Control of activated sludge treatment process using pre-compensated multi-variable quantitative feedback theory-based controller

Author(s):  
Sandipan Prasad Chakravarty ◽  
Aniket Roy ◽  
Prasanta Roy

This paper deals with the design of a pre-compensated multi-variable quantitative feedback theory (QFT)-based fully populated matrix controller for an activated sludge treatment process (ASTP) of a waste water treatment plant (WWTP). The regulation of the concentration of biochemical oxygen demand ([Formula: see text]) and ammonium-ion ([Formula: see text]) is the control objective. The plant dynamics are obtained using physical laws available in the literature. The parametric uncertainty is quantified from the measurement data obtained from a real ASTP of an oil refinery. The model is duly cross-validated. A novel technique is proposed to design a pre-compensator that will enhance the diagonal dominance of the plant transfer function matrix. A diagonal controller and a pre-filter, are then designed using a sequential multi-input multi-output (MIMO) QFT-based methodology to meet a set of performance specifications such as relative stability, disturbance rejection, robust tracking and so forth. The simulation results validate the effectiveness of the proposed control scheme. A comparative analysis with reported works shows that the proposed control scheme outperforms some of the reported control strategies.

2016 ◽  
Vol 9 (2) ◽  
Author(s):  
Dinda Rita K. Hartaja ◽  
Imam Setiadi

Generally, wastewater of nata de coco industry contains suspended solids and COD were high, ranging from 90,000 mg / l. The high level of of the wastewater pollutants, resulting in nata de coco industry can not be directly disposed of its wastewater into the environment agency. Appropriate technology required in order to process the waste water so that the treated water can meet the environmental quality standards that are allowed. Designing the waste water treatment plant that is suitable and efficient for treating industrial wastewater nata de coco is the activated sludge process. Wastewater treatment using activated sludge process of conventional (standard) generally consists of initial sedimentation, aeration and final sedimentation.Keywords : Activated Sludge, Design, IPAL


REAKTOR ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 33
Author(s):  
Yunardi Yunardi

A laboratory study was  conducted to determine the feasibility of activated sludge reactor for treating humic acid waste waterand examine the effect of the presence of glucose as the second carbon source on treatment performance. Activated sludge obtained from a waste water treatment plant treating domestic wastewater was used as a seed for reactors. Synthetic wastewater containing humid acid as the sole carbon source and glucose as the second carbon source were used as feeds for the reactors operated in a fill-and-draw mode. The result showed  tht the presence of glucose in the wastewater enhanced the production of higher MLSS (mixed liquor suspended solids) than that without of glucose. The TOC (Total Organic Carbon) concentration in both reactors fluctuated greatly until the end of the experiment due to inability of keeping the input TOC at desired level. However the decrease in TOC suggested that there are some microorganisms capable of degrading the humic acid. Addition of glucose to the simulated humic acid wastewater improved the capability of microbes in degrading the acids. Most ammonium nitrogen in the wastewater was converted to nitrate nitrogen. Although the performance was lower compared to that of conventional system, activated sludge process was capable of degrading wastewater containing humic acids.Keywords : activated sludge, ammonium nitrogen, fill and draw, glucose, humic acid, wastewater


2006 ◽  
Vol 1 (4) ◽  
Author(s):  
N. Engelhardt ◽  
W. Lindner

With the commissioning of the waste water treatment plant Nordkanal, which has been dimensioned for a design capacity of 80,000 population equivalents, new worldwide standards for the implementation of large membrane-activated sludge plants have been created both from a technical and from an economic point of view. The hitherto successful operation of this plant has already now contributed towards this technology becoming suitable for use in large waste water treatment plants. The now two years the waste water treatment plant Nordkanal has been in operation have once again demonstrated that even on a large scale, membrane-activated sludge plants are able to reliably produce purified effluent of excellent quality, while simultaneously providing a small-sized design. They prove advantageous everywhere small-sized designs are sought after and the purified effluent has to meet high or special requirements. Wherever purification requirements are intensified in the foreseeable future, whether with regard to the hygienisation of effluent, or in the framework of re-using purified waste water as industrial water or potable water or in order to protect natural drinking water resources from critical anthropogenic impacts, the membrane bioreactor process or membrane filtration is trend setting and will increasingly gain in importance.


1999 ◽  
Vol 40 (11-12) ◽  
pp. 231-239 ◽  
Author(s):  
Nikolaus Kaindl ◽  
Ulf Tillman ◽  
Christian H. Möbius

The capacity and efficiency of the existing activated sludge waste water treatment plant at SCA Graphic Laakirchen AG needs to be enhanced due to an expected future increase in waste water flow and COD-load. For the case of an existing upper limit of COD discharges into the river, the COD reduction rate of the waste water treatment has to be increased to a degree which is unobtainable by biodegradation only. Laboratory and pilot plant trials using a moving bed biofilm technique and an activated sludge treatment combined with ozone treatment and subsequent biofiltration have been performed with the aim to increase the COD reduction capacity and efficiency of the plant. The results show that the COD reduction capacity of the existing activated sludge plant can be increased by more than 100% by integrating a moving bed biofilm pre-treatment stage into the plant. In addition, improved sludge separation in the secondary clarifier was established. A special benefit of the ozonation plus biofilter treatment is a controllable COD reduction between 20 - 90% related to the outflow of the activated sludge plant. It is concluded that by integrating the investigated treatment techniques in the existing activated sludge plant the future increases in waste water flow and COD-Load can be handled satisfactorily without increasing bioreactor volume.


1997 ◽  
Vol 36 (12) ◽  
pp. 75-82 ◽  
Author(s):  
T. Kuba ◽  
M. C. M. van Loosdrecht ◽  
J. J. Heijnen

The effect of pH on phosphorus release under anaerobic conditions was examined for denitrifying phosphorus removing bacteria (DPB) cultivated in an anaerobic-anoxic sequencing batch reactor. Also batch tests were conducted with activated sludge from a full-scale waste water treatment plant (WWTP) in order to investigate occurrence and contribution of DPB in phosphorus removal processes. In the experiments for the pH effect, enriched DPB sludge was maintained under anaerobic conditions with acetic acid (HAc) present at 5 different pH conditions (6.0∼8.0), and released phosphorus and consumed HAc concentrations were measured. When the biomass concentration was around 2.7 g-VSS/l, the observed P/C (released-P/consumed-HAc) ratios were 0.7, 1.1 and 1.2 g-P/g-C at pH=6, 7 and 8. At 4.2 g-VSS/l, the observed P/C ratios were 0.9, 1.3 and 1.2 g-P/g-C, respectively. The difference between the two experiments resulted from the endogenous phosphorus release. The same pH effect as observed for conventional anaerobic-aerobic SBR sludge, was obtained for the DPB sludge in the range of pH=6.0∼7.5. However due to precipitates formation at pH=8.0, the apparent P/C ratio was approximately 20% less than the ratio calculated from the biological released phosphorus concentration by DPB. From the results of the batch tests with activated sludge and observations on the full-scale WWTP, it was also shown that clearly denitrifying dephosphatation occurs and approximately 50% of the phosphorus removal occurs via denitrifying activities in the WWTP.


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