On-line estimation of suspended solids in biological reactors of WWTPs using a Kalman observer

2009 ◽  
Vol 60 (3) ◽  
pp. 567-574 ◽  
Author(s):  
S. Beltrán ◽  
I. Irizar ◽  
H. Monclús ◽  
I. Rodríguez-Roda ◽  
E. Ayesa
Keyword(s):  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Internal Flow ◽  
Pilot Scale ◽  
Experimental Information ◽  
Design Development ◽  
Stability Performance ◽  
Solids Concentration ◽  
On Line ◽  
The Stability

The total amount of solids in Wastewater Treatment Plants (WWTPs) and their distribution among the different elements and lines play a crucial role in the stability, performance and operational costs of the process. However, an accurate prediction of the evolution of solids concentration in the different elements of a WWTP is not a straightforward task. This paper presents the design, development and validation of a generic Kalman observer for the on-line estimation of solids concentration in the tank reactors of WWTPs. The proposed observer is based on the fact that the information about the evolution of the total amount of solids in the plant can be supplied by the available on-line Suspended Solids (SS) analysers, while their distribution can be simultaneously estimated from the hydraulic pattern of the plant. The proposed observer has been applied to the on-line estimation of SS in the reactors of a pilot-scale Membrane Bio-Reactor (MBR). The results obtained have shown that the experimental information supplied by a sole on-line SS analyser located in the first reactor of the pilot plant, in combination with updated information about internal flow rates data, has been able to give a reasonable estimation of the evolution of the SS concentration in all the tanks.

Performance of activated sludge diffusion for biological treatment of hydrogen sulphide gas emissions

2013 ◽  
Vol 68 (9) ◽  
pp. 1932-1939 ◽  
Author(s):  
Vera L. Barbosa ◽  
Richard M. Stuetz
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Hydrogen Sulphide ◽  
Biological Treatment ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Broad Application ◽  
H2s Removal ◽  
Treatment Performance ◽  
Solids Concentration

Odours from wastewater treatment plants are comprised of a mixture of various gases with hydrogen sulphide (H2S) often being the dominant constituent. Activated sludge diffusion (ASD) as a biotreatment system for odour abatement has been conducted for over 30 years but has limited broad application due to disagreement in the literature regarding the effect that ASD may have on wastewater treatment performance. The effects of continuous H2S diffusion at 25 ppmv, with weekly peaks of approximately 100 ppmv, on H2S removal efficiency and wastewater treatment performance was evaluated over a 2-month period using an activated sludge pilot plant. H2S removal averaged 100% during diffusion at 25 ppmv, and 98.9% during the 100 ppmv peak periods. A significant increase in mixed liquor volatile suspended solids concentration (P < 0.01) was observed during H2S diffusion, which may be due to an increase in H2S-degrading microorganisms. There was no adverse effect of H2S on nitrification throughout the ASD trials. Ammonia (NH3) removal was slightly better in the test receiving H2S diffusion (87.6%) than in the control (85.4%). H2S diffusion appeared to improve robustness of the AS biomass to operational upsets.

Increased performance of secondary clarifiers using dynamic distribution of minimum return sludge rates

2009 ◽  
Vol 60 (9) ◽  
pp. 2439-2445 ◽  
Author(s):  
A. Lynggaard-Jensen ◽  
P. Andreasen ◽  
F. Husum ◽  
M. Nygaard ◽  
J. Kaltoft ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Suspended Solids ◽  
Considerable Increase ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Total Flow ◽  
Equal Distribution ◽  
Solids Concentration ◽  
Hydraulic Load ◽  
And Control

Most wastewater treatment plants have several secondary clarifiers or even more sets of clarifiers including several secondary clarifiers, and in practice it is a well known problem that equal distribution of the load to the single clarifier (or set of clarifiers) is very difficult—not to say impossible—to obtain. If the problem is neglected, quite a big percentage of the total clarifier capacity—measured as the max. allowed hydraulic load—can be lost. Further, return sludge rates are seldom controlled by any other means than as a (typically too high) percentage of the inlet to the wastewater treatment plant—giving a varying and too low suspended solids concentration in the return sludge, which again can lead to an unnecessary use of polymer in the pre-dewatering of the surplus sludge taken from the return sludge. A control of the return sludge rate divided into two parts - control of the total return sludge flow and control of how the total flow shall be distributed between the secondary clarifiers - is able to solve the mentioned problems. Finally, as shall be demonstrated on full scale wastewater treatment plants, a considerable increase of the hydraulic capacity of the treatment plants can be obtained.

