On-line determination of respiration rates of aquatic organisms in a mono-phase oxystat at steady-state dissolved oxygen tensions

1997 ◽  
Vol 128 (2) ◽  
pp. 181-189 ◽  
Author(s):  
N. T. Eriksen ◽  
J. J. L. Iversen
1996 ◽  
Vol 33 (1) ◽  
pp. 311-323 ◽  
Author(s):  
A. Witteborg ◽  
A. van der Last ◽  
R. Hamming ◽  
I. Hemmers

A method is presented for determining influent readily biodegradable substrate concentration (SS). The method is based on three different respiration rates, which can be measured with a continuous respiration meter which is operated in a cyclic way. Within the respiration meter nitrification is inhibited through the addition of ATU. Simulations were used to develop the respirometry set-up and decide upon the experimental design. The method was tested as part of a large measurement programme executed at a full-scale plant. The proposed respirometry set-up has been shown to be suitable for a semi-on-line determination of an influent SS which is fully based on the IAWQ #1 vision of the activated sludge process. The YH and the KS play a major role in the principle, and should be measured directly from the process.


1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.


1994 ◽  
Vol 16 (2) ◽  
pp. 59-62 ◽  
Author(s):  
A. C. Ariza ◽  
P. Linares ◽  
M. D. Luque de Castro ◽  
M. Valcárcel

A fully automated flow system for on-line monitoring of analytes/parameters of interest in aquaculture is described. The approach has been optimized for the photometric determination of nitrite and ammonia and the continuous monitoring of pH, conductivity and dissolved oxygen, but these analytes/parameters are readily changeable as required. The system has been tested by monitoring these species in the input and output sea water streams of tanks at a fish breeding farm and also by monitoring water containing high concentrations of fish feed.


2015 ◽  
Vol 2 (1) ◽  
pp. 67
Author(s):  
Hokcu Suhanda

Plastic membrane sensor for polarographic oxygen measurement has been investigated. The Probe was constructed of: Pt as a working electrode; Ag- AgCl as a reference electrode and an auxiliary electrode; solution of KCl as an electrolyte solution; plastic wrap (thickness 72.7  m) as a membrane; and polyester polymer as a body of sensor. It was found that the polarographic oxygen sensor plastic membrane probe was suited for determination of dissolved oxygen with an optimum operating characteristics at applied voltage of  –0.65 V and solution KCl 30% as an electrolyte. The probe showed that reduction current achieved steady state after 75 seconds. The standard calibration curve (concentration – current) showed that the linear relationships were achieved for dissolved oxygen in the range of 1.0 – 30.6 ppm. The analytical performance characteristics of the probe were: precision 0.87% – 30.0 %; calibration sensitivity 0.17 ppm/  A; analytical sensitivity 0.56 – 0.84 ppm/  A; and detection limit 0.8 ppm. The t- test and F-test at 95% confidence level showed that there was no significant difference between the determinations of dissolved oxygen by polarographic oxygen sensor membrane plastic and by Winkler method. Key words: membrane plastic, polarographic, steady state, Winkler method.


1997 ◽  
Vol 33 (3-4) ◽  
pp. 805-808 ◽  
Author(s):  
Young-Hae Lee ◽  
Kyou-Hyung Kyung ◽  
Chang-Sik Jung
Keyword(s):  

1999 ◽  
Vol 71 (21) ◽  
pp. 4965-4968 ◽  
Author(s):  
Leonard I. Wassenaar ◽  
Geoff Koehler
Keyword(s):  

Author(s):  
M.A. Gribelyuk ◽  
M. Rühle

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.


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