A NEW SIMPLE MODEL FOR THE PREDICTION OF WASTE SLUDGE FLOW RATE IN THE STEADY-STATE COMPLETELY MIXED ACTIVATED SLUDGE PROCESS

2016 ◽  
Vol 15 (12) ◽  
pp. 2613-2630 ◽  
Author(s):  
Kaan Yetilmezsoy
Keyword(s):  
Steady State ◽  
Simple Model ◽  
Activated Sludge ◽  
Flow Rate ◽  
Activated Sludge Process ◽  
Waste Sludge

Comparison of Aerobic and Anoxic-Aerobic Digestion of Waste Activated Sludge

1985 ◽  
Vol 17 (8) ◽  
pp. 1475-1478 ◽  
Author(s):  
A P. C. Warner ◽  
G. A. Ekama ◽  
G v. R. Marais
Keyword(s):  
Experimental Data ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Activated Sludge Process ◽  
Cycle Times ◽  
Waste Sludge ◽  
Volatile Solids ◽  
In Series ◽  
Flow Through ◽  
Theoretical Simulations

The laboratory scale experimental investigation comprised a 6 day sludge age activated sludge process, the waste sludge of which was fed to a number of digesters operated as follows: single reactor flow through digesters at 4 or 6 days sludge age, under aerobic and anoxic-aerobic conditions (with 1,5 and 4 h cycle times) and 3-in-series flow through aerobic digesters each at 4 days sludge age; all digesters were fed draw-and-fill wise once per day. The general kinetic model for the aerobic activated sludge process set out by Dold et al., (1980) and extended to the anoxic-aerobic process by van Haandel et al., (1981) simulated accurately all the experimental data (Figs 1 to 4) without the need for adjusting the kinetic constants. Both theoretical simulations and experimental data indicate that (i) the rate of volatile solids destruction is not affected by the incorporation of anoxic cycles and (ii) the specific denitrification rate is independent of sludge age and is K4T = 0,046(l,029)(T-20) mgNO3-N/(mg active VSS. d) i.e. about 2/3 of that in the secondary anoxic of the single sludge activated sludge stystem. An important consequence of (i) and (ii) above is that denitrification can be integrated easily in the steady state digester model of Marais and Ekama (1976) and used for design (Warner et al., 1983).

Operational Determination of the Activated Sludge Process Using Neural Networks

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2461-2464 ◽  
Author(s):  
R. D. Tyagi ◽  
Y. G. Du
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Steady State ◽  
Activated Sludge ◽  
Feedforward Neural Network ◽  
Training Data ◽  
Activated Sludge Process

A steady-statemathematical model of an activated sludgeprocess with a secondary settler was developed. With a limited number of training data samples obtained from the simulation at steady state, a feedforward neural network was established which exhibits an excellent capability for the operational prediction and determination.

Specific organic and nutrient loads in stabilized sludge from municipal treatment plants

1996 ◽  
Vol 33 (12) ◽  
pp. 243-250 ◽  
Author(s):  
O. Nowak ◽  
A. Franz ◽  
K. Svardal ◽  
V. Müller
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Single Stage ◽  
Nutrient Loads ◽  
Activated Sludge Process ◽  
Waste Sludge ◽  
Sludge Stabilization ◽  
Nitrogen Loads ◽  
Theoretical Considerations ◽  
P Removal

By means of theoretical considerations and of statistical evaluations, specific organic and nitrogen loads in separately stabilized sludge have been found to be in the range of 16 to 20g VSS/PE/d and of 1.1 to 1.5 g N/PE/d respectively. About 0.6g P/PE/d are removed from the wastewater in activated sludge plants without chemical or enhanced biological P removal. By using the single-stage activated sludge process without primary sedimentation and without separate sludge stabilization, almost complete nitrogen removal can be achieved, but specific organic and nitrogen loads in the waste sludge are up to two times higher than in separately stabilized sludge.

Sensitivity of Effluent Variables in Activated Sludge Process

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
B Vivekanandan ◽  
K Jeyannathann ◽  
A. Seshagiri Rao
Keyword(s):  
Activated Sludge ◽  
Flow Rate ◽  
Oxygen Transfer Rate ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Maximum Flow ◽  
Activated Sludge Process ◽  
Flow Conditions ◽  
Treated Effluent ◽  
Influent Flow

Abstract The quality of a treated effluent changes when there is a sudden variation in the influent flow to the wastewater treatment plant during dry, rain, and storm weather conditions. In this study, various influent flow conditions in an activated sludge process are considered that affect the sensitivity of effluent variables such as chemical oxygen demand (COD), biological oxygen demand (BOD), nitrate nitrogen (SNO), ammonical nitrogen (SNH), and total nitrogen (TN) with respect to varying internal recycle flow rate (Qa), sludge recycle flow rate (Qr), sludge wastage flow rate (Qw) and oxygen transfer rate co-efficient of aerobic tanks (KLa(3,4,5)). The analysis has been carried out based on benchmark simulation model no.1 (BSM 1) plant layout which comprises of two models namely activated sludge model no.1 (ASM 1) and simple one dimensional (Simple 1-D) Takacs model. Based on the present analysis, it is observed that the changes in influent flow rate have larger impact on the effluent variables. This variation can be subdued by introducing additional tanks to smoothen the perturbations or using internal recycle rate from the fifth tank in order to maintain the flow around the optimal influent flow rate. The sludge wastage rate has a greater impact on all effluent variables except nitrogenous variables during maximum flow conditions.

