospital sewage was richest in human-associated bacteria and contained the highest relative levels of ARGs. Yet, the abundance of ARGs was comparable in WWTPs with and without hospital wastewater, suggesting that hospitals do not contribute to the spread of ARGs in countries with a functioning sewerage system.

Membrane aerators and stirring systems for the operation in large and small wastewater treatment plants

1996 ◽  
Vol 34 (3-4) ◽  
pp. 329-338 ◽  
Author(s):  
Marcus W. A. Höfken ◽  
Peter Huber ◽  
Marcus Schäfer ◽  
Ralf Steiner
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Energy Demand ◽  
Wastewater Treatment Plants ◽  
Air Bubbles ◽  
Process Step ◽  
Optimum System ◽  
Activated Sludge Processes ◽  
Silicone Membranes

Stirring and aeration processes are the major operations needed for effective wastewater treatment. Especially in activated sludge processes and the variants of this process stirring and aeration systems need to be chosen carefully since both operations are crucial for the purification power and the energy demand of wwtp's. The aim of the present work is to define the demands on stirring and aeration systems for activated sludge treatment plants, to give an overview about suitable systems currently available on the market including latest developments and to give advice how to choose the optimum system. A brief review of the literature and the market of stirring and aeration systems leads to a simple classification of the existing numerous systems. In order to choose the optimum system, first one has to decide, about the demands in each process step. In anaerobic and anoxic reactors the use of hyperboloid stirring systems or combined hyperboloid stirring and aeration systems which distribute small air bubbles throughout the entire reactor in the aeration mode (for intermittent aeration) and gently circulate bacteria flocks in the stirring mode is recommended. For aerobic processes like BOD-removal and nitrification highly efficient membrane aerating systems using silicone membranes are recommended.

Model and Sensor Based Optimization of Nitrogen Removal at Klagshamn Wastewater Treatment Plant

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1315-1323 ◽  
Author(s):  
H. Aspegren ◽  
B. Andersson ◽  
U. Nyberg ◽  
J. la C. Jansen
Keyword(s):  
Wastewater Treatment ◽  
Carbon Source ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
On Line ◽  
Ammonia Sensors

Optimization of wastewater treatment plants with extensive phosphorus and nitrogen removal is complicated. The Klagshamn wastewater treatment plant in Sweden is operated with pre-precipitation of phosphorus with ferric chloride and denitrification with methanol as carbon source. An activated sludge process, operated with pre-precipitation and denitrification with external carbon source in a compartmentalized plant, requires only small tank volumes but increases the need for proper operation and optimization. On-line nitrogen, ammonia, and TOC sensors are used for a day-to-day control and optimization while mathematical modelling is used for long term strategic planning. The on-line measurements are further used as the basis for the modelling. TOC and ammonia sensors at the influent clearly identify typical and extreme loading variations and nitrate measurements in the activated sludge tanks and the effluent shows the dynamics of the processes. These measurements provide a basis for model calibration. In combination low residuals of nitrogen, phosphorus and organic matter can be achieved.

Nitrification Inhibition - A Source Identification Method for Combined Municipal and/or Industrial Wastewater Treatment Plants

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1135-1146 ◽  
Author(s):  
H. Kroiss ◽  
P. Schweighofer ◽  
W. Frey ◽  
N. Matsche
Keyword(s):  
Wastewater Treatment ◽  
Industrial Wastewater ◽  
Wastewater Treatment Plants ◽  
Ammonia Nitrogen ◽  
Nitrification Inhibition ◽  
Sewer System ◽  
Effluent Standards ◽  
Inhibition Of Nitrification ◽  
Short Time ◽  
The Relationship

Inhibition of nitrification at combined municipal and/or industrial treatment plants can cause serve problems in regard to the future low effluent standards for ammonia nitrogen. As inhibition problems often occur only for limited periods and are caused by different substances it is very difficult to find the sources of these substances within the sewer system. Using a two step strategy based on a respiration test it is possible to locate these sources within a short time and to concentrate then on the abatement of the inhibiting wastewaters. The method of the respiration test was developed and the relationship between dilution and inhibition could be described by a new mathematical inhibition model. The method was applied at an Austrian city (Linz) with more than 50% wastewater load coming from industry during the design period for the extension of the existing plant (800 000 PE).

