Evaluation of Control Strategies in Activated Sludge Process for Biological Wastewater Treatment

2016 ◽  
Vol 11 (4) ◽  
pp. 279-289 ◽  
Author(s):  
B. Vivekanandan ◽  
A. Seshagiri Rao

Abstract In this paper, benchmark simulation model no.1 (BSM1) of an activated sludge process is used to evaluate various control strategies. Control configurations such as feedback control and feed-forward plus feedback (FF-FB) control are applied and compared with respect to effluent discharge requirements under specified constraints and operating costs. Feed-forward control is incorporated in the PI control configuration for preventing the influent loading disturbance affecting the process. No case studies of BSM1 model have been reported in the literature for the Indian wastewater. In this work, the dynamic simulation of an activated sludge process is performed using the data collected from the sewage treatment plant, located in India. The influent load data are collected during the dry weather period. The influent fractionation is carried out using the activated sludge model no.1 (ASM1). The results of the dynamic simulation indicate that FF-FB control of the activated sludge process is more effective than feedback control in meeting the constraints, especially effluent ammonia concentration which is considered as very important. From the comparison of performance evaluation criteria, it is observed that FF-FB control has achieved almost the same operating costs as with feedback control.

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Young H. Yoon ◽  
Jae R. Park ◽  
Sang W. Ahn ◽  
Kwang B. Ko ◽  
Kyung J. Min ◽  
...  

Hybrid Activated Sludge Process (HASP) with IMET was developed and applied to an activated sludge process for the advanced nutrient treatment in Korea. The characteristics of nitrogen removal from the HASP were investigated through a kinetic study by batch-type experiment. Online DB analysis produced from the IMET was conducted for the nutrient removal performance in the field demonstration plant treating 10,000 m3/day in G city of Korea. In this paper, we aimed to determine the effect of increasing NHM4+-N load on the specific nitrification rate (SNR) and the specific denitrification rate (SDNR) through a batch-type experiment, and to estimate the net reaction time for the phase-transfer rate using online DB analysis in the HASP operation. Experimental results include: (1) both the nitrification and denitrification followed first-order kinetics; (2) the maximum SNR and SDNR were 4.0301 mgN/gVSS·hr and 2.785 mgN/gVSS·hr, respectively; (3) comparison of reaction rates between nitrification and denitrification from the non-linear regression analysis found that nitrification rate was higher than denitrification.


1989 ◽  
Vol 21 (10-11) ◽  
pp. 1161-1172 ◽  
Author(s):  
M. Hiraoka ◽  
K. Tsumura

The authors have been developing a hierarchical control system for the activated sludge process which consists of an upper level system controlling long-term seasonal variations, a control system of intermediate level aiming at optimization of the process and a control system of lower level controlling diurnal changes or hourly fluctuations. The control system using the multi-variable statistical model is one of the most appropriate control systems based on the modern control theory, for applying the lower level control of the activated sludge process. This paper introduces our efforts for developing the reliable data acquisition system, the control experiments applying the AR-model, one of the statistical models which were conducted at a pilot plant and present studies on the system identification and control at a field sewage treatment plant.


1988 ◽  
Vol 20 (4-5) ◽  
pp. 143-152 ◽  
Author(s):  
M. Tendaj-Xavier ◽  
J. Hultgren

Bromma sewage treatment plant is the second largest plant in Stockholm with a design flow of 160,000 m3/d. The wastewater is treated mechanically, chemically by pre-precipitation with ferrous sulphate, and biologically by the activated sludge process. The requirements for the plant are 8 mg BOD7/l, 0.4 mg P/l and 2 mg NH4+-N/l. The requirement for ammonia refers to the period July-October. In order to meet those rather stringent requirements, the biological step was expanded 3 years ago with 6 new sedimentation tanks. The 6 new tanks have the same area as the 6 old ones but they have only a depth of 3.7 m compared with the depth of the old tanks, 5.7 m. Experience from the first years of operation of the new tanks is that these tanks are more sensitive and less efficient than the older ones. It seems that the effluent suspended solids concentration from the old tanks is less influenced by rapid flow variations than the concentration in the effluent from the new secondary sedimentation tanks. During the nitrification period denitrification takes place to some degree in the secondary sedimentation tanks. This may cause loss of solids and it has been observed that the deeper old tanks usually produce an effluent of better quality and seem to be less influenced by denitrification than the new ones.


2002 ◽  
Vol 45 (4-5) ◽  
pp. 413-420 ◽  
Author(s):  
K. Krause ◽  
K. Böcker ◽  
J. Londong

Buchenhofen wastewater treatment plant of Wupperverband (650,000 p.e.) is currently being expanded for targeted nitrogen elimination. In view of the limited space available for extension, an optimized control concept is to be used in order to minimize the number of additional tanks required. This concept was investigated by dynamic simulation based on Activated Sludge Model No. 1. The investigations included a pure feedback control configuration and a configuration combining feedback und feedforward control, considering the influent ammonium load, for aeration. The results show that combined feedforward/feedback control has significant advantages over pure feedback control. In particular, this configuration allows a reduction in the effluent NH4-N peaks, which is especially important because of the low NH4-N limit of 5 mg NH4-N/L in a grab sample.


