Design and evaluation of advanced automatic control strategies in a total nitrogen removal activated sludge plant

2020 ◽  
Author(s):  
E. S. S. Tejaswini ◽  
G. Uday Bhaskar Babu ◽  
A. Seshagiri Rao
Keyword(s):  
Activated Sludge ◽  
Automatic Control ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Control Strategies ◽  
Total Nitrogen Removal

scholarly journals Sensor bias impact on efficient aeration control during diurnal load variations

2021 ◽  
Author(s):  
Oscar Samuelsson ◽  
Gustaf Olsson ◽  
Erik Lindblom ◽  
Anders Björk ◽  
Bengt Carlsson
Keyword(s):  
Energy Efficiency ◽  
Automatic Control ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Oxygen Sensor ◽  
Control Strategies ◽  
Sensor Data ◽  
Negative Effects ◽  
Total Nitrogen Removal ◽  
The Impact

Abstract This study highlights the need to increase our understanding of the interplay between sensor drift and the performance of the automatic control system. The impact from biased sensors on the automatic control systems is rarely considered when different control strategies are assessed in water resource recovery facilities. Still, the harsh measurement environment with negative effects on sensor data quality is widely acknowledged. Simulations were used to show how sensor bias in an ammonium cascade feedback controller impacts aeration energy efficiency and total nitrogen removal in an activated sludge process. Response surface methodology was used to reduce the required number of simulations, and to consider the combined effect of two simultaneously biased sensors. The effects from flow variations, and negatively biased ammonium (−1 mg/L) and suspended solids sensors (−500 mg/L) reduced the nitrification aeration energy efficiency by between 7 and 25%. Less impact was seen on total nitrogen removal. There were no added non-linear effects from the two simultaneously biased sensors, apart from an interaction between a biased ammonium sensor and dissolved oxygen sensor located in the last aerated zone. Negative effects from sensor bias can partly be limited if the expected bias direction is considered when the controller setpoint-limits are defined.

Upgrading the Activated-Sludge Process for Total Nitrogen Removal in Hong Kong

1995 ◽  
Vol 9 (1) ◽  
pp. 82-91
Author(s):  
D. K. C. WU ◽  
H. C. LAI ◽  
K. W. LAW ◽  
W. C. WONG
Keyword(s):  
Hong Kong ◽  
Activated Sludge ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Activated Sludge Process ◽  
Total Nitrogen Removal

Simultaneous Nitrification/Denitrification in a Single Reactor using Ciliated Columns Packed with Granular Sulfur

2005 ◽  
Vol 40 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Yong-Woo Hwang ◽  
Chang-Gyun Kim ◽  
In-Jun Choo
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Glass Beads ◽  
Denitrification Rate ◽  
The Other ◽  
Simultaneous Nitrification And Denitrification ◽  
Total Nitrogen Removal ◽  
Anoxic Zones

Abstract This study was conducted to assess the possibility of simultaneous nitrification and denitrification in an activated sludge using a cilia media packed with granular sulfur in a single reactor. For the granular sulfur column adopted, the total nitrogen removal was up to 67%. This facilitated the simultaneous decomposition of autotrophic and heterotrophic denitrifiers present at a 5:2 ratio. On the other hand, the control incubation test employing glass beads achieved only 18% denitrification. Regardless of the NH4-N loadings, the use of ciliated granular sulfur columns, made denitrification 1.5 times faster than when cilia was not used. The size of the granular sulfur columns directly contributed to the extent of denitrification, which was correlated to the void sphere of anoxic zones through the columns. Dissolved oxygen (DO) concentrations lower than 4.0 mg/L did not influence the level of denitrification. However, when higher than 4.0 mg/L, the DO began to negatively impact the denitrification rate. The study found that the simple installation of a cilia media packed with granular sulfur in an existing activated sludge could simultaneously achieve an efficient nitrification/denitrification in a single reactor.

Theoretical analysis on nitrogen removal of the step-feed anoxic-oxic activated sludge process and its application for the optimal operation

1996 ◽  
Vol 34 (1-2) ◽  
pp. 459-466 ◽  
Author(s):  
Shigeo Fujii
Keyword(s):  
Theoretical Analysis ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Optimal Operation ◽  
Activated Sludge Process ◽  
R Value ◽  
Total Nitrogen Removal ◽  
Reaction Patterns

The nitrogen removal efficiency of the step-feed anoxic-oxic activated sludge process, which has two anoxic tanks and two oxic tanks, was theoretically discussed on the basis of the stoichiometry of denitrification and nitrification reactions. As the first step, effluent NH4-N and NO3-N concentrations were formulated with four parameters; 1) a, equivalent ratio of alkalinity to ammonia in influent, 2) b, that of substrate to ammonia, 3) r, step ratio of influent to the second anoxic tank and 4) R, return (+ recycle) sludge ratio. This calculus was done for the possible sixteen (=24) cases which show different reaction patterns in four tanks, and 12 cases out of 16 were found to be available. The effects of step ratio, r were examined in its range of 0 - 1 at a fixed R value, and it was found that the increase of r alters the outcome in a different way depending on the ranges of a and b. Consequently, zoning of a-b coordinates was successfully made, and the optimal r value for maximum total nitrogen removal was obtained in each zone. In addition, the optimal volume allocation of the four tanks was discussed and the ratios were formulated for each zone.