The limits and ultimate possibilities of technology of the activated sludge process

2008 ◽  
Vol 58 (8) ◽  
pp. 1671-1677 ◽  
Author(s):  
A. F. van Nieuwenhuijzen ◽  
A. G. N. van Bentem ◽  
A. Buunnen ◽  
B. A. Reitsma ◽  
C. A. Uijterlinde
Keyword(s):  
Wastewater Treatment ◽  
The Netherlands ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Method ◽  
Activated Sludge Process ◽  
Municipal Wastewater Treatment ◽  
Nitrogen And Phosphorus ◽  
Activated Sludge Processes

The (low loaded) biological nutrient removing activated sludge process is the generally accepted and applied municipal wastewater treatment method in the Netherlands. The hydraulical and biological flexibility, robustness and cost efficiency of the process for advanced removal of nutrients like nitrogen and phosphorus without (too much) chemicals results in a wide application of the activated sludge process within Dutch waterboards. Presumably, wastewater treatment plants will have to contribute to the improvement of the quality of the receiving surface waters by producing cleaner effluent. In this perspective, the Dutch research organisation STOWA initiated a research project entitled “The Boundaries of the Activated Sludge Process” to investigate the possibilities and limitations of activated sludge processes to improve the effluent quality. It is concluded that the activated sludge process as applied and operated at WWTP's in the Netherlands has the potential to perform even better than the current effluent discharge standards (10 mg Ntotal/l and 1 mg Ptotal/l). Reaching the B-quality effluent (<5mg Ntotal/l and <0.3 mg Ptotal/l) will be possible at almost all WWTPs without major adjustments under the conditions that:   the sludge load is below 0.06 kg BOD/kg TSS.d   the internal recirculation is above 20   the BOD/N ratio of the influent is above 3. Complying with the A-quality effluent (<2.2 Ntotal/l and <0.15 mg Ptotal/l) seems to be difficult (but not impossible) and requires more attention and insight into the activated sludge process. Optimisation measures to reach the A-quality effluent are more thorough and are mostly only achievable by additional construction works (addition of activated sludge volume, increasing recirculation capacity, etc.). It is furthermore concluded that the static HSA-results are comparable to the dynamic ASM-results. So, for fast determinations of the limits of technology of different activated sludge processes static modelling seems to by sufficient.

Modelling, Control and On-Line Estimation of Activated Sludge Bulking

1993 ◽  
Vol 28 (11-12) ◽  
pp. 249-256 ◽  
Author(s):  
J. Chen ◽  
M. B. Beck
Keyword(s):  
Kalman Filter ◽  
Activated Sludge ◽  
Process Model ◽  
Model Simulation ◽  
Control Strategies ◽  
Unit Process ◽  
Operating Variables ◽  
Sludge Bulking ◽  
On Line ◽  
Activated Sludge Processes

Sludge bulking is a problem widespread in the operation of activated sludge processes. Over the past fifteen years much research has been applied to identifying the nature of the microbial species responsible for bulking and to developing an understanding of their population dynamics. While some isolated attempts have been made at developing a unit process model capable of simulating the behaviour of bulking, none have been extensively evaluated against field data from full scale plants. This paper describes the development of a multiple-species model of the activated sludge process (for both the reactor and settler), its application to the assessment of various operational strategies for the control of bulking, and its simplification for incorporation into an on-line estimation scheme using a Kalman filter. Routine operating data from the Davyhulme Wastewater Treatment Works in Manchester are used for identification (calibration) of the model. Simulation studies of control strategies are based on the same Works. By using the Kalman filter to reconstruct real-time estimates of the “unmeasurable” states of the process model, the paper also explores the extent to which this filter-based control can bring improvements over similar control based entirely upon conventionally measured operating variables.

PHA-accumulating microorganisms in full-scale wastewater treatment plants

2008 ◽  
Vol 58 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Mamoru Oshiki ◽  
Hiroyasu Satoh ◽  
Takashi Mino ◽  
Motoharu Onuki
Keyword(s):  
Activated Sludge ◽  
Staining Method ◽  
Wastewater Treatment Plants ◽  
Nile Blue ◽  
Buoyant Density ◽  
Full Scale ◽  
Oligonucleotide Probes ◽  
Microbial Groups ◽  
Activated Sludge Processes ◽  
Bacterial Groups

A study was conducted to clarify phylogenetic affiliations of polyhydroxyalkanoate (PHA)-accumulating microorganisms in full-scale activated sludge processes. Activated sludge samples obtained from three full-scale activated sludge processes were aerobically incubated with excess acetate to increase their PHA content. The buoyant density separation method was applied to selectively collect PHA-accumulating cells, which were then analysed by the group-level FISH and the PCR-DGGE-sequencing methods, and possible PHA-accumulating microbial groups were screened. A set of oligonucleotide probes targeting the microbial groups suspected to accumulate PHA was introduced, and seven oligonucleotide probes were newly designed for this purpose. PHA accumulation of probe-positive cells was confirmed by the post-FISH PHA staining method, wherein PHA staining with Nile Blue A (NBA) was applied after FISH. As a result, the following seven bacterial groups were found to have PHA: Dechloromonas, Accumulibacter, Thauera, Zoogloea, Comamonas, Competibacter and a novel cluster in Beta-proteobacteria. Based on the results of the post-FISH PHA staining method, these seven bacterial groups were estimated to account for around four-tenths to two-thirds of total PHA-accumulating microorganisms.

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