2008 ◽  
Vol 58 (4) ◽  
pp. 953-956 ◽  
Author(s):  
L. Balest ◽  
G. Mascolo ◽  
C. Di Iaconi ◽  
A. Lopez

The removal of selected endocrine disrupter compounds (EDCs), namely estrone(E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), bisphenol A (BPA) and 4-tert-octylphenol (4t-OP) from municipal wastewater was investigated using a sequencing batch biofilter granular reactor (SBBGR), a new system for biological treatment based on aerobic granular biomass. This new biological treatment is characterized by high biomass concentration (up to 40 g/L), high sludge retention times (up to 6 months) and low sludge production (i.e., an order of magnitude lower than commonly reported for conventional biological technologies). The investigation was carried out comparing a demonstration SBBGR system with a conventional full-scale activated sludge process. Results showed that the SBBGR performed better than a conventional activated sludge process in removing E1, E2, BPA and 4t-OP. In fact, the average removal percentages of the above mentioned EDCs, obtained during a four month operating period, were 62.2, 68, 91.8, 77.9% and 56.4, 36.3, 71.3, 64.6% for the demonstrative SBBGR system and the conventional activated sludge process of the municipal sewage treatment plant, respectively


Author(s):  
Mohieldeen M. A. Ahmed ◽  
Mohammed H. M. Gaily ◽  
Khalid M.O. Ortashi ◽  
Omer M.A. Al Ghabshawi ◽  
Nagwa F. Bashir ◽  
...  

Hydrogen sulphide is a toxic gas, it can cause a range of physiological responses from simple annoyance to permanent injury and death. There are a number of approaches to deal with the impacts of toxic gases. This study focused on minimizing the hazard exposure for hydrogen sulfide in the different operational zones for activated sludge process in sewage waterplant. Research tools/ approaches conducted were interviews, toxic gas testers, analysis report interpretation &amp; quantitative risk assessment method. The study was conducted on Arabian Peninsula during the period (September 2019- September 2021). The (13) operational locations tested for toxic gas concentrations were inlet chamber, outlet channel, coarse /fine screens, primary sedimentation tank, activated sludge tanks, secondary sedimentation tanks, gas desulfurization unit, disc filters, chlorine dosing unit, sludge dewatering, sludge silos and digester tanks. The study found that the highest concentration for H<sub>2</sub>S in the inlet chamber/ outlet channel. The severity hazards in the sewage treatment plant using activated sludge process are the asphyxiation by H<sub>2</sub>S was extremely high can cause harm to public health, followed by the radiation hazard followed by electrical hazard, then (working at height, mechanical, traffic, health, chemical, physical, ergonomic, environmental, microbial and natural). The frequency of hazards occurrence is asphyxiation by H<sub>2</sub>S was extremely high followed by the radiation hazard and health hazard including the infection with Covid 19 virus followed by mechanical hazard then (electrical, traffic, ergonomic, natural, chemical, physical and natural). Control measures were recommended to minimize the risk of asphyxiation by H<sub>2</sub>S in the working environment at the STP.


2017 ◽  
Vol 1 ◽  
pp. 1
Author(s):  
Zhan Yang

Activated sludge process is the most widely used technology in sewage bioremediation up to now. However, there is also a serious problem with this technology, that is, a great amount of sludge will be left over. In view of this situation, a study has been carried out through the domestic activated technology for sludge treatment and also research on the effective sludge treatment. They made use of the microbial decomposition to decompose the oxide by using the means of physical, chemical, biological, etc. to minimize the effluent from the sewage treatment plant and thus, reduced the amount of sludge produced.


2009 ◽  
Vol 4 (2) ◽  
Author(s):  
S. M. Faheem ◽  
M. A. Khan

A study was conducted on filamentous bacteria implicated in bulking and foaming problems in activated sludge process of sewage treatment plant in Dubai, United Arab Emirates over a period of six months. To determine morphological characteristics of diverse filaments, foam and mixed liquor samples were collected and studied using various simple and differential staining techniques. Fluorescent in situ hybridization analysis was carried out in mixed liquor samples with nocardioform group specific probes using VIT kit (Vermicon Identification Technology, Vermicon, Munich). The dominant filamentous bacteria identified from mixed liquor and foam samples included: A long branched form of Gram varibale nocardioform actinomycetes species, Thiothrix, Eikelboom Type 021N, Sphaerotilus natans, Beggiatoa and Nostocoida limicola type I. Occasionally attached growth forms of Eikelboom type 0041/0675 like filaments were observed in mixed liquor and foam samples especially during warm weather. All filamentous bacteria identified were found in both the samples throughout the study period. FISH analysis successfully identified filamentous and non-filamentous morphotypes of nocardioform group members. It is concluded that specific filamentous bacterial population in mixed liquor and foaming activated sludge was constant and not dependent on variable wastewater characteristics.


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