Real time control of a combined UASB-activated sludge wastewater treatment configuration

2002 ◽  
Vol 45 (4-5) ◽  
pp. 279-287
Author(s):  
C.M. Polito-Braga ◽  
M. von Sperling ◽  
A.R. Braga ◽  
R.T. Pena
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Real Time ◽  
Control Strategy ◽  
Suspended Solids ◽  
Biomass Concentration ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Successful Implementation ◽  
Solids Concentration

This paper presents a combined wastewater treatment configuration composed by an Upflow Anaerobic Sludge Blanket (UASB) reactor followed by an Activated Sludge (AS) system. A control strategy has been developed for this innovative (especially for domestic sewage) treatment configuration and tested in a real pilot-scale system called STEPAA – Wastewater Treatment System by Anaerobic and Aerobic Processes. The proposed UASB–AS control strategy, including fault detection and recovery, and its successful implementation in real time is presented. This novel control strategy was developed to keep the final effluent suspended solids concentration in the range specified by the State environmental agency, in spite of incoming load disturbances. The control strategy is based on two cascaded PI (Proportional + Integral) controllers, which manipulates the recycling rate into the AS-reactor to control the effluent suspended solids concentration. A 2-dimensional nonlinear mapping (an empirical look-up table), which gives the sludge waste rate as a function of the influent flowrate and AS-reactor biomass concentration, is used to keep the AS-reactor biomass concentration in a range that guarantees a good substrate removal without inconveniences to the AS-settler operation (and consequently to the solids removal). Experimental results are provided to demonstrate the system performance.

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.

scholarly journals Swine wastewater treatment using an anaerobic baffled (ARB) and a UASB reactor system

2017 ◽  
Vol 38 (6) ◽  
pp. 3705
Author(s):  
Luciano Dos Santos Rodrigues ◽  
Ana Cristina Araujo Pinto ◽  
Joyce Da Cruz Ferraz Dutra ◽  
Renata Rodrigues Sampaio ◽  
Stella Rubim de Sousa ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Swine Wastewater ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Promising Alternative ◽  
The Mean ◽  
Anaerobic Sludge Blanket

The purpose of this study was to assess the swine wastewater treatment system, consisting of the anaerobic baffled reactor (ABR), followed by the upflow anaerobic sludge blanket (UASB) reactor at full scale. The system was monitored by analyzing samples collected in the influent and effluent of ABR and UASB. The following parameters were analyzed: temperature, pH, total suspended solids (TSS), volatile suspended solids (VSS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD). Averages of total removal of COD and BOD were 96.7 and 98.4%, respectively. The mean concentrations of COD, BOD, TSS, and VSS at the final effluent were 611, 124, 138, and 134 mg L-1, respectively. The mean volumetric organic loadings (VOL) at the ABR and UASB were 10.29 and 0.99 kg COD m-1d-1. Therefore, the ABR-UASB system was found to be a promising alternative for the swine wastewater treatment.

scholarly journals Domestic Wastewater Treatment: A Comparison between an Integrated Hybrid UASB-IFAS System and a Conventional UASB-AS System

2021 ◽  
Vol 13 (4) ◽  
pp. 1853
Author(s):  
Ayman M. Dohdoh ◽  
Ibrahim Hendy ◽  
Martina Zelenakova ◽  
Ahmed Abdo
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
High Efficiency ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Climatic Conditions ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge

The current study presents a detailed evaluation and comparison between two integrated anaerobic–aerobic systems for biological wastewater treatment under equal conditions in all aspects (wastewater characteristics, climatic conditions, reactor sizing, and even the measurement methods). The two examined systems are (i) a hybrid upflow anaerobic sludge blanket (hybrid UASB) coupled with integrated fixed-film activated sludge (IFAS) and (ii) a conventional UASB coupled with activated sludge (AS). The present comparative study aims to evaluate and assess the effect of adding carrier-filling media on the performance of the classical integrated UASB-AS. The two parallel pilot-scale systems, hybrid UASB-IFAS and UASB-AS, were installed and operated at a wastewater treatment plant. Three sets of experiments were conducted to examine the influence of the hydraulic retention time (HRT) on the consequent organic and hydraulic loads, temperature, and recirculation rate of the proposed systems. The main results showed that the two investigated systems had a comparably high efficiency for the removal of organic matters and ammonia. Moreover, a paired sample t-test indicated there was a statistically significant effect of the filling media, and the performance of the hybrid UASB-IFAS increased significantly compared with that of the UASB-AS system. An additional benefit of the filling media on the hybrid system was its high stability when changing the organic and hydraulic loads. The optimum HRT was 6 h, with a total chemical oxygen demand (TCOD) percentage removal of approximately 95% in both examined systems. Treatment of sewage under high and low temperatures indicated that increasing the temperature improved the efficiency of the overall process for both systems significantly.

