Quantifying fat, oil, and grease deposit formation kinetics.

Fat, oil, and grease (FOG) deposits formed in sanitary sewers are calcium-based saponified solids that are responsible for a significant number of nationwide sanitary sewer overflows (SSOs) across United States. In the current study, the kinetics of lab-based saponified solids were determined to understand the kinetics of FOG deposit formation in sewers for two types of fat (Canola and Beef Tallow) and two types of calcium sources (calcium chloride and calcium sulfate) under three pH (7 ± 0.5, 10 ± 0.5, and ≈14) and two temperature conditions (22 ± 0.5 and 45 ± 0.5 °C). The results of this study displayed quick reactions of a fraction of fats with calcium ions to form calcium based saponified solids. Results further showed that increased palmitic fatty acid content in source fats, the magnitude of the pH, and temperature significantly affect the FOG deposit formation and saponification rates. The experimental data of the kinetics were compared with two empirical models: a) Cotte saponification model and b) Foubert crystallization model and a mass-action based mechanistic model that included alkali driven hydrolysis of triglycerides. Results showed that the mass action based mechanistic model was able to predict changes in the rate of formation of saponified solids under the different experimental conditions compared to both empirical models. The mass-action based saponification model also revealed that the hydrolysis of Beef Tallow was slower compared to liquid Canola fat resulting in smaller quantities of saponified solids. This mechanistic saponification model, with its ability to track the saponified solids chemical precursors, may provide an initial framework to predict the spatial formation of FOG deposits in municipal sewers using system wide sewer collection modeling software.

[1]  L. D. Jones.  Saponification stressing the newer methods , 1958 .

[2]  Xia He,et al.  Mechanisms of fat, oil and grease (FOG) deposit formation in sewer lines. , 2013, Water research.

[3]  S. Duckett,et al.  Effect of Cooking on the Fatty Acid Composition of Beef Intramuscular Lipid , 1998 .

[4]  Russell C. Eberhart,et al.  Tracking and optimizing dynamic systems with particle swarms , 2001, Proceedings of the 2001 Congress on Evolutionary Computation (IEEE Cat. No.01TH8546).

[5]  K. Warner.  Impact of high-temperature food processing on fats and oils. , 1999, Advances in experimental medicine and biology.

[6]  J. Susini,et al.  Kinetics of oil saponification by lead salts in ancient preparations of pharmaceutical lead plasters and painting lead mediums. , 2006, Talanta.

[7]  T. S. Raghunathan,et al.  Thermal hydrolysis of vegetable oils and fats. 1. Reaction kinetics , 1988 .

[8]  G. Eglinton,et al.  Conversion of Oleic Acid to Saturated Fatty Acids in Severn Estuary Sediments , 1971, Nature.

[9]  Peter J. Angeline,et al.  Evolutionary Optimization Versus Particle Swarm Optimization: Philosophy and Performance Differences , 1998, Evolutionary Programming.

[10]  T. Bounahmidi,et al.  On the modeling of calcium sulfate solubility in aqueous solutions , 2006 .

[11]  Everett P. Partridge,et al.  THE SOLUBILITY OF CALCIUM SULFATE FROM 0 TO 200 , 1929 .

[12]  Joel J Ducoste,et al.  Factors that influence properties of FOG deposits and their formation in sewer collection systems. , 2014, Water research.

[13]  Sergey Vyazovkin,et al.  Thermal analysis. , 2006, Analytical chemistry.

[14]  Lino Guzzella,et al.  A generic particle swarm optimization Matlab function , 2012, 2012 American Control Conference (ACC).

[15]  Luc Taerwe,et al.  CHEMICAL, MICROBIOLOGICAL AND IN SITU TEST METHODS FOR BIOGENIC SULFURIC ACID CORROSION OF CONCRETE , 2000 .

[16]  Xia He,et al.  Evidence for fat, oil, and grease (FOG) deposit formation mechanisms in sewer lines. , 2011, Environmental science & technology.

[17]  J. Williams,et al.  Fat, oil and grease deposits in sewers: characterisation of deposits and formation mechanisms. , 2012, Water research.

[18]  Peter A. Vanrolleghem,et al.  Dynamic mathematical model of the crystallization kinetics of fats , 2002 .

[19]  Joel J Ducoste,et al.  Field Characterization of External Grease Abatement Devices , 2012, Water environment research : a research publication of the Water Environment Federation.

[20]  Joel J Ducoste,et al.  Properties Influencing Fat, Oil, and Grease Deposit Formation , 2008, Water environment research : a research publication of the Water Environment Federation.

[21]  I Nopens,et al.  Application of a mechanistic UV/hydrogen peroxide model at full-scale: sensitivity analysis, calibration and performance evaluation. , 2011, Communications in agricultural and applied biological sciences.

[22]  T. S. Raghunathan,et al.  Thermal hydrolysis of vegetable oils and fats. 3. An analysis of design alternatives , 1988 .

[23]  Zéphirin Mouloungui,et al.  Fourier-transform infrared spectra of fatty acid salts—Kinetics of high-oleic sunflower oil saponification , 2003 .

[24]  Antonio Lopez,et al.  Fat, oil and grease waste from municipal wastewater: characterization, activation and sustainable conversion into biofuel. , 2015, Water science and technology : a journal of the International Association on Water Pollution Research.