Nitrification-denitrification of UASB effluents highly loaded with nitrogen in an activated sludge reactor operated with short cycled aeration

2001 ◽  
Vol 44 (4) ◽  
pp. 279-286 ◽  
Author(s):  
S. Villaverde ◽  
M. L. Lacalle ◽  
P. A. García-Encina ◽  
F. Fdz-Polanco
Keyword(s):  
Activated Sludge ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Potato Starch ◽  
Organic Carbon Content ◽  
Conventional Activated Sludge ◽  
Activated Sludge Reactor ◽  
Total Nitrogen Removal ◽  
Continuous Flow Reactors ◽  
Activated Sludge Processes

A conventional activated sludge reactor operated with short cycled aeration was used for total nitrogen removal of UASB anaerobic reactor effluent containing nitrogen (up to 1,200 mg NKT/L) and organic matter (up to 2,000 mg COD/L). Initially the reactor was fed with synthetic water to progressively introduce the UASB effluent. This favored the acclimation of the microorganisms to the real environment. The results obtained throughout this study showed that initially the tested technology is feasible and can report significant cuts on operation and maintenance when compared to conventional activated sludge processes. Total nitrogen removal up to 66% was attained treating the effluent of an UASB process designed for treating the wastewater of a potato starch factory. Total nitrogen removal capacities ranging between 0.1 and 0.58 kg of nitrogen per cubic metre per day are reported. Short-cycled aeration allowed for a more efficient use of the oxygen supply for nitrification and the organic carbon content present in the wastewater for denitrification. This operating protocol has demonstrated serious advantages in terms of operation costs and simplicity when total nitrogen removal is wanted. Most of the existing activated sludge processes, i.e. single continuous flow reactors, can be updated for total nitrogen removal essentially at no cost, the inversion (aeration control system) is rapidly returned as reduction in energy expenditure.

Improving total nitrogen removal in aeration basin retrofitted with entrapped biomass

2014 ◽  
Vol 69 (7) ◽  
pp. 1558-1564 ◽  
Author(s):  
Yeong-Nan Chao ◽  
Jui-Hsien Lin ◽  
Kok-Kwang Ng ◽  
Chung-Hsin Wu ◽  
Pui-Kwan Andy Hong ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Growth Process ◽  
Suspended Solids ◽  
Electron Source ◽  
Mixed Liquor ◽  
Suspended Growth ◽  
Total Nitrogen Removal ◽  
Influent Wastewater

This study presented a method to upgrade existing aeration tanks to remove total nitrogen (TN). Bioplates carrying entrapped biomass were installed in an aeration basin to create anoxic/anaerobic zones where denitrification can proceed. In a reactor that coupled bioplates containing entrapped biomass (equivalent to as high as 7,500 mg/L of biomass) and an activated sludge suspension (at mixed liquor suspended solids of 1,300–2,400 mg/L), nitrification efficiency exceeded 95% for an influent wastewater containing 21–54 mg/L of NH3-N. In all cases amended with alkalinity and with or without added methanol as an electron source, TN removal was between 60 and 70%. The results demonstrated anoxic/oxic or anaerobic/anoxic/oxic processes could be incorporated in a conventional aeration basin, requiring no substantial modifications of the vessel and operation, and thus providing improved treatment in terms of nitrogen removal in the conventional suspended-growth process.

Operational Results of the Wolfsburg Wastewater Treatment Plant

1992 ◽  
Vol 25 (4-5) ◽  
pp. 203-209 ◽  
Author(s):  
R. Kayser ◽  
G. Stobbe ◽  
M. Werner
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Content ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Phosphate Removal ◽  
Total Nitrogen Content ◽  
Activated Sludge Process

At Wolfsburg for a load of 100,000 p.e., the step-feed activated sludge process for nitrogen removal is successfully in operation. Due to the high denitrification potential (BOD:TKN = 5:1) the effluent total nitrogen content can be kept below 10 mg l−1 N; furthermore by some enhanced biological phosphate removal about 80% phosphorus may be removed without any chemicals.

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