Ten Years Experience with a Highly Loaded Activated Sludge Plant

1984 ◽  
Vol 16 (12) ◽  
pp. 649-660
Author(s):  
P Balmér ◽  
S Hallquist ◽  
M Hernebring
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Residence Time ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Volume Index ◽  
Sludge Volume Index ◽  
Solids Concentration ◽  
Cell Residence Time ◽  
Highly Loaded

The Rya wastewater treatment plant in Gothenburg, Sweden serves 640 000 population equivalents. It is an extremely highly loaded activated sludge plant without presetting with a mean cell residence time of about 0.5 days. Ten years experience proves that the plant is capable of removing about 70% of the BOD load. The effluent BOD is mainly caused by non settleable suspended solids due to the partly dispersed growth of the activated sludge. The low mean cell residence time and the high suspended solids concentration in the aeration basin influent gives an activated sludge with low viability and in mass balance studies it was determined that only 12% of the influent COD and about 40% of the BOD was oxidized by the activated sludge. The activated sludge has consistently had a very low sludge volume index and the settling basins could thus be very highly loaded. The surplus activated sludge could be thickened to solids concentrations over 6%. After dewatering the sludge was either lime treated or co-composted with bark. The plant is manned only eight hours five days a week. During unmanned time there are standby personnel. Data is presented on man power, energy and chemical use, and on costs.

Relationship for Clarification Efficiency of Circular Secondary Clarifiers

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2539-2542 ◽  
Author(s):  
N. S. Voutchkov
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Full Scale ◽  
Solids Concentration

This paper discusses a regression-based model describing clarification efficiency of circular activated sludge secondary clarifiers. Surface overflow rate was found to be well correlated with effluent suspended solids, sidewater depth and settled sludge volume at three full scale wastewater treatment plants during a six month study. Relationship was verified to be sufficiently accurate for prediction of effluent suspended solids concentration over a six month period at another three treatment plants.

Advanced treatment by anaerobic process followed by aerobic membrane bioreactor for effluent reuse in paper mill industry

2004 ◽  
Vol 50 (3) ◽  
pp. 245-252 ◽  
Author(s):  
N. Stahl ◽  
A. Tenenbaum ◽  
N.I. Galil
Keyword(s):  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Paper Mill ◽  
Anaerobic Treatment ◽  
Development Project ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Operation Performance ◽  
Anaerobic Process

The operation of an activated sludge process at a paper mill (AIPM) in Hedera, Israel, was often characterized by disturbances. As part of a research and development project, a study on new biological treatment was initiated. The study included the operation of three pilot units: a. anaerobic treatment by upflow anaerobic sludge blanket (UASB); b. aerobic treatment by two pilot units including activated sludge and membrane bioreactor (MBR), which have been operated in parallel for comparison reasons. The pilot plant working on anaerobic treatment performed COD reduction from 2,365 to 755 mg/L, expressed as average values. Based on the pilot study, a full scale anaerobic treatment system has been erected. During a period of 100 days, after achieving steady state, the MBR system provided steady operation performance, while the activated sludge produced effluent characterized by oscillatory qualities. The following results, based on average values, indicate much lower suspended solids concentrations in the MBR effluent, 2.5 mg/L, as compared to 25 mg/L in the activated sludge. The ability to develop and maintain a concentration of over 11,000 mg/L of mixed liquor volatile suspended solids in the MBR enabled an intensive bioprocess at relatively high cell residence time. This study demonstrates that the anaerobic process, followed by aerobic MBR can provide effluent of high quality which can be considered for economic reuse in the paper mill industry.

Evaluating the treatment performance of a full scale Activated Sludge Plant in Islamabad, Pakistan

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
S. S. Fatima ◽  
S. Jamal Khan
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Full Scale ◽  
Operational Parameter ◽  
Mixed Liquor ◽  
Treatment Performance

In this study, the performance of wastewater treatment plant located at sector I-9 Islamabad, Pakistan, was evaluated. This full scale domestic wastewater treatment plant is based on conventional activated sludge process. The parameters which were monitored regularly included total suspended solids (TSS), mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), biological oxygen demand (BOD), and chemical oxygen demand (COD). It was found that the biological degradation efficiency of the plant was below the desired levels in terms of COD and BOD. Also the plant operators were not maintaining consistent sludge retention time (SRT). Abrupt discharge of MLSS through the Surplus Activated sludge (SAS) pump was the main reason for the low MLSS in the aeration tank and consequently low treatment performance. In this study the SRT was optimized based on desired MLSS concentration between 3,000–3,500 mg/L and required performance in terms of BOD, COD and TSS. This study revealed that SRT is a very important operational parameter and its knowledge and correct implementation by the plant operators should be mandatory.

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