Modeling Bacterial Decay Coefficient during SSDML Process
Publication: Journal of Environmental Engineering
Volume 122, Issue 11
Abstract
The simultaneous sludge digestion and metal leaching (SSDML) process can leach out heavy metals, achieve sludge solids reduction, and eliminate sludge pathogens. The potential for application in the wastewater treatment industry requires a sound knowledge of the system kinetics. The present work targets a better understanding of the qualitative as well as quantitative relationships between solids reduction rate and other parameters such as sludge pH, initial MLSS concentration, and availability of oxygen during the SSDML process. Experiments were carried out in laboratory batch reactors (20 L working volume) as well as in a 4,000 L capacity pilot facility. Based on the results of these experiments, it was concluded that degradation rate of sludge volatile matter is influenced by (1) sludge pH; (2) availability of oxygen; and (3) initial mixed liquor suspended solids (MLSS) concentration of the sludge. The degradation rate constant for biodegradable fraction of the mixed liquor volatile suspended solids [MLVSS(B)] was computed for various initial MLVSS concentration and sludge pH ranges. The value of k d decreased with decreasing pH in all cases. Effect of initial MLSS concentration on the value of k d was found to be minimal for the sludge studied. The relation between the sludge pH and k d for this sludge was expressed in the form of two polynomials. The relations developed were used in conjunction with previous results on the SSDML process kinetics to simulate the overall SSDML process. Results of these simulation studies were found satisfactory when compared to actual experimental results.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 122 • Issue 11 • November 1996
Pages: 995 - 1002
Copyright
Copyright © 1996 American Society of Civil Engineers.
History
Published online: Nov 1, 1996
Published in print: Nov 1996
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