University of North Florida
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Contact Info

Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Classification: Waste -> water -> treated

Citations 3

"Online Determination Of Residual Aluminum In Potable And Treated Waters By Flow Injection Analysis"
Anal. Chim. Acta 1990 Volume 238, Issue 1 Pages 177-182
Richard L. Benson and Paul J. Worsfold, Frank W. Sweeting

Abstract: A portable, automated, flow injection based solid-state spectrophotometric field monitor is described. The Al was complexed with pyrocatechol violet to produce a colloidal lake which was measured at 580 nm. The interference from Fe(III) was masked by reduction to Fe(II) with hydroxylammonium chloride and complexation with 1,10-phenanthroline. The response was rectilinear up to 1000 µg L-1 and the limit of detection was 45 µg l-1. The coefficient of variation (n = 10) were 1.2 to 12.1% for 50 to 1000 µg L-1 and the reliability was >90% over 3 months. The monitor operates on a 30-min analytical cycle to give 48 results per day, and each cycle includes an autocalibration step. The performance conforms to industrial specifications.
Aluminum Spectrophotometry Complexation Interferences Portable

"A Flow Injection Approach To The Continuous Monitoring Of Residual Coagulants In Potable And Treated Waters"
Sci. Total Environ. 1993 Volume 135, Issue 1-3 Pages 17-25
Richard L. Benson and Paul J. Worsfold

Abstract: An automated flow-injection analyzer. for the on-line monitoring of dissolved monomeric aluminium and dissolved iron in potable and treated waters is described. The aluminium method is based on complexation with pyrocatechol violet (PCV) and the iron method is based on the complexation with ferene S. The limits of detection using a solid-state light emitting diode - photodiode flow through detector - were 13 and 11 µg L-1 for aluminium and iron, respectively, and the linear range for both was 0-1000 µg l-1. Improvements to the monitor design of a previously reported system include a new computer system and detector modifications for increased sensitivity. The monitor performance met all the required industry specifications, e.g. for accuracy and precision and was > 98% reliable during on-line trials.
Aluminum Iron

"Batch Test Procedures As Tools For Calibration Of Activated Sludge Model - A Pilot Scale Demonstration"
Water Sci. Technol. 1998 Volume 37, Issue 4-5 Pages 235-242
Gert Holm Kristensen, Jes la Cour Jansen and Per Elberg Jørgensen

Abstract: Various mathematical models have been developed to facilitate the design and operation of biological nutrient removal plants. Proper calibration of such models can be a difficult task due to the large number of variable process coefficients. The paper describes a strategy for model calibration based on batch characterizations of wastewater and activated sludge biomass and demonstrates its applicability through modeling of the process dynamics in a highly dynamic activated sludge pilot plant. A comprehensive experimental program was undertaken comprising batch characterizations of readily degradable and easily hydrolyzable COD in influent wastewater, maximum and endogenous process rates for functional microorganism groups in the activated sludge, and half-satuaration process constants to describe the impact of oxygen on nitrification and denitrification. An online measurement of ammonia and nitrate and nitrite using a flow injection analysis system was conducted for two consecutive days to study the process dynamics in a BioDenitro pilot plant for two parallel activated sludge process tanks. It was possible to closely mimic the dynamics of the nitrogen removal processes in the two tanks based on the model calibration strategy using wastewater and biomass characteristics determined in batch experiments.
Ammonia Nitrate Nitrite Process monitoring