Knowledge based diagnosis of solids-liquid separation problems

1996 ◽  
Vol 33 (2) ◽  
pp. 219-226 ◽  
Author(s):  
Sven-Göran Bergh ◽  
Gustaf Olsson
Keyword(s):  
Suspended Solids ◽  
Dynamic Models ◽  
Treatment Plant ◽  
Sensor Calibration ◽  
Knowledge Based ◽  
Good Ability ◽  
Solids Concentration ◽  
Hydraulic Conditions ◽  
Process Failure ◽  
On Line

Often the suspended solids concentration in activated sludge treatment plants may display both large amplitudes and unnaturally fast changes. If the sensor calibration has been found satisfactory, the abnormal appearance has to be explained by the process itself. There may be three principal reasons for such a behaviour: severe hydraulic conditions, poor floc separation properties or very high sludge blanket. During these circumstances it is very informative to qualitatively examine the relationships between the suspended solids concentration variations and important influencing variables, such as the flow rates and the sludge blanket level. This kind of knowledge based diagnosis is superior to dynamic models for such odd behaviour. A simple on-line method to perform the diagnosis is presented. The method has been tested on a massive set of data from a full scale wastewater treatment plant in Sweden and shown unexpected good ability to supply early warnings. It is also shown that small hydraulic disturbances may purposefully be injected into the settler in order to analyse the risk for process failure.

Microsieving in primary treatment: effect of chemical dosing

2016 ◽  
Vol 74 (2) ◽  
pp. 438-447 ◽  
Author(s):  
J. Väänänen ◽  
M. Cimbritz ◽  
J. la Cour Jansen
Keyword(s):  
Wastewater Treatment ◽  
Phosphorus Removal ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Primary Treatment ◽  
Municipal Wastewater Treatment ◽  
Chemically Enhanced Primary Treatment ◽  
Municipal Wastewater Treatment Plants

Primary and chemically enhanced primary wastewater treatment with microsieving (disc or drum filtration) was studied at the large pilot scale at seven municipal wastewater treatment plants in Europe. Without chemical dosing, the reduction of suspended solids (SS) was (on average) 50% (20–65%). By introducing chemically enhanced primary treatment and dosing with cationic polymer only, SS removal could be controlled and increased to >80%. A maximum SS removal of >90% was achieved with a chemical dosing of >0.007 mg polymer/mg influent SS and 20 mg Al3+/L or 30 mg Fe3+/L. When comparing sieve pore sizes of 30–40 μm with 100 μm, the effluent SS was comparable, indicating that the larger sieve pore size could be used due to the higher loading capacity for the solids. Phosphorus removal was adjusted with the coagulant dose, and a removal of 95–97% was achieved. Moreover, microsieving offers favourable conditions for automated dosing control due to the low retention time in the filter.

EXPERIMENTAL INVESTIGATION INTO THE EFFECTS OF REDUCED VERTICAL CENTRE OF GRAVITY OF AN ARTICULATED CONCRETE MATTRESS IN CURRENT FLOW

2021 ◽  
Vol 159 (A3) ◽  
Author(s):  
A Neville ◽  
R McLaren ◽  
J Weber ◽  
C Chin ◽  
J Binns ◽  
...  
Keyword(s):  
Current Flow ◽  
Experimental Testing ◽  
Force Sensor ◽  
Experimental Information ◽  
Centre Of Gravity ◽  
Stability Performance ◽  
Fluid Velocities ◽  
Uniform Current ◽  
The Stability ◽  
Six Degree Of Freedom

An articulated concrete mattress model has been utilised to investigate the effects of reduced vertical centre of gravity on the stability of a 400 series block. Experimental testing was conducted at the AMC CWC, Beauty Point. To determine the effects that a reduced centre of gravity has on stability, the 3 by 3 articulated concrete mattress model was subject to pure uniform current flow. The subsequent forces were analysed with a six degree of freedom underwater force sensor. In order to gain a range of real world scenarios, the experimental model was tested at six flow angles ranging from -15 degrees through to 60 degrees, at 15 degree increments. Additionally, five fluid velocities starting at 0.6 m/s through to 1.4 m/s, at 0.2 m/s increments were investigated. These results explain how the inversion of a 400 series block increases its hydrodynamic coefficients and subsequently decreases its stability performance in current flow. Ultimately, this study provides experimental information for the installation of 400 series articulated concrete mattresses in the inverted orientation.

Prediction of Suspended Solids in Urban Sewers by Transfer Function Model

1994 ◽  
Vol 29 (1-2) ◽  
pp. 171-179 ◽  
Author(s):  
J. W. Delleur ◽  
Y. Gyasi-Agyei
Keyword(s):  
Transfer Function ◽  
Suspended Solids ◽  
Remote Access ◽  
Transfer Function Model ◽  
Concentration Data ◽  
Function Model ◽  
Main Trunk ◽  
Solids Concentration ◽  
On Line

There is increasing concern about the sediments transported in urban storm sewers. Progress has been made on the measurement of suspended solids, and telemetry systems have been installed that permit remote access to flow, temperature and suspended solids concentration data. Using observations obtained in the main trunk sewer in Brussels, Belgium, a transfer function model for the prediction of suspended load concentration from temperature and discharge measurements was developed. This model is based on the transfer function methodology developed by Box and Jenkins. It is shown that the transfer function model correctly tracks the suspended solids observations and makes reasonable forecasts. It provides a valid alternative for the determination of suspended solids in urban sewers from discharge and water temperature observations which are more easily measurable on line than suspended solids.

