Tarek Aziz

Using CFD (Computational Fluid Dynamics) to explore artificial circulation in reservoirs

Analysis of grease abatement devices and the measurement of fat, oil, and grease in food service establishment waste streams

Page 1. ABSTRACT AZIZ, TAREK NADIM. Analysis of Grease Abatement Devices and the Measurement of F... more

Industrial Symbiosis Waste Exchange Identification and Optimization

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Determination of Biosolids Phosphorus Solubility and Its Relationship to Wastewater Treatment

Water environment research : a research publication of the Water Environment Federation, 2016

In North Carolina (NC), biosolids land application rates governed by crop nitrogen (N) requiremen... more In North Carolina (NC), biosolids land application rates governed by crop nitrogen (N) requirements typically surpass crop phosphorus (P) needs, increasing surface water pollution potential. The NC Department of Environmental Quality (NCDEQ) is considering P-based biosolids application guidelines for some nutrient-impaired watersheds using the P Loss Assessment Tool (PLAT), but important biosolids information is lacking: total P (TP), water-extractable P (WEP), and percent water-extractable P (PWEP). In each of three seasons, we sampled 28 biosolids from 26 participating water resource recovery facilities (WRRFs) and analyzed for TP, WEP, and percent dry matter (DM), from which PWEP and nonsoluble P were calculated. Based on descriptive statistics and an online survey of treatment processes, biosolids were divided into Class A-alkaline, Class A-heat, Class B-slurry, and Class B-cake. The average TP in Class A alkaline stabilized biosolids was more than five times less than the avera...

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Life Cycle Assessment of Grease Trap Waste Co-Digestion, Land Application, and Composting

Proceedings of the Water Environment Federation, 2012

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Observation and Analysis of Popular Root Control Methods in Pilot Scale Sanitary Sewer

Proceedings of the Water Environment Federation, 2007

1Civil, Construction, and Environmental Engineering, North Carolina State University 208 Mann Hal... more

Field Assessment of Grease Abatement Devices

Proceedings of the Water Environment Federation, 2010

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Anaerobic Co-Digestion of Grease Trap Waste

Proceedings of the Water Environment Federation, 2012

Performance of Grease Abatement Devices for Removal of Fat, Oil, and Grease

Journal of Environmental Engineering, 2011

Performance of Grease Abatement Devices for Removal of Fat, Oil, and Grease. [Journal of Environm... more

Municipal solid waste conversion to transportation fuels: a life-cycle estimation of global warming potential and energy consumption

Journal of Cleaner Production, 2014

ABSTRACT This paper utilizes life cycle assessment (LCA) methodology to evaluate the conversion o... more ABSTRACT This paper utilizes life cycle assessment (LCA) methodology to evaluate the conversion of U.S. municipal solid waste (MSW) to liquid transportation fuels via gasification and Fischer-Tropsch (FT). The model estimates the cumulative energy demand and global warming potential (GWP) associated with the conversion of 1 Mg (1 Mg = 1000 kg) of MSW delivered to the front gate of a refuse-derived fuel (RDF) facility into liquid transportation fuels. In addition, net energy production is reported to quantify system performance. The system is expanded to include substituted electricity and fuel. Under a set of default assumptions, the model estimates that 1 Mg of MSW entering the RDF facility yields 123 L of gasoline, 57 L of diesel, 79 kg of other FT products, and 193 kWh of gross electricity production. For each Mg of MSW, the conversion process consumes 4.4 GJ of primary energy while creating fuels and electricity with a cumulative energy content of 10.8 GJ. Across a range of waste compositions, the liquid fuels produced by gasification and FT processing resulted in a net GWP ranging from -267 to -144 kg CO(2)e per Mg MSW, including offsets for conventional electricity and fuel production. The energy requirement associated with syngas compression for FT processing was significant and resulted in high levels of process-related GWP. The model demonstrates that an increased biogenic MSW fraction, assumed to be carbon neutral, reduced the GWP. However, a greater GWP reduction could be obtained through reduced FT pressure requirements, increased gas reaction rates, or a less carbon intensive power mix.

Numerical Model Studies of Turbulent Jets

Performance of Grease Abatement Systems

Proceedings of the Water Environment Federation, 2010

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Simulation of vertical plane turbulent jet in shallow water

Advances in Civil Engineering, 2011

A plane, turbulent, nonbuoyant, vertical jet in shallow water is simulated numerically using a th... more A plane, turbulent, nonbuoyant, vertical jet in shallow water is simulated numerically using a three-dimensional computation model employing standard k-ε and renormalized group k-ε turbulent closure schemes. Existing data of mean and turbulent flow quantities, measured using laser Doppler velocimeter, are used to assess the two turbulent closure schemes. Comparisons between the measured and simulated flow field data are made in the free jet region, within the zone of surface impingement, and in the zone of horizontal jets at the surface. The results show that the standard k-ε scheme performs equally well and in some areas better than the more complicated renormalized group k-ε scheme in simulating the mean and turbulent flow quantities in this case.