Fuzzy Control of a Dynamic Activated Sludge Process for the Forecast and Control of Effluent Suspended Solid Concentration

1993 ◽  
Vol 28 (11-12) ◽  
pp. 355-367 ◽  
Author(s):  
Y. P. Tsai ◽  
C. F. Ouyang ◽  
M. Y. Wu ◽  
W. L. Chiang
Keyword(s):  
Fuzzy Control ◽  
Activated Sludge ◽  
Flow Rate ◽  
Suspended Solid ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Solid Concentration ◽  
Suspended Solid Concentration ◽  
And Control ◽  
Influent Flow

The effluent total BOD (or COD) concentration of the activated sludge process (A.S.P.) usually increases with suspended solid concentration. How to reduce effluent S.S. concentration, therefore, is the key issue of treatment efficiency for A.S.P. The varied return sludge and influent flow rate are two major operational factors of those affecting effluent S.S. concentration. However, the wastewater flow rate and substrate concentration in municipal wastewater treatment plant, due to the differences of city scale and life style, are significantly time-varied every day. Based on the above, the purpose of this study is to control in timely fashion return sludge flow rate with the variation of influent flow rate to minimize effluent S.S. concentration and meanwhile decrease the effluent total BOD (or COD) concentration. The fuzzy control theory is utilized in this study to forecast and control effluent S.S. concentration and further predict the MLSS concentration in aeration tank. It reveals that the inferred control strategies not only enable one to decrease effluent S.S.

Fundamental nonlinearities of the reactor-settler interaction in the activated sludge process

2012 ◽  
Vol 66 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Stefan Diehl ◽  
Sebastian Farås
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Practical Importance ◽  
Simulation Models ◽  
Nonlinear Process ◽  
Normal Operation ◽  
Activated Sludge Process ◽  
General Rules ◽  
Input Variables ◽  
Soluble Substrate

The activated sludge process can be modelled by ordinary and partial differential equations for the biological reactors and secondary settlers, respectively. Because of the complexity of such a system, simulation models are most often used to investigate them. However, simulation models cannot give general rules on how to control a complex nonlinear process. For a reduced-order model with only two components, soluble substrate and particulate biomass, general results on steady-state solutions have recently been obtained, such as existence, uniqueness and stability of solutions. The aim of the present paper is to utilize those results to formulate some implications of practical importance. In particular, strategies are described for the manual control of the effluent substrate concentration subject to the constraint that the settler is maintained in normal operation (with a sludge blanket in the thickening zone) in steady state. Such strategies contain how the two control parameters, the recycle and waste volumetric flow ratios, should be chosen for any (steady-state) values of the input variables.

Modelling Simulation and Control of an Existing Activated Sludge Wastewater Treatment Process

1976 ◽  
Vol 11 (1) ◽  
pp. 108-121
Author(s):  
N. Thérien ◽  
P. Harrington
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Flow Rate ◽  
Treatment Plant ◽  
Organic Substrate ◽  
Activated Sludge Process ◽  
Two Phase ◽  
Wastewater Treatment Process ◽  
Wastewater Stream ◽  
And Control

Abstract The dynamic response of the activated sludge process in the wastewater treatment plant of the Centre Hospitalier Universitaire de Sherbrooke was analysed with respect to large disturbances in both the flow rate and the quality of wastewater entering the plant. A mass balance conducted for the organic substrate and biomass entering and leaving the process led to a model consisting of two separate differential equations in terms of BOD and VSS with a two-phase bio-kinetic relationship for the reaction term. Predictions of the model for BOD and VSS variations in time were compared to experimental observations at the plant. A model using mean daily values for VSS and expressed in terms of BOD for the stream flowing out the clarifier unit in response to flow rate and BOD cyclic fluctuations of the entering wastewater stream to the process was found apt at describing the time at which BOD peaks in the process effluent occurred as well as predicting the magnitude of these peaks. The dynamic behaviour of the activated sludge process has been simulated for periods of one to several days using this model. Its use in predicting appropriate control action in time in order to improve the treatment efficiency is also indicated.

scholarly journals Adsorption of heavy metals by EPS of activated sludge

2001 ◽  
Vol 43 (6) ◽  
pp. 59-66 ◽  
Author(s):  
Y. Liu ◽  
M. C. Lam ◽  
H. H. Fang
Keyword(s):  
Activated Sludge ◽  
High Speed ◽  
Suspended Solids ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Freundlich Isotherm ◽  
Activated Sludge Process ◽  
Heavy Metal Concentrations ◽  
Waste Sludge ◽  
Adsorption Data

Extracellular polymeric substances (EPSs) were extracted by high-speed centrifugation at 20,000 G for 30 min from an activated sludge treating municipal wastewater. Each gram of sludge, as measured in volatile suspended solids (VSS), contained 7.3 mg of EPS, including 6.5 mg of protein (EPSp) and 0.8 mg of carbohydrate (EPSc). The EPSp had a mean MW of 2.0×105; about 18% of EPSp had MW over 5×104 and 16% below 5×103. For heavy metal concentrations ranging 10-100 mg/l, EPS on average removed 99% of Zn2+, 98% of Cu2+, 97% of Cr3+, 85% of Cd2+, 69% of Co2+, 37% of Ni2+, and 26% of CrO42-. The relative degrees of metal removals were inconsistent with those reported for the activated sludge process. Each mg of ESP had the capacity to remove up to 1.48 mg of Zn2+, 1.12 mg of Cu2+, 0.83 mg of Cr3+, 0.90 mg of Cd2+, 1.10 mg of Co2+, 0.25 mg each of Ni2+ and CrO42-. Results suggest the feasibility of recovering ESP from waste sludge for use as adsorbent. Freundlich isotherm correlated satisfactorily with the adsorption data of Ni2+,Cu2+, Cd2+, and CrO42-, (R2 ranging 0.89-0.97), whereas Langmuir isotherm correlated satisfactorily with those of Zn2+, Cr3+ and Ni2+ (R2 ranging 0.93-0.96). Both correlated poorly for those of Co2+.

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