PHYSICAL-CHEMICAL TREATMENT OF WASTE EFFLUENTS FROM CANNING OF LEAFY GREEN VEGETABLES

1974 ◽  
Vol 37 (4) ◽  
pp. 205-208 ◽  
Author(s):  
Wayne A. Bough
Keyword(s):  
Activated Carbon ◽  
Chemical Treatment ◽  
Suspended Solids ◽  
Pilot Scale ◽  
Cationic Polymer ◽  
Anionic Polymer ◽  
Physical Chemical ◽  
Solids Concentration ◽  
Waste Effluents ◽  
Turnip Greens

Suspended soilds in waste effluents from the canning of leafy green vegetables were effectively reduced by segregation and separate physical-chemical treatment of the unit wastes. Turbidity in the dunker washer effluent from spinach was reduced by treatment with 0.04 mg of an anionic polymer per liter at pH 4.0. The most concentrated effluent (from the tumbler fillers) contained 11% of the total suspended solids load and 16% of the COD in only 1.3% of the waste water flow. Treatment with 20 mg cationic polymer per liter, 80 mg ferric sulfate per liter, and 2 mg anionic polymer per liter reduced the suspended solids concentration from 1,348 mg/l to 63 mg/l—a reduction of 95%. The tumbler filler effluent from turnip greens and diced roots was treated on a pilot-scale with 70 mg cationic polymer per liter, 80 mg calcium chloride per liter and 10 mg anionic polymer per liter to reduce the suspended solids from 1,148 to 140 mg/l The composite effluent from canning of turnip greens and diced roots was treated with polymeric flocculating agents and activated carbon in a physical-chemical treatment system. The suspended solids concentration was reduced by 92% and the COD by 19% through flocculation and settling. The clarified effluent was applied to a downpass column of activated carbon which adsorbed 89% of the COD applied.

Influence of denitrification on suspended solids and phosphorus removal in multimedia filters

2006 ◽  
Vol 6 (1) ◽  
pp. 113-120
Author(s):  
V. Miska ◽  
J.H.J.M. van der Graaf ◽  
J. de Koning
Keyword(s):  
The Netherlands ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Phosphate Removal ◽  
Treatment Technique ◽  
Wwtp Effluent ◽  
Removal Efficiencies

Due to more stringent WWTP-effluent requirements in The Netherlands, caused by adoption of the European legislation, the characteristics of WWTP-effluents need to be improved. For existing wastewater treatment plants extended nutrient removal will be required with final effluent concentrations of Ptot≤0.15 mg/L and Ntot≤2.2 mg/L. For suspended solids and phosphorus removal flocculation-filtration is used frequently as advanced treatment technique. Simultaneous denitrification would provide a tertiary treatment step for combined nutrient removal under the condition that simultaneous denitrification has no adverse effects on suspended solids and phosphate removal. Pilot-scale experiments have been carried out at the WWTP in Utrecht and lab-scale investigations at the WWTP in Beverwijk, both in the Netherlands. The removal efficiencies for phosphorus and suspended solids in multimedia filters, operated under optimal denitrifying conditions, had been evaluated by phosphorus analyses and particle counting. It is examined that denitrifying biomass has no negative effect on the removal efficiencies.

On the stability and settling of suspended solids in settling ponds. Part II. Diffusion analysis of initial settling of suspended solids

1984 ◽  
Vol 21 (4) ◽  
pp. 644-656 ◽  
Author(s):  
R. N. Yong ◽  
D. Elmonayeri
Keyword(s):  
Suspended Solids ◽  
Solids Concentration ◽  
Diffusion Analysis ◽  
Convection Model ◽  
Comparative Results ◽  
The Stability ◽  
Diffusion Convection ◽  
Settling Ponds ◽  
Settling Performance ◽  
Fluid Diffusion

The initial settling behaviour of the low solids concentration suspensions is examined and analyzed to provide information on sedimentation characteristics and distribution of solids concentration profiles with time. The presence of surface-active forces, which participate in development of the suspended solids settling characteristics, does not always permit easy application of standard sedimentation models for calculating settling rates of the suspended solids. A simplified diffusion–convection model using the relative flux approach has been developed to predict the initial settling performance of the suspended solids. Experimentally determined fluid diffusion coefficients relative to diffused volumetric fluid contents are obtained to provide input to the calculations for prediction of actual test cases. Comparisons using laboratory settling test data, together with information from a field settling pond, are made with predictions obtained using the model. The comparative results show that the analyses obtained using the theoretical model can predict initial settling of the suspended solids. Key words: suspended solids, settling, sedimentation, diffusion, solids concentration, fines thickening.

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