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Anaerobic co-digestion of fat, oil, and grease (FOG): A review of gas production and process limitations

Process Safety and Environmental Protection, 2012

The addition of readily available high strength organic wastes such as fats, oils, and grease (FO... more The addition of readily available high strength organic wastes such as fats, oils, and grease (FOG) from restaurant grease abatement devices may substantially increase biogas production from anaerobic digesters at wastewater treatment facilities. This FOG addition may provide greater economic incentives for the use of excess biogas to generate electricity, thermal, or mechanical energy. Co-digestion of FOG with municipal biosolids

Determining the limits of anaerobic co-digestion of thickened waste activated sludge with grease interceptor waste

Water Research, 2013

Anaerobic co-digestion of thickened waste activated sludge (TWAS) with grease interceptor waste (... more Anaerobic co-digestion of thickened waste activated sludge (TWAS) with grease interceptor waste (GIW) from a food service establishment was conducted in lab scale semi-continuous digesters. GIW included the entire contents of the grease interceptor (GI) including fat, oil, and grease (FOG), food residuals, and associated wastewater. GIW was added in step increases to identify the maximum methane production and the corresponding threshold input of GIW that led to inhibition of methanogenesis. The experiment was performed at mesophilic conditions (37 C) with a solids retention time (SRT) of 20 days. The highest GIW addition rate achieved without digester failure was 20% (v/v), or 65.5% (w/w) of volatile solids (VS) added, enhancing the methane yield from 0.180 to 0.752 m 3 CH4 =kg VS added , biogas production from 2.2 Â 10 À3 to 1.4 Â 10 À2 m 3 /d, and methane content from 60.2% to 70.1%. The methane yield of 0.752 m 3 CH4 =kg VS added is the highest value reported to date for codigestion of GIW. Stepwise increases in co-substrate addition led to better microbial acclimation and reduced the GIW inhibitory effect. The limit for GIW addition leading to an inhibited digestion process was identified to be between 20 and 40% (v/v) or 65.5 and 83.5% (w/w) of VS added. The results show the significant benefits of anaerobic co-digestion of GIW and the positive impacts of gradual addition of GIW.

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Field Characterization of External Grease Abatement Devices

This study characterized some of the physical and chemical features of large outside field grease... more This study characterized some of the physical and chemical features of large outside field grease abatement devices (GADs). 24-hour measurements of several food service establishments' (FSEs') influent GAD fiowrates indicated highly intermittent conditions with hydraulic retention times (HRTs) that exceeded the common recommendation (30 minutes) by two to five times. Investigation into the chemical characteristics of GADs indicated highly variable influent and effluent fat, oil, and grease (FOG) concentrations. Low pH and dissolved oxygen values were measured throughout the GAD, indicating the likely occurrence of anaerobic microbial processes. Detailed spatial and temporal observations of the accumulation of FOG and food solids were also discussed. Though the FOG layer remained relatively constant for all GAD configurations investigated, results indicated that commonly-used GAD configurations with a straight submerged inlet tee or no-inlet tee configuration may result in the transport of food solids into the second compartment. The present research showed increased accumulation of food solids in the first compartment with a retro-fit fiow distributive inlet. This retro-fit displays promise for potentially improving the separation characteristics of existing GADs. Water Environ. Res., 84, 237 (2012).

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Assessment of Internal and External Grease Interceptor Performance for Removal of Food-Based Fats, Oil, and Grease from Food Service Establishments

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Performance of Grease Abatement Devices for Removal of Fat, Oil, and Grease

by John Groninger, Tarek Aziz, and Kevin Keener

Journal of Environmental Engineering-asce, 2010

This study assessed the performance of a conventional grease abatement device and the impact of i... more This study assessed the performance of a conventional grease abatement device and the impact of internal geometry modifications on fat, oil, and grease ͑FOG͒ removal efficiency. Analysis was performed using experimental results and computational fluid dynamics ͑CFD͒ on alternative inlet, outlet, and baffle wall designs. Numerical and experimental results indicated that the conventional two-compartment design leads to substantial FOG short circuiting when operated at a 20-min hydraulic retention time ͑HRT͒. Alterations to the inlet configuration and baffle wall arrangement yielded FOG removal enhancements with the 20-min HRT that approached removal performance levels obtained with the standard configurations at the 1-h HRT. CFD simulations effectively reproduced performance trends observed on the lab-scale with the exception of simulations using a distributive inlet tee, where CFD over predicted the removal performance.

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Anaerobic co-digestion of fat, oil, and grease (FOG): A review of gas production and process limitations

Process Safety and Environmental Protection, 2000

The addition of readily available high strength organic wastes such as fats, oils, and grease (FO... more The addition of readily available high strength organic wastes such as fats, oils, and grease (FOG) from restaurant grease abatement devices may substantially increase biogas production from anaerobic digesters at wastewater treatment facilities. This FOG addition may provide greater economic incentives for the use of excess biogas to generate electricity, thermal, or mechanical energy. Co-digestion of FOG with municipal